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2. Simple and recyclable ionic liquid based system for the selective decomposition of formic acid to hydrogen and carbon dioxideElectronic supplementary information (ESI) available: Table of all experiments and further experimental information. See DOI: 10.1039/c0gc00829jThis paper was published as part of the themed issue of contributions from the Green Solvents – Alternative Fluids in Science and Application conference held in Berchtesgaden, October 2010.
- Author
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Berger, M. E. M., Assenbaum, D., Taccardi, N., Spiecker, E., and Wasserscheid, P.
- Subjects
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IONIC liquids , *CHEMICAL decomposition , *FORMIC acid , *HYDROGEN , *CARBON dioxide , *ACETATES , *ORGANIC solvents ,CATALYSTS recycling - Abstract
Exploitation of hydrogen as an energy carrier requires the development of systems for its storage and delivery. Formic acid has been proposed as valuable hydrogen carrier compound, due to its relatively high hydrogen content (53 g L−1), the latter being easily and cleanly released in catalytic reactions under mild conditions (HCOOH → H2+ CO2). Ionic liquids are interesting solvents for homogeneous catalyzed formic acid decomposition systems as their extremely low volatility avoids solvent contamination of the produced hydrogen stream. In this paper an outstandingly simple, robust and active catalyst system is presented, namely RuCl3dissolved in 1-ethyl-2,3-dimethylimidazolium acetate (RuCl3/[EMMIM][OAc]). This system proved to be fully recyclable over 10 times. Turnover frequencies (TOF) of 150 h−1and 850 h−1were obtained at 80 °C and 120 °C, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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3. Dehydrogenative cyclization of 2-arylbenzoic acid and 2-arylbenzamide with hydrogen evolution in a photoelectrochemical cell.
- Author
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Li, Haoran, Qiao, Kaikai, Jiang, Wenfeng, Li, Fei, and Shi, Lei
- Subjects
PHOTOELECTROCHEMICAL cells ,CELLULAR evolution ,CATHODES ,HYDROGEN ,IRRADIATION - Abstract
This paper describes photoelectrochemical dehydrogenative cyclization of 2-arylbenzoic acid and 2-arylbenzamide in a PEC cell consisting of a mesoporous WO
3 photoanode and Pt cathode. The cyclization reaction is effectively driven by this PEC system at room temperature with blue LED irradiation under external oxidant- and metal-free conditions, delivering a series of benzolactones and benzolactams in up to 95% isolated yields. Meanwhile, hydrogen is released as the only byproduct of this process. [ABSTRACT FROM AUTHOR]- Published
- 2024
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4. Methylthio-functionalized UiO-66 to promote the electron–hole separation of ZnIn2S4 for boosting hydrogen evolution under visible light illumination.
- Author
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Li, Xiang, Li, Qiulin, Shang, Wenjing, Lou, Yongbing, and Chen, Jinxi
- Subjects
VISIBLE spectra ,HYDROGEN as fuel ,HYDROGEN production ,CLEAN energy ,HYDROGEN - Abstract
Solar-driven water splitting offers a leading-edge approach to storing abundant and intermittent solar energy and producing hydrogen as a clean and sustainable energy carrier. More importantly, constructing well-designed photocatalysts is a promising approach to develop clean hydrogen energy. In this paper, flower spherical UiO-66-(SCH
3 )2 /ZnIn2 S4 (UiOSC/ZIS) photocatalysts are successfully synthesized by a simple two-step hydrothermal method, and they exhibit high hydrogen production activity in light-driven water splitting. The optimized 30-UiOSC/ZIS (the content of UiOSC was 30 mg) composite exhibits optimal hydrogen production activity with a hydrogen production of 3433 μmol g−1 h−1 , which is 5 and 235 times higher than that of pure ZIS and UiOSC, respectively. In addition, a long-cycling stability test has shown that the UiOSC/ZIS composite has good stability and recyclability. Experimental and characterization results show the formation of a type-II heterojunction between UiOSC and ZIS. This effectively suppresses the recombination of electrons–holes and promotes the carrier transfer, thus significantly improving the hydrogen production performance. This research further promotes the application of UiO-66-(SCH3 )2 in the field of photocatalytic hydrogen production and provides a reference for the rational design of UiO-66-based composite photocatalysts. [ABSTRACT FROM AUTHOR]- Published
- 2023
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5. A high-porosity carbon molybdenum sulphide composite with enhanced electrochemical hydrogen evolution and stability.
- Author
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Laursen, Anders B., Vesborg, Peter C. K., and Chorkendorff, Ib
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CARBON fibers ,ACIDS ,HYDROGEN ,CATALYSTS ,ELECTRODES - Abstract
This work describes a highly active and stable acid activated carbon fibre and amorphous MoS
x composite hydrogen evolution catalyst. The increased electrochemical-surface area is demonstrated to cause increased catalyst electrodeposition and activity. These composite electrodes also show an improved stability towards the mechanical degradation of the MoSx catalyst. [ABSTRACT FROM AUTHOR]- Published
- 2013
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6. S-Scheme heterojunction based on the in situ coated core–shell NiCo2S4@WS2 photocatalyst was constructed for efficient photocatalytic hydrogen evolution.
- Author
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Xu, Shengming, Xu, Jing, Hu, Linying, Liu, Ye, and Ma, Lijun
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PHOTOCATALYSTS ,HETEROJUNCTIONS ,HYDROGEN evolution reactions ,INTERSTITIAL hydrogen generation ,HYDROGEN production ,BAND gaps ,HYDROGEN ,TRANSPORTATION rates - Abstract
In this paper, NiCo
2 S4 was coated on the surface of WS2 of a 1T/2H mixed phase by a two-step hydrothermal method to form an in situ core–shell structure. The unique S-scheme heterojunction of the NiCo2 S4 @WS2 core–shell composite photocatalyst improved the easy recombination of carriers caused by the narrow band gap of NiCo2 S4 and WS2 , and improved the photocatalytic hydrogen production performance. The loading ratio of NiCo2 S4 @WS2 , the addition of Eosin Y, and the pH value of TEOA were optimized. Under the optimal conditions, the hydrogen production rate reached 5.814 mmol g−1 h−1 , which is about 8.55 times and 3.35 times the hydrogen evolution rates of NiCo2 S4 and WS2 , respectively. The composite catalyst exhibits excellent charge separation efficiency in photoelectrochemistry, PL and BET tests, carrier transport rate and large specific surface area that can provide more active sites, which are the main factors for the improvement of the hydrogen evolution performance. This paper demonstrates new design strategies to drive efficient photocatalytic hydrogen production by building in situ core–shell structures and optimizing the carrier transport paths, which will yield new insights. [ABSTRACT FROM AUTHOR]- Published
- 2022
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7. Ti3C2 MXene cocatalyst supported Ti3C2/SrTiO3/g-C3N4 heterojunctions with efficient electron transfer for photocatalytic H2 production.
- Author
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Ye, Xiaoyun, Zhong, Hangyu, Zhang, Yumei, Liu, Xuehua, Tian, Wei, Ma, Li-An, and Wang, Qianting
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CHARGE exchange ,HETEROJUNCTIONS ,HETEROSTRUCTURES ,HYDROGEN ,SUNSHINE - Abstract
Previous studies on photocatalytic technology have shown that doping co-catalysts and constructing composite heterojunctions are effective strategies for improving the photocatalyst performance. The Ti
3 C2 /SrTiO3 /g-C3 N4 composite photocatalyst with a gradient heterostructure was prepared by the high-temperature calcination method with Ti3 C2 as the co-catalyst. The effects of g-C3 N4 content on the microstructure and hydrogen evolution rate of the Ti3 C2 /SrTiO3 /g-C3 N4 composites were investigated under simulated sunlight. The results showed that the photocatalyst with 60 wt% of g-C3 N4 had the optimal hydrogen evolution rate of 1733.13 μmol g−1 h−1 after simulated sunlight irradiation for 4 h, which was approximately 3.3 times higher than that of Ti3 C2 /SrTiO3 . After four photocatalytic hydrogen evolution cycles, no significant decrease in the hydrogen evolution rate of the Ti3 C2 /SrTiO3 /g-C3 N4 composite was observed. This work may serve as a rational reference on the synergistic effect of heterostructures and cocatalysts to improve the separation effect of electron–hole pairs, thus improving the hydrogen evolution effect of the catalyst. [ABSTRACT FROM AUTHOR]- Published
- 2024
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8. Two nickel-added poly(polyoxometalate)s built of Keggin-type {Ni6PW9} and Anderson-type NiW6O24via WO4/Sb2O bridges and Ni–O–W linkages with efficient hydrogen evolution activity
- Author
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Zhang, Peng-Yun, Lian, Chen, Wang, Zhen-Wen, Chen, Juan, Lv, Hongjin, and Yang, Guo-Yu
- Subjects
HETEROGENEOUS catalysts ,POLYOXOMETALATES ,HYDROGEN - Abstract
Two Ni-added poly(polyoxometalate)s built of Keggin-type {Ni
6 PW9 } and Anderson-type NiW6 O24 units via WO4 /Sb2 O bridges and Ni–O–W linkages, Na4 H8 [Ni(enMe)2 ][(Sb2 O)2 (NiW6 O24 )-{Ni12 O2 (OH)4 (enMe)4 (H2 O)3 (WO4 )2 (B-α-PW9 O34 )2 }2 ]·39H2 O (1) and H9 [Ni(en)2 (H2 O)][Ni0.5 (en)2 (H2 O)][Ni-(enMe)2 (H2 O)][(Sb2 O)2 (NiW6 O24 ){Ni12 O2 (OH)4 (en)2 (enMe)2 (H2 O)3 (WO4 )2 }-{Ni12 O2 (OH)4 (en)4 (H2 O)3 (WO4 )2 }(B-α-PW9 O34 )4 ]·45H2 O (2), have been hydrothermally synthesized and characterized, in which the {Ni12 (WO4 )2 (PW9 )2 } subunit was obtained by the synergistic directing effect of 2 lacunary PW9 O34 (PW9 ) fragments and further linked by a central Anderson-type (Sb2 O)2 (NiW6 O24 ) bridge. Both compounds represent the first example of Ni-added polyoxometalates (POMs) simultaneously based on Keggin-type and Anderson-type POM components. Photocatalytic studies revealed that 2 can work as an efficient heterogeneous catalyst towards a light-driven H2 evolution reaction, achieving a hydrogen evolution rate of as high as 19 214 μmol g−1 h−1 (TON = 1500), which is superior to most of the reported POM-based heterogeneous catalysts. [ABSTRACT FROM AUTHOR]- Published
- 2024
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9. Enhancing photocatalytic hydrogen evolution from water splitting over CaTaO2N via engineering the surface of a platinum cocatalyst.
