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As one of the effective methods for hydrogen production, water electrolysis has been widely studied. However, the high overpotential challenge faced by the anode and the limitation of the electron transfer rate in this process significantly inhibit the efficiency of hydrogen production, which has become the main obstacle to overcome in the current research. The use of thermodynamically more favorable organic compounds to oxidize at the anode instead of traditional water oxidation (OER) is an effective strategy to optimize the process of electrolytic hydrogen production. In this paper, Ni3S2 catalysts co-doped with non-noble metals Li and Mn were prepared on nickel foam and used for the glycerol oxidation reaction (GOR) coupled with the hydrogen evolution reaction (HER). In alkaline solution, Li, Mn–Ni3S2@NF exhibits good GOR and HER performance. Specifically, overpotentials of 1.58 V vs. RHE and 0.54 V vs. RHE are required to reach a current density of 200 mA cm−2, respectively, and the catalytic performance of the material remains good after a long-term test. Li, Mn–Ni3S2@NF as a bifunctional catalytic material oxidizes glycerol to formate, and its faradaic efficiency (FE) is as high as 91%, and the volume of hydrogen production is close to the theoretical value. In addition, the replacement of the OER by the GOR can reduce the energy consumption by about 17.44%. [ABSTRACT FROM AUTHOR]

In this paper, a NiAl-LDH with the characteristic structure of a hydrotalc-like compound was applied as a carrier in a two-step hydrothermal process, and a MnCdS/In2S3/NiAl-LDH composite material was successfully prepared by loading MnCdS and In2S3 on the flower spherical-like surface of NiAl-LDH. The combination of NiAl-LDH with In2S3 and MnCdS made the band gap smaller and the light absorption range larger, thus increasing the utilization rate of light. 50% MnCdS/In2S3/NiAl-LDH composites had the best photoinduced charge separation and highest surface enrichment of photogenerated electrons. In the degradation experiment of crystal violet (CV), 50% MnCdS/In2S3/NiAl-LDH composites showed superior photocatalytic degradation efficiency (>98.5%) under full spectrum light. Furthermore, the applicability and universality of photocatalysts were studied by observing the degradation of CV by MnCdS/In2S3/NiAl-LDH composites under different conditions. In addition, the composites showed excellent hydrogen production capacity in the photolysis of water, in which hydrogen production within 8 hours was about 7661.51 μmol g−1. By combining the results of active species capture experiments, density functional theory (DFT) calculations and photoelectrochemical experiments, the possible mechanism of double S-scheme heterojunction photocatalysis among NiAl-LDH, In2S3 and MnCdS was inferred, which is one of the main reasons for the enhancement of photocatalytic activity. [ABSTRACT FROM AUTHOR]

In this paper, ultrathin layers of carbon nitride were obtained by dissolving urea in different amounts of water and used as a carrier to prepare catalysts for formic acid dehydrogenation. The catalytic activity of the carbon nitride supported Pd catalyst in formic acid dehydrogenation was investigated. The ratio of urea to water played a key role in the type and content of nitrogen-containing functional groups, and then enhanced the catalytic performance by regulating the electronic properties of Pd. The Pd/CN-U1W5 catalyst exhibited excellent catalytic activity for the production of hydrogen from formic acid with an initial TOF of 1058 h−1 at 348 K. It was found that the high catalytic performance of the catalyst could be attributed to the strong interaction between Pd nanoparticles and pyridinic N, small Pd nanoparticle size and highly dispersed Pd nanoparticles. [ABSTRACT FROM AUTHOR]

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]

ZIF-67 has garnered much attention in the field of photocatalytic water splitting due to the advantages of MOFs and zeolite sieves. However, post-modification and composite strategies have emerged as effective approaches to enhance its photocatalytic performance, particularly in enabling bi-functionality for oxidation-coupled reduction reactions. In this study, 2-mercaptobenzimidazole (MBI) modified ZIF-67 and cadmium sulfide (CdS) composites were prepared to investigate their application in photocatalytic oxidation-coupled hydrogen evolution reactions. The results demonstrated an enhancement in hydrogen production performance over CdS@ZIF-67-MBI, with an increase from 2.39 mmol g−1 h−1 to 4.49 mmol g−1 h−1 upon the introduction of MBI. Moreover, the conversion efficiency of benzyl alcohol reached an improved value of 58.5%. The study findings revealed that the heterogeneous coupling between ZIF-67 and CdS, along with the effective charge transfer facilitated by the anion S, played a decisive role in promoting charge–hole separation of composite materials and improving carrier transport efficiency. This demonstrates the viability of utilizing ZIF-67 in a bifunctional photocatalytic reaction system, thereby paving the way for broader applications of ZIF-67. [ABSTRACT FROM AUTHOR]

Designing cost-effective catalysts with high activity and stability for the oxygen evolution reaction (OER) is important to scale-up the water electrolysis process for hydrogen production. Herein, (FeNiCuCoZn)90−xVxP10 (x = 10, 15, and 20, denoted as V10, V15, and V20) high entropy alloys (HEAs) with well-integrated amorphous phase and Fe2P crystalline phase heterostructures were successfully synthesized by a facile ball milling method. The designed composite exhibits very small charge transfer resistance and high active area, enabling rapid charge/mass transport and sufficient access to catalytic sites. Consequently, it only requires an ultra-low overpotential of 228 mV at a current density of 10 mA cm−2 and a small Tafel slope of 23.6 mV dec−1 in an alkaline environment, outperforming other amorphous contrast samples and commercial RuO2. The excellent activity and high durability make the reconstructed V20-HEA a promising candidate for catalyzing the OER process. This work brings fresh insights into heterogeneous interface engineering for advanced electrocatalyst designing. [ABSTRACT FROM AUTHOR]

Active and stable electrocatalysts based on earth-abundant elements for the acidic oxygen evolution reaction (OER) are crucial for hydrogen production using proton-exchange membrane water electrolyzers. Herein, nickel-doped manganese oxide nanorods (Ni–MnO2) are prepared using a hydrothermal method in an acidic environment. The nanorods exhibit moderate stability towards the OER in 0.1 M HClO4. Doping Ni enhances OER activity, which originates from the electronic interaction that tunes the adsorption energy of OH*, which is an important OER intermediate. The most active electrode exhibits an overpotential of 390 mV to reach 10 mA cm−2 OER current density in 0.1 M HClO4. All electrodes prepared are stable towards 10 mA cm−2 galvanostatic test for at least 5 h. The dissolution of Ni and Mn species is observed, and the crystalline phase transforms to the amorphous phase under prolonged OER. [ABSTRACT FROM AUTHOR]

So far, the study of efficient and durable photocatalysts for hydrogen production from water splitting has remained a paramount avenue for mitigating the ongoing energy crisis and environmental pollution. Nevertheless, CdS nanoparticles, which are one of the most popular photocatalysts for research, still have problems such as easy agglomeration and low separation efficiency of photogenerated carriers. Herein, a low-temperature heat treatment strategy assisted by NaCl–KCl mixed molten salts was employed to synthesize a superior CdS photocatalyst for hydrogen production. During the heating process under only 500 °C, the complex molten salts existed in a "semi-liquid solution" state due to their Tammann temperature, which helped to not only improve the crystallinity and inhibit the oxidation of CdS, but also introduce Cl dopants and S vacancies into CdS. It has been experimentally and theoretically evidenced that the defects in CdS facilitated the phase transition of CdS from a cubic to a more stable hexagonal structure, and also provided increased carrier density as well as more active sites for CdS. As a result, the modified CdS exhibited a 40 times boosted photocatalytic hydrogen evolution rate up to 4.33 mmol h−1 g−1 with an apparent quantum efficiency of 5.8% at 420 nm without a co-catalyst. This work highlighted the critical role of complex chloride molten salts in obtaining high-quality semiconductor photocatalysts during the calcination process. [ABSTRACT FROM AUTHOR]

The synthesis of noble metal/TiO2 composites without the use of additional reducing agents or surfactants is a notable achievement in catalyst preparation, as it simplifies the process and reduces potential impurities. A detailed analysis of catalysts using a range of methods like XRD, TEM, XPS, BET, and FT-IR offers a comprehensive insight into their structural and surface characteristics, essential for understanding their catalytic performance. The observation of enhanced catalytic activity with Pt-loaded composite catalysts compared to Pd and Au-loaded counterparts highlights the importance of noble metal selection in catalytic applications. Through BET and TEM characterization, it can be observed that there is no significant difference between the specific surface area of all noble metal/TiO2 composites and the size of the noble metal, which ranges from 2–7 nm. The correlation between the catalytic efficiency and the metal work function, along with the insights from XPS analysis, underscores the significance of the metal–titanium dioxide interaction in determining catalytic efficiency. This interaction may involve tuning the surface's electronic structure, the chemical bonding between the metal and the carrier, and the formation of surface active sites. These sites can adsorb reactants and facilitate the reaction, thus improving the catalytic activity and selectivity. This study provides an in-depth understanding and an important reference for the design and optimization of catalysts for hydrogen production from formic acid, which can help promote progress and applications in related fields. [ABSTRACT FROM AUTHOR]

Overall urea–water electrolysis has the potential to be employed in the purification of urea-containing wastewater and the production of hydrogen. However, the lack of cost-effective catalysts currently presents a significant obstacle to the further development of this technology. Through a simple template-directed selenium reaction in a novel type of highly active solution, an interface engineering strategy was designed to synthesize hollow CuSe nanocubes as an efficient bifunctional catalyst. The unique hollow CuSe nanocubes exhibit significant catalytic efficiency because of their larger electrolyte contact area and faster ion transport. In 1 M KOH with a 0.5 M urea electrolyte, CuSe/NF required an overpotential of 199 mV for HER and a potential of 1.38 V for UOR to achieve a current density of 10 mA cm−2. It can work stably for 24 h without significant degradation of activity at 10 mA cm−2, showing excellent durability and excellent stability. For overall urea–water electrolysis, it exhibits a remarkable activity with a low cell voltage of 1.61 V at 10 mA cm−2. Consequently, the design strategy of this unique hollow-structured CuSe provides a new insight to improve electrocatalytic performance and stability. [ABSTRACT FROM AUTHOR]

Low efficiency of photogenerated electron–hole separation has been a challenge for organic conjugated polymer photocatalysts. Our preceding studies have revealed that polymers containing B←N coordination bonds can form a localized built-in electric field that effectively promotes photogenerated charge separation. However, B←N coordination units are still scarce and require more examples to find regularities in their structural design. The systematic development and testing of B←N coordination units is necessary for the efficient development of subsequent polymers containing B←N coordination bonds. In this work, three conjugated polymers containing B←N coordination bonds, PBN–Ni, PBP–Ni, and PBS–Ni, were synthesized by changing the substituents of the boron atoms and introducing narrow-band thiophene units to form conjugate and energy band gradients. The energy band modulation and localized built-in electric field construction were both achieved as planned, while the bandgap and photogenerated charge transport capabilities caused performance discrepancies. The experimental results showed that PBN–Ni had a better photocatalytic hydrogen evolution (HER) performance, reaching 104.6 μmol h−1 (λ > 420 nm). The optimal optical absorption edge of PBS–Ni was up to 643 nm, but the HER was lower, at 33.2 μmol h−1 (λ > 420 nm, 1% Pt). PBP–Ni optimized some of the optical absorption efficiencies (511 nm) while ensuring the HER activity (96.6 μmol h−1, λ > 420 nm). This work tentatively explores the characterization of the B←N coordination bond-containing base units serving as photocatalysts and provides the basic model experience and data reference for the subsequent expansion of B←N coordination bond-containing units and the development of B←N coordination bond-containing copolymer systems. [ABSTRACT FROM AUTHOR]

This report addresses the synthesis, characterisation, and photoelectrochemical performances of α-Fe2O3 nanorods decorated with g-C3N4. Photoanode composites were fabricated in a two-step procedure in which fluorine-doped tin oxide (FTO) glass was coated with α-Fe2O3 nanorods via a hydrothermal method, followed by incorporation of g-C3N4via a wet-impregnation method. In particular, the study investigates the effects of precursors of g-C3N4 (urea, dicyandiamide, and melamine) on the photoelectrochemical properties of the prepared α-Fe2O3/g-C3N4 films. The films were thoroughly analysed by means of X-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area analysis, Fourier transform infrared (FTIR) spectroscopy, and UV-vis spectrometry. The highest photoelectrochemical output of the nanorod composite films was achieved with the use of g-C3N4 synthesized from urea, generating 15.3 μA cm−2 of photocurrent density as a result of better charge transfer driven by the formation of a semiconductor heterojunction. This is a staggering 12-fold improvement compared to the unmodified hematite nanorods which managed to only produce 1.2 μA cm−2 of photocurrent density. The merits of g-C3N4 prepared from urea as the best semiconductor couple for α-Fe2O3 are driven by its unique crystallinity and morphology with significantly larger surface area than g-C3N4 prepared from other precursors. The addition of glycerol as a sacrificial agent further improves the photocurrent to ca. 24 μA cm−2. The findings in this study show the potential of α-Fe2O3/g-C3N4 composites for sustainable photoelectrochemical hydrogen production. [ABSTRACT FROM AUTHOR]

