Highly efficient visible-light-driven photocatalytic H2 production over a p−n Mn0.2Cd0.8S/NiCo2O4 heterojunction modified with Ni2P

In this work, the Mn_0.2Cd_0.8S/NiCo₂O₄ composite modified with Ni₂P as a co-catalyst was fabricated via a simple two-step hydrothermal method. The as-prepared ternary Mn_0.2Cd_0.8S/NiCo₂O₄/Ni₂P composite displayed excellent H₂ production performance. The ternary composite loaded with 5 wt% NiCo₂O₄ and 2 wt% Ni₂P obtained the optimal H₂ production performance of 24.47 mmol g^?1 h^?1 and a maximum AQE of 23.75%. The enhanced H₂ production activity was assigned firstly to efficient spatial charge separation through the p?n Mn_0.2Cd_0.8S/NiCo₂O₄ heterojunction and secondly to sufficient surface active sites provided by Ni₂P co-catalysts. This research provides a new approach to design effective ternary heterojunction.     

Design and fabrication of C–Mn0.5Cd0.5S/Cu3P ternary heterojunction catalyst for photocatalytic hydrogen evolution

Photocatalytic hydrogen evolution from water splitting is a promising strategy to solve the energy demand of human beings. Here, we first designed a C–Mn_0.5Cd_0.5S/Cu₃P ternary heterojunction catalyst for photocatalytic hydrogen production. The results show that the combination of C and Cu₃P can effectively improve the photocatalytic activity of Mn_0.5Cd_0.5S. C–Mn_0.5Cd_0.5S loading with 5 wt% Cu₃P exhibits the highest hydrogen evolution rate (44.1 mmol g⁻¹ h⁻¹), which is 3.2 and 2.8 times higher than that of pure Mn_0.5Cd_0.5S (13.7 mmol g⁻¹ h⁻¹) and Mn_0.5Cd_0.5S/3 wt%Pt (15.6 mmol g⁻¹ h⁻¹), respectively. In addition, it shows a high hydrogen evolution rate (19.6 mmol g⁻¹ h⁻¹) under visible light (≥420 nm) irritation and the apparent quantum efficiency (AQE) is detected to be 3.2% at 420 nm. The enhanced photocatalytic activity can be attributed to the good conductivity of C and the formation of p-n heterojunction, which is beneficial for light harvesting and the separation and transportation of charge carriers. Besides, a possible mechanism is proposed. This work provides an effective way to improve the photocatalytic activity of Mn_0.5Cd_0.5S by using non noble metal co-catalysts.     

Boosting hydrogen evolution under simulated sunlight via constructing close electron transfer interface between 1D CdxZn1-xS nanorod and 2D MoS2@MoOy nanosheet

Designing an efficient non-noble metal photocatalyst, which utilizes solar energy, has great potential to produce clean energy hydrogen. The microstructural refinement of 1D Cd_0.2Zn_0.8S nanorod was induced by doping with 2D MoS₂@MoO_y layer during microwave hydrothermal treatment. The maximum H₂ production rate of the composite prepared at optimum conditions was 186 mmol g⁻¹ h⁻¹, which increased by 34.8% compared with that of Cd_0.2Zn_0.8S (138 mmol g⁻¹ h⁻¹). The apparent quantum yields of the optimized composite were 10.3% and 15.6% at 365 and 420 nm, respectively. The tight S-scheme heterojunction contributed to the separation of photogenerated electron-hole pairs effectively, as confirmed by the characterization analysis of ·OH and ·O⁻₂ radicals, surface potential under illumination and darkness and in situ XPS spectra. Moreover, the active species of sulfur coordinated-Mo⁵⁺ as low-coordinate center promoted the dissociation of water and decreased the over potential of H₂ production. Furthermore, the optimal composite showed excellent stable catalytic activity for hydrogen evolution, and the H₂ production rate was 176.7 mmol g⁻¹ h⁻¹ after five cycles (95% of the first cycle). Overall, this work provides a promising strategy for improving the effectiveness of H₂ production by preparing non-noble metal composite photocatalysts.     