- Author
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Liu, Xuecheng, Pei, Tingting, Yan, Linjie, Lei, Xiaoyi, Zheng, Tingting, Ha, Xia, and Xu, Hui
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PEROVSKITE ,PLATINUM ,HYDROGEN ,WAVELENGTHS ,DISPERSION (Chemistry) ,HYDROGEN evolution reactions - Abstract
Cocatalyst loading is of critical importance in efficient photocatalytic water splitting over perovskite oxynitrides. Perovskite CaTaO
2 N was synthesized for enhancing photocatalytic hydrogen evolution via decoration of a Pt cocatalyst by impregnation–reduction and photodeposition methods. The Pt-loaded CaTaO2 N photocatalyst evolves 6.4 μmol H2 per hour, with an apparent quantum yield as high as 0.67% at a wavelength of 420 nm. Decorating the cocatalyst with uniform dispersion and intimate contact onto the surface of narrow-bandgap perovskite oxynitrides is an efficient method to upgrade photocatalytic hydrogen evolution from water splitting. [ABSTRACT FROM AUTHOR]- Published
- 2024
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10. Enhancement of covalent triazine frameworks containing S heteroatom for photocatalytic hydrogen evolution: the role of composite PEG.
- Author
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Yao, Chan, Wang, Shuhao, Zha, Yixuan, and Xu, Yanhong
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POLYETHYLENE glycol ,HYDROGEN evolution reactions ,CHARGE carrier mobility ,HYDROGEN ,POLYMERS ,PHOTOCATALYSIS - Abstract
Covalent triazine frameworks (CTFs) containing S heteroatom are promising materials for applications in photocatalysis due to their donor–acceptor-type structures, which can improve the mobility of carriers in polymers. Herein, a series of composites (TTBT-COF@PEG
x , x = 10, 20, and 30) were prepared based on CTF containing S heteroatom and polyethylene glycol (PEG) by a two-step reaction. The results show that the photocatalytic hydrogen evolution rate of TTBT-COF@PEG30 is 1.51 times that of pristine TTBT-COF. This significant improvement was attributed to PEG in the pores, which resulted in a stable layered structure, reuced distortion and deformation of the skeleton, and rapid separation and transportation of photogenerated electron holes. [ABSTRACT FROM AUTHOR]- Published
- 2024
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11. The highly improved hydrogen evolution performance of a 0D/0D MoP-modified P-doped Mn0.5Cd0.5S photocatalyst.
- Author
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Yan, Jiaowei, Wang, Ying, and Shi, Lei
- Subjects
PRECIPITATION (Chemistry) ,HYDROGEN production ,HYDROGEN ,PRECIOUS metals ,HYDROGEN evolution reactions ,OVERPOTENTIAL - Abstract
In this paper, we present a MoP/P–Mn
0.5 Cd0.5 S photocatalytic material (PMOMCS-Px). A novel catalyst can efficiently split water into hydrogen without precious metals. In the sacrificial agent environment, the HER (hydrogen evolution rate) of PMOMCS-P5 was 4368.25 μmol g−1 h−1 which was 11.4 times greater than the HER of Mn0.5 Cd0.5 S (383.19 μmol g−1 h−1 ), and its hydrogen production performance was better than that of Pt/Mn0.5 Cd0.5 S (2.0 wt% Pt). Furthermore, the hydrogen evolution performance of PMOMCS-P5 under pure water conditions was also examined, and the HER of PMOMCS-P5 was 209.76 μmol g−1 h−1 , which was 20.4 times that of Mn0.5 Cd0.5 S (10.29 μmol g−1 h−1 ). Its characterization proved that the introduction of the co-catalyst MoP and P doping inhibited the recombination of e− and h+ , enhanced the reduction capacity, and reduced the hydrogen precipitation reaction overpotential of PMOMCS-Px, thus enhancing the hydrogen production performance of PMOMCS-Px. Therefore, an efficient and economical photocatalyst was prepared. [ABSTRACT FROM AUTHOR]- Published
- 2022
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12. Probing for non-statistical effects in dissociation of the 1-methylallyl radicalElectronic supplementary information (ESI) available: Radical precursor synthesis, geometries, energies, vibrational frequencies of the ab initiocalculations and RRKM rates. See DOI: 10.1039/c0cc01899fThis article is part of the ‘Emerging Investigators’ themed issue for ChemComm.
- Author
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Gasser, Michael, Frey, Jann A., Hostettler, Jonas M., and Bach, Andreas
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MOLECULAR probes ,DISSOCIATION (Chemistry) ,RADICALS (Chemistry) ,ORGANIC synthesis ,HYDROGEN ,CHEMICAL decomposition ,HYDROCARBONS ,INDICATORS & test-papers - Abstract
The 1-methylallyl radical loses a hydrogen atom following photoexcitation to its lowest valence electronically excited state and displays statistical behavior in decomposition, implying that the presence of methyl rotors cannot be depended upon as an indicator for non-statistical dissociation dynamics in hydrocarbon radicals. [ABSTRACT FROM AUTHOR]
- Published
- 2010
13. A dual photocarrier separation channel in CdS/ZnS for outstanding photocatalytic hydrogen evolution.
- Author
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Zheng, Yi, Chen, Qiaoling, Zhang, Wenjing, Zhang, Chongwen, Ma, Rong, Li, Chunlei, and Zhang, Jing
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EPITAXY ,HYDROGEN evolution reactions ,HYDROGEN ,X-ray diffraction ,ENERGY futures ,ENERGY consumption - Abstract
The photocatalytic hydrogen evolution half-reaction (HER) is a promising technology for meeting future energy demands. An excellent photocarrier separation is essential for the HER. Here, a CdS/ZnS composite (CZS) with a dual photocarrier separation channel has been synthesized using the epitaxial growth method to achieve this aim. XRD and TEM show that pre-adsorption of S
2− on the CdS surface facilitates the conversion of CdS into ZnS with a larger solubility product, implying a good carrier transport channel between CdS and ZnS. Based on XPS, PL, and photo-deposition experiments, a dual-channel photocarrier separation mechanism has been proposed, which is the source of the great photocarrier separation, and thus the hydrogen evolution rate of the CZS-2 sample (22.05 mmol g−1 h−1 ) becomes 18.5 and 73.5 times higher than those of CdS and ZnS. The apparent quantum yield (AQY) of CZS-2 at 420 nm is 4.68%. [ABSTRACT FROM AUTHOR]- Published
- 2024
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14. Steam-assisted electro-reduction of NiO: a sustainable alternative to conventional hydrogen reduction.
- Author
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Xie, Kaiyu and Kamali, Ali Reza
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HIGH temperature electrolysis ,CATHODES ,HYDROGEN ,STEAM reforming ,HYDROLYSIS ,FUSED salts ,HYDROGEN production ,ENERGY consumption - Abstract
Conventional methods of hydrogen reduction employed for green nickel production face challenges due to the high potentials required for water splitting at room temperature (>1.8 V) and/or the necessity for expensive catalysts. Additionally, the transportation of hydrogen from the production unit to the reduction unit (generally at 900 °C) presents hazards due to potential hydrogen leakage. Our findings address these challenges by proposing an innovative approach that utilises hydrogen generated via electrolysis at high temperatures for the in situ reduction of NiO in molten salt electrolytes. This process involves the hydrolysis of molten salts, generating protons which are then cathodically discharged to produce hydrogen at a low cell voltage, ranging from 1.0 to 1.4 V. Two different setups are investigated, utilising either NiO cathode pellets or NiO powder immersed in the melt to explore the hydrogen evolution and subsequent reduction of the oxide phase. Various parameters, including cell voltage, cell configuration, electrolyte chemical composition and temperature are examined for their impact on the reduction process. It is observed that the composition of the molten salt electrolyte significantly influences the reduction kinetics. The addition of KCl to LiCl electrolyte aids the reduction process by improving the wettability of electrodes, while CaCl
2 enhances the hydrolysis of the molten electrolyte. In particular, NiO pellets demonstrate efficient reduction to Ni in LiCl–30 wt% KCl, achieving a remarkable current efficiency of 97.4% with an energy consumption of 1.28 kW h per kilogram of produced Ni. [ABSTRACT FROM AUTHOR]- Published
- 2024
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15. A sandwiched Co4-added polyoxometalate for efficient visible light-driven hydrogen evolution.
- Author
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Wang, Zhen-Wen, Chen, Chong-An, and Yang, Guo-Yu
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CHEMICAL stability ,CHEMICAL structure ,X-ray diffraction ,HYDROGEN ,OCTAHEDRA - Abstract
A new Co
4 -added polyoxometalate (CoAP) Cs4 [(Co(H2 O)5 )2 {(μ2 -Co(H2 O)4 )2 Co4 (H2 O)2 (B-α-GeW9 O34 )2 }]·6H2 O (1) has been made using a lacunary directing strategy under hydrothermal conditions. Single-crystal X-ray diffraction analysis demonstrated that 1 is a one-dimensional (1D) chain, in which CoAP is linked by cobalt-oxygen octahedra to form a 1D structure with excellent chemical stability. The visible light-driven H2 evolution test demonstrated that 1 has high activity, with an H2 evolution rate of 1485.95 μmol h−1 g−1 . PXRD and FT-IR tests demonstrated that compound 1 exhibits excellent heterogeneous catalytic stability. [ABSTRACT FROM AUTHOR]- Published
- 2024
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16. Carbon-negative hydrogen: aqueous phase reforming (APR) of glycerol over NiPt bimetallic catalyst coupled with CO2 sequestration.
