Photocatalytic H2 Evolution Rate Research Articles

Construction of two-dimensional heterojunctions based on metal-free semiconductor materials and Covalent Organic Frameworks for exceptional solar energy catalysis

Covalent organic frameworks (COFs) are newly developed crystalline substances that are garnering growing interest because of their ultra-high porosity, crystalline nature, and easy modified architecture, showing promise in the field of photocatalysis. However, it is difficult for pure COFs materials to achieve excellent photocatalytic hydrogen production due to their severe carrier recombination problems. To mitigate this crucial issue, establishing heterojunction is deemed an effective approach. Nonetheless, many of the metal-containing materials that have been used to construct heterojunctions with COFs own a number of drawbacks, including small specific surface area and rare active sites (for inorganic semiconductor materials), wider bandgaps and higher preparation costs (for MOFs). Therefore, it is necessary to choose metal-free materials that are easy to prepare. Red phosphorus (RP), as a semiconductor material without metal components, with suitable bandgap, moderate redox potential, relatively minimal toxicity, is affordable and readily available. Herein, a range of RP/TpPa-1-COF (RP/TP1C) composites have been successfully prepared through solvothermal method. The two-dimensional structure of the two materials causes strong interactions between the materials, and the construction of heterojunctions effectively inhibits the recombination of photogenic charge carrier. As a consequence, the 9% RP/TP1C composite, with the optimal photocatalytic ability, achieves a photocatalytic H2 evolution rate of 6.93 mmol g−1 h−1, demonstrating a 10.19-fold increase compared to that of bare RP and a 4.08-fold improvement over that of pure TP1C. This article offers a novel and innovative method for the advancement of efficient COFs-based photocatalysts.

Unlocking the potential of multifunctional and highly porous Ti3C2/TiO2@Bi2O3 – based MXene: Synergetic photocatalytic activation of peroxymonosulfate, hydrogen evolution and antimicrobial activity

A novel and efficient solar light responsive multi layered highly porous MXene-based Ti3C2/TiO2@Bi2O3 photocatalyst was synthesized by hydro/solvothermal technique. The optimized band gap (2.09 eV), high surface area (28.39 m2/g), schottky and p-n junctions remarkably enhanced the effectiveness of TTB20 in the solar region. The degradation of sulfadiazine (SDZ) by TTB20 under solar light was enhanced from 76.60 % to 97.40 % when coupled with 0.5 mM peroxymonosulfate (HSO5–) at an irradiation time of 30 min. The radical scavenging investigations indicated that SO4•−, O2•− and h+ are primarily engaged in photocatalytic activity. Moreover, the TTB20 sample showed promising activity against E-coli. In addition, the TTB20 sample displayed a remarkable 4.15-fold higher photocatalytic H2 evolution rate than the TTB0 sample. Thus, the present study suggests that TTB20/HSO5–/solar light is an auspicious approach for addressing environmental pollution, health issues and energy crises.

Revealing the synergistic effect of bulk and surface co-doped boron on TiO2 for enhanced photocatalytic H2 evolution

Boron(B) doping is considered as a promising modification method for TiO2 photocatalyst due to the facilitation of separation and migration of photogenerated carriers. However, the modification mechanisms of bulk or surface doping modes on photocatalyst are controversial, and the catalytic activity still needs to be improved. Here, a bulk and surface B co-doped TiO2 (B(B&S)-TiO2) derived from B-containing Ti-MOF (MIL-125(B)) precursor was demonstrated, which achieved a H2 evolution rate of 9.56 mmol∙g−1∙h−1 under 365 nm light without co-catalyst. Detailed investigations reveal the synergistic effect between bulk and surface co-doped B, which optimizes the microstructure, activates the 3-coordinated O (O3C) atoms of B-Ti-O structural units as active sites, enhances the transfer of photoelectrons and inhibits the recombination, balances H* adsorption–desorption during the photocatalytic reactions. This work exhibits a novel strategy of bulk and surface B co-doped photocatalysts and highlights the potential for achieving high photocatalytic H2 evolution rate without co-catalyst.