In-situ construction of Mo3S4/Cd0.5Zn0.5S heterojunction: An efficient and stable photocatalyst for H2 evolution

In this work, Mo₃S₄/Cd_0.5Zn_0.5S heterojunction with abundant porosity was in-situ synthesized by one-step hydrothermal method. Characterization results clearly indicate that the composite material are composed of nanoparticles with an average particle diameter about 65 nm and abundant inter-particle pores are present in between. The XPS analysis found that when Mo₃S₄ was introduced, the XPS peak positions of Cd²⁺ and Zn²⁺ were shifted from the XPS peak positions of Cd²⁺ and Zn²⁺ in pristine Cd_0.5Zn_0.5S, which indicates that there is an interaction between Mo₃S₄ and Cd_0.5Zn_0.5S at the interface. Subsequently, the Mo₃S₄/Cd_0.5Zn_0.5S (72.1 mmol h⁻¹ g⁻¹) heterojunction can achieve much higher photocatalytic hydrogen production rate than the pristine Cd_0.5Zn_0.5S (7.54 mmol h⁻¹ g⁻¹), and even higher than Cd_0.5Zn_0.5S (56.44 mmol h⁻¹ g⁻¹) loaded with the noble metal Pt (2.0%), indicating that heterojunction can effectively enhance photocatalytic activity. In addition, the improvement in photocatalytic activity of Mo₃S₄/Cd_0.5Zn_0.5S is highly related with enhanced absorption and utilization of light due to the presence of the inter-particle pores which inhibit recombination of electron-hole pairs, promote charge separation and accelerate the migration of photogenerated carriers.     

Designing of a novel Mn0.2Cd0.8S@ZnO heterostructure with Type-II charge transfer path for efficient photocatalytic hydrogen evolution reaction

The development of photocatalysts with efficient hydrogen evolution activity has been the goal for sustainable hydrogen production. In this work, heterojunction composite photocatalyst is formed by hydrothermal coupling of ZnO and Mn_0.2Cd_0.8S. Compared with pure ZnO and Mn_0.2Cd_0.8S, the composite photocatalyst has the ability to provide more abundant active sites and better photogenerated carriers separation efficiency. The optimized composite photocatalyst shows a 9.36-fold increase in hydrogen evolution activity (4297.99 μmol g^?1 h^?1) compared to Mn_0.2Cd_0.8S (459.31 μmol g^?1 h^?1) and exhibits excellent cycling stability. Density functional theory calculations identifies Type-II charge transfer path in the composite photocatalyst, achieving effective separation in space of photogenerated electrons from holes and suppressing recombination within the semiconductor. The results show that the construction of Type-II heterojunction in this work achieves a significant enhancement of the hydrogen evolution activity of the photocatalyst by constructing carrier transport channels at the contact interface of the heterojunction.     

Highly efficient Bi2O3/MoS2 p-n heterojunction photocatalyst for H2 evolution from water splitting

The design of p-n heterojunction photocatalysts to overcome the drawbacks of low photocatalytic activity that results from the recombination of charge carriers and narrow photo-response range is promising technique for future energy. Here, we demonstrate the facile hydrothermal synthesis for the preparation of Bi₂O₃/MoS₂ p-n heterojunction photocatalysts with tunable loading amount of Bi₂O₃ (0–15 wt%). The structure, surface morphology, composition and optical properties of heterostructures were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–visible absorption spectroscopy, Brunauer-Emmett-Teller (BET) surface area, photoluminescence (PL), electrochemical impedance spectroscopy (EIS). Compare to pure Bi₂O₃ and MoS_2, the Bi₂O₃/MoS₂ heterostructures displayed significantly superior performance for photocatalytic hydrogen (H₂) production using visible photo-irradiation. The maximum performance for hydrogen evolution was achieved over Bi₂O₃/MoS₂ photocatalyst (10 μmol h⁻¹g⁻¹) with Bi₂O₃ content of 11 wt%, which was approximately ten times higher than pure Bi₂O₃ (1.1 μmol h⁻¹g⁻¹) and MoS₂ (1.2 μmol h⁻¹g⁻¹) photocatalyst. The superior performance was attributed to the robust light harvesting ability, enhanced charge carrier separation via gradual charge transferred pathway. Moreover, the increased efficiency of Bi₂O₃/MoS₂ heterostructure photocatalyst is discussed through proposed mechanism based on observed performance, band gap and band position calculations, PL and EIS data.     

