Efficient H2 Production Research Articles

D-Band Center Engineering of Nickel Nanoparticles Accelerates Water Dissociation for Hydrogen Evolution in Neutral NaCl Solution.

While Pt is highly efficient for hydrogen evolution reaction (HER), its widespread use is limited by scarcity and high cost. Herein, a vertically aligned electrocatalyst is present comprising Ni3S2 nanotube arrays (NTAs) and Ni nanoparticles (NPs) (Ni3S2/Ni NTAs) for neutral HER. In a neutral 4 wt.% NaCl solution (pH = 7), the Ni3S2/Ni NTAs achieves a current density of 100mA cm-2 at a low overpotential of 540mV, outperforming both Ni3S2 NTAs and Ni NTAs and even the commercial Pt plate. The hollow tubular structure offers ample mass transfer channels, and strong electronic interaction between Ni3S2 and Ni is observed. Theoretical studies reveal that the lowered d-band center (ɛd) of Ni 3d orbital significantly reduces the activation energy for H2O dissociation and facilitates the movement of an H atom in H2O away from OH to form a transition state, consequently promoting H2 evolution. When Ni3S2/Ni NTAs is used as the cathode in a two-electrode diaphragm-free electrolyzer with a RuSnTi anode, efficient H2 production and energy-saving Cl2 evolution are achieved. This work highlights the potential of uniquely structured electrocatalysts for HER in neutral NaCl solutions.

Dynamic Coordination Engineering of Z‐Scheme (FFV)2PdCl2/C3N4 Heterojunction for Superior Photocatalytic Hydrogen Evolution

AbstractRealizing highly efficient photocatalytic hydrogen evolution reaction (HER) is a key challenge. Herein, a (FFV)2PdCl2 complex is developed with dynamic coordination engineering between the PdII site and Fluoflavin (FFV) ligands, and couple it with graphite carbon nitride (g‐C3N4) ultrathin nanosheets to construct a novel Z‐scheme heterojunction ((FFV)2PdCl2/C3N4). The resultant heterojunction delivers a HER activity of 648 µmol h−1 under visible light (λ ≥ 400 nm) illumination and an apparent quantum yield up to 40.1% at 400 nm, far superior to those g‐C3N4‐based catalysts reported previously. Mechanistic and theoretical studies reveal that the dynamic coordination between the PdII site and FFV ligands not only significantly accelerates the electron transfer from g‐C3N4 to (FFV)2PdCl2 and then to the PdII sites via a Z‐scheme mechanism, but also effectively maintain the efficacy and stability of the PdII active sties, and thus the (FFV)2PdCl2/C3N4 with a ultralow Pd‐loading amount (ca. 0.1 wt.%) exhibits the impressive activity and durability. The present dynamic coordination and structural evolution of (FFV)2PdCl2 are also applicable for significantly improving the HER performance of other semiconductors, thus paving a potential way for manufacturing highly efficient and active H2 production systems.

MIL-125-PDI/ZnIn2S4 Inorganic-Organic S-Scheme Heterojunction With Hierarchical Hollow Nanodisc Structure for Efficient Hydrogen Evolution from Antibiotic Wastewater Remediation.

Efficient photocatalytic production of H2 from wastewater is expected to address environmental pollution and energy crises effectively. However, the rapid recombination of photoinduced carriers results in low photoconversion efficiency. At present, inorganic-organic S-scheme heterojunction have become a prominent and promising technology. In this study, an organic ligand modified MIL-125-PDI/ZnIn2S4 (ZIS) inorganic-organic S-scheme heterojunction catalyst is designed. ZIS nanosheets are grown on the disc-shaped MIL-125-PDI surface to form a distinctive hollow nanodiscs with hierarchical structure, giving the material an abundance of surface active sites, an optimized electronic structure, and a spatially separated redox surface. Consequently, the optimal 100MIL-125-PDI250/ZIS exhibited high photocatalytic HER of 508.99 µmol g-1 h-1 in Tetracycline hydrochloride (TC-HCl) solution. Meanwhile, the catalyst achieved complete TC-HCl removal and mineralization rate of 66.62% in 4h. Experimental and theoretical calculations corroborate that the staggered band alignment and work function difference between MIL-125-PDI and ZIS induce the formation of a built-in electric field, thus regulating the charge transfer routes and consequently enhancing charge separation efficiency. The possible photocatalytic mechanism is analyzed using liquid chromatography-mass spectrometry (LC-MS), and the toxicities of the degradation products are also evaluated. This work presents a green dual-function strategy for H2 production and antibiotic wastewater recycling.