In this work, CoV-LDH/ZnIn2S4 (CoV-LDH/ZIS) nanocomposites were synthesized through a self-assembly process in order to investigate the influence of CoV-LDH addition on the rate of hydrogen production. XRD and TEM measurements confirmed the effective preparation of CoV-LDH/ZIS nanocomposites. Among all the nanocomposite photocatalysts, 2.0%-CoV-LDH/ZIS showed the best photocatalytic performance with a hydrogen production rate of 1397.3 μmol g−1 h−1, approximately 2.2 times that of pure ZnIn2S4 (ZIS). The X-ray photoelectron spectroscopy (XPS) measurement indicated that there is a strong interfacial interaction between ZIS and CoV-LDH, indicating that more than simple mechanical mixing had occurred. The steady-state fluorescence spectroscopy (PL) and time-resolved photoluminescence (TRPL) spectroscopy results showed that the electron and hole recombination in CoV-LDH/ZIS is significantly reduced and that efficient interface charge transfer and separation are achieved. This work sheds light on the interfacial electron transfer between two semiconductor materials, which promotes the separation of photogenerated carriers and thus enhances photocatalytic hydrogen production activity. [ABSTRACT FROM AUTHOR]

Electrocatalysts for hydrogen production play a crucial role in advancing the green economy. However, the sluggish kinetics of the hydrogen evolution reaction (HER) limited its application. Therefore, efficient strategies with a tailored d-band center adjustment are highly desirable. In this study, we synthesized N, P-doped carbon matrix-confined Mo-doped FeP nanoparticles using a simple strategy to optimize the catalyst's d-band center. Mo-FeP@NPC presents an excellent HER performance of 63 mV (H2SO4) and 116 mV (KOH) at −10 mA cm−2 in acid and alkaline electrolytes, separately. Theoretical calculations confirm that the outstanding HER performance originates from the strong electronic coupling between atoms, thus upshifting the d-band center and increasing H intermediate adsorption on the active sites. Furthermore, the N, P-doped carbon matrix protects the Mo-doped FeP nanoparticles from aggregation, exposing more active sites during hydrogen production. This work provides new avenues for applying highly efficient metal phosphide catalysts for the HER. [ABSTRACT FROM AUTHOR]

Finding efficient photocatalysts is the key to achieving sustainable hydrogen production. In this work, a rational design of Cd2+-doped Zn3In2S6 (ZIS) and a heterojunction structure with g-C3N4 (GCN) was carried out to form a GCN/Cd/ZIS composite. The synergistic effect of Cd2+ doping and heterojunction construction in the photocatalytic hydrogen production process was probed. The results showed that doping Cd2+ modified the bandgap structure of ZIS and improved the photocatalytic activity. The heterojunction construction between Cd/ZIS and GCN also effectively promoted the separation and migration of photogenerated carriers, which significantly improved the hydrogen production performance of the GCN/Cd/ZIS composite. The hydrogen production rate of 15% Cd/ZIS and 5% GCN/Cd/ZIS was 2.45 mmol g−1 h−1, 3.34 mmol g−1 h−1, which was 4.3 and 5.9 times higher than that of ZIS (0.57 mmol g−1 h−1), respectively. This study provides strong evidence that doping and heterojunction construction can synergistically improve photocatalytic activity. [ABSTRACT FROM AUTHOR]

Electro-catalytic water splitting is widely viewed as an efficient and viable strategy for green hydrogen production. Herein, we designed nanostructured nickel–cobalt alloy grown on the reduced graphene oxide-single walled carbon nanotube (rGO-SWCNT) thin film by means of electro-deposition, which was used to catalyze water splitting for hydrogen evolution reaction (HER) in an alkaline medium. It was found that the HER performance of nickel–cobalt alloys was determined by the Co/Ni ratio and better than their corresponding single components Co and Ni. Nickel–cobalt alloy with a Co/Ni ratio of 2 (CoNi21) exhibited the most notable HER efficiency with an overpotential of 83.5 mV and 291.8 mV vs. reversible hydrogen electrode at 10 mA cm−2 and 100 mA cm−2, respectively. Furthermore, the significantly lower Tafel slope (112.6 mV dec−1) of CoNi21 indicates that the HER kinetics of the nickel–cobalt alloy is accelerated due to the synergistic effect of Ni and Co. The charge-transfer resistance of CoNi21 is significantly low compared to any single component, validating the intensified interfacial charge transfer. Besides, CoNi21 has the highest active surface area of 147.1 mF cm−2 on the basis of the ECSA measurements, which can be beneficial for providing rich active sites. The CoNi21 catalyst offered excellent durability for HER in the alkaline medium. This work provides a combinatorial method integrating rich interfaces of Co–Ni alloy on highly conductive carbon substrate to design efficient and low-cost electrocatalysts for improving the HER performance. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen production has garnered considerable attention as a latent solution to various energy challenges. Because of their distinct optical characteristics, persistent luminescence nanoparticles (PLNPs) can emit light long after illumination ends, making them highly advantageous for round-the-clock photocatalysis. However, photocatalytic activity is currently restricted owing to the low specific surface area and the high number of photogenerated electron–hole pairs. In this study, PLNP (ZnGa5Si5O18)/sulfur-doped carbon nitride (SCN) was synthesized via a solvothermal method and calcination. Under irradiation with a xenon lamp, the resulting PLNPs/SCN (1 : 1) composite exhibited excellent photocatalytic hydrogen evolution activity, with a hydrogen evolution rate of 3963.80 μmol g−1 h−1, which was 15 times and 1.4 times higher than that of PLNPs (307.1 μmol g−1 h−1) and SCN (2800.80 μmol g−1 h−1), respectively. The formation of a stable type II heterojunction is responsible for the high photocatalytic activity. This heterojunction effectively suppressed the electron–hole complexation generated during photoexcitation and enhanced the carrier flexibility. In addition, the PLNPs/SCN (1 : 1) composite had a larger specific surface area than the PLNPs. The synthesis of this novel composite heterojunction under mild conditions not only provides a new strategy for preparing PLNP-based composite catalysts but also holds significant potential for enabling round-the-clock photocatalysis. [ABSTRACT FROM AUTHOR]

The unsatisfactory performance of the oxygen evolution reaction (OER) and the complex preparation methods are the main challenges hindering the industrial application of OER electrocatalysts in electrochemical water splitting for hydrogen production. Herein, a convenient two-step method including electrodeposition and subsequent chemical bath deposition was utilized to synthesize a FeOOH/Ni/NiO tri-component composite on Ti mesh (TM), during which Ni(Ac)2 and FeSO4 were used as feedstocks. XRD, Raman, XPS, SEM and TEM characterizations revealed nanosheet-assembled nanospheres composed of crystalline Ni coated by amorphous NiO, and amorphous FeOOH nanosheets successively deposited on the TM surface by electrodeposition and chemical bath deposition strategies. When serving as the OER electrocatalyst, the optimized FeOOH/Ni/NiO/TM presented a superb OER performance with an overpotential of 246 mV at 50 mA cm−2, outperforming FeOOH-5/NF (321 mV), Ni/NiO/TM (348 mV) and the recently reported electrocatalysts. Additionally, its OER performance had no obvious change with only 4.3% attenuation after working for 16 h at a constant current density. The high OER performance could be assigned to the interfacial electronic engineering due to the strong coupling effect between FeOOH and Ni/NO, which increased the intrinsic activity of the active sites, modulated the adsorption of the reactant and also enhanced the stability. The simple preparation strategy, low cost and high performance endow the self-supporting FeOOH/Ni/NiO/TM with potential applications in industrial water electrolysis for hydrogen production. [ABSTRACT FROM AUTHOR]

Developing low-cost high-efficient electrocatalysts for alkaline hydrogen evolution reaction (HER) is of critical significance in hydrogen production via alkaline electrolyzers. Herein, we prepared CeO2/Co4N heterostructure for the catalyst in alkaline HER, which introduced a synergistic effect within the CeO2 and Co4N catalytic sites that facilitates the two consecutive steps in alkaline HER reaction. More importantly, plasma treatment was further applied to the material to tune the electronic structure of the catalytic sites by creating multiple anion vacancies. The introduced O vacancies accelerated the H2O cleaving process on CeO2, while the N vacancies in Co4N optimized the H adsorption strength on the Co sites. The catalytic activity of the catalyst improved significantly after plasma treatment. It only required an overpotential of 36 mV@10 mA cm−2 for the HER operated in 1 M KOH electrolyte and provided one of the best precious metal-free catalysts ever reported. [ABSTRACT FROM AUTHOR]

The efficient production of hydrogen through water electrolysis requires stable, high-performance and rather cost-effective electrocatalysts to promote the hydrogen evolution reaction (HER). Platinum (Pt) is known to be a benchmark electrocatalyst for the HER, but its high-cost is a major obstacle for large-scale applications. Therefore, reducing Pt loading on electrodes, with a minimal influence on the electrochemical performance is of significant importance. Here, we report on the effective utilization of Pt through a simple two-step magneto-electrodeposition synthesis method, leading to the formation of uniformly dispersed Pt/NiCu electrocatalysts with an excellent catalytic activity. Under optimum conditions, NiCu substrates are fabricated under a vertical static magnetic field of 0.5 T, followed by pulsed electrodeposition of Pt under the same magnetic field. The electrocatalyst (0.5 T NiCu + 0.5 T Pt) exhibits a high stability and superior HER activity, characterized by low overpotentials of 10.6, 54.6, and 87.8 mV obtained at current densities of 10, 100, and 200 mA cm−2, respectively, accompanied by a small Tafel slope of 13.4 mV dec−1 in alkaline media (1 M KOH). This work provides a new approach enabling the optimum utilization of Pt-based electrocatalysts employed for the HER. [ABSTRACT FROM AUTHOR]

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]

Organic polymer photocatalysts are a promising material platform for photosynthetic hydrogen peroxide production from water and oxygen. However, limited by the controlled structural design and lack of effective active sites, their photocatalytic efficiency is unsatisfactory. To address these above issues, we precisely designed and prepared two alkyne-based porous polymers via the Sonogashira cross-coupling reaction (POP-DT and POP-DF). Acetylene served as the oxygen-reducing active site, tuning the thiophene or furan ring as the electron donor unit. They exhibited a large specific surface area and rich pore architecture. Under visible light irradiation, the H2O2 generation rate of POP-DT was as high as 2422.2 μmol g−1 h−1, which was 4.3 times higher than that of POP-DF, representing one of the best performances ever reported for polymeric photocatalysts. We found that the combination of acetylene and thiophene resulted in faster charge separation and transfer efficiency, significantly improving the kinetic behaviour of the oxygen reduction reaction. More importantly, combined with in situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations, we demonstrate that acetylene-connected thiophene is more beneficial to the electron enrichment of the acetylene active site, enhancing the adsorption and activation of oxygen, thus boosting the photocatalytic efficiency for the oxygen reduction reaction. Our work provides a novel strategy for designing advanced polymer photocatalysts for enhanced solar energy conversion efficiency. [ABSTRACT FROM AUTHOR]

Hydrogen, as a promising energy carrier, can be extracted from renewable biomass derived acetic acid (HAc). Ni-based catalysts supported on solid solution of Sm2−xPrxO3±δ were prepared using a coprecipitation method and evaluated in auto-thermal reforming (ATR) of HAc for hydrogen production. The results revealed that Pr species infiltrated the Sm2O3 lattice and formed a solid solution structure with oxygen vacancy defects, in which the redox process of Sm3+ + Pr3+ Sm2+ + Pr4+ enhanced oxygen mobility, facilitating gasification of the coking precursor and suppressing carbon deposition. DFT analysis also confirmed that Pr doping into the Sm2−xPrxO3±δ solid solution significantly lowered the energy barrier by 112 kJ mol−1 for formation of oxygen vacancies. Additionally, the interaction between Ni0 and Sm2−xPrxO3±δ effectively improved the dispersion of Ni0 metal particles, inhibiting sintering of Ni species. Consequently, the NSP10 catalyst (Ni0.80Sm1.72Pr0.24O3.74±δ) exhibited outstanding catalytic performance for hydrogen production: the conversion of HAc approached 100%, while the hydrogen yield remained stable at 2.75 mol-H2/mol-HAc. [ABSTRACT FROM AUTHOR]

This study developed an efficient photocatalyst for hydrogen production, consisting of CdS nanorods and the CoTPPBr4 co-catalyst. The synthesized photocatalyst was characterized using a suite of techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), photoluminescence (PL) spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). Additionally, transient photocurrent response and electrochemical impedance spectroscopy (EIS) were carried out to further probe the material's properties. Our findings demonstrate that the CoTPPBr4 co-catalyst significantly enhances the photocatalytic H2 evolution efficiency under visible light irradiation. Notably, among the tested photocatalysts, a 12.5% CoTPPBr4/CdS composite exhibited the most superior photocatalytic performance, achieving a hydrogen production rate of 41.3 mmol g−1 h−1, which is 4.1 times higher than that of pristine CdS. The introduction of CoTPPBr4 effectively facilitates charge transfer within CdS, enhances the separation efficiency of light-induced electron–hole pairs, and boosts the surface H2-evolution kinetics. This research not only introduces a promising photocatalyst for visible light-driven hydrogen production but also provides a way for the development of highly efficient and stable CdS-based hybrid semiconductor nanocomposites suitable for diverse photocatalytic applications. [ABSTRACT FROM AUTHOR]

Electricity-driven water splitting is a promising approach for cost-effective and environment-friendly hydrogen production. However, the anodic oxygen evolution reaction (OER) remains a major bottleneck for its industrial application. An alternative strategy to bypass the OER is the electrocatalytic oxidation of benzyl alcohol for promoting hydrogen production, though achieving this efficiently remains challenging. In this study, we introduce a CoV-layered double hydroxide (LDH) designed specifically for the selective oxidation of benzyl alcohol. This is achieved by incorporating high valence vanadium into Co(OH)2, a conventional OER catalyst. Due to the synergistic enhancement in electron and proton transfer processes resulting from vanadium incorporation, the CoV-LDH grown on nickel foam (CoV-LDH/NF) displays outstanding activity and selectivity for the benzyl alcohol oxidation reaction (BOR). Notably, the CoV-LDH/NF achieves current densities of 10 and 100 mA cm−2 at just 1.28 and 1.31 V (vs. RHE), respectively. Moreover, the CoV-LDH/NF demonstrates remarkable durability, showing no decrease in the electrochemical performance over ten consecutive cycles. [ABSTRACT FROM AUTHOR]

A potassium (K)-promoted Ru-based siliceous molecular sieve catalyst, K-nRu-MCM-41, was successfully synthesized via a hydrothermal method. The combined analysis of XRD, FT-IR and XPS data revealed that Ru exists in the framework of the molecular sieves as RuO2 species, leading to structural alterations. SEM and TEM images demonstrated that Ru doping disrupts the morphology of the molecular sieves, while K addition effectively preserves the original morphology and further enhances particle dispersion. The ammonia decomposition performance test indicated that K promotes the activity of the molecular sieve catalysts. At 450 °C and 12 000 mL gcat−1 h−1, K-4Ru-MCM-41 achieved 82.7% ammonia conversion and 253.6 mmol gRu−1 min−1 hydrogen production, respectively, which was a 7.6% increase in ammonia conversion compared with 4Ru-MCM-41. Furthermore, the K-4Ru-MCM-41 catalyst exhibited excellent reusability, maintaining its stable catalytic activity performance after 30 h. [ABSTRACT FROM AUTHOR]

The application of non-noble metal catalysts to photocatalytic hydrogen production from water holds a high practical application value. In this study, photocatalysts were obtained by the hydrothermal and photodeposition methods. The optimal photocatalytic hydrogen production from water decomposition was 2641 μmol g−1 h−1. The results showed that compared with traditional composites, a ZnCdS(Two-Step)/Ni photocatalyst synthesized with Prussian blue analogue (PBA) as the precursor shows better photocatalytic performance for hydrogen evolution. Moreover, the introduction of Ni is found to be a feasible strategy to modulate the performance of photocatalysts, providing a reference for the construction of materials with excellent photocatalytic properties. [ABSTRACT FROM AUTHOR]

MoSe2 as one graphene-like 2D transition metal selenide has attracted great attention. However, its application for the hydrogen evolution reaction (HER) is still restricted by the poor electrical conductivity and structural restacking. In this work, an excellent electrocatalyst for hydrogen production is developed based on the in situ synthesis of V-doped MoSe2 confined on carbon black nanoparticles (denoted as V-MoSe2/CB) via a sol–gel process. The characterization results show that the carbon black nanoparticles can protect the V-MoSe2 nanosheets from agglomeration, resulting in ultra-thin thickness and short vertical lattice arrays. Meanwhile, density functional theory (DFT) calculations indicate that vanadium doping can optimize the electronic structure of MoSe2. Accordingly, compared to the pure MoSe2, V-MoSe2 and MoSe2/CB electrocatalysts, V-MoSe2/CB exhibits improved electrocatalytic activity with a small overpotential of 166 mV at −10 mA cm−2 and a small Tafel slope of 65 mV dec−1. This work paves a new way for improving the HER performance through synergistic morphology, structure and electronic regulation. [ABSTRACT FROM AUTHOR]

In the photocatalytic processes of ferroelectric semiconductor materials, how to induce a depolarized electric field (Edp) by polarization to reduce the electron–hole recombination rate is still a big problem. Here, the ABO3-type K0.5Na0.5NbO3 (KNN) material is modified by Nd and Ni elements at A/B sites to narrow the band gap and maintain the room-temperature ferroelectric behavior. The 0.96KNN–0.04NdNiO3 sample shows the narrowed band gap (∼2.75 eV) and high residual polarization value (∼11.56 μC cm−2). After high-field poling, the hydrogen production rate of the sample in the full spectrum reaches 926.28 μmol g−1 h−1, indicating an increase of approximately 5 times compared to the 170.45 μmol g−1 h−1 of the unpoled sample. The improved performance of photocatalytic hydrogen production mainly results from the reduction of band gap and the formation of Edp after polarization. The change in the position of the top of the valence band after sample polarization reveals that high-field poling can improve charge transport efficiency by energy band bending. [ABSTRACT FROM AUTHOR]

Cadmium sulphide (CdS) is a promising material for photocatalytic hydrogen production. Compared with hexagonal CdS (h-CdS), the research on cubic CdS (c-CdS) is much less. Especially, detailed studies on the preparation condition optimization and photostability of c-CdS are still insufficient. In this paper, c-CdS was prepared by a simple precipitation method and characterized by XRD, SEM, TEM and XPS techniques. Firstly, the Cd to S molar ratio and aging time were optimized to find out their influences on the crystal structure, morphology, chemical state and hydrogen production performance of CdS. The c-CdS obtained at a Cd : S ratio of 5 : 8 and an aging time of 6 h (denoted as CdS-8-6) possesses the highest performance of 37.7 μmol h−1. Secondly and more importantly, cyclic hydrogen production tests were conducted on CdS-8-6 and a series of determinations were carried out on the recovered samples to investigate its photostability during reaction. [ABSTRACT FROM AUTHOR]

Artificial photosynthetic production of hydrogen peroxide (H2O2) using conjugated organic polymer semiconductor photocatalysts is a promising approach. However, its application is limited mainly by the rapid rate of photogenerated carrier complexation. Here, we have prepared three novel porphyrin-based donor–acceptor conjugated organic polymers using porphyrin as a precursor and benzene–diamine ligands as basic blocks for the photocatalytic and efficient production of H2O2 under pure water. Density functional theory (DFT) calculations show that aniline ligands act as electron donors (D) and porphyrins act as electron acceptors (A). The TCFPP-TPD exhibits efficient photocatalytic H2O2 production with an initial rate of 1180 μmol g−1 h−1 under visible light (λ > 420 nm) irradiation without any additional sacrificial agents or co-catalysts. By increasing the number of benzene rings, the electron-donating ability of the benzene–diamine ligands was significantly enhanced, improving their electron-donor–acceptor (D–A) interactions with the porphyrins and facilitating the separation of the photogenerated electron–hole pairs. Moreover, the possible process for producing H2O2 through TCFPP-TPD photocatalysis was disclosed through in situ FT-IR and electron spin resonance (ESR). This study proposes novel design concepts for the rational construction of D–A structures with the aim of increasing the charge separation efficiency, which is crucial for the effective production of H2O2. [ABSTRACT FROM AUTHOR]

Methanol steam reforming is considered as a potential hydrogen supply pathway, and Cu-based catalysts are commonly used catalysts for this reaction. A series of CZAT-x catalysts were synthesized, which are derived from Cu/ZnO/Al2O3 catalysts by modifying the method of introducing TiO2 in this study. Characterization techniques (BET, XRF, XRD, H2-TPR, N2O chemisorption, TEM, and XPS) revealed that the mode of TiO2 introduction primarily influences surface Cu dispersion, reducibility and Cu–Ti interaction, subsequently affecting CZAT-x catalysts' catalytic activity and thermal stability in methanol steam reforming. The TiO2-doped catalyst prepared through solvent-assisted ball milling demonstrated the highest activity. The complete conversion of methanol could be achieved under the conditions of a water-to-methanol ratio of 1.2 and a reaction temperature of 493 K, and the H2 time-space yield could reach 103.9 mol kg−1 h−1. Furthermore, even after 10 h of thermal treatment test at 723 K, the CZAT-EA catalyst maintained a high methanol conversion rate. [ABSTRACT FROM AUTHOR]

Perovskite oxides are considered promising efficient and cost-effective water splitting electrocatalysts under alkaline conditions because of their excellent hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activity. However, due to their poor electron transfer and lack of exposed active sites, their HER activity is still much lower than that of precious metal catalysts. Besides, to date, few studies have been reported on the HER in complex water systems. In this study, a new composite electrocatalyst, SrCo0.7Fe0.3O3−δ@CdS, with a core–shell structure (denoted as SCF@CdS) was successfully prepared using an in situ coprecipitation method, which exhibited efficient HER activity in an alkaline environment and oilfield wastewater. The better electrocatalytic performance of SCF@CdS than pure SCF can be attributed to the larger specific surface area and more exposed active sites in this core–shell structure, and the lone pair electrons from S in CdS can also form coordination bonds with the vacant orbital of Co in the perovskite by sharing electron pairs, thus increasing the concentration of oxygen vacancies. This study provides a strategy to improve the HER performance of perovskite catalysts in complex water systems via the construction of a core–shell structure. [ABSTRACT FROM AUTHOR]

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 MoS2/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]

Developing novel catalysts with excellent photocatalytic hydrogen evolution activity is crucial for expediting current research on solar-chemical energy conversion. In the present study, unique Sn3O4/CdS composites were carefully designed and prepared using a facile hydrothermal method to achieve outstanding photocatalytic H2 production activity. Various techniques were employed to determine the crystalline structure, chemical composition, microstructure, and optical and electrochemical characteristics of the prepared samples. The experimental results indicate that zero-dimensional (0D) CdS quantum dots were tightly attached to the surface of three-dimensional (3D) Sn3O4 nanoflowers. Furthermore, enhanced light-absorbing capacity and accelerated electron–hole separation and transfer were achieved after incorporating CdS quantum dots into Sn3O4 nanoflowers. The generation rate of hydrogen using the optimal sample (Sn3O4/CdS QDs-2) was about 20.74 μmol g−1 h−1, which was 2.86 and 3.16 times those of pure Sn3O4 and CdS, respectively. In addition, the possible photocatalytic H2 production mechanism of Sn3O4/CdS nanocomposites was also revealed. This work is highly desirable to provide valuable inspiration for rational design and preparation of efficient photocatalysts for H2 evolution. [ABSTRACT FROM AUTHOR]

In the present work, a ternary composite MoS2/soluble g-C3N4/CdS was synthesized using a facile one-pot hydrothermal reaction and conventional reflux reaction method. The composition, morphology, and properties of the ternary composite were characterized. The photocatalytic performance of the ternary composite was evaluated for hydrogen generation under LED lamp irradiation (450 nm < λ < 465 nm) with lactic acid (LA) used as a sacrificial reagent. The results demonstrated that the maximum hydrogen production reached 4869.6 μmol under the optimal hydrogen production conditions, including a composition of 20% soluble g-C3N4, 9% MoS2, a solution pH of 1, and an irradiation time of 6 hours. The corresponding hydrogen production rate for the ternary composite was calculated to be 8116 μmol g−1 h−1. Furthermore, a possible electron transfer mechanism of the ternary composite system was briefly explored. The interaction and synergistic effects between MoS2, soluble g-C3N4, and CdS in the ternary composite likely facilitate efficient electron transfer, resulting in enhanced photocatalytic activity for hydrogen production. Mechanistic research showed that the electron transfer pathway represented either a double or single type II heterojunction photocatalytic system. [ABSTRACT FROM AUTHOR]

The construction of heterojunction photocatalysts is an effective strategy to improve photocatalytic activity. Inspiringly, this is studied by the successful fabrication of new composites of a robust Zr-MOF and low-cost g-C3N4via a simple method of mechanical grinding followed by low-temperature heating. The synthesized composites exhibit characteristics of wide-range visible-light absorption, good long-term stability and significant photocatalytic hydrogen production. The optimal H2 production rate of the Zr-MOF/g-C3N4 (5.0 wt%) heterojunction was 1.252 mmol h−1 g−1, which was 41.7 and 15.7 times higher than that of pure Zr-MOF and g-C3N4, respectively. The Z-scheme charge transfer mechanism in Zr-MOF/g-C3N4 effectively improves charge separation and maintains its high redox ability, thus greatly enhancing photocatalytic hydrogen production activity. This study presents the rational fabrication of heterojunctions for photocatalytic applications and also provides new high-performance and low-cost MOF/g-C3N4 photocatalysts for H2 production. [ABSTRACT FROM AUTHOR]

A novel approach for creating a hybrid material consisting of molecular polyoxometalate–polyhedral oligomeric silsesquioxane (POM–POSS) was developed, with a primary emphasis on overcoming the challenges related to the solar-driven production of hydrogen (H2) and the elimination of harmful bacteria in polluted wastewater. Herein, the Lindqvist-type polyoxometalate cluster, tetrabutylammonium hexamolybdate [LPOM(Mo)] and the aminopropyl heptaisobutyl silsesquioxane (POSS–NH2) were combined through covalent linkage to form the POM organoimido POSS hybrid material by a dehydration reaction. Various analytical techniques, such as FT-IR spectroscopy, BET, NMR spectroscopy, and ESI–MS, were used to investigate the development of a covalent POM–POSS hybrid material. HR-TEM images of the POM–POSS hybrid material demonstrated that the flat sheets were rectangular in shape with a size distribution ranging from 2.5 ± 0.2 μm in length to 0.2 ± 0.02 μm in width. The POM–POSS hybrid material showed a more efficient photocatalytic system compared to POM prompted by a visible region absorption shift, photoluminescence quenching effect, and increased photocurrent generation (2.1 μA cm−2). Antibacterial tests demonstrated the highest photoinactivation against Escherichia coli (E. coli) cells after 45 min of sunlight exposure. The POM–POSS hybrid material exhibited excellent H2 generation (2461 μmol g−1 h−1) than LPOM(Mo) (2051 μmol g−1 h−1) owing to the improved photocatalytic system via the covalently linked organoimide ligand from POSS–NH2. Furthermore, the reusability of the POM–POSS hybrid material was assessed by measuring its photocatalytic H2 production rate over ten consecutive cycles, and the stability of the catalytic activity was demonstrated. These findings demonstrate a rational method for constructing POM–POSS material with controlled chemical composition and architecture for H2 production under abundant sunlight. [ABSTRACT FROM AUTHOR]

Covalent triazine frameworks (CTFs) involving donor-π bridge-acceptor (D–π–A) motifs with the electron-withdrawing triazine unit as the acceptor have been regarded as one of the most promising materials for photocatalytic water splitting. The intrinsic features of π-bridges play a critical role in tailoring the polymer properties as well as the photocatalytic performance. Introducing suitable conjugated units as the π-bridge is expected to effectively tune the electronic structure of the resultant D–π–A CTFs and facilitate photo-generated charge separation. However, systematic studies on how different π-bridges would influence the photoelectronic properties of D–π–A type CTFs are still limited. Herein, three types of CTFs with well-defined D–π–A structures named Ben-CTF, BenT-CTF and BenP-CTF were synthesized to investigate the effects of different π-bridges (benzene, thiophene and pyridine units) on the performance of photocatalytic water splitting for hydrogen production. Comprehensive experiments and density functional theory (DFT) calculations revealed that BenP-CTF with the pyridine unit as the π-bridge exhibited superior charge migration ability and higher photocatalytic hydrogen evolution reaction (HER) rates compared to the other CTFs. This work may provide a reference for the rational design and controllable synthesis of CTF materials for efficient photocatalysis. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis of bare TiO2 and various molar concentrations of ruthenium (Ru)-doped TiO2 nanoparticles by the precipitation method. The as-synthesized photocatalysts were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), N2 adsorption/desorption techniques, X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), Raman spectroscopy, photoluminescence spectroscopy (PL), and electrochemical measurements. The results from the UV-vis spectroscopy clearly indicated a red-shift of the optical response toward the visible region owing to the reduced band gap energy, thus showing an enhancement of the absorption in the visible spectrum. The XRD study showed that the samples were crystallized with the photoactive anatase phase of TiO2. The microstructural study using Raman spectroscopy indicated that the Ru dopant occupied the substitutional sites in the TiO2 lattice. According to the Mott–Schottky analysis, the flat band potential of the Ru-doped TiO2 was shifted to the negative potential. The photocurrent, electrochemical impedance spectroscopy, and photoluminescence revealed a higher photogenerated charge-carriers separation efficiency of the doped sample. The photocatalytic activities of the bare TiO2 and (0.05–0.2 mol%) Ru-doped TiO2 nanoparticles were examined by studying the hydrogen production from water using methanol as a sacrificial reagent and Pt nanoparticles as a cocatalyst under light of λ≥ 320. The optimal iron content was determined to be 0.1 mol% and the corresponding hydrogen production rate was 3400 μmol h−1 in aqueous methanol, which is enhanced by more than 2 times compared to bare TiO2 (1500 μmol h−1) under the same reaction conditions. The higher activity for the doped materials was attributed to the presence of the Ru dopant to facilitate the visible-light-driven activity by introducing the electron donor/acceptor level of ruthenium and the mid-band energy level of defects between the conduction band minimum and valence band maximum of TiO2. [ABSTRACT FROM AUTHOR]

The combustion of fossil fuels has brought about serious energy shortages and environmental pollution issues. This study involves the development of green and environment-friendly nonprecious metal photocatalysts with high hydrogen production performance. Hence, a series of CoxSy/Mn0.5Cd0.5S composites was prepared through a simple hydrothermal process. When the loading amount of amorphous CoxSy was 3 wt%, the CoxSy/Mn0.5Cd0.5S composite catalyst showed the best photocatalytic activity under visible light irradiation (λ > 420 nm), giving a hydrogen production rate of 5677.6 µmol g−1 h−1, which is 121.6 times that of pure CdS and 4.8 times that of Mn0.5Cd0.5S. Moreover, the 3 wt%-CoxSy/Mn0.5Cd0.5S catalyst exhibited good photostability. The experimental results demonstrate that the construction of the CoxSy/Mn0.5Cd0.5S heterojunction effectively facilitates the separation of charge carriers, resulting in an enhanced photocatalytic activity. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) is an important chemical widely used in the chemical industry. However, the current technical methods of producing H2O2 are limited by high cost, excessive energy consumption and environmental impact. Here, we construct Ti3C2 to modify K-doped g-C3N4 heterojunctions for the production of H2O2. Through the pretreatment of K-doped g-C3N4 and the electrostatic self-assembly method, Ti3C2 is closely bonded to effectively adjust the band position, resulting in a good synergistic effect and an excellent photogenerated electron transfer ability. The construction of this structure has improved the yield of H2O2 and the production of H2O2 under visible light illumination reached as high as 3401 μmol L−1, which is much higher than that of g-C3N4. In addition, the photocatalytic mechanism shows that the two-step single-electron reduction of O2 is the main reaction step of H2O2 production. The improvement of photocatalytic performance can be attributed to the doping of K and the construction of the heterojunction, which not only expands the absorption range of visible light, but also inhibits the recombination of photogenerated electron–hole pairs and accelerates carrier separation. At the same time, the catalyst has good stability and can be recycled. This work provides a deep understanding of the modification of g-C3N4 and a new strategy for the development of high-efficiency H2O2-producing photocatalysts. [ABSTRACT FROM AUTHOR]

The development of single-atom catalysts (SACs) offers a novel strategy to minimize catalyst loadings while maintaining high electrocatalytic activity. Herein, a novel Ni/Ni single atom anchored porous graphitic nanocarbon (Ni/Ni-SA--NC) is synthesized by an alkali-assisted etching approach combined with post-calcination protocol. It is manifested that the in situ formed AlN not only can function as a template for the generation of porous nanoarchitecture but can also serve as an anchoring agent for synthesized Ni--Nx species. Benefitting from the high specific surface area, abundant electroactive sites, and highly conductive graphitic carbon matrix, the fabricated Ni/Ni-SA--NC displays superior HER performances with a quite low overpotential of 159 mV to achieve a current density of 10 mA cm-2, far outperforming the Ni/C counterpart and long-term stability for over 50 h with unnoticeable current fluctuation in alkaline medium. Our work inspires the exploration of remarkable SACs electrocatalysts for cost-effective and large-scale hydrogen production in the energy conversion and storage field. [ABSTRACT FROM AUTHOR]

The Mn0.2Cd0.8S/NiCo2S4 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 Mn0.2Cd0.8S and NiCo2S4 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 Mn0.2Cd0.8S/NiCo2S4, the amount of hydrogen production was higher than with NiCo2S4 and Mn0.2Cd0.8S alone. Different amounts of NiCo2S4 were loaded onto Mn0.2Cd0.8S for the photocatalytic hydrogen production reaction. The hydrogen photocatalytic hydrogen production of Mn0.2Cd0.8S/NiCo2S4-3 was 28.97 times higher than of the Mn0.2Cd0.8S. The Mn0.2Cd0.8S/NiCo2S4 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]

C/Ti3C2/g-C3N4 hollow microspheres (HM) were prepared by the template method to construct Ti3C2/g-C3N4 Schottky junctions on the spherical surface. The C/Ti3C2/g-C3N4 HM Schottky junctions presented excellent photocatalytic properties for producing hydrogen and decomposing organic pollutants simultaneously from wastewater without the addition of a sacrifice agent. The research revealed that the built-in electric field between g-C3N4 and Ti3C2 MXene could decrease the charge transfer resistance, leading to efficient photo charge separation, and the organic pollutant tetracycline (TC) could act as a sacrifice agent for splitting water. The H2 evolution rate of the CN-TCM-3 sample in deionized water with a sacrifice agent reached 105.4 μmol g−1 h−1, and the TC removal rate reached 100% within 120 min. The hydrogen production efficiency of CN-TCM-3 in the natural water of Slender West Lake without or with TC as a sacrifice agent was 2.3 μmol g−1 h−1 and 3.2 μmol g−1 h−1, respectively. The addition of TC improved the hydrogen production efficiency by 39%. This research indicated that the C/Ti3C2/g-C3N4 HM Schottky junctions could be a potential photocatalyst for producing hydrogen and decomposing organic pollutants in sewage simultaneously. [ABSTRACT FROM AUTHOR]

Rational construction of low-cost, high-activity electrocatalysts is essential for hydrogen production from electrolytic water. Herein, a Co0.75Mo3S3.75/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 Co0.75Mo3S3.75/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]

Solar-driven photocatalytic hydrogen generation via splitting water requires an efficient visible light active photocatalyst. In this work, Ni cocatalysts on a TiO2 composite photocatalyst with different graphene oxide (GO) contents were prepared using a hydrothermal method and characterized by TEM, XRD, UV-vis, Raman and PL spectra. The results show that the synthesized TiO2/GO/Ni nanosheet composites have a large specific surface area and can provide a large number of active sites for a photocatalytic hydrogen production reaction. GO can broaden the optical absorption range of TiO2 and absorb more visible light, thus stimulating more photogenerated electron–hole pairs. At the same time, GO can collect electrons and promote the separation of photogenerated electron–hole pairs. Ni, as a cocatalyst, can be used as an active site for hydrogen ion adsorption, which is conducive to promoting the migration of photogenerated electrons in the system and prolonging the life of photogenerated electrons and holes, thus ensuring the high efficiency of the photocatalytic reaction. [ABSTRACT FROM AUTHOR]

In this paper, a type of three-dimensionally ordered macroporous (3DOM) composite of Sn4+-doped titanium dioxide (Sn–TiO2) was synthesized by the colloidal crystal template technology, and Pt metal particles were successfully supported on the composite by the photoreduction method (3DOM Pt/Sn–TiO2). The crystal structure, morphology, composition and surface physicochemical properties of 3DOM Pt/Sn–TiO2 were characterized by various analytical methods. The characterization data showed that 3DOM Pt/Sn–TiO2 had the typical anatase and rutile mixed phase as well as a well-ordered three-dimensional macroporous structure. After photoreduction, Pt in the composites was present mainly in the form of a simple substance, and it was evenly distributed on the surface of the 3DOM composite. Meanwhile, the local surface plasmon resonance effect (SPR) of the noble metal increased visible-light absorption of the composite. Multi-mode photocatalytic experiments showed that 3DOM Pt/Sn–TiO2 exhibited significantly higher activity in photodegradation and photolysis for hydrogen evolution than pure anatase TiO2. In photodegradation experiments, 3DOM Pt/Sn–TiO2 showed the highest photodegradation activity and degradation rate. Simultaneously, the hydrogen evolution ability of 3DOM Pt/Sn–TiO2 significantly improved in the water hydrogen production experiment. Compared with the result of P25, the hydrogen evolution capacity of 3DOM Pt/Sn–TiO2 increased by 40 times. [ABSTRACT FROM AUTHOR]

In this investigation, we report the synthesis of quaternary chalcogenide semiconductor Cu2BaVS4 (CBVS) nanostructures through the solvothermal method for the first time. Various methods of characterization involving the X-ray diffraction (XRD) technique, scanning electron microscopy (SEM), Raman spectroscopy, and UV-visible and photoluminescence spectroscopy were applied to analyze the properties of CBVS nanostructures. XRD analysis represents the orthorhombic crystal structure of CBVS with a calculated average crystallite size of 27 nm. The SEM images indicate a tetragonal to grain-like morphology with 50–60 nm diameter. CBVS nanoparticles show absorption spectra within the UV-Visible range of about 220–320 nm. The optical band gap calculated for CBVS nanoparticles using PL spectra is 1.55 eV. The electrochemical performance of the produced nanostructures for energy production was also revealed in the dark and under light. For the hydrogen evolution reaction (HER), the Cu2BaVS4/NF500 electrodes showed low overpotentials of 256 mV with a Tafel slope of 105 mV dec−1 under visible light, indicating better catalytic activity. The Cu2BaVS4/NF500 electrode showed a reduced overpotential of 112 mV at a current density of 10 mA cm−2, with a Tafel slope of 37 mV dec−1 under visible light, indicating a rapid and effective OER. Based on these findings, these nanostructures show promise as electrode materials in water-splitting applications. [ABSTRACT FROM AUTHOR]