High-temperature sulfurized synthesis of MnxCd1-xS composites for enhancing solar-light driven H2 evolution

In recent years, tremendous efforts have been devoted to develop new photocatalyst with wide spectrum response for H₂ generation from water or aqueous solution. In this paper, Mn_xCd_1-xS composites were in-situ fabricated via the high-temperature sulfurization to enhance the solar-light photocatalytic capacity of H₂ evolution. Benefiting from the S defects and junction interface between MnS and CdS, Mn_xCd_1-xS composites exhibited the better H₂ evolution rate than pure MnS. The H₂ evolution rate of optimal Mn_0.5Cd_0.5S with a Mn(II) content of 22.52% and a Mn/Cd mole ratio of 0.95:1 was 9.27 mmol g^?1 h^?1, which was 35.65 and 2.38 times higher than pure MnS (0.26 mmol g^?1 h^?1) and CdS (3.89 mmol g^?1 h^?1), respectively. In addition, H₂ evolution capacity of Mn_0.5Cd_0.5S decreased from 44.83 to 41.66 mmol g^?1 after three cycles. Mn_0.5Cd_0.5S prepared via the high-temperature sulfurization was thus a potential material for solar-light induced H₂ generation.     

Rationally designed ternary CdSe/WS2/g-C3N4 hybrid photocatalysts with significantly enhanced hydrogen evolution activity and mechanism insight

Excellent light harvest, efficient charge separation and sufficiently exposed surface active sites are crucial for a given photocatalyst to obtain excellent photocatalytic performances. The construction of two-dimensional/two-dimensional (2D/2D) or zero-dimensional/2D (0D/2D) binary heterojunctions is one of the effective ways to address these crucial issues. Herein, a ternary CdSe/WS₂/g-C₃N₄ composite photocatalyst through decorating WS₂/g-C₃N₄ 2D/2D nanosheets (NSs) with CdSe quantum dots (QDs) was developed to further increase the light harvest and accelerate the separation and migration of photogenerated electron-hole pairs and thus enhance the solar to hydrogen conversion efficiency. As expected, a remarkably enhanced photocatalytic hydrogen evolution rate of 1.29 mmol g⁻¹ h⁻¹ was obtained for such a specially designed CdSe/WS₂/g-C₃N₄ composite photocatalyst, which was about 3.0, 1.7 and 1.3 times greater than those of the pristine g-C₃N₄ NSs (0.43 mmol g⁻¹ h⁻¹), WS₂/g-C₃N₄ 2D/2D NSs (0.74 mmol g⁻¹ h⁻¹) and CdSe/g-C₃N₄ 0D/2D composites (0.96 mmol g⁻¹ h⁻¹), respectively. The superior photocatalytic performance of the prepared ternary CdSe/WS₂/g-C₃N₄ composite could be mainly attributed to the effective charge separation and migration as well as the suppressed photogenerated charge recombination induced by the constructed type-II/type-II heterojunction at the interfaces between g-C₃N₄ NSs, CdSe QDs and WS₂ NSs. Thus, the developed 0D/2D/2D ternary type-II/type-II heterojunction in this work opens up a new insight in designing novel heterogeneous photocatalysts for highly efficient photocatalytic hydrogen evolution.     

Construction of noble-metal-free FeWO4/Mn0.5Cd0.5S photocatalyst to optimize H2 evolution performance in water splitting

Designing cost-effective photocatalysts with remarkable performance is a foresighted strategy to foster the evolution of H₂ in water splitting. In this study, a p-n heterojunction FeWO₄/Mn_0.5Cd_0.5S photocatalyst modified by low-cost and non-toxic FeWO₄ was synthesized using hydrothermal and calcination methods. The hydrogen evolution activity of Mn_0.5Cd_0.5S was strengthened by varying the amount of FeWO₄ loading. The hydrogen production rate of FeWO₄/Mn_0.5Cd_0.5S photocatalyst loaded with 10% FeWO₄ can reach 9.63 mmol g^?1 h^?1, which is equivalent to 2.16 times of pure Mn_0.5Cd_0.5S. The enhancement of the H₂ evolution activity was primarily contributed to a p-n heterojunction formed at the interface of FeWO₄ and Mn_0.5Cd_0.5S. It provides a fast pathway for the migration and separation of photogenerated charges and effectively inhibits the photo-corrosion of Mn_0.5Cd_0.5S.     

Surface oxygen vacancy facilitated Z-scheme MoS2/Bi2O3 heterojunction for enhanced visible-light driven photocatalysis-pollutant degradation and hydrogen production

An oxygen-vacancy rich, bismuth oxide (Bi₂O₃) based MoS₂/Bi₂O₃ Z-scheme heterojunction catalyst (2-BO-MS) was prepared in an autoclave hydrothermal method using ethanol and water. The performance of MoS₂/Bi₂O₃ catalyst was examined for photocatalytic hydrogen evolution, photoelectrochemical activity, and crystal violet (CV) dye degradation by comparing with pristine Bi₂O₃ and MoS₂. The hydrogen evolution performances of 2-BO-MS catalyst exhibited 3075.21 μmol g⁻¹ h⁻¹, which is 7.18 times higher than that of MoS₂ (428.14 μmol g⁻¹ h⁻¹). The XPS, XRD and HRTEM analyses covered that the superior photocatalytic performance of 2-BO-MS catalyst might have stemmed out due to the existence of oxygen vacancies, enhanced strong interfacial interaction between MoS₂ and Bi₂O₃ and specific surface area. The in-depth investigation has been performed for MoS₂/Bi₂O₃ Z-scheme heterojunction using several characterization techniques. Moreover, the photocatalytic mechanism for hydrogen evolution and photodegradation were proposed based on trapping experiment results. This results acquired using MoS₂/Bi₂O₃ Z-scheme heterojunction would be stepping stone for developing heterojunction catalyst towards attaining outstanding photocatalytic activity.     

ZnCo2S4/Zn0.2Cd0.8 S Z-scheme heterojunction: Efficient photocatalytic H2 evolution coupling selective oxidation of benzyl alcohol

The Z-scheme heterojunction photocatalysts possess excellent photocatalytic activity benefitting from their properly matched edge potentials. In this work, ZnCo₂S₄ nanoparticles are anchored on Zn_0.2Cd_0.8S solid solution nanowires and assembled into binary ZnCo₂S₄/Zn_0.2Cd_0.8S nanocomposites. The as-synthesized ZnCo₂S₄/Zn_0.2Cd_0.8S nanocomposites act as bifunctional photocatalysts, which can be used for high-performance H₂ production coupling synthesis of high-value-added benzaldehyde in low concentration benzyl alcohol solution. Under visible light irradiation, 20%-ZnCo₂S₄/Zn_0.2Cd_0.8S nanocomposite shows the highest H₂ evolution rate of 23.02 mmol g^?1 h^?1 in the first photocatalytic cycle, which is 395.0 and 526.7 times higher than that of Zn_0.2Cd_0.8S and ZnCo₂S₄ under the same conditions. Eventually, after six-time cycles, the conversion rate and selectivity of benzyl alcohol oxidation to benzaldehyde are 54.3% and 92.2%, respectively. The enhancement of photocatalytic performance is mainly attributed to the Z-scheme heterojunction between ZnCo₂S₄ and Zn_0.2Cd_0.8S, which promote the separation and transfer of photogenerated charge carriers. This work provides strong support for the rational design of Z-scheme nano-heterojunction of highly efficient photocatalytic application in H₂ evolution and fine chemicals production.     

Efficient photocatalytic hydrogen evolution on amorphous MoSx-modified CdS/KTaO3 heterojunctions under visible light irradiation

Constructing heterostructures with efficient charge separation is a promising route to improve photocatalytic hydrogen production. In this paper, MoS_x/CdS/KTaO₃ ternary heterojunction photocatalysts were successfully prepared by a two-step method (hydrothermal method and photo deposition method), which improved the photocatalytic hydrogen evolution activity. The results show that the rate of hydrogen evolution for the optimized photocatalyst is 2.697 mmol g^?1·h^?1under visible light, which is 17 times and 2.6 times of the original CdS (0.159 mmol g^?1 h^?1) and the optimal CdS/KTaO₃(1.033 mmol g^?1 h^?1), respectively, and the ternary photocatalyst also shows good stability. The improvement on photocatalytic hydrogen evolution performance can be attributed to the formation of heterojunction between the prepared composite materials, which effectively promotes the separation and migration of photo-generated carriers. Amorphous MoS_x acts as an electron trap to capture photogenerated electrons, providing active sites for proton reduction. This provides beneficial enlightenment for hydrogen production by efficiently utilizing sunlight to decompose water.     

Hydrogen generation by photocatalytic reforming of glucose with heterostructured CdS/MoS2 composites under visible light irradiation

A binary heterostructured CdS/MoS₂ flowerlike composite photocatalysts was synthesized via a simple one-pot hydrothermal method. This photocatalyst demonstrated higher photocatalytic hydrogen production activity than pure MoS₂. The heterojunction formed between MoS₂ and CdS seems to promote interfacial charge transfer (IFCT), suppress the recombination of photogenerated electron–hole pairs, and enhance the hydrogen generation. Based on the good match between the conduction band (CB) edge of CdS and that of MoS₂, electrons in the CB of CdS can be transferred to MoS₂ easily through the heterojunction between them, which prevents the accumulation of electrons in the CB of CdS, inhibiting photocorrosion itself and greatly enhancing stability of catalyst. Hydrogen evolution reaction (HER) using Na₂S/Na₂SO₃ or glucose as sacrificial agents in aqueous solution was investigated. The ratio between CdS and MoS₂ plays an important role in the photocatalytic hydrogen generation. When the ratio between CdS and MoS₂ reaches 40 wt%, the photocatalyst showed a superior H₂ evolution rate of 55.0 mmol g⁻¹ h⁻¹ with glucose as sacrificial agent under visible light, which is 1.2 times higher than using Na₂S/Na₂SO₃ as sacrificial agent. Our experimental results demonstrate that MoS₂-based binary heterostructured composites are promising for photocorrosion inhibition and highly efficient H₂ generation.     

Highly efficient white-LED-light-driven photocatalytic hydrogen production using highly crystalline ZnFe2O4/MoS2 nanocomposites

Designing efficient photocatalytic systems for hydrogen evolution is extremely important from the viewpoint of the energy crisis. Highly crystalline heterostructure catalysts have been established, considering their interface electric field effect and structural features, which can help improve their photocatalytic hydrogen-production activity. In this study, we fabricated a highly crystalline heterojunction consisting of ZnFe₂O₄ nanobricks anchored onto 2D molybdenum disulfide (MoS₂) nanosheets (i.e., ZnFe₂O₄/MoS₂) via a hydrothermal approach. The optimized ZnFe₂O₄/MoS₂ photocatalyst, with a ZnFe₂O₄ content of 7.5 wt%, exhibited a high hydrogen-production rate of 142.1 μmol h⁻¹ g⁻¹, which was 10.3 times greater than that for the pristine ZnFe₂O₄ under identical conditions. The photoelectrochemical results revealed that the ZnFe₂O₄/MoS₂ heterojunction considerably diminished the recombination of electrons and holes and promoted efficient charge transfer. Subsequently, the plausible Z-scheme mechanism for photocatalytic hydrogen production under white-LED light irradiation was discussed. Additionally, the influence of cocatalysts on the photocatalytic hydrogen evolution for the ZnFe₂O₄/MoS₂ heterostructure was investigated. This work has demonstrated a simplified coupling of one-dimensional or zero-dimensional structures with 2D nanosheets for improving the photocatalytic hydrogen production activity as well as confirmed that MoS₂ is a viable substitute for precious metal-free photocatalysis.     

Insight into NiCo-based nanosheets modified MnS/Mn0·2Cd0·8S hybrids for enhanced visible-light photocatalytic H2 evolution

Bimetallic compounds nanocrystals exhibited great potential in catalysis due to the synergistic effects and encouraging performance. Herein, a series of NiCo-based nanosheets, including NiCo LDH/NiCo(OH)₂, NiCo, and NiCo₂O₄, have been developed to modify MnS/Mn_0·2Cd_0·8S (MMCS) nanoparticles for photocatalytic H₂ production under visible light (λ > 420 nm). The two-dimensional (2D) NiCo₂O₄ and NiCo were derived from the oxidation and reduction process of the as-prepared NiCo LDH/NiCo(OH)₂ nanosheets, respectively. MMCS nanoparticles were prepared using a one-pot solvothermal method and then integrated into three different NiCo-based nanosheets through a simple hybridization approach. Compared to pure MMCS, the resultant NiCo-based nanosheets/MMCS hybrids show dramatically improved visible-light photocatalytic activities. Moreover, among the three types of composites, NiCo₂O₄-MMCS (7%NiCo₂O₄-MMCS) displays the highest H₂ production rate of 3.31 mmol g^?1 h^?1 with the apparent quantum efficiency of 6.42% at 420 nm, approximately 22 and 5 times that of pure MMCS (0.15 mmol g^?1 h^?1) and Pt/MMCS (0.67 mmol g^?1 h^?1), respectively. The remarkably enhanced photocatalytic activities of the NiCo LDH/NiCo(OH)₂-MMCS, NiCo-MMCS, and NiCo₂O₄-MMCS are mainly ascribed to the formed type-II, Schottky, and p-n heterojunctions, respectively, which efficiently boost photogenerated charge carrier separation and migration. In this paper, we intensively investigate the roles of three different NiCo-based nanosheets in the Mn_xCd_1-xS-based system. This work provides an effective strategy to design and construct the innovative 2D bimetallic compounds-based catalysts for high-efficiency photocatalytic H₂ production.     

Experimental evaluation of Pt/TiO2/rGO as an efficient HER catalyst via artificial photosynthesis under UVB & visible irradiation

The study investigated the synergistic effects of rGO and Pt over TiO₂ for the HER via artificial photosynthesis under UVB and visible light irradiation. The introduction of glycerol and industrial wastewater to the system as sacrificial reductants signifies that the major reaction pathway is photocatalytic partial water splitting. The material characterizations revealed successful heterojunction formation and provided insight into chemistry behind the activity of the photocatalysts. Amongst various combinations of rGO on TiO₂, 1GNT exhibited an HER yield five times that of bare TiO₂ under UVB light. Addition of Pt led to the formation of a strong Schottky barrier at the heterojunction and consequently boosted HER performance. 1P0.5 GT presented the highest of 28.5 mmol g⁻¹ h⁻¹ with glycerol and 9.6 mmol g⁻¹ h⁻¹ with wastewater under UVB light respectively. For both binary and ternary photocatalysts, the HER performances dwindled under visible light irradiation, accentuating the insufficient activation of the TiO₂. In addition, 1PT outperformed all the other photocatalysts thereby elucidating the impression that rGO and Pt does not work well together in enhancing HER despite quenching the exciton recombination rate of TiO₂ significantly. The role of pH in the synthesis and the experiments has been discussed. Finally, the underlying mechanisms in the photodeposition and photoreformation have been proposed.     

Mn0.2Cd0.8S nanorods assembled with 0D CoWO4 nanoparticles formed p-n heterojunction for efficient photocatalytic hydrogen evolution

In this work, p-type semiconductor CoWO₄ nanoparticles was successfully anchored on the surface of n-type Mn_0.2Cd_0.8S nanorods, and p-n type heterostructure photocatalysts with low cost and high efficiency were synthesized. By optimizing the loading of CoWO₄ nanoparticles, the hydrogen evolution rate of the compound can reach a maximum, the peak is 408 μmol/5 h. Under visible light irradiation, it is equivalent to 3.61 times pure Mn_0.2Cd_0.8S. In addition, the composite catalyst has favorable durability and structural stability. In terms of morphology, the combination of nanorods (S_BET = 24 m²g^-1) and nanoparticles (S_BET = 12 m²g^-1) increased the specific surface area of the composite catalyst (S_BET = 31 m²g^-1), thus the composite exposed more active sites. In terms of heterojunction, the conduction bands of two semiconductors were determined by UV–vis diffuse reflection and Mott-Schottky, and the construction of p-n heterojunction was verified. The results of photochemical experiment further indicate that the built-in electric field in the p-n type heterostructure not only accelerates the electron-hole pair transfer, but vastly enhances the carrier average lifetime. In this paper, the morphology of the photocatalyst was modified and p-n heterojunction was constructed. The result is that the performance of Mn_0.2Cd_0.8S MCS was improved and the possible mechanism of photocatalytic hydrogen evolution was proposed.     

NiSe2/Cd0.5Zn0.5S as a type-II heterojunction photocatalyst for enhanced photocatalytic hydrogen evolution

A designed type-II heterojunction photocatalyst, NiSe₂/Cd_0.5Zn_0.5S (NiSe₂/CZS), was successfully synthesized and it exhibits outstanding photocatalytic hydrogen evolution performance. The optimal loading amount of NiSe₂ on Cd_0.5Zn_0.5S is 13 wt %, and the corresponding hydrogen production rate is approximately 121.01 mmol g^?1 h^?1 under visible light. The heterojunction structure between Cd_0.5Zn_0.5S and NiSe₂ promoted the separation of photogenerated electron-hole pairs, effectively suppressed the photogenerated carrier recombination and endowed the material with excellent interfacial charge transfer properties, thus improving the photocatalytic performance.     

Dual CdS–CoS/S,N-doped TiO2 nanofibers for efficient visible-light induced H2 evolution

Solar-light driven water splitting acted as an important technology to solve the energy crisis has attracted much more attention. To restrain the recombination rate of charge carriers and enhance the surface activity of TiO₂, integrating dual CdS–CoS with S,N-codoped TiO₂ with a Cd/Co mole ratio of 1:1 (Cd_0.5Co_0.5S/SN-TiO₂) nano-fibers were fabricated via the electro-spinning and one-pot hydrothermal routes. H₂-evolution rate of Cd_0.5Co_0.5S/SN-TiO₂ nano-fibers was higher than TiO₂, CoS/SN-TiO₂ and CdS/SN-TiO₂ nano-fibers. The optimal 3-Cd_0.5Co_0.5S/SN-TiO₂ with a Cd_0.5Co_0.5S ratio of 5.0 wt% performed the highest photocatalytic activity (4.55 mmol g^?1 h^?1), and the best photocatalytic durability after five cycles. It's owing to the hybrid effect of CdS and CoS for efficient transfer and separation of charge carriers at the junction interface between Cd_0.5Co_0.5S nanoparticles and S,N-codoped TiO₂ nanofibers. Meanwhile, the extending visible-light response and sufficient active sites of TiO₂-based heterojunctions are favorable for the water splitting.     

MoS2 grown in situ on CdS nanosheets for boosted photocatalytic hydrogen evolution under visible light

A novel nano-heterojunction photocatalysts of CdS/MoS₂ with appropriate interfacial contact was successfully obtained by the facile two-step hydrothermal synthesis. The MoS₂ ultrathin layer was well combined with CdS nanosheets and formed the interaction, which facilitated the transfer and separation of charges. The CdS/MoS₂ 15 wt% possessed much higher H₂ evolution photocatalytic performance (35.24 mmol h^?1 g^?1), exhibiting an 85.95 times enhancement as compared to that of pure CdS (0.41 mmol h^?1 g^?1). Moreover, the photochemical stability of CdS/MoS₂ heterojunctions was excellent, which showed no significant decrease in activity after four cycles of experiments. The finding provides a novel method to integrate the structure of MoS₂ with CdS, which exhibits great potential in solar energy conversion.