Sites For Hydrogen Production Research Articles

A novel noble-metal-free FeS2/Mn0.5Cd0.5S heterojunction for enhancing photocatalytic H2 production activity: Carrier separation, light absorption, active sites

BackgroundThe development of efficient and noble-metal-free photocatalysts is greatly essential for photocatalytic hydrogen production. However, the photocatalytic activity of a single photocatalyst is usually limited for various reasons. MethodsHerein, FeS2/Mn0.5Cd0.5S (FSMCS) heterojunctions were constructed by a simple solvent evaporation method. The morphological characterizations revealed a raspberry-like hollow microsphere structure for FeS2 and irregular granularity for Mn0.5Cd0.5S. Photoluminescence (PL) and electrochemical experiments indicated that the FSMCS composite effectively facilitated the separation of photogenerated electron-hole pairs. The UV–vis diffuse reflectance spectrum (DRS) showed that, in FSMCS composite, the visible light absorption range was effectively expanded to the full visible light. Significant findingsExcellent photocatalytic activity in FSMCS heterojunctions without loading noble metals because FeS2 could serve an active site for hydrogen production. The optimum FSMCS composite had excellent photocatalytic hydrogen production activity (6.1 mmol·g−1·h−1), which was 5.6 and 2.3 times higher than that of the pristine Mn0.5Cd0.5S (1.1 mmol·g−1·h−1) and Mn0.5Cd0.5S-1 %Pt (2.7 mmol·g−1·h−1). Meanwhile, in four round-robin tests, the activity of the 5FSMCS photocatalyst did not significantly decrease. This work proved that combining Mn0.5Cd0.5S and non-precious metal cocatalysts to construct heterojunctions is a promising strategy for photocatalytic hydrogen production.

Construction of Au/ZnWO4/CdS Ternary Photocatalysts with Oxygen Vacancy Modification for Efficient Photocatalytic Hydrogen Production

AbstractRational design and optimization of the photocatalyst architecture, aimed at effectively enhancing light absorption and accelerating charge separation and transfer, can lead to the accomplishment of sustainable photocatalytic hydrogen production. In this study, a ternary system of Au/ZnWO4/CdS is prepared with oxygen vacancy modification through a combination of hydrothermal, chemical precipitation, and photochemical deposition methods. The addition of CdS and Au nanoparticles significantly enhances the light absorption range of ZnWO4 (ZWO) and creates more active sites for hydrogen production. The type‐II engineered heterojunction, in combination with Au as a cocatalyst, is a viable and efficient method for enhancing the separation and transport of electron–hole pairs, thereby facilitating the effective precipitation of hydrogen through photocatalysis. 5A10ZC exhibits a hydrogen production rate of 5483.62 µmol g−1 h−1, which is 167 times higher than that of unmodified ZWO and 29 times higher than that of pure CdS. In addition, it exhibits excellent cycle stability in the hydrogen production cycle stability test. The photoelectrochemical test results show that the construction of the system improves the separation and transfer efficiency of photogenerated carriers. This study provides a new inspiration for the construction of high‐performance photocatalytic materials.

Developing and applying the Hydrogen Economics and infRAstructure optimization model (HERA)

This study aims at developing the Hydrogen Economics and InfRAstructure optimization model (HERA) to support the technical-economic assessment of hydrogen supply chain infrastructures. It is developed at an hourly scale, in Mixed Integer Linear Programming (MIP), and includes the hydrogen production and delivery via road transportation or pipelines, as well as hydrogen and electricity storage options. To be tested, HERA was applied in a case study, to compare two different locations for hydrogen production. Findings show that the use of HERA can support the technical-economic assessment of a hydrogen infrastructure, highlighting the impact of the distance between the hydrogen production site and the demand, and the use of batteries and complementary renewable resources, to smooth the variability, on total costs. Besides, the proposed model was able to find out the optimal equipment combination for the supply chain by considering the modular (integer) nature of the problem to be solved.