- Author
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Santiago-Martínez, Leoncio, Li, Mengting, Munoz-Briones, Paola, Vergara-Zambrano, Javiera, Avraamidou, Styliani, Dumesic, James A., and Huber, George W.
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BIMETALLIC catalysts ,GREENHOUSE gases ,BOND market ,CATALYST supports ,ELECTRIC power consumption ,HYDROGEN ,GLYCERIN ,METHANE - Abstract
Herein we report the production of high-pressure (19.3 bar), carbon-negative hydrogen (H
2 ) from glycerol with a purity of 98.2 mol% H2 , 1.8 mol% light hydrocarbons (mainly methane), and 400 ppm of CO. Aqueous phase reforming (APR) of 10 wt% glycerol solution was studied with a series of NiPt alumina bimetallic catalysts supported on alumina. The Ni8 Pt1 -450 catalyst had the highest hydrogen selectivity (95.6%) and the lowest alkanes selectivity (3.7%) of the tested catalysts. The hydrogen selectivity decreased in the order of Ni8 Pt1 -450 > Ni8 Pt1 -260 > Ni1 Pt1 -260 > Pt-260. The CO2 was sequestered with CaO adsorbent which formed CaCO3 . We measured the adsorption capacity of the CaO adsorbent at different temperatures. Life cycle analysis showed that the APR of glycerol coupled with CO2 capture has net negative CO2 equivalent greenhouse gas emissions. The CO2 emissions are −9.9 kg CO2 eq./kg H2 and −50.1 kg CO2 eq./kg H2 when grid electricity and renewable electricity are used, respectively, and the CO2 is allocated respectively to the mass of products produced. The cost of this H2 (denoted as "green-emerald") was estimated to be 2.4 USD per kg H2 when grid electricity is used and 2.7 USD per kg H2 when using renewable electricity. The cost of glycerol has the highest contribution of 1.71 USD per kg H2 . Participation in the carbon credit markets can further decrease the price of the produced H2 . [ABSTRACT FROM AUTHOR]- Published
- 2024
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17. A sustainable strategic approach for N-alkylation of amines with activation of alcohols triggered via a hydrogen auto-transfer reaction using a Pd(II) complex: evidence for metal–ligand cooperativity.
- Author
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Kumar Chaudhary, Virendra, Kukreti, Prashant, Sharma, Keshav, Kumar, Kapil, Singh, Sain, Kumari, Sheela, and Ghosh, Kaushik
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AMINES ,HYDROGEN ,ALIPHATIC alcohols ,AROMATIC amines ,CATALYSTS ,PALLADIUM - Abstract
This work describes a new well-defined, air-stable, phosphine free palladium(II) [Pd(L)Cl] (1) catalyst. This catalyst was utilized for N-alkylation of amines and indole synthesis where H
2 O was found to be the by-product. A broad range of aromatic amines were alkylated using this homogeneous catalyst with a catalyst loading of 0.1 mol%. Greener aromatic and aliphatic primary alcohols were utilized and a hydrogen auto-transfer strategy via a metal–ligand cooperative approach was investigated. The precursor of the antihistamine-containing drug molecule tripelennamine was synthesized on a gram scale for large-scale applicability of the current synthetic methodology. A number of control experiments were performed to investigate the possible reaction pathway and the outcomes of these experiments indicated the azo-chromophore as a hydrogen reservoir during the catalytic cycle. [ABSTRACT FROM AUTHOR]- Published
- 2024
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18. Facile grinding method synthesis of SnS2@HKUST-1 and SnS2@Ni-MOF for electrocatalytic hydrogen evolution.
- Author
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Cui, Hongtao, Gong, Lige, Lv, Hongyan, Dong, Limin, Wang, Jihua, Zhang, Jingyu, Mu, Yitong, Gu, Yunhao, Li, Hui, Yang, Binghe, and Wang, Meijia
- Subjects
HYDROGEN evolution reactions ,CATALYTIC activity ,MASS transfer ,INTERSTITIAL hydrogen generation ,ELECTROCATALYSTS ,HYDROGEN - Abstract
The development of high-performance and highly stable electrocatalysts is crucial and challenging for the hydrogen evolution reaction (HER). MOFs complexed with SnS
2 can form complexes with inserted structures, and their large specific surface area and numerous pores favor mass transfer, exposing the S active sites to more SnS2 , improving the utilisation of the active sites and enhancing the catalytic activity for the HER. Structural collapse can be hindered to improve the stability of the HER composites. Herein, six different kinds of SnS2 were synthesized by a hydrothermal method under discrete conditions, and SI8-SnS2 was screened out to have optimal morphology and electrocatalytic performance. Two innovative SnS2 @Ni-MOF and SnS2 @HKUST-1 as efficient electrocatalysts were synthesized by a facile grinding method for hydrogen generation. SnS2 @Ni-MOF and SnS2 @HKUST-1 catalysts showed lower overpotentials of 117 mV and 142 mV at 10 mA cm−2 (η10) and smaller Tafel slopes (58 mV dec−1 and 93 mV dec−1 ) than six different kinds of SnS2 , Ni-MOF and HKUST-1 in 0.5 M H2 SO4 . Meanwhile, the Cdl values for SnS2 @Ni-MOF and SnS2 @HKUST-1 were estimated to be 11.5 mF cm−2 and 8.0 mF cm−2 , and the stabilities of SnS2 , Ni-MOF, HKUST-1, SnS2 @Ni-MOF, and SnS2 @HKUST-1 were tested at a current density of 10 mA cm−2 . The current densities of SnS2 @Ni-MOF and SnS2 @HKUST-1 were stable over 8 h compared to the pure samples, and SEM, XPS tests were run after the HER test, indicating that the materials have excellent electrocatalytic stability. The syntheses of SnS2 @Ni-MOF and SnS2 @HKUST-1 enhance their intrinsic catalytic activity, and the porous structure promotes mass transfer efficiency, thereby improving the HER performance, which will guide the development of new and promising electrocatalysts for HER. [ABSTRACT FROM AUTHOR]- Published
- 2024
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19. Carbonic anhydrase assisted acidogenic fermentation of forest residues for low carbon hydrogen and volatile fatty acid production: enhanced in situ CO2 reduction and microbiological analysis.
- Author
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Sarkar, Omprakash, Antonopoulou, Io, Xiros, Charilaos, Bruce, Ylva, Souadkia, Sarra, Rova, Ulrika, Christakopoulos, Paul, and Matsakas, Leonidas
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CARBONIC anhydrase ,FATTY acids ,FERMENTATION ,MICROBIAL diversity ,CELLULOSE acetate ,HYDROGEN ,MICROBIAL metabolites - Abstract
Carbonic anhydrase (CA) is considered an efficient enzyme for fermentation systems exhibiting a wide range of applications, enhancing both the efficacy and output of the fermentation process. The present study aimed to evaluate the production of acidogenic biohydrogen (bioH
2 ) and volatile fatty acids (VFA) using forest residues as a renewable feedstock. Specifically, the study examined the integration of CA derived from Desulfovibrio vulgaris into the acidogenic fermentation (AF) process. The experimental procedure involved a cascade design conducted in two distinct phases. In phase I, the concentration of CA in the AF was systematically optimized, with glucose serving as the substrate. In phase II, three influential parameters (pH, pressurization with in situ generated gas and organic load) were evaluated on AF in association with optimized CA concentration from phase I. In phase II, glucose was replaced with renewable sugars obtained from forest residues after steam explosion pretreatment followed by enzymatic saccharification. The incorporation of CA in AF was found to be beneficial in steering acidogenic metabolites. Alkaline conditions (pH 8) promoted bioH2 , yielding 210.9 mLH2 gCOD-1 , while introducing CA further increased output to 266.6 mLH2 gCOD-1 . This enzymatic intervention improved the production of bioH2 conversion efficiency (HCE) from 45.3% to 57.2%. Pressurizing the system accelerated VFA production with complete utilization of in situ produced H2 + CO2 compared to non-pressurized systems. Particularly, caproic acid production was improved under pressurized conditions which was accomplished by the targeted enrichment of chain-elongating bacteria in the mixed culture. The microbial diversity analysis showed the dominance of Firmicutes suggesting a significant degree of adaptation to the experimental contexts, leading to an enhanced production of acidogenic metabolites. [ABSTRACT FROM AUTHOR]- Published
- 2024
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20. Rare earth material CeO2 modified CoS2 nanospheres for efficient photocatalytic hydrogen evolution.
- Author
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Ma, Lijun, Xu, Jing, Zhang, Juan, Liu, Zhenlu, and Liu, Xinyu
- Subjects
RARE earth metals ,HYDROGEN evolution reactions ,PROBLEM solving ,HYDROGEN production ,VISIBLE spectra ,HYDROGEN - Abstract
The development of high-efficiency and low-cost photocatalysts for hydrogen production reactions is very important to solve energy problems. In this paper we study the photocatalytic H
2 evolution activity of a CeO2 /CoS2 heterojunction catalyst under visible light. Characterization studies such as XRD and XPS proved the successful synthesis of a CeO2 /CoS2 catalyst. The composite catalyst with a CeO2 and CoS2 mass ratio of 1 : 20 had the best activity, and the hydrogen evolution rate reached 5172.20 μmol g−1 h−1 . BET and UV-Vis DRS characterization showed that the introduction of CeO2 not only increased the specific surface area of the composite catalyst, but also improved the response of the photocatalyst to visible light. In addition, PL and electrochemical experiments showed that the electrons and holes of the CeO2 /CoS2 catalyst could be quickly separated and transferred, thereby accelerating the kinetics of the hydrogen evolution reaction. This work provided an experimental basis for designing a composite photocatalyst with high stability and hydrogen production activity. [ABSTRACT FROM AUTHOR]- Published
- 2021
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21. MoC/MAPbI3 hybrid composites for efficient photocatalytic hydrogen evolution.