Ultraviolet–Visible-near infrared induced photocatalytic H2 evolution over S-scheme Cu2-xSe/ZnSe heterojunction with surface plasma effects

Localized surface plasmon resonance (LSPR) effect plays a crucial role in the field of solar energy utilization. In this work, we successfully prepared a Cu2-xSe/ZnSe S-scheme heterojunction with a broad-spectrum response using the hot-injection and low-temperature water bath method. Importantly, we demonstrated that the photothermal effect induced by the LSPR of nonstoichiometric Cu2-xSe can significantly improve the slow kinetics of water splitting, resulting in an apparent activation energy reduction from 50.1 to 28.7 kJ·mol−1. This improvement is responsible for achieving the highest photocatalytic H2 evolution rate of 63.6 mmol·g−1·h−1 over 2.7 % Cu2-xSe/ZnSe under the wavelength ranged from 200 to 2500 nm, which is 3.4 and 5.6 times higher than that of ZnSe and Cu2-xSe, respectively. Furthermore, the composite exhibits a remarkable H2 production rate of 0.108 mmol·g−1·h−1 under near-infrared spectroscopy (800<λ<2500 nm), while ZnSe shows limited capability in H2 releasing. Additionally, Cu2-xSe/ZnSe demonstrates distinct photocurrent response when λ > 800 nm. The enhanced performance in H2 evolution can be attributed to the synergistic effect of LSPR-induced light absorption and S-scheme heterojunction, which not only expands the light absorption range to the near-infrared region but also facilitates hot electron injection, charge carrier separation and transfer, leading to a faster surface reaction kinetics. This study provides an effective approach for designing a broad-spectrum light responsive non-precious metal-based photothermal-assisted photocatalytic system.

Crystal facet engineering of hollow cadmium sulfide for efficient photocatalytic hydrogen evolution

Metal sulfides have been considered as potential candidates for photocatalytic hydrogen production, but their practical applications are still limited by incident light utilization and charge separation despite the impressive advances in recent decades. To address these challenges, the construction of hollow nanostructure with exposing high active facets offers a desirable pathway for developing novel and high-efficiency photocatalysts. Here, by taking wurtzite CdS as an example, we first develop a general template-assisted cation exchange route for the preparation of hollow CdS nanostructures with diverse exposed facets. The obtained hollow CdS octahedrons with dominant {101} facets exhibit superior photocatalytic H2 evolution rate under visible-light irradiation compared with common CdS nanorods. According to the characterization results and density functional theory calculations, the excellent photocatalytic performance is attributed to the construction of hollow nano-octahedrons with exposed {101} active facets, which facilitates efficient light harvesting and photoinduced charge separation of CdS photocatalyst. The present approach gives a reference to design advanced semiconductors with remarkable photocatalytic activity for realizing efficient solar-to-chemical conversion.

Photodeposition of NiS thin film enhanced the visible light hydrogen evolution performance of CdS nanoflowers

The use of loaded co-catalysts has been found to be effective in addressing the issue of rapid recombination of photogenerated carriers, which can limit photocatalytic efficiency. Herein, we report on the adsorption of Ni2+ on the surface of CdS by photodeposition to obtain NiS/CdS composites. It improves visible light response while providing abundant active sites for photocatalytic reaction. NiS/CdS exhibits a superior photocatalytic H2 evolution rate of up to 7557 μmol·g−1·h−1, which is approximately 4.9 times higher than that of CdS. The corresponding AQE is 19.6% at 420 nm. XPS and photoelectrochemical testing provide a possible mechanism, indicating that the heterojunction between NiS and CdS promotes the transfer and separation of interfacial charge, thus accelerating the water decomposition reaction. This work demonstrates the effectiveness of loading two-dimensional thin film co-catalysts to design high-performance and low-cost composites for promoting the photocatalytic reaction.

Enhanced internal electric field of CdS/NU-M Z-scheme heterojunction for efficient photocatalytic hydrogen evolution

Metal-organic frameworks (MOFs) as high-efficiency photocatalysts often face limitations due to the inadequate charge separation and sluggish charge transfer kinetics. Herein, we construct an interfacial linker coordinated heterostructure cadmium sulfide/zirconium-based metal–organic framework (CdS/NU-M) for high-efficiency photocatalytic H2 evolution. The interfacial thiol coordination significantly narrows the energy difference between conduction band of NU-M and valence band of CdS, achieving a Z-scheme charge transfer channel in CdS/NU-M. As a result, a robust internal electric field is found in the formed Z-scheme heterojunction of CdS and NU-M, which is 20 times higher than that of NU-M. Thus, photogenerated charge carries are efficiently separated and transported to the surface, which induces CdS/NU-M with a 10-fold increase of photocatalytic H2 evolution rate over the contrast photocatalyst, up to 84.3 mmol g−1h−1, prominently surpassing most of the reported MOFs and CdS-based photocatalysts. This work highlights the crucial role of interfacial linker coordination in enhancing charge separation and transfer, significantly improving the photocatalytic performance and providing an effective strategy for designing advanced photocatalysts and related technologies.

Enhanced photocatalytic hydrogen production of Ag and N-doped NaTaO3 perovskite nanocubes

In the current study, a simple hydrothermal method was used to successfully synthesize NaTaO3 and Ag, N doped NaTaO3 catalysts. The band edge potential was accessible through UV–visible spectroscopic analysis, and the diffