12 results
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2. 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
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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-(SCH3)2/ZnIn2S4 (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
- Full Text
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3. 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, NiCo2S4 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 NiCo2S4@WS2 core–shell composite photocatalyst improved the easy recombination of carriers caused by the narrow band gap of NiCo2S4 and WS2, and improved the photocatalytic hydrogen production performance. The loading ratio of NiCo2S4@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 NiCo2S4 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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4. Recent advances in cobalt-based catalysts for efficient electrochemical hydrogen evolution: a review.
- Author
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Sun, Ran, Huang, Xing, Jiang, Jibo, Xu, Wenxiu, Zhou, Shaobo, Wei, Ying, Li, Mingjing, Chen, Yukai, and Han, Sheng
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HYDROGEN evolution reactions , *COBALT phosphide , *CATALYSTS , *CATALYTIC activity , *DENSITY functional theory , *HYDROGEN , *STRUCTURAL engineers - Abstract
Hydrogen (H2) 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
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- View/download PDF
5. 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
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PRECIPITATION (Chemistry) , *HYDROGEN production , *HYDROGEN , *PRECIOUS metals , *HYDROGEN evolution reactions , *OVERPOTENTIAL - Abstract
In this paper, we present a MoP/P–Mn0.5Cd0.5S 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 Mn0.5Cd0.5S (383.19 μmol g−1 h−1), and its hydrogen production performance was better than that of Pt/Mn0.5Cd0.5S (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 Mn0.5Cd0.5S (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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6. 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
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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 H2 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
- Full Text
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7. 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
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HYDROGEN evolution reactions , *INTERSTITIAL hydrogen generation , *CHARGE transfer , *HYDROGEN , *HYDROGEN production , *PEROVSKITE , *CHARGE carriers - Abstract
Metal halide perovskites, such as iodine methylamine lead (MAPbI3), 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
- Full Text
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8. 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
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HYDROGEN , *CARBON monoxide , *OLEIC acid - Abstract
A new vision of using carbon dioxide (CO2) 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 (C3H6) oxidative dehydrogenation (ODH) involving CO2 and propane (C3H8) 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
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9. Direct conversion of methanol to n-C4H10 and H2 in a dielectric barrier discharge reactor.
- Author
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Wang, L., Liu, S. Y., Xu, C., and Tu, X.
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METHANOL , *BIOMASS conversion , *BUTANE , *HYDROGEN , *DIELECTRICS , *THERMAL plasmas , *PLASMA materials processing - Abstract
Methanol is an important H-carrier and C1 chemical feedstock. In this paper, a direct conversion of methanol to n-C4H10 and H2 was achieved for the first time in a dielectric barrier discharge (DBD) non-thermal plasma reactor. The selective formation of n-C4H10 by limiting COx (x = 1 and 2) generation was obtained by optimizing different plasma processing parameters including the methanol inlet concentration, discharge power, and pre-heating temperature. The results showed that a higher methanol inlet concentration and a higher pre-heating temperature favors the formation of n-C4H10, while a higher methanol inlet concentration and a lower discharge power can effectively limit the formation of CO. The optimal selectivity for n-C4H10 (37.5%), H2 (28.9%) and CO (14%) was achieved, with a methanol conversion of 40.0%, at a methanol inlet concentration of 18 mol%, a discharge power of 30 W and a pre-heating temperature of 140 °C using N2 as a carrier gas. Value-added liquid chemicals (e.g., alcohols, acids, and heavy hydrocarbons) were also obtained from this reaction. Emission spectroscopy diagnostics reveals the formation of various reactive species (e.g., CH, C2, CN, H and metastable N2) in the CH3OH/N2 DBD. Possible reaction pathways for the formation of n-C4H10 were proposed and discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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10. Hydrogen-mediated affinity of ions found in compressed potassium amidoborane, K[NH2BH3].
- Author
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Magos-Palasyuk, Ewelina, Palasyuk, Taras, Zaleski-Ejgierd, Patryk, and Fijalkowski, Karol
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POTASSIUM , *HYDROGEN , *X-ray diffraction , *HYDROGEN storage , *RAMAN spectroscopy - Abstract
The paper reports on the experimental and theoretical investigation of bonding properties of potassium amidoborane, (K[NH2BH3]), which is one of the most promising compounds for hydrogen storage material among metallated derivatives of ammonia borane (NH3BH3). For this purpose, in situ Raman spectroscopy, synchrotron X-ray diffraction measurements and complementary ab initio calculations study have been performed under static pressure conditions in the range from ambient pressure up to 25 GPa. Unusual interplay between strong electrostatic and weak dispersive interactions has been revealed, resulting in experimental observation of pressure induced formation of relatively strong conventional hydrogen bonding between negatively charged molecular ions. This finding provides new insight for tailoring materials with desirable properties for various uses. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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11. Lamellar NiMoCo@CuS enabling electrocatalytic activity and stability for hydrogen evolution.
- Author
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He, Weidong, Wei, Wei, Wen, Bin, Chen, Dongyi, Zhang, Jiancong, Jiang, Yue, Dong, Guanping, Meng, Yuying, Zhou, Guofu, Liu, Jun-Ming, Kempa, Krzysztof, and Gao, Jinwei
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ELECTROCATALYSTS , *HYDROGEN evolution reactions , *HYDROGEN , *BIOLOGICAL evolution , *CATALYSTS - Abstract
We demonstrate a lamellar NiMoCo@CuS catalyst, showing not only an excellent catalyst performance (η100@72 mV and a Tafel slope of 47 mV dec−1), but also a good stability (20 mA cm−2@30 hours), outperforming the NiMo system and noble Pt. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
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12. Correction: Mo-Doped/Ni-supported ZnIn2S4-wrapped NiMoO4 S-scheme heterojunction photocatalytic reforming of lignin into hydrogen.
- Author
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Su, Hang, Rao, Cheng, Zhou, Lan, Pang, Yuxia, Lou, Hongming, Yang, Dongjie, and Qiu, Xueqing
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HETEROJUNCTIONS , *HYDROGEN , *REFORMS , *STEAM reforming , *LIGNINS , *SILVER - Abstract
Correction for 'Mo-Doped/Ni-supported ZnIn2S4-wrapped NiMoO4 S-scheme heterojunction photocatalytic reforming of lignin into hydrogen' by Hang Su et al., Green Chem., 2022, DOI: 10.1039/d1gc04397h. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
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