Hydrolysis behavior and mechanistic insights of CaMg2InX (X = 0.1, 0.3, 0.5, 0.7) ternary alloy for sustainable hydrogen production

The hydrolysis behavior of CaMg2In0.1, CaMg2In0.3, CaMg2In0.5, and CaMg2In0.7 ternary alloys in an MgCl2 solution following casting and hydrogenation were investigated. The hydrolysis mechanism of these alloys is elucidated through an analysis of microstructure, phase composition, and kinetics before and after hydrolysis. The nucleation-growth Avrami model is employed to accurately model the hydrolysis kinetics, revealing improved hydrolysis yields and reaction rates following hydrogenation. Notably, CaMg2In0.1 has demonstrated exceptional hydrolysis characteristics, exhibiting a yield of 1140 mL/g, an initial hydrolysis rate of 113 mL/g·s, and an activation energy of 24.3 ± 1.7 kJ·mol−1. The yield of H-CaMg2In0.1 further escalates to 1800 mL/g with a rate of 221 mL/g·s, attributed to the formation of Ca4Mg3H14 and In phases subsequent to the hydrogenation of In2Ca and Mg3In phases in the alloy. These newly formed phases act as catalysts and actively participate in the hydrolysis process, providing active sites for hydrogen production, thus enhancing hydrolysis yields and kinetics. It is observed that with increasing In content, the order of hydrolysis performance of the alloy is as follows: CaMg2In0.1 > CaMg2In0.3 > CaMg2In0.5 > CaMg2In0.7, consistent with the trend after hydrogenation. These findings indicate that the addition of In significantly enhances the hydrolysis performance of CaMg2 alloys, offering a promising strategy for preparing magnesium-based alloys with high yields and favorable kinetic properties.

Heterogeneous nucleation on defects in MoS2 nanostructures as a proxy for assessing active sites for hydrogen production

In the present work, we applied heterogeneous nucleation of gold nanoparticles to assess the density of defects on MoS2 nanostructures presenting different morphologies and surface areas. The use of L-cysteine resulted in the formation of flower-shaped MoS2 nanostructures with a diameter of about 300 nm and petals measuring around 30 nm. In contrast, when 3-mercaptopropionic acid was employed, it led to the formation of large agglomerates, here referred to as nanoclouds, with a diameter of approximately 500 nm. The nucleation of gold nanoparticles on defect sites of MoS2 suggested that MoS2 obtained from 3-mercaptopropionic acid has a higher content of active sites for hydrogen production compared to MoS2 obtained from L-cysteine.

Reinforced photogenerated electron convergence on graphdiyne(g-CnH2n-2) “as an active site and substrate” for enhance photocatalytic hydrogen production

Graphdiyne(GDY), as a carbon-based catalyst with tunable electronic structure, has a significant impact on the advancement of sustainable photocatalytic technology. Its tunable electronic structure can effectively regulate the activity and selectivity of photocatalytic reaction. In this paper, GDY was prepared by a new method of ball milling HEB-TMS, and CoWO4 nanoparticles were uniformly loaded on the surface of GDY to construct a Type-II heterojunction. GDY provides a dispersed and effective substrate for CoWO4, forming a closer contact interface. Based on GDY's unique electronic structure and the formation of Type-II heterojunction, GDY/CoWO4 enhances the separation of photoexcited electrons and holes, thus increasing the electron cloud density on GDY. As an electron acceptor and active site for hydrogen production, GDY promotes the proton reduction reaction. In addition, the charge transfer process of GDY/CW-15 was demonstrated by in-situ XPS and UPS, and the corresponding hydrogen production mechanism was proposed. This study provides a facile and efficient method for preparing GDY and a new idea for heterojunction photocatalyst based on GDY substrate.

Bridging CdS with Ti3C2Tx nanosheets via ligands for enhanced charge transfer in photocatalytic H2 production

Loading a co-catalyst is an effective approach for enhancing the performance of photocatalysts. In this study, we used a novel co-catalyst, Ti3C2Tx, to fabricate an efficient and cost-effective heterogeneous nanostructured catalyst based on CdS for photocatalytic hydrogen production via water splitting. The composite catalyst denoted as Ti3C2Tx-cys-CdS-x was synthesized through via hydrothermal treatment. The heterostructure of Ti3C2Tx-cys-CdS enabled the efficient separation and transfer of space charges during photocatalytic hydrogen evolution. With the aid of the l-cysteine, Ti3C2Tx and CdS form a unique covalently bonded structure that generates numerous heterojunctions and reactive sites for hydrogen production. The results indicated that Ti3C2Tx-cys-CdS-2 exhibits superior performance in photocatalytic hydrogen production, with a hydrogen evolution rate of 4275 μmol g−1 achieved in 2 h. This rate is 9.2 times higher than that obtained using pristine CdS as the catalyst.

Preparation of Palladium‐Doped Nickel Phosphide Nanoparticles as Efficient Electrocatalysts for Alkaline Hydrogen Evolution Reaction

AbstractHydrogen production through electrochemical water splitting has gained significant attention owing to its environmental benefits over traditional methods. However, designing an efficient electrocatalyst for the hydrogen evolution reaction (HER) in an alkaline electrolyte remains a significant challenge. In this study, colloidal Pd‐doped Ni2P nanoparticles were prepared via a thermal decomposition‐based strategy and used as electrocatalysts for the hydrogen evolution reaction. The Pd dopant is atomically dispersed within the Ni2P nanoparticles, regulating their electronic structure and providing an efficient active site for hydrogen production. The Pd‐doped Ni2P nanoparticles exhibited excellent electrocatalytic performance with an overpotential of 77 mV at 10 mA cm−2 in an alkaline electrolyte and a small Tafel slope of 46 mV dec−1.

Mobile Proton-Exchange Membrane Fuel Cell Powered by Diesel Fuel: System Simulation and Life Cycle Analysis

Diesel engine generators used at construction sites generate noise, vibration, and large amounts of pollutant emissions. With the strengthening of emission standards for construction equipment, technologies must be developed to meet new requirements. We proposed and analyzed a mobile proton-exchange membrane fuel cell diesel-powered system to address these issues. The proposed system consisted of an autothermal reformer, a proton-exchange membrane fuel cell, and a balance of plant components. Previous studies on the system have not explored the optimal design and operating condition of the system and have not shown whether the proposed system is superior to the system using the hydrogen-fueled proton-exchange membrane fuel cell system in the life-cycle greenhouse gas emissions point of view. In this study, we clarified system operation characteristics, determined the operational design point, and evaluated system performance and life-cycle greenhouse gas emissions. The system was analyzed by constructing a zero-dimensional simulation model. Several control parameters were varied in parametric studies to determine the operational design point (steam-to-carbon ratio of 2, oxygen-to-carbon ratio of 0.5, fuel utilization factor of 0.85, and heat exchanger effectiveness of 0.85). Considering system performance, the determined design point achieved a 32.3% efficiency. Additionally, we assessed the life-cycle greenhouse gas emissions of the system and compared them with those of an alternative system, which is a hydrogen-fueled proton exchange membrane fuel cell system. It was confirmed that in the United States of America, the proposed system emits 1010.2 g-CO2-eq/kWh of greenhouse gas at a 300 km fuel transportation distance, which is similar to a hydrogen-fueled proton-exchange membrane fuel cell system (1001.1 g-CO2-eq/kWh). The proposed system emits less greenhouse gas emissions than the hydrogen-fueled proton-exchange membrane fuel cell system if the distance from the hydrogen production site to the construction site is more than 318 km. Therefore, for a construction site far from a hydrogen production plant, the proposed diesel-fueled proton-exchange membrane fuel cell system is preferable from both the greenhouse gas emissions and convenience perspectives.

Charge Density Modulation of Pyrene-Related Small Molecules by Nitrogen Heteroatoms Precisely Regulates Photocatalytic Generation of Hydrogen.

Organic semiconductor materials hold promising applications in photocatalytic hydrogen evolution due to their high modifiability and wide range of light absorption capability. In this study, we present an effective strategy for promoting the separation of photoexcited electrons from organic conjugated centers to active sites by modifying different nitrogen-containing groups on pyrene molecules. Building on this foundation, the well-designed catalyst Py-m-2N has demonstrated good performance by achieving a photocatalytic hydrogen evolution rate of 48.86 mmol g-1 h-1, even in the absence of the precious metal platinum cocatalyst. This achievement places the pyrene-based photocatalyst ahead of the majority of its organic counterparts. Our comprehensive characterization and density functional theory calculations reveal that the nitrogen atom not only serves as an active site for hydrogen production but also plays a pivotal role in efficiently accumulating bulk-phase electrons. This electron enrichment process enhances the transport of photoexcited electrons from the light-absorbing pyrene units to the active nitrogen sites. This work provides inspiration for the future design of effective nitrogen-atom-modified organic semiconductor photocatalysts at the molecular level.

Life Cycle Global Warming Impact of Long-Distance Liquid Hydrogen Transport from Africa to Germany

The global interest in hydrogen as an energy carrier is steadily increasing. In this study, multiple scenarios of liquid hydrogen exports from Africa to Germany are analyzed by life cycle assessment (LCA) to quantify the global warming potential (GWP) of 1 kg hydrogen. The investigation is driven by the promise that hydrogen can be sustainably and economically produced by photovoltaic (PV)-powered electrolysis in Africa, benefiting from the geographical location near the equator and, consequently, higher solar irradiation levels. Given the absence of a pipeline network, shipping hydrogen emerges as the most efficient short-term transportation option to Germany. In this paper, supply locations—Morocco, Senegal, and Nigeria—are evaluated by means of an LCA and compared to hydrogen supply from Germany. Results show that emissions from hydrogen production and transportation by ship from Morocco range from 3.32 to 3.41 kgCO2-eq/kgH2. From Senegal, the range is 3.88 to 3.99 kgCO2eq/kgH2, and from Nigeria, it falls between 4.38 and 4.27 kgCO2-eq/kgH2. These emission levels are influenced by factors such as the GWP of PV electricity, the efficiency of the electrolyzer, and the transportation distance. Interestingly, the analysis reveals that PV-powered electrolysis of hydrogen in Germany, including 300 km distribution, causes, in most scenarios, a lower GWP in the range of 3.48 to 3.61 kgCO2-eq/kgH2 than hydrogen from the analyzed African regions. Opting for grid electricity instead of PV (with a value of 0.420 kgCO2-eq/kWh) for hydrogen production in Germany yields a GWP ranging from 24.35 to 25.42 kgCO2-eq/kgH2. Hence, we can conclude that in any event, PV-powered hydrogen electrolysis has a low environmental impact not only within Africa but also in Germany. However, it is crucial to carefully consider the balance of the GWP of production versus transportation given the distance between a hydrogen production site and the location of consumption.

Fabrication of Noble-Metal-Free Mo2C/CdIn2S4 Heterojunction Composites with Elevated Carrier Separation for Photocatalytic Hydrogen Production

Molybdenum-based cocatalyst being used to construct heterojunctions for efficient photocatalytic H2 production is a promising research hotspot. In this work, CdIn2S4 was successfully closely supported on bulk Mo2C via the hydrothermal method. Based on their matching band structures, they formed a Type Ⅰ heterojunction after the combination of Mo2C (1.1 eV, -0.27 V, 0.83 V) and CdIn2S4 (2.3 eV, -0.74 V, 1.56 V). A series of characterizations proved that the heterojunction composite had higher charge separation efficiency compared to a single compound. Meanwhile, Mo2C in heterojunction could act as an active site for hydrogen production. The photocatalytic H2 production activity of the heterojunction composites was significantly improved, and the maximum activity was up to 1178.32 μmmol h-1 g-1 for 5Mo2C/CdIn2S4 composites. 5Mo2C/CdIn2S4 heterojunction composites possess excellent durability in three cycles (loss of 6%). Additionally, the mechanism of increased activity for composites was also investigated. This study provides a guide to designing noble-metal-free photocatalyst for highly efficient photocatalytic H2 evolution.

Techno-economic assessment of hydrogen production from seawater

Population growth and the expansion of industries have increased energy demand and the use of fossil fuels as an energy source, resulting in release of greenhouse gases (GHG) and increased air pollution. Countries are therefore looking for alternatives to fossil fuels for energy generation. Using hydrogen as an energy carrier is one of the most promising alternatives to replace fossil fuels in electricity generation. It is therefore essential to know how hydrogen is produced. Hydrogen can be produced by splitting the water molecules in an electrolyser, using the abondand water resources, which are covering around ⅔ of the Earth's surface. Electrolysers, however, require high-quality water, with conductivity in the range of 0.1–1 μS/cm. In January 2018, there were 184 offshore oil and gas rigs in the North Sea which may be excellent sites for hydrogen production from seawater. The hydrogen production process reported in this paper is based on a proton exchange membrane (PEM) electrolyser with an input flow rate of 300 L/h. A financially optimal system for producing demineralized water from seawater, with conductivity in the range of 0.1–1 μS/cm as the input for electrolyser, by WAVE (Water Application Value Engine) design software was studied. The costs of producing hydrogen using the optimised system was calculated to be US$3.51/kg H2. The best option for low-cost power generation, using renewable resources such as photovoltaic (PV) devices, wind turbines, as well as electricity from the grid was assessed, considering the location of the case considered. All calculations were based on assumption of existing cable from the grid to the offshore, meaning that the cost of cables and distribution infrastructure were not considered. Models were created using HOMER Pro (Hybrid Optimisation of Multiple Energy Resources) software to optimise the microgrids and the distributed energy resources, under the assumption of a nominal discount rate, inflation rate, project lifetime, and CO2 tax in Norway. Eight different scenarios were examined using HOMER Pro, and the main findings being as follows:The cost of producing water with quality required by the electrolyser is low, compared with the cost of electricity for operation of the electrolyser, and therefore has little effect on the total cost of hydrogen production (less than 1%).The optimal solution was shown to be electricity from the grid, which has the lowest levelised cost of energy (LCOE) of the options considered. The hydrogen production cost using electricity from the grid was about US$ 5/kg H2.Grid based electricity resulted in the lowest hydrogen production cost, even when costs for CO2 emissions in Norway, that will start to apply in 2025 was considered, being approximately US$7.7/kg H2.From economical point of view, wind energy was found to be a more economical than solar.

Hierarchical macro-mesoporous electrocatalysts with dual-active sites of Ru single atoms and monodispersed Ru–Mo nanoclusters for efficient hydrogen evolution

Rationally designing high-performance electrocatalysts with high density and multiactive sites is an effective strategy to accelerate the alkaline hydrogen evolution reaction (HER) kinetics, yet it remains challenging. Herein, a catalyst comprising numerous Ru–Mo-based single atoms and subnanoclusters incorporated into a hierarchical macro-mesoporous carbon framework with a P-doped skeleton (Ru–Mo/PC) was successfully developed via a simple template-assisted pyrolysis method. Spherical aberration correction electron microscopy and X-ray absorption fine structure measurements revealed that the dual-active sites consisted of Ru–C5 single atoms and ultrasmall Ru–Mo nanoclusters (mean diameter of 0.94 nm). In particular, the as-constructed RuMo1.5/PC catalyst exhibited a high activity towards the HER, requiring an overpotential of only 17.9 mV at 10 mA/cm2, which outperformed a commercial Pt/C catalyst in alkaline media. Electrochemical performance results also indicated that introducing moderate Mo species played a crucial role in further boosting the HER activity compared to Ru/PC. The present work provides a step forward in designing efficient and stable catalysts with high-density, atomically dispersed active sites for hydrogen production.