Synthesis of concave Au NRs-Pt-CdS plasmonic photocatalyst with efficient hydrogen production rate

Light-driven water photolysis for hydrogen (H2) generation has been proven to be exceptionally efficient in the field of energy transformation. Nevertheless, the practical applications of many single-component semiconductors still suffer from a relatively low energy conversion efficiency. In this work, concave gold nanorods (Au NRs) with three plasmon resonance modes were synthesized using a one-step method in an aqueous solution. Pt nanoparticles and CdS nanocrystals were rational grown onto Au NRs to design the plasmonic photocatalysts with specific morphology and structure characteristic. Photocatalytic test indicated that concave Au NRs-Pt-CdS hetero-nanostructure possess efficient H2 production rate under visible and near-infrared regions. These findings offer a blueprint for creating a novel group of hetero-nanostructures that combine faceted noble metal nanoparticles with semiconductor materials, demonstrating promise for applications across fields such as photocatalysis and energy storage.

Emerging Trends in CdS-Based Nanoheterostructures: From Type-II and Z-Scheme toward S-Scheme Photocatalytic H2 Production.

Cadmium sulfide (CdS) based heterojunctions, including type-II, Z-scheme, and S-scheme systems emerged as promising materials for augmenting photocatalytic hydrogen (H2) generation from water splitting. This review offers an exclusive highlight of their fundamental principles, synthesis routes, charge transfer mechanisms, and performance properties in improving H2 production. We overview the crucial roles of Type-II heterojunctions in enhancing charge separation, Z-scheme heterojunctions in promoting redox potentials to reduce electron-hole (e-/h+) pairs recombination, and S-scheme heterojunctions in combining the merits of both type-II and Z-scheme frameworks to obtain highly efficient H2 production. The importance of this review is demonstrated by its thorough comparison of these three configurations, presenting valuable insights into their special contributions and capability for augmenting photocatalytic H2 activity. Additionally, key challenges and prospects in the practical applications of CdS-based heterojunctions are addressed, which provides a comprehensive route for emerging research in achieving sustainable energy goals.

Ultra‐Durable Solar‐Driven Seawater Electrolysis for Sustainable Hydrogen Production

AbstractIons in seawater hinder direct sewage electrolysis due to the extreme corrosion of Cl− to the anode and reaction of Mg2+ and Ca2+ on the cathode producing solid substances, which reduce the electrolytic efficiency. However, traditional desalination consuming fossil fuel with massive CO2 emissions threatens human survival. Therefore, zero‐carbon emission, ultra‐durable, large‐scale production of freshwater from seawater for water electrolysis is urgently needed. Herein, a multifunctional system for seawater is demonstrated electrolysis based on ultra‐durable solar desalination outdoors. The solar evaporators reach an evaporation flux of 1.88 kg m−2 h−1 with a photothermal conversion efficiency of solar energy as high as 91.3% with excellent ultra‐durable salt resistance even for saturated saltwater due to the Marangoni effects. Moreover, the condensation of pure water from solar desalination based on the evaporation system reaches 0.54 L m−2 h−1 outdoors, which is suitable for a 20 cm × 20 cm engineered electrode equipped with a Janus membrane powered by a solar panel to produce H2 outdoors. The ultrafast unidirectional transport of H2 bubbles enabled by Janus membranes can greatly improve the H2 production efficiency at a rate approaching 85 mL h−1 for continuous 24 h outdoors.

Tin-doped titanium dioxide film-enhanced electrocatalytic hydrogen evolution

Electrocatalyst water-splitting based on metal oxide nanocomposites has gained considerable interest in hydrogen evolution applications. Here, undoped titanium dioxide and tin-doped titanium dioxide films (TiO2 and Sn/TiO2, respectively) are presented for highly efficient H2 production applications. The crystal structure analysis is performed by analyzing the XRD patterns using the Rietveld refinement method and the Williamson-Hall method. XRF scans are used to confirm the doping mechanism between Sn and TiO2. The bandgap energies of undoped TiO2 and Sn/TiO2 films are 3.33 and 3.15 eV, respectively. On the other hand, the electrical conductivity values of undoped TiO2 and Sn/TiO2 films are 0.10 and 0.25 mS.cm−1, respectively. The electrochemical H2 production performance of undoped TiO2 and Sn/TiO2 films is investigated through two different methods: potentiostat measurements and analytical methods. It can be concluded that the Sn/TiO2 film exhibits higher HER performance and H2 production efficiency than the undoped TiO2 film.

Optimizing H-adsorption affinity on electron-enriched Pdδ- active sites for efficient photocatalytic H2 evolution

Noble metal Pd is a promising H2-evolution cocatalyst and has attracted expansive attention in photocatalytic water splitting. However, the present H2-production rate of Pd cocatalysts is still limited due to its strong hydrogen adsorption on Pd active sites, resulting in poor hydrogen evolution kinetics. In this work, an electron-enriched Pdδ- modulation strategy is developed to weaken the hydrogen adsorption on Pd active sites by producing PdAu alloy, resulting in an increased H2-production rate. In this case, the PdAu homogeneous alloy with a particle size of 9–20 nm is uniformly deposited on the TiO2 surface to produce PdAu-modified TiO2 photocatalysts (TiO2/PdAu). It is found that the prepared TiO2/Pd79Au21 sample achieves the maximal photocatalytic H2-production performance of 31.98 mmol g-1 h−1, which is 1.53 times higher than that of TiO2/Pd photocatalyst. Experimental and theoretical studies show that in addition to the promoted transfer of photogenerated carriers, the PdAu alloy can spontaneously induce the electron transfer from Au to Pd to form electron-enriched Pdδ- sites, which prominently weakens the Pd-Hads bonds and thus improve the H2-production efficiency. This study provides further insight into the rational optimization of active sites to facilitate the design of efficient photocatalysts.

Unraveling the mechanism of CH3CH2OH dehydrogenation on m-ZrO2(111) surface, Au13 cluster, and Au13 cluster/m-ZrO2(111) surface: A DFT and microkinetic modeling study

The dehydrogenation of CH3CH2OH to produce CH3CHO and H2 is crucial for generating valuable chemicals. This study uses density functional theory (DFT) and microkinetic modeling to elucidate the reaction pathways on the m-ZrO2 (111) surface, Au13 cluster, and Au13 cluster/m-ZrO2(111) surface. Dehydrogenation on both the m-ZrO2(111) surface and Au13 cluster occurs via two key steps. The first step involves the cleavage of the OH bond in CH3CH2OH, forming a CH3CH2O moiety and an OH bond with the lattice oxygen on m-ZrO2 (111) surface or with a low-coordination Au atom in the Au13 cluster, respectively; while the formation of H2 takes place in the second step; however, the results microkinetic modeling render low values for the corresponding rate constants for this reaction path. Although the Au13cluster/m-ZrO2(111) surface introduces an additional step, where the H atom migrates from the m-ZrO2 (111) surface to the Au13 cluster, we shown that the relative energy of the three transition states is similar, the activation barriers are lower, and the rate constants are favorable for the dehydrogenation of CH3CH2OH. These results demonstrate the potential of the Au13 cluster supported on m-ZrO2(111) for efficient and selective CH3CHO and H2 production, providing valuable insights for advanced catalytic system design.

Urea-induced low crystallization of Rh nanoparticles for efficient H2 production

Developing highly efficient catalysts for the hydrogen evolution reaction (HER) is crucial for advancing renewable hydrogen energy technologies. Heterophase nanomaterials have shown great promise in catalysis, owing to the synergistic effect among various phases and the abundance of active sites located at the phase boundaries or interfaces. However, achieving precise control over these phase structures during synthesis remains a significant challenge. In this work, we explored a one-pot synthesis method for amorphous/crystalline heterophase Rh nanoparticles, with crystallinity tunable by adjusting the quantity of urea and reaction duration. Due to the increased electrochemical active sites, enhanced electron transport, the resulting amorphous/crystalline heterophase Rh exhibits superior HER activities in both acidic (with an overpotential of 27 mV) and alkaline media (with an overpotential of 21 mV), surpassing that of commercial Pt/C and crystalline Rh. Theoretical calculations indicate that the amorphous/crystalline structure reduces the kinetic barrier for water splitting and optimizes adsorption free energy of hydrogen (ΔGH∗), thereby enabling the catalyst to exhibit significantly enhanced HER performance. This exploration offers a valuable reference for designing amorphous/crystalline heterophase structures and demonstrates the great potential of phase engineering strategy in the development of electrocatalysts.

Unravelling the efficiency of CoAl-LDH / g-C3N4 nanosheets: Type-II heterojunction for photocatalytic hydrogen production and dye degradation under solar light irradiation

The generation of hydrogen fuel, and wastewater treatment according to solar-driven catalysis possesses considerable prospective for establishing a carbon-neutral and ecologically sound power infrastructure. Driven by this problem, we suggest in this study, adopting a simple impregnation method, a customized association of CoAl-LDH and graphitic carbon nitride (CN), a visible light active narrow and wide band gap semiconductors. Several characterization approaches were implemented to understand the CoAl-LDH@g-C3N4 (CACN) composites' physiochemical and optical features. The CACN hetero structural forms exhibited significantly improved solar light-induced photocatalytic H2 generation and dye pollutants decomposition in contrast with pristine materials. The most effective catalyst 5 wt% CoAl-LDH@g-C3N4 (5-CACN) generated the highest hydrogen (∼430.7 μmolg−1h−1), which is 11.9-fold H2 production efficiency compared with CN and depicted significant Brilliant black dye removal efficacy via photocatalytic degradation (up to ∼79%). This was primarily ascribed to the development of the Type-II CACN heterojunctions, which promoted the separation of charges and expanded the abundance of surface-active sites while absorbing the visible spectrum of solar light.

Unveiling the facet-dependent electrocatalytic activity of a 3D-CoSn(OH)6 perovskite material for overall water splitting: Interfacial engineering with Mn3+ and CH3COO- ions

In this study, we report morphologically dependent electrocatalytic oxygen and hydrogen evolution reactions in an alkaline medium. The bifunctional electrocatalyst such as cobalt tin hydroxide (CoSn(OH)6) was prepared by hydrothermal method. Importantly, tuning the morphological variation of CoSn(OH)6 into cubes, octa- and dodecahedra and their corresponding growth mechanisms are analyzed and explored the electrochemical studies. Among the different morphologies, the CoSn(OH)6 dodecahedron (CTH-DH) displays a substantially enhanced overall electrocatalytic water splitting reaction. It is firmly due to the [Mn3+] and [CH3COO-] ions do enable the morphological progression of the CTH cubic crystals with more facets. The highly active catalytic sites on the facets of CTH-DH permit the adsorption of abundant OH groups during the hydrogen and oxygen evolution reactions. Moreover, in a two-electrode system, the CTH-DH ǁ CTH-DH electrolyzer exhibits a cell potential of 1.60 V at 10 mA cm–2 with a remarkable reliable long-term stability. In addition, the structural transformations of the as-prepared CoSn(OH)6 crystals are monitored before and after electrocatalysis using TEM study. As a result, the study highlights the potential of Mn-containing CTH-DH facets as viable electrocatalysts in efficient H2 production.

Photocatalytic H2 production over CoxNi0.85-xSe decorated TiO2 S-scheme heterojunction

The construction of an S-scheme heterojunction facilitates the efficient separation of charges and preserves its high REDOX potential. In this study, a series of CoxNi0.85-xSe(x=0.05,0.1,0.2,0.3and0.4) and TiO2 nanoparticles were both prepared using solvothermal method, and then Co0.3Ni0.55Se was combined with TiO2 to form Co0.3Ni0.55Se/TiO2 heterojunction through a solvent evaporation strategy for efficient photocatalytic H2 production. It found that the H2 production rate of 10 wt%-Co0.3Ni0.55Se/TiO2 composite can reach 10,070.9 µmol∙g−1∙h−1 with TEOA as a sacrificial agent under a simulated sunlight irradiation, which is 307.9, 33.5and 3.3 times higher than those of pure Co0.3Ni0.55Se,TiO2 and 10 wt%-Ni0.85Se/TiO2, respectively. This enhanced performance is primarily attributed to the formation of an S-scheme heterojunction between TiO2 and Co0.3Ni0.55Se, which effectively enhances light absorption capacity and facilitates charge separation and migration during light irradiation processes. Especially, the S-scheme charge separation can retain the active REDOX capacity of electrons in the conduction band of CoxNi0.85-xSe and the holes in the valance band of TiO2, thereby promoting H2 generation. This study demonstrates that CoxNi0.85-xSe serves as a reducing photocatalyst that offers a viable approach for achieving ideal S-scheme heterojunctions.

Photocatalytic activity of molybdenum-doped LOS- zeolite for efficient dye degradation and hydrogen production

This research investigates the synthesis and application of Losod-zeolite (LOS-Z), a crystalline hydrated sodium aluminosilicate (Na12Al12Si12O48.xH2O) as a potential photocatalyst for dye degradation and H2 production from dye-degraded water. The photocatalytic properties are enhanced by impregnating molybdenum (Mo) into LOS-Z (Mo@LOS-Z). XRD, FTIR, SEM, EDX, and elemental mapping were used to study the physicochemical properties of synthesized materials while UV–vis and PL were employed to explore the optoelectronic properties. The photocatalytic activities for dye degradation and H2 production were evaluated using methylene blue (MB) under visible light irradiation. An enhancement in the efficiency of dye degradation (56%–82%) and H2 production rate was demonstrated due to the competitive photocatalytic performance of 10% Mo@LOS-Z compared to the pristine LOS-Z and CFA-BFA blend. It exhibited 2.5 times higher (∼1200 μmol g−1h−1) H2 production than the LOS-Z (∼480 μmol g−1h−1) due to the synergistic effects of narrowed band gap and recombination rate. This study could pave the way forward into the synthesis of waste-derived photocatalysts for efficient dye degradation and H2 production.

Selective Electrooxidation of Crude Glycerol to Lactic Acid Coupled With Hydrogen Production at Industrially-Relevant Current Density.

Transforming glycerol (GLY, biodiesel by-product) into lactic acid (LA, biodegradable polymer monomer) through sustainable electrocatalysis presents an effective strategy to reduce biodiesel production costs and consequently enhance its applications. However, current research faces a trade-off between achieving industrially-relevant current density (>300mA cm-2) and high LA selectivity (>80%), limiting technological advancement. Herein, a Au3Ag1 alloy electrocatalyst is developed that demonstrates exceptional LA selectivity (85%) under high current density (>400mA cm-2). The current density can further reach 1022mA cm-2 at 1.2V versus RHE, superior to most previous reports for GLY electrooxidation. It is revealed that the Au3Ag1 alloy can enhance GLY adsorption and reactive oxygen species (OH*) generation, thereby significantly boosting activity. As a proof of concept, a homemade flow electrolyzer is constructed, achieving remarkable LA productivity of 68.9mmolh-1 at the anode, coupled with efficient H2 production of 3.5 Lh-1 at the cathode. To further unveil the practical possibilities of this technology, crude GLY extracted from peanut oil into LA is successfully transformed, while simultaneously producing H2 at the cathode. This work showcases a sustainable method for converting biodiesel waste into high-value products and hydrogen fuel, promoting the broader application of biodiesel.

Simultaneous efficient production of hydrogen peroxide, urea and H2 by bifunctional Cu-doped TiO2 electrocatalyst from CO2, N2 and water

The production of three separated, high-value chemicals (H2O2, urea and H2) from CO2, N2, and H2O represents a significant challenge. It is a prospective and innovative way to simultaneously produce these chemicals in an anion exchange membrane (AEM) electrolyzer, which couples anodic 2e- water oxidation (2e-WOR) and cathodic CO2, N2 and water reduction reaction (CNWRR), but has not yet been realized. Here, we found that bifunctional CuxTi1-xO2-y catalysts can be employed in the electrochemical production of H2O2, urea and H2 from CO2, N2 and water, and the optimized Cu0.12Ti0.88O2-y catalyst exhibits an excellent productivity of 11.8 μmol cm−2 min−1, 0.3 mg cm-2h−1 and 0.82 mmol cm-2h−1 for H2O2, urea and H2 at 4.0 V (50 mA cm−2) in AEM electrolyzer, respectively. Theoretical calculations reveal that the superior performance of the 2e-WOR and CNWRR is attributed to the Cu doping effect, which not only promotes the coupling of *OH but also optimizes the adsorption energy barriers of COOH* and NNH*. It is worth noting that the AEM electrolyzer assembled by bifunctional Cu0.12Ti0.88O2-y reaches a current density of 50 mA cm−2 with a cell voltage of 4.0 V and exhibits excellent stability of 50-hour continuous operation.

Study of an enhanced photocatalytic hybrid MnO2@SnO2 core-shell Z-scheme nano heterojunction for efficient H2 production

The usage of non-renewable carbon-base fuel energy have created multiple issues such as global warming, environmental degradations etc. Replacing these non-renewable sources of energy with renewable energy (photocatalytic H2 production) is a hot topic for researchers due to its sustainability and eco-friendliness. In this work MnO2, SnO2 and their nanocomposites have been synthesized through simple hydrothermal and co-precipitation methods. The purpose of such nanocomposite fabrication is to synthesize a suitable heterostructure for maximum solar energy harvesting in water splitting. All the prepared samples of pure MnO2, SnO2, and nanocomposites have been characterized through various techniques, which confirm the structure, functional groups, absorbance, morphology, elemental compositions, chemical compositions, and increase in photo-induced current as well as the photostability of such nanocomposites. The highest apparent quantum yield of the optimized MnO2@SnO2 (first time reported as photocatalyst for H2 production) were 21.7% at wavelength 420 nm, which is the highest ever reported for such (MnO2@SnO2) nanocomposite. The enhanced photocatalytic behavior for H2 production has been observed which is 3.67 times greater than pristine MnO2. Such an enhancement is due to the synergistic effect of SnO2 NPs decorated on the NTs of MnO2. The present work provides a novel approach to produce hydrogen with high performance as efficient solar harvesting.

Boosting the electrocatalytic performance of CuCo2S4 via surface-state engineering for ampere current water electrolysis applications

For the efficient production of green H2 on an industrial scale, developing durable, cost-effective electrocatalysts using earth-abundant transition-metals is crucial. Herein, we report a robust, bifunctional sulfurized CuCo2O4 (CCS/Ov) catalyst with engineered oxygen-vacancies, in which the metal catalyst is tunes to high valence state, significantly altering the intrinsic reaction kinetics and generating better catalytic activity for efficient ion transport in various electrolytes (neutral, seawater, alkaline simulated-seawater (ASW), and KOH). The optimized dual-strategy synthesized CCS/Ov catalysts with hierarchical morphology exhibits modest overpotential of 383 and 355 mV at 1000 mA cm−2 for OER and HER, respectively, in 1 M KOH. Impressively, an electrolyzer cell (CCS/Ov||CCS/Ov) demonstrates low cell-voltage of 1.487 V (6 M KOH), with excellent robustness in an ASW (1 and 2 M) environment against corrosive chlorine. The bifunctional CCS/Ov||CCS/Ov catalyst outperforms a state-of-the-art paired Pt/C||RuO2 catalyst and maintains the lowest potential response at up to 2000 mA cm−2, while demonstrating remarkably stable simultaneous O2 and H2 generation over 10 days at various current rates. Additionally, DFT calculations confirmed that CCS/Ov catalysts demonstrate significantly enhanced HER and OER activities due to reduced H2O dissociation energy and strong intermediate binding energy, which is attributed to the anionic vacancy near Co3+. The excellent bifunctional performance of the hierarchical CCS/Ov highlights its potential as non-precious catalyst with facile fabrication approach.

Zinc Vaporization Induced Formation of Desired Ni Nanoparticles Coated with Ultrathin Carbon Shells for Efficient Electrocatalytic H2 Production Coupling with Methanol Upgrading.

The integration of the hydrogen evolution reaction (HER) with the methanol oxidation reaction (MOR) has been demonstrated to be a viable strategy for the energy-saving generation of H2 and value-added formate, which relies primarily on highly active and cost-effective bifunctional electrocatalysts. Herein, an efficient electrocatalyst consisting of controllable Ni nanoparticles (NPs) coated with ultrathin graphitic carbon shells was obtained by the pyrolysis of a Ni-Zn metal-organic framework. Intriguingly, we found that zinc vaporization not only resulted in the relatively small Ni NPs but also ultrathin carbon shells (≤3 layers). The density functional theory simulations confirmed that these ultrathin carbon shells significantly influenced electrocatalytic activity by facilitating electron transfer from the Ni core to the carbon shell. The optimized Ni1(Zn)@C demonstrated high catalytic activity for both HER and MOR, and only a low potential of 97 mV at 10 mA cm-2 was required for HER and 1.48 V at 30 mA cm-2 for MOR. In a two-electrode electrocatalytic cell measurement, a cell voltage of 1.63 V was observed at 10 mA cm-2 in the presence of methanol, 240 mV lower than that without methanol.

MoS2/CuS/g-C3N4 double S-scheme with charge storage ability for efficient photocatalytic H2 production

The photocatalytic H2 production technology exhibits promising potential in addressing the challenges of environmental pollution and energy crisis. In this work, CuS particles decorated MoS2 seaweed spheres (MoS2/CuS) were synthesized through a hydrothermal method, then they are loaded on the surface of g-C3N4 nanosheets using a solvent evaporation strategy to form MoS2/CuS/g-C3N4 double S-scheme heterojunction. The investigation reveals the H2 production rate of 25 wt% MoS2/CuS/g-C3N4 can reach up to 1438 μmol·g-1·h-1, which is 14.8-fold of g-C3N4 (97 μmol·g-1·h-1). Further studies indicate that the introduction of MoS2/CuS can broaden the light absorption range, increase electrochemical specific surface area, reduce the activation energy for H2 production and increase hydrophilicity of the composite. Especially, CuS can suppress carrier recombination effectively through its electron storage and release ability. Based on the experimental and theoretical analysis of band structures, the charge transfer in MoS2/CuS/g-C3N4 shares optimized double S-scheme charge transfer pathways with a dual reduction site, leading to an enhanced H2 evolution kinetics. This work offers valuable insights for the advancement of novel double S-scheme heterojunctions, showcasing their potential in energy storage and photothermal enhancement effects.