- Author
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Zhang, Tiantian, Yu, Jianfei, Huang, Jiyao, Lan, Shengnan, Lou, Yongbing, and Chen, Jinxi
- Subjects
HYDROGEN evolution reactions ,INTERSTITIAL hydrogen generation ,CHARGE transfer ,HYDROGEN ,HYDROGEN production ,PEROVSKITE ,CHARGE carriers - Abstract
Metal halide perovskites, such as iodine methylamine lead (MAPbI
3 ), have received extensive attention in the field of photocatalytic decomposition of HI for hydrogen evolution, due to their excellent photoelectric properties. In this paper, a new MAPbI3 -based composite, MoC/MAPbI3 , was synthesized. The results show that 15 wt% MoC/MAPbI3 has the best hydrogen production performance (38.4 μmol h−1 ), which is approximately 24-times that of pure MAPbI3 (1.61 μmol h−1 ). With the extension of the catalytic time, the hydrogen production rate of MoC/MAPbI3 reached 165.3 μmol h−1 after 16 h due to the effective separation and transfer of charge carriers between MoC and MAPbI3 , showing excellent hydrogen evolution rate performance under visible light. In addition, the cycling stability of MoC/MAPbI3 did not decrease in multiple 4 h cycle tests. This study used the non-precious metal promoter MoC to modify MAPbI3 , and provides a new idea for the synthesis of efficient MAPbI3 -based composite catalysts. [ABSTRACT FROM AUTHOR]- Published
- 2021
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22. A millimeter water-in-oil droplet as an alternative back exchange prevention strategy for hydrogen/deuterium exchange mass spectrometry of peptides/proteins.
- Author
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Lui, T.-Y., Chen, Xiangfeng, Zhang, Simin, Hu, Danna, and Chan, T.-W. Dominic
- Subjects
DEUTERIUM ,MASS spectrometry ,PEPTIDES ,AIR-water interfaces ,HYDROGEN ,ORGANIC solvents - Abstract
Hydrogen/deuterium exchange mass spectrometry (HDX-MS) is a versatile bioanalytical technique for protein analysis. Since the reliability of HDX-MS analysis considerably depends on the retention of deuterium labels in the post-labeling workflow, deuterium/hydrogen (D/H) back exchange prevention strategies, including decreasing the pH, temperature, and exposure time to protic sources of the deuterated samples, are widely adopted in the conventional HDX-MS protocol. Herein, an alternative and effective back exchange prevention strategy based on the encapsulation of a millimeter droplet of a labeled peptide solution in a water-immiscible organic solvent (cyclohexane) is proposed. Cyclohexane was used to prevent the undesirable uptake of water by the droplet from the atmospheric vapor through the air–water interface. Using the pepsin digest of deuterated myoglobin, our results show that back exchange kinetics of deuterated peptides is retarded in a millimeter droplet as compared to that in the bulk solution. Performing pepsin digestion directly in a water-in-oil droplet at room temperature (18–21 °C) was found to preserve more deuterium labels than that in the bulk digestion with an ice-water bath. Based on the present findings, it is proposed that keeping deuterated peptides in the form of water-in-oil droplets during the post-labelling workflow will facilitate the preservation of deuterium labels on the peptide backbone and thereby enhance the reliability of the H/D exchange data. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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23. Metal- and ligand-substitution-induced changes in the kinetics and thermodynamics of hydrogen activation and hydricity in a dinuclear metal complex.
- Author
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Isegawa, Miho
- Subjects
METAL complexes ,THERMODYNAMICS ,DENSITY functional theory ,HYDROGEN ,HYDRIDES - Abstract
Catalytic function in organometallic complexes is achieved by carefully selecting their central metals and ligands. In this study, the effects of a metal and a ligand on the kinetics and thermodynamics of hydrogen activation, hydricity degree of the hydride complex, and susceptibility to electronic oxidation in bioinspired NiFe complexes, [Ni
II X FeII (Cl)(CO)Y]+ ([NiFe(Cl)(CO)]+ ; X = N,N′-diethyl-3,7-diazanonane-1,9-dithiolato and Y = 1,2-bis(diphenylphosphino)ethane), were investigated. The density functional theory calculations revealed that the following order thermodynamically favored hydrogen activation: [NiFe(CO)]2+ > [NiRu(CO)]2+ > [NiFe(CNMe)]2+ ∼ [PdRu(CO)]2+ ∼ [PdFe(CO)]2+ ≫; [NiFe(NCS)]+ . Moreover, the reverse order thermodynamically favored the hydricity degree. [ABSTRACT FROM AUTHOR]- Published
- 2024
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- View/download PDF
24. Mechanisms of hydrogen evolution by six-coordinate cobalt complexes: a density functional study on the role of a redox-active pyridinyl-substituted diaminotriazine benzamidine ligand as a proton relay.
- Author
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Thammanatpong, Kittimeth and Surawatanawong, Panida
- Subjects
COBALT ,PROTONS ,BENZAMIDINE ,CHARGE exchange ,HYDROGEN ,PROTON transfer reactions ,HYDROGEN evolution reactions - Abstract
The hydrogen evolution reaction is an important process for energy storage. The six-coordinate cobalt complex [Co
III (L1− )(LH)]2+ (LH = N-(4-amino-6-(pyridin-2-yl)-1,3,5-triazin-2-yl)benzamidine) was found to catalyze photocatalytic hydrogen evolution. In this work, we performed density functional calculations to obtain the reduction potentials and the proton-transfer free energy of possible intermediates to determine the preferred pathways for proton reduction. The mechanism involves the metal-based reduction of Co(III) to Co(II) before the protonation at the amidinate N on the pyridinyl-substituted diaminotriazine benzamidinate ligand L1− to form [CoII (LH)(LH)]2+ . Essentially, the subsequent electron transfer is not metal-based reduction, but rather ligand-based reduction to form [CoII (LH)(LH˙1− )]1+ . Through a proton-coupled electron transfer process, the cobalt hydride [CoII H(LH)(LH2 ˙)]1+ is formed as the key intermediate for hydrogen evolution. As the cobalt hydride complex is coordinatively saturated, a structural change is required when the hydride on Co is coupled with the proton on pyridine. Notably, the redox-active nature of the ligand results in the low acidity of the protonated pyridine moiety of LH2 ˙, which impedes its function as a proton relay. Our findings suggest that separating the proton relay fragment from the electron reservoir fragment of the redox-active ligand is preferred for fully utilizing both features in catalytic H2 evolution. [ABSTRACT FROM AUTHOR]- Published
- 2024
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25. Promoting water splitting by transforming its presence status for enhanced hydrogen evolution.
- Author
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Han, Yanxia, Hou, Lijie, Shuai, Chao, Song, Xiaoli, and Kong, Chao
- Subjects
HYDROGEN-ion concentration ,CARBONIC acid ,DENSITY functional theory ,DYE-sensitized solar cells ,HYDROGEN - Abstract
Non-acidic hydrogen evolution systems have a low concentration of hydrogen ions, and the H
2 evolution reaction (HER) is often limited by the water dissociation step. Preparing catalysts that can accelerate water dissociation is a common method for achieving high-efficiency evolution of hydrogen. In the current work, the performance of a hydrogen evolution system was first improved by introducing CO2 to transform the presence status of H2 O. According to density functional theory (DFT) calculations, water reacts with CO2 to produce carbonic acid which can reduce the barrier of adsorbed H generation. Subsequently, under same pH conditions, a constructed dye-sensitized Ni–CO2 system shows an H2 evolution rate 1.5 times higher than that shown by dye-sensitized Ni. This result indicates that transforming the presence status of H2 O may be a new strategy for further improving H2 evolution efficiency. [ABSTRACT FROM AUTHOR]- Published
- 2024
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26. Preparation of a novel cadmium-containing coordination polymer and catalytic application in the synthesis of N-alkylated aminoquinoline derivatives via the borrowing hydrogen approach.
- Author
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Li, Jiahao, Mao, Anruo, Hu, Xinyu, Wang, Likui, Wang, Dawei, and Duan, Zheng-Chao
- Subjects
QUINOLINE derivatives ,COORDINATION polymers ,BIOACTIVE compounds ,MOLECULAR structure ,ALKYLATING agents ,HYDROGEN ,CATALYTIC activity - Abstract
Herein, we report an efficient and straightforward approach for the synthesis of N-alkylated aminoquinoline derivatives by recyclable Cd-containing coordination polymer-catalyzed reactions of aminoquinolines with primary alcohols via the borrowing hydrogen strategy. In this work, a new type of coordination polymer [Cd(CIA)(phen)
2 (H2 O)]n was successfully designed and fabricated. The molecular structure was corroborated by single-crystal X-ray diffraction and fully characterized by PXRD, FT-IR, TGA, and XPS. Importantly, this polymer revealed high catalytic activity for the N-alkylation reaction of 2-aminoquinoline and 8-aminoquinoline with inexpensive and low-toxicity alcohols as alkylating agents in excellent yields up to 95%. Interestingly, the present synthetic protocol was successfully applied for the gram-level synthesis of several biologically active compounds. In addition, several control reactions were carried out to investigate the possible mechanisms of this transformation. Finally, recycling experiments indicated that the cadmium coordination polymer showed good recovery performance for borrowing hydrogen reactions. [ABSTRACT FROM AUTHOR]- Published
- 2024
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27. Solar light-driven hydrogen evolution by co-catalyst-free subphthalocyanine-sensitized photocatalysts.