Tuning the photocatalytic properties of porphyrins for hydrogen evolution reaction: An in-silico design strategy

Porphyrins constitute a class of attractive materials for harvesting sunlight and promote chemical reactions following their natural activity for the photosynthetic process in plants. In this work, we employ an in-silico design strategy to propose novel porphyrin-based materials as photocatalysts for hydrogen evolution reaction (HER). More specifically, a set of meso-substituted porphyrins with donor-acceptor architecture are evaluated within the density functional theory (DFT) framework, according to these screening criteria: i) broad absorption spectrum in the ultraviolet–visible (UV–Vis) and near infrared (NIR) range, ii) suitable redox potentials to drive the uphill reaction that lead to molecular hydrogen formation, iii) low exciton binding free energy ( E b ), and iv) low hydrogen binding free energy (ΔG H ), a quantity that should present low HER overpotentials, ideally ΔG H = 0. The outcomes indicate that the Se-containing compound, where the donor ligands are attached to the porphyrin core by the spacer, outstands as the most promising candidate that is presented in this work. It displays a broad absorption in the visible and NIR regions to up to 1000 nm, suitable catalytic power, low E b (in special in high dielectric constant environment, such as water) and the lowest ΔG H = +0.082 eV. This is comparable, in absolute values, to the value exhibited by platinum (ΔG H = −0.10 eV), one of the most efficient catalysts for HER. • Novel porphyrin-based materials are proposed as photocatalysts for HER. • The screening strategy includes the UV–Vis absorption profile, catalytic power and ΔG H . • All candidates have catalytic power for electron transfer. • The Se-based compound is the most promising candidate in the series. • Nitrogen is the most relevant catalytic site for hydrogen production in these materials.

Simultaneous hydrogen production with the selective oxidation of benzyl alcohol to benzaldehyde by a noble-metal-free photocatalyst VC/CdS nanowires

In this work we used CdS NWs (nanowires) with vanadium carbide (VC) attached via facile electrostatic self-assembly and calcination method. The results showed that compared to pristine CdS NWs, the photocatalytic activity of CdS NWs loaded with the particular amount of VC was dramatically enhanced. Among them, the VC/CS-15 indicated the highest enhancement for simultaneous production of H2 with selective oxidation of benzyl alcohol (BO) into benzaldehyde (BD). The highest hydrogen evolution rate of 20.5 mmol g–1 h–1 was obtained with more than 99% selectivity for BD production under visible light (λ > 420 nm) irradiation for 2 h, which was almost 661 times higher than the pristine CdS NWs. This enhancement of photocatalytic activity is due to the VC, which provides a favorable attraction for BO by lowering the zeta potential, along with the active site for hydrogen production, and retard the recombination of electron-hole pairs by increasing the conductivity of the photocatalyst. Moreover, the apparent quantum efficiency (AQE) of VC/CS-15 for BD and H2 production at monochromatic 420 nm is about 7.5%. At the end of the hydrogen evolution test, the selective oxidation with more than 99% selectivity was obtained. It hopes this work will prove its future significance and move scientific community toward a more economical way for achieving the commercialization of H2 by photocatalysis.

Synergetic Photo-Thermo Catalytic Hydrogen Production by Carbon Materials.

Photo-thermo catalytic hydrogen production represents one of the most promising routes for channeling solar energy but typically suffers from high reaction temperatures. In this work, we develop photo-thermo catalytic hydrogen production at low temperatures by cost-effective, nonplasmonic, and metal-free nitrogen-doped carbon materials (CNO1-x). We demonstrate that due to the photothermal conversion of CNO1-x, carrier generation is improved and electron migration is enhanced to suppress the recombination of electron-hole pairs, both of which promote hydrogen production by photocatalysis, while generated hydrogen radicals facilitate the regeneration of active sites for hydrogen production by thermocatalysis. Such synergy greatly promotes photo-thermo catalytic hydrogen production at low temperatures. These results demonstrate the great promise of photo-thermo catalytic hydrogen production over carbon materials at low temperatures.

Photocatalytic hydrogen generation using colloidal covalent organic polymers decorated bimetallic Au-Pd nanoalloy (COPs/Pd-Au)

Photocatalytic H2 generation has been considered as an effective method for H2 generation, in which the cocatalysts play a critical role. Here, we report highly reactive nanocomposites composed of two-dimensional triazine-based covalent organic Polymers (COPs), Pd and Au nanocomponents which is designed to benefit from the alloying and visible light illumination effects as well as LSPR effect. Photocatalytic hydrogen production was achieved under low-cost visible light-driven. The COP/Pd-Au exhibited higher photocatalytic outstanding turnover frequency of 260.5 h − 1, which was 1.47 times of that under no light (177.3 h − 1). Additionally, it exhibits much advanced catalytic performance, which is 2.83-fold that of COP/Pd (91.98 h − 1) and 434.17-fold that of COP/Au (0.60 h − 1), under the similar reaction conditions. The great photocatalytic activity for COP/Pd-Au was also ascribed to the strong interface between Pd-Au NPs and COPs, and the preparation of single hollow construction of Pd-Au alloy with porous nature that presented active sites for hydrogen production.

Constructing a WC/NCN Schottky Junction for Rapid Electron Transfer and Enrichment for Highly Efficient Photocatalytic Hydrogen Evolution.

The low charge-transfer efficiency and slow surface reaction kinetics are the main factors affecting the performance of carbon nitride photocatalysts. Here, a Schottky heterostructure (WCN) was constructed by combining WC with porous carbon nitride nanosheets with a cyanide group (NCN). The Schottky junction provides a convenient way for photoinduced electrons to transfer and promotes the effective separation of photoinduced carriers. Furthermore, due to the good conductivity of WC and an electronic structure similar to Pt, the W atom in WC as the active site of hydrogen production can realize efficient reaction kinetics. In this way, the WCN Schottky heterostructure showed a 2.0- and 5.0-fold enhancement in photocatalytic H2 evolution as compared to the single NCN component under visible-light and near-infrared light irradiation. By combining with theoretical simulations, as an electron acceptor in the WCN heterostructure, WC can effectively improve the charge-transfer efficiency and also act as an active site for hydrogen production.

In-situ-formed Cd and Ag2S decorated CdS photocatalyst with boosted charge carrier spatial separation for enhancing UV-vis-NIR photocatalytic hydrogen evolution

CdS demonstrate superior potential for H2 production, but exist deficiencies of low carrier separation efficiency and photostability limit their large-scale application. Hence, a novel Ag2S/CdS/Cd2SO4(OH)2 composite has been designed. In-depth measurements reveal that Cd2SO4(OH)2 will be in-situ reduced to Cd metal as an excellent electron trap and hydrogen production site during the photocatalytic process. As a result, photogenerated electrons and holes will directionally transfer to Cd metal and Ag2S respectively, leading to the separation of oxidation and reduction reaction sites. As expected, Ag2S/CdS/Cd2SO4(OH)2 and final Ag2S/CdS/Cd systems exhibit considerably promoted photocatalyst properties than many other CdS-based photocatalysts no matter on the illumination of UV, Vis or NIR light. The research not only provide a new insight to develop a low-cost, carrier spatial separation and full-spectrum-responsive photocatalytic hydrogen evolution system, but also displays a novel strategy for in-situ deposition of metal clusters on the photocatalyst surface during the photocatalytic process.