- Author
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Dogan, Şifa, Güntay, Buket, Demircioglu, Perihan Kübra, Akyıldız, Yigit Osman, Aydın, Hasan, Aslan, Emre, Can, Mustafa, Hatay Patir, Imren, and Ince, Mine
- Subjects
HYDROGEN evolution reactions ,PHOTOCATALYSTS ,CARBOXYLIC acid derivatives ,CATALYTIC activity ,TURNOVER frequency (Catalysis) ,HYDROGEN ,ORGANIC dyes - Abstract
Subphthalocyanines (SubPcs) have emerged as promising organic dyes for the development of efficient artificial photosynthetic devices, offering intense absorption in the visible region along with excellent charge transport properties. In this study, four novel SubPc derivatives containing carboxylic acid and various peripheral substituents were synthesized as a panchromatic photosensitizer to prepare an efficient and stable TiO
2 -based photocatalytic system for co-catalyst-free photocatalytic hydrogen evolution. To compare the influence of the nature of the peripheral substituents on photocatalytic activity, SubPc derivatives (coded as SubPc 1–4) were decorated with substituents having different electron-donating capabilities, such as alkyl thio, benzodioxin, amine, and iodo units, respectively. Photocatalytic activities were examined in the presence of TEOA as a sacrificial agent under irradiation with λ > 400 nm without co-catalyst loading. SubPc 1/TiO2 shows the best photocatalytic activity among the SubPc-sensitized photocatalysts, with a hydrogen evolution rate of 0.176 mmol h−1 . While the activity of all four SubPc-based photocatalysts increased significantly after 24 h irradiation, notably, SubPc 1/TiO2 exhibited remarkable catalytic activity, achieving a hydrogen evolution rate of 6.017 mmol with a high turnover number (TON) value of 12 279 for hydrogen production. This study highlights the potential of SubPc-based sensitizers for co-catalyst-free photocatalytic H2 production and offers valuable insights into the impact of peripheral units in SubPc/TiO2 -based photocatalytic systems. [ABSTRACT FROM AUTHOR]- Published
- 2024
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28. PtCu nanoalloy loaded on sulfur-doped porous g-C3N4 for electrocatalytic hydrogen evolution.
- Author
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Chang, Can, Wu, Jicheng, Wu, Dandan, Jiang, Guojian, Xu, Xiaowei, and Chang, Shufang
- Subjects
HYDROGEN evolution reactions ,NITRIDES ,CARBON-based materials ,METAL nanoparticles ,WATER electrolysis ,OVERPOTENTIAL ,HYDROGEN - Abstract
Graphitic carbon nitride (g-C
3 N4 ), as a carbon support material with excellent stability and abundant active sites, has found widespread applications in various fields, including photocatalytic water splitting, electrolysis of water, and CO2 reduction. Presently, research on the modification of g-C3 N4 primarily focuses on atomic doping, defect engineering, and the decoration of metal nanoparticles. In this study, a method involving the high-temperature pyrolysis of a solution containing thiourea and urea was successfully employed to synthesize sulfur-doped porous g-C3 N4 (S-C3 N4 ) nanosheets. Subsequently, PtCu nanoparticles were loaded onto the S-C3 N4 through a hydrothermal process. In the case of Pt loading of less than half of 20% Pt/C, this catalyst exhibited a low overpotential of only 10 mV at a current density of 10 mA cm−2 , which is significantly better than the 35 mV overpotential of 20% Pt/C. Furthermore, after a long period of continuous current stability testing, the overpotential of the catalyst did not increase by more than 30 mV, demonstrating excellent stability. The porous S-C3 N4 nanosheets possess a large specific surface area, providing abundant active sites for the HER reaction. This research introduces a fresh method for creating innovative catalysts based on Pt alloys supported by a carbon carrier. [ABSTRACT FROM AUTHOR]- Published
- 2024
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29. Unprecedented Mo3S4 cluster-catalyzed radical C–C cross-coupling reactions of aryl alkynes and acrylates.
- Author
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Mateu-Campos, Juanjo, Guillamón, Eva, Safont, Vicent S., Junge, Kathrin, Junge, Henrik, Beller, Matthias, and Llusar, Rosa
- Subjects
RADICALS (Chemistry) ,ACRYLATES ,ALKYNES ,CATALYSTS ,CATALYSIS ,HYDROGEN - Abstract
A new method for the generation of benzyl radicals from terminal aromatic alkynes has been developed, which allows the direct cross coupling with acrylate derivatives. Our additive-free protocol employs air-stable diamino Mo
3 S4 cubane-type cluster catalysts in the presence of hydrogen. A sulfur-centered cluster catalysis mechanism for benzyl radical formation is proposed based on catalytic and stoichiometric experiments. The process starts with the cluster hydrogen activation to form a bis(hydrosulfido) [Mo3 (μ3 -S)(μ-S)(μ-SH)2 Cl3 (dmen)3 ]+ intermediate. The reaction of various aromatic terminal alkynes containing different functionalities with a series of acrylates affords the corresponding Giese-type radical addition products. [ABSTRACT FROM AUTHOR]- Published
- 2024
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30. Construction of one-dimensional ZnCdS(EDA)/Ni@NiO for photocatalytic hydrogen evolution.
- Author
-
Guo, Changyan, Zou, Yangyang, Ma, Yanqiu, Akram, Naeem, Ahmad, Ali, and Wang, Jide
- Subjects
GREEN fuels ,HYDROGEN as fuel ,HYDROGEN evolution reactions ,HYDROGEN ,CLEAN energy - Abstract
The development of photocatalysts plays a pivotal role in facilitating the production of green hydrogen energy through water splitting. In this study, one-dimensional (1D) organic–inorganic ZnCdS(EDA)/Ni@NiO (EDA: ethylenediamine) nanorods were prepared by combining organic molecules of EDA into ZnCdS. The EDA molecule possesses two amino functional groups with strong electron-donating capacity, thereby facilitating electron transfer to ZnCdS(EDA)/Ni@NiO and enabling efficient hydrogen evolution through photocatalytic water splitting. The H
2 evolution rate of ZnCdS(EDA)/Ni@NiO was 159 μmol g−1 h−1 in the absence of sacrificial agents, and its H2 evolution rate in the system with EDA as the sacrificial agent can reach 5760 μmol g−1 h−1 . The combination of EDA, a S vacancy, and heterojunction was proved to be the main factor for improving the separation and transfer rate of photogenerated carriers. The incorporation of ZnCdS(EDA)/Ni@NiO enhances the participation of photogenerated electrons in the photocatalytic hydrogen evolution reaction, thereby improving the overall photocatalytic activity. The synthesis of this one-dimensional composite catalyst holds great potential for advancing the development of efficient photocatalytic materials. [ABSTRACT FROM AUTHOR]- Published
- 2024
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31. CdIn2S4 microspheres embedded with mesoporous Zn-doped g-C3N4 ultrathin nanosheets for efficient photocatalytic hydrogen evolution.
- Author
-
Tian, Shaopeng, Ren, Huaping, Sun, Wuge, Song, Yixuan, Ge, Hang, Yang, Anye, Zheng, Weilong, and Zhao, Yuzhen
- Subjects
HYDROGEN evolution reactions ,MICROSPHERES ,NANOSTRUCTURED materials ,ELECTRON-hole recombination ,PHOTOCATALYSTS ,HYDROGEN - Abstract
Herein, mesoporous Zn-doped g-C
3 N4 wrapped CdIn2 S4 microsphere nanostructures were fabricated using a simple hydrothermal route. It is found that the CdIn2 S4 /Zn–g-C3 N4 nanocomposite exhibits the most efficient photocatalytic activity for hydrogen evolution. The photocatalytic activity of the CdIn2 S4 /Zn–g-C3 N4 composite presents the optimum performance for hydrogen evolution of 101.74 μmol h−1 , which is ∼10.8 and 7.3 times that of pure g-C3 N4 and bare CdIn2 S4 , respectively. The results of varied characterization such as TEM and XPS demonstrate that a tight heterojunction has been successfully built in CdIn2 S4 /Zn–g-C3 N4 nanocomposites, which is highly favorable to limit the recombination of photogenerated electron–hole pairs. Furthermore, Zn could partially replace the C element in the g-C3 N4 framework and enhance the separation of photo-induced electrons and holes. Moreover, the incorporation of Zn-doped g-C3 N4 nanosheets with mesoporous features considerably improves the photo-stability of CdIn2 S4 microspheres. We hope that these CdIn2 S4 /Zn–g-C3 N4 nanocomposites with the tight heterojunction structure may provide new insight into designing novel photocatalysts with high efficiency and excellent stability. [ABSTRACT FROM AUTHOR]- Published
- 2024
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- View/download PDF
32. Synergistic optimization of triple phase junctions and oxygen vacancies over MnxCd1−xS/Ov-WO3 for boosting photocatalytic hydrogen evolution.
- Author
-
Zhao, Haitao, Zhu, Hongjie, Wang, Min, Liu, Heyuan, and Li, Xiyou
- Subjects
HYDROGEN evolution reactions ,SURFACE charges ,HYDROGEN ,CHARGE carriers ,CHARGE transfer ,ABSORPTION spectra - Abstract
Strengthening the separation of photogenerated charge carriers is crucial for improving the efficiency of photocatalytic hydrogen evolution. Herein, t-Mn
0.5 Cd0.5 S/Ov-WO3 (t-MCSW) triple-phase junctions with rich oxygen vacancies were developed using the calcination-hydrothermal method. The corresponding morphology and structure of the samples were examined by XRD, TEM and XPS. The formation of the S-scheme heterostructure in t-MCSW has also been confirmed with in situ XPS, work function analysis and free radical capture tests. The experimental results demonstrate that t-MCSW-7 exhibited optimal activity (194.2 mmol g−1 h−1 ), which was about 4 times higher than that of the individual Mn0.5 Cd0.5 S (t-MCS, 48.8 mmol g−1 h−1 ). The apparent quantum yield of t-MCSW-7 is 29.14% at 420 nm, and the material exhibits excellent stability after seven cycles of photocatalytic reaction. The excellent photocatalytic activity of t-MCSW-7 is attributed to more efficient separation of charge carriers by triple-phase junctions connected by homojunctions and heterojunctions. Moreover, the existence of oxygen vacancies broadens absorption spectra and accelerates surface charge transfer. The synergistic effect of phase junctions and oxygen vacancies leads to an enhancement of hydrogen evolution activity. This work provides a new idea for preparing efficient photocatalysts. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
33. Recent advances in cobalt-based catalysts for efficient electrochemical hydrogen evolution: a review.
- Author
-
Sun, Ran, Huang, Xing, Jiang, Jibo, Xu, Wenxiu, Zhou, Shaobo, Wei, Ying, Li, Mingjing, Chen, Yukai, and Han, Sheng
- Subjects
HYDROGEN evolution reactions ,COBALT phosphide ,CATALYSTS ,CATALYTIC activity ,DENSITY functional theory ,HYDROGEN ,STRUCTURAL engineers - Abstract
Hydrogen (H
2 ) is a new type of renewable energy that can meet people's growing energy needs and is environmentally friendly. In order to improve the industrial application prospects and electrochemical performance of hydrogen evolution catalysts, extensive research on transition metal materials has been carried out. Among the many catalytic materials, cobalt is an element with potential for the hydrogen evolution reaction (HER) due to its abundant reserves, low cost, and small energy barrier for H adsorption. This review classifies the latest research on cobalt-based catalysts according to the types of compound, including cobalt-based sulfides, phosphides, carbides, borides, oxides, etc., and summarizes the latest research progress of cobalt-based compound catalysts in acidic and alkaline media. Strategies to tune the properties of cobalt-based compound catalysts for high catalytic activity for HER are focused on, including structural engineering, defect engineering, and doping, etc. The advantages and limitations of each modified approach are reviewed. Not only that, but also the catalytic activity and advantages of the catalyst are evaluated by using density functional theory (DFT) calculation-related descriptors, activity evaluation parameters, etc. Finally, limitations and challenges of cobalt-based materials for HER are presented, as well as prospects for future research. This paper aims to understand the chemical and physical factors that affect cobalt-based catalysts, and to find directions for future research on cobalt-based catalysts. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
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34. Structures and reaction dynamics of N 2 and H 2 binding at FeMo-co, the active site of nitrogenase.
- Author
-
Dance I
- Subjects
- Binding Sites, Hydrogen chemistry, Iron chemistry, Models, Molecular, Molecular Structure, Molybdenum chemistry, Nitrogen chemistry, Nitrogenase chemistry, Tricarboxylic Acids, Hydrogen metabolism, Iron metabolism, Molybdenum metabolism, Nitrogen metabolism, Nitrogenase metabolism
- Abstract
The chemical reactions occurring at the Fe
7 MoS9 C(homocitrate) cluster, FeMo-co, the active site of the enzyme nitrogenase (N2 → NH3 ), are enigmatic. Experimental information collected over a long period reveals aspects of the roles of N2 and H2 , each with more than one type of reactivity. This paper reports investigations of the binding of H2 and N2 at intact FeMo-co, using density functional simulations of a large 486 atom relevant portion of the protein, resulting in 27 new structures containing H2 and/or N2 bound at the exo and endo coordination sites of the participating Fe atoms, Fe2 and Fe6. Binding energies and transition states for association/dissociation are determined, and trajectories for the approach, binding and separation of H2 /N2 are described, including diffusion of these small molecules through proximal protein. Influences of surrounding amino acids are identified. FeMo-co deforms geometrically when binding H2 or N2 , and a procedure for calculating the energy cost involved, the adaptation energy, is introduced here. Adaptation energies, which range from 7 to 36 kcal mol-1 for the reported structures, are influenced by the protonation state of the His195 side chain. Seven N2 structures and three H2 structures have negative binding free energies, which include the estimated entropy penalties for binding of N2 , H2 from proximal protein. These favoured structures have N2 bound end-on at exo -Fe2, exo -Fe6 and endo -Fe2 positions of FeMo-co, and H2 bound at the endo -Fe2 position. Various postulated structures with N2 bridging Fe2 and Fe6 revert to end-on-N2 at endo positions. The structures are also assessed via the calculated potential energy barriers for association and dissociation. Barriers to the binding of H2 range from 1 to 20 kcal mol-1 and barriers to dissociation of H2 range from 3 to 18 kcal mol-1 . Barriers to the binding of N2 , in either side-on or end-on mode, range from 2 to 18 kcal mol-1 , while dissociation of bound N2 encounters barriers of 3 to 8 kcal mol-1 for side-on bonding and 7 to 18 kcal mol-1 for end-on bonding. These results allow formulation of mechanisms for the H2 /N2 exchange reaction, and three feasible mechanisms for associative exchange and three for dissociative exchange are identified. Consistent electronic structures and potential energy surfaces are maintained throughout. Changes in the spin populations of Fe2 and Fe6 connected with cluster deformation and with metal-ligand bond formation are identified.- Published
- 2021
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35. One-pot three-component synthesis of α-methylated ketones from secondary and primary aryl alcohols.
- Author
-
Samser, Shaikh, Biswal, Priyabrata, Mohapatra, Omkar, Pullarat, Sanu Siyad, Meher, Sushanta Kumar, and Venkatasubbaiah, Krishnan
- Subjects
KETONES ,DEUTERIUM ,ALCOHOL ,CATALYSTS ,HYDROGEN - Abstract
One-pot three-component synthesis of α-methylated ketones from secondary and primary alcohols via a triple dehydrogenative method is presented here. This protocol uses a polystyrene-supported catalyst and the catalyst is reused for five runs without any drop in its activity. Detailed mechanistic investigation was carried out with control reactions and deuterium labelling experiments revealed that secondary and primary alcohols act as a hydrogen source in this one-pot synthesis of α-methylated substituted ketones. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Heterogeneous electrocatalysts of MoS2/NiCoP for highly stable hydrogen evolution.
- Author
-
Wang, Minmin, Xu, Hao, Zhou, Li, Sun, Tongming, and Tang, Yanfeng
- Subjects
HYDROGEN evolution reactions ,HYDROGEN as fuel ,ELECTROCATALYSTS ,HYDROGEN ,CHARGE transfer ,HYDROGEN production - Abstract
The development of high-efficiency, precious-metal-free electrical catalysts for hydrogen evolution reactions is expected to facilitate the production of hydrolytic hydrogen fuels. Heterogeneous structures with a one-dimensional (1D) morphology exhibit efficient electrocatalytic effects owing to their abundance of active centers in the radial direction and convenient axial charge transfer in interconnected networks. Hence, a 1D MoS
2 /NiCoP heterogeneous junction for highly efficient hydrogen evolution performance was developed. As expected, the optimized MoS2 /NiCoP/NF showed a low overpotential of 148 mV for hydrogen evolution with a current density of 10 mA cm−2 in 1.0 M KOH. Meanwhile, the developed heterogeneous structure exhibited high stability within 50 hours of continuous testing. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
37. Electrocatalytic hydrogen evolution of MOF-derived materials based on conjugated or unconjugated ligands.
- Author
-
Duan, Chun-Pu, Ni, Ya-Lu, Yang, Xu-Dong, Huang, Jing-Yu, Shen, Yong-Hui, Gu, Xun-Gang, Ni, Gang, Ma, Miao-Lian, Li, Juan, and Qin, Ling
- Subjects
LIGANDS (Chemistry) ,HYDROGEN ,METAL-organic frameworks ,HYDROGEN evolution reactions ,ORGANIC bases - Abstract
Two organic ligands, one rigid and one flexible, were designed and used to construct two cobalt-based metal–organic frameworks (MOFs) with coligands to obtain 3D and 2D structures, respectively. Both the Co-based MOFs were pyrolyzed at different temperatures to obtain the derived materials, and their electrocatalytic hydrogen evolution properties were studied. The results show that the electrocatalytic hydrogen evolution performance of MOF derivatives based on the rigid ligand was better than that of MOF derivatives based on the flexible organic ligand. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Construction of core–shell CoSe2/ZnIn2S4 heterostructures for efficient visible-light-driven photocatalytic hydrogen evolution.
- Author
-
Xie, Yuhan, Dong, Boyu, Wang, Xuemin, Wang, Siyuan, Chen, Jinxi, and Lou, Yongbing
- Subjects
HETEROJUNCTIONS ,CHARGE transfer kinetics ,HETEROSTRUCTURES ,SOLAR energy conversion ,HYDROGEN ,PRECIOUS metals - Abstract
The use of photocatalysts based on semiconductor heterostructures for hydrogen evolution is a prospective tactic for converting solar energy. Herein, visible-light-responsive three-dimensional core–shell CoSe
2 /ZnIn2 S4 heterostructures were successfully fabricated via in situ growth of ZnIn2 S4 ultrathin nanosheets on spherical CoSe2 . Without any noble metal co-catalysts, the as-prepared CoSe2 /ZnIn2 S4 composite achieved attractive photocatalytic hydrogen evolution activity under visible light illumination. Optimal CoSe2 /ZnIn2 S4 achieved a hydrogen evolution rate of 2199 μmol g−1 h−1 , which was 7 times higher than that of pristine ZnIn2 S4 and even exceeded that of ZnIn2 S4 loaded with platinum. In this distinctive core–shell heterostructure, the presence of CoSe2 could considerably improve the ability to harvest light, quicken the charge transfer kinetics, and avoid the agglomeration of ZnIn2 S4 nanosheets. Meanwhile, the experimental results demonstrated that the strong interaction between CoSe2 and ZnIn2 S4 at the compact interface could appropriately boost the photogenerated electron–hole pair migration and relieve charge recombination, thus improving photocatalytic hydrogen evolution activity. This work has bright prospects in constructing noble-metal-free core–shell heterostructures for solar energy conversion. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
39. CAAC-stabilised 9,10-diboraanthracene: an electronically and structurally flexible platform for small-molecule activation and metal complexation.
- Author
-
Dietz, Maximilian, Arrowsmith, Merle, and Braunschweig, Holger
- Subjects
METAL activation ,SMALL molecules ,HYDROGEN ,ATOMS ,BORON - Abstract
A biradical cyclic alkyl(amino)carbene-stabilised 9,10-diboraanthracene (DBA) activates small molecules such as hydrogen, phenyl azide or TEMPO (2,2,6,6-tetramethylpiperidin-1-oxyl) across its two boron atoms, while reactions with [(MeCN)
3 M(CO)3 ] (M = Cr, Mo, W) yield the first half-sandwich DBA complexes of the form [(η6 -DBA)M(CO)3 ]. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
40. The elusive reaction mechanism of Mn(II)-mediated benzylic oxidation of alkylarene by H2O2: a gem-diol mechanism or a dual hydrogen abstraction mechanism?
- Author
-
Wang, Shoujun, Sun, Dongru, Wu, Zhimin, Zhao, Yufen, and Wang, Yong
- Subjects
STRUCTURE-activity relationships ,ALCOHOL oxidation ,OXIDATION ,DENSITY functional theory ,STACKING interactions ,HYDROGEN - Abstract
The direct oxygenation of alkylarenes at the benzylic position employing bioinspired nonheme catalysts has emerged as a promising strategy for the production of bioactive arene ketone scaffolds in drugs. However, the structure–activity relationship of the active species and the mechanism of these reactions remain elusive. Herein, the reaction mechanism of the Mn(II)-mediated benzylic oxygenation of phenylbutanoic acid (PBA) to 4-oxo-4-phenylbutyric acid (4-oxo-PBA) by H
2 O2 was investigated using density functional theory calculations. The calculated results demonstrated that the MnIII –OOH species (1) is a sluggish oxidant and needs to be converted to a high-valent manganese–oxo species (2). The conversion of PBA to 4-oxo-PBA by 2 occurs via the consecutive hydroxylation of PBA to 4-hydroxyl-4-phenylbutyric acid (4-OH-PBA) and the alcohol oxidation of 4-OH-PBA to 4-oxo-PBA. The hydroxylation of PBA proceeds via a novel hydride transfer/hydroxyl-rebound mechanism and the alcohol oxidation of 4-OH-PBA occurs via three pathways (gem-diol, dual hydrogen abstraction (DHA), and reversed-DHA pathways). The regio-selectivity of benzylic oxidations was caused by a strong π–π stacking interaction between the pyridine ring of the nonheme ligand and the phenyl ring of the substrate. These mechanistic findings enrich the knowledge of biomimetic alcohol oxidations and play a positive role in the rational design of new non-heme catalysts. [ABSTRACT FROM AUTHOR]- Published
- 2023
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41. Tailoring a sulfur doped carbon nitride skeleton to enhance the photocatalytic hydrogen evolution activity.
- Author
-
Zhou, Tianyu, Cui, Feifan, Li, Guijie, Sun, Xiaozhong, Sun, Dongshu, Liu, Chunbo, Zhao, Chun, and Li, Shangyu
- Subjects
HYDROGEN evolution reactions ,NITRIDES ,DOPING agents (Chemistry) ,SULFUR ,HYDROGEN ,PHOTOCATALYSTS ,CONDUCTION bands - Abstract
Although graphite phase carbon nitride (CN) photocatalysts possess great potential in solving the global energy crisis, their photocatalytic activity is severely affected by sluggish charge dissociation/migration efficiency, a high carrier recombination rate, low active site exposure, and limited visible-light harvesting. Herein, a sulfur doped CN (x-DZCN) was tailored via one-step thermally-induced polymerization of urea with dithizone, which could evolve hydrogen at a rate of 1930 μmol g
−1 h−1 (7.1 times higher than that of a single CN). The characterization of the catalyst confirmed that the boosted photocatalytic activity originated from the improved specific surface area from 46 to 61 m2 g−1 , broadened visible light harvesting from 470 nm to over 600 nm, more negative conduction band (shift up of 0.54 eV), and promoted charge behavior (improved exciton dissociation and carrier migration efficiency, as well as suppressed carrier recombination capacity). The stable and efficient photocatalytic hydrogen evolution performance verifies the feasibility and potential of this photocatalyst in clean energy production. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
42. Electrocatalytic hydrogen evolution mediated by an organotelluroxane macrocycle stabilized through secondary interactions.
- Author
-
Narsimhulu, Gujju, Samuel, Calvin, Palani, Sathishkumar, Dasari, Sai Hemant Kumar, Krishnamoorthy, Kothandam, and Baskar, Viswanathan
- Subjects
HYDROGEN evolution reactions ,SILVER salts ,TELLURIUM compounds ,BISMUTH telluride ,STRUCTURAL stability ,HYDROGEN ,SULFONIC acids - Abstract
A discrete liphophilic organotelluroxane macrocycle has been found to catalyse the hydrogen evolution reaction (HER) by proton reduction efficiently. The macrocycle is synthesized via chloride abstraction from bis(p-methoxyphenyl) tellurium dichloride (p-MeOC
6 H5 )2 TeCl2 (1) by silver salts AgMX4 (MX4 = BF4 − , and ClO4 − ) resulting in in situ generated di-cationic tetraorganoditelluroxane units; two such units are held together by two weak anions μ2 -MX4 , bridging to form 12-membered di-cationic macrocycles [((p-MeO-C6 H4 )2 Te)2 (μ-O)(μ2 -F2 BF2 )2 ]2+ (2) and [((p-MeO-C6 H4 )2 Te)2 (μ-O)(μ2 -O2 ClO2 )2 ]2+ (3) stabilized via Te–(μ2 -BF4 /ClO4 ), with secondary interactions. The charge is balanced by the presence of two more anions, one above and another below the plane of the macrocycle. Similar reaction at higher temperatures leads to the formation of telluronium salts R3 TeX [X = BF4 − (4), ClO4 − (5)] as a major product. The BF4 − anion containing macrocycle and telluronium salt were monitored using19 F NMR. HRMS confirmed the structural stability of all the compounds in the solution state. The organotelluroxane macrocycle 2 has been found to act as an efficient electrocatalyst for proton reduction in an organic medium in the presence of p-toluene sulfonic acid as a protic source. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
43. Upgrading polyethylene terephthalate plastic into commodity chemicals paired with hydrogen evolution over a partially oxidized CuIn5S8 nanosheet photocatalyst.
- Author
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Du, Mengmeng, Xing, Mengyuan, Yuan, Wenfang, Zhang, Liang, Sun, Tao, Sheng, Tian, Zhou, Chunyu, and Qiu, Bocheng
- Subjects
POLYETHYLENE terephthalate ,HYDROGEN evolution reactions ,ARTIFICIAL photosynthesis ,WASTE management ,HYDROGEN ,PLASTICS ,HYDROGEN as fuel - Abstract
The improper disposal of plastic waste raises significant concerns due to its severe threat to ecosystems and public health. Artificial photosynthesis, compared with the conventional strategies (e.g., pyrolysis) operated under harsh conditions, has emerged as a green and sustainable approach to convert plastic waste into commodity chemicals under ambient conditions. In this study, we have developed a partially oxidized CuIn
5 S8 nanosheet photocatalyst (O-CuIn5 S8 ) to promote the conversion of polyethylene terephthalate (PET) waste into value-added chemicals while producing hydrogen fuel. After oxygen incorporation, the as-obtained O-CuIn5 S8 catalyst demonstrates significantly improved activity, with a hydrogen evolution rate of 2.57 ± 0.02 mmol g−1 h−1 , which is 7 times higher than that of the pristine CuIn5 S8 . Furthermore, O-CuIn5 S8 allows an effective transformation of pretreated PET into a range of valuable commodity chemicals, including formate, acetate, and glycolate, via a hole-induced oxidation mechanism. This work paves the way for the rational development of photocatalysts to manage plastic pollution and meanwhile reclaim the carbon source within PET plastic waste. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
44. Electrochemical-induced solvent-tuned selective transfer hydrogenation of imidazopyridines with carbazates as hydrogen donors.
- Author
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Tang, Zhicong, Hong, Gang, Chen, Jian, Huang, Ting, Zhou, Zichao, and Wang, Limin
- Subjects
TRANSFER hydrogenation ,IMIDAZOPYRIDINES ,TRANSITION metal catalysts ,HYDROGEN ,CYCLIC voltammetry ,ELECTROSYNTHESIS - Abstract
A solvent-tuned electrochemical protocol for the selective transfer hydrogenation of imidazopyridines using carbazates as hydrogen donors has been developed. This electrosynthesis strategy provides a more sustainable and greener way to access partially saturated N-heterocycles by avoiding traditionally employed transition metal catalysts and high-pressure hydrogen. Remarkably, the method is scalable and applicable to late-stage functionalization of complex molecules. A possible mechanism has been proposed on the basis of radical-trapping and cyclic voltammetry experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
45. Insight into forced hydrogen re-arrangement and altered reaction pathways in a protocol for CO2 catalytic processing of oleic acid into C8–C15 alkanes.
- Author
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Xing, Shiyou, Lv, Pengmei, Yuan, Haoran, Yang, Lingmei, Wang, Zhongming, Yuan, Zhenhong, and Chen, Yong
- Subjects
HYDROGEN ,CARBON monoxide ,OLEIC acid - Abstract
A new vision of using carbon dioxide (CO
2 ) catalytic processing of oleic acid into C8 –C15 alkanes over a nano-nickel/zeolite catalyst is reported in this paper. The inherent and essential reasons which make this achievable are clearly resolved by using totally new catalytic reaction pathways of oleic acid transformation in a CO2 atmosphere. The yield of C8 –C15 ingredients reaches 73.10 mol% in a CO2 atmosphere, which is much higher than the 49.67 mol% yield obtained in a hydrogen (H2 ) atmosphere. In the absence of an external H2 source, products which are similar to aviation fuel are generated where aromatization of propene (C3 H6 ) oxidative dehydrogenation (ODH) involving CO2 and propane (C3 H8 ) and hydrogen transfer reactions are found to account for hydrogen liberation in oleic acid and achieve its re-arrangement in the final alkane products. The reaction pathway in the CO2 atmosphere is significantly different from that in the H2 atmosphere, as shown by the presence of 8-heptadecene, γ-stearolactone, and 3-heptadecene as reaction intermediates, as well as a CO formation pathway. Because of the highly dispersed Ni metal center on the zeolite support, H2 spillover is observed in the H2 atmosphere, which inhibits the production of short-chain alkanes and reveals the inherent disadvantage of using H2 . The CO2 processing of oleic acid described in this paper will significantly contribute to future CO2 utilization chemistry and provide an economical and promising approach for the production of sustainable alkane products which are similar to aviation fuel. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
46. Facile synthesis of hierarchical CdS nanoflowers for efficient piezocatalytic hydrogen evolution.
- Author
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Lu, Xiaoxiao, Shan, Tao, Deng, Lixun, Li, Mengqing, Pan, Xiaoyang, Yang, Xuhui, Zhao, Xiaojing, and Yang, Min-Quan
- Subjects
HYDROGEN evolution reactions ,INTERSTITIAL hydrogen generation ,CLEAN energy ,MECHANICAL energy ,HYDROGEN production ,HYDROGEN - Abstract
Piezocatalytic hydrogen evolution has emerged as a promising field for the collection and utilization of mechanical energy, as well as for generating sustainable energy throughout the day. Hexagonal CdS, an established semiconductor photocatalyst, has been widely investigated for its ability to split water into H
2 . However, its piezocatalytic performance has received less attention, and the relationship between its structure and piezocatalytic activity remains unclear. In this study, we prepared 3D ultrathin CdS nanoflowers with high voltage electrical response and low impedance. In pure water, without the use of any cocatalyst, CdS exhibited a piezoelectric catalytic hydrogen production rate of 1.46 mmol h−1 g−1 , which was three times higher than that of CdS nanospheres (0.46 mmol h−1 g−1 ). Furthermore, the value-added oxidation product H2 O2 was produced during the process of piezoelectric catalysis. These findings provide new insights for the design of high-efficiency piezoelectric catalytic hydrogen production. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
47. Facile construction of a sulfur vacancy defect-decorated CoSx@In2S3 core/shell heterojunction for efficient visible-light-driven photocatalytic hydrogen evolution.
- Author
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Zhang, Jian, Zhao, Weixian, Qian, Canhui, Cui, Yan, Li, Yonghua, Chen, Wei, Li, Jin, Huang, Huajie, Li, Xing'ao, and Zhu, Xinbao
- Subjects
HYDROGEN evolution reactions ,HETEROJUNCTIONS ,SULFUR ,HYDROGEN ,DENSITY functional theory ,HYDROGEN production ,PHOTOCATHODES - Abstract
Photoinduced electron-separation and -transport processes are two independent crucial factors for determining the efficiency of photocatalytic hydrogen production. Herein, a sulfur vacancy defect-decorated CoS
x @In2 S3 (CoSx @VS -In2 S3 ) core/shell heterojunction photocatalyst was synthesized via an in situ sulfidation method followed by a liquid-phase corrosion process. Photocatalytic hydrogen evolution experiments showed that the CoSx @VS -In2 S3 nanohybrids delivered an attractive photocatalytic activity of 4.136 mmol h−1 g−1 under visible-light irradiation, which was 8.23 times higher than that of the pristine In2 S3 samples. As expected, VS could enhance the charge-separation efficiency of In2 S3 through rearranging the electrons of the In2 S3 basal plane, in addition to improving the electron-transfer efficiency, as visually verified by transient absorption spectroscopy. Mechanism studies based on density functional theory calculations confirmed that the In atoms adjacent to VS played a key role in the translation, rotation, and transformation of electrons for water reduction. This scalable strategy focused on defect engineering paves a new avenue for the design and assembly of 2D core/shell heterostructures for efficient and robust water-splitting photocatalysts. [ABSTRACT FROM AUTHOR]- Published
- 2023
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48. 3D nanorod-like Mn0.2Cd0.8S modified by amorphous NiCo2S4 was used for high efficiency photocatalytic hydrogen evolution.
- Author
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Shang, Yan, Xu, Jing, Ma, Yue, Li, Zezhong, and Li, Qian
- Subjects
HYDROGEN evolution reactions ,HYDROGEN production ,SCHOTTKY barrier ,HYDROGEN ,PHOTOCATALYSTS ,ELECTRON transport - Abstract
The Mn
0.2 Cd0.8 S/NiCo2 S4 was prepared using an electrostatic self-assembly method. It was confirmed by analyses of the crystal structure, morphology, and elemental composition. The photoelectrochemical measurement confirmed that Mn0.2 Cd0.8 S and NiCo2 S4 had a close interaction and can form a Schottky barrier. The construction of the Schottky junction speeded up the transport of the photogenerated electrons and inhibited the recombination of the photogenerated electrons and holes. Using Mn0.2 Cd0.8 S/NiCo2 S4 , the amount of hydrogen production was higher than with NiCo2 S4 and Mn0.2 Cd0.8 S alone. Different amounts of NiCo2 S4 were loaded onto Mn0.2 Cd0.8 S for the photocatalytic hydrogen production reaction. The hydrogen photocatalytic hydrogen production of Mn0.2 Cd0.8 S/NiCo2 S4 -3 was 28.97 times higher than of the Mn0.2 Cd0.8 S. The Mn0.2 Cd0.8 S/NiCo2 S4 composite exhibited excellent photocatalytic activity and stability, which provided reference values for exploring bimetallic sulfide composite materials, and demonstrated great potential in photocatalytic applications. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
49. Nitrogen doped CoP on ammoniated black phosphorus nanosheets enabling highly efficient hydrogen evolution electrocatalysis.
- Author
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Fang, Liang, Xie, Yanping, Xu, Feiya, Wang, Miao, and Wang, Gang
- Subjects
HYDROGEN evolution reactions ,OXYGEN evolution reactions ,ELECTROCATALYSIS ,NANOSTRUCTURED materials ,HYDROGEN as fuel ,ELECTRON mobility ,PHOSPHORUS ,HYDROGEN - Abstract
Developing a rational and cost-effective approach for designing highly-efficient and sustainable electrocatalysts is essential for clean and renewable hydrogen energy. Herein, we report nitrogen-doped CoP on two-dimensional ammoniated black phosphorus (BP) nanosheets (N-CoP/NH
2 -BP) as novel and highly-active heterostructure electrocatalysts for the hydrogen evolution reaction (HER). Using the reactive defects on the BP nanosheets as the original sites under NH3 gas, N-doped CoP nanocrystals were grown on the surface of the BP nanosheets that were functionalized with NH2 groups at their edge. The N-CoP/NH2 -BP heterostructure exhibits low overpotentials of 90 and 246 mV at 10 and 200 mA cm−2 , respectively, in an alkaline electrolyte. The excellent HER activity should be attributed to the synergistic effect between N-doped CoP and NH2 -functionalized BP, in which NH2 -BP, with its high electron mobility and hydrophilicity, accelerates the charge transfer and offers more active sites, moreover, N-doped CoP modulates the electronic structure of CoP for enhanced HER activity. This work not only provides a novel and effective electrocatalyst, but also opens up a straightforward strategy for the design of phosphorene-based electrocatalysts for highly efficient hydrogen evolution and beyond. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
50. A synergistic heterogeneous interface of a NC-Co-MoS2/CC-450 electrocatalyst for efficient alkaline hydrogen evolution.
- Author
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Zhang, Kaiqi, Wu, Hequn, Xiong, Guanghui, and Yao, Weifeng
- Subjects
HYDROGEN evolution reactions ,CARBON fibers ,HYDROGEN ,DOPING agents (Chemistry) ,HYDROGEN production ,CRYSTAL defects - Abstract
Rational construction of low-cost, high-activity electrocatalysts is essential for hydrogen production from electrolytic water. Herein, a Co
0.75 Mo3 S3.75 /MoS2 heterogeneous interfacial structure and nitrogen and carbon co-doped on a carbon cloth hydrogen evolution electrocatalyst (NC-Co-MoS2 /CC-450) was synthesized by a simple drop coating and pyrolysis method. NC-Co-MoS2 /CC-450 exhibits excellent hydrogen evolution performance, achieving a current density of 10 mA cm−2 at only 56 mV, while exhibiting a Faraday efficiency of 99.85% and good stability. Moreover, at high current densities (100 mA cm−2 and 200 mA cm−2 ), only 155 mV and 220 mV overpotentials are required, respectively, with a small Tafel slope (69.2 mV dec−1 ). This is due to the intrinsic nitrogen and carbon doped multiphase composite Co0.75 Mo3 S3.75 /MoS2 heterogeneous interface synergistic crystalline-amorphous material system, which generates a large number of lattice defects and exposes a richer active area, accelerating the efficiency of hydrogen evolution and hydrogen desorption. The hydrogen evolution performance of NC-Co-MoS2 /CC-450 prepared by the rational design is significantly better than that of many previously reported molybdenum-based catalysts, and this work suggests a further way to continue the development of low-cost and efficient alkaline hydrogen evolution electrocatalysts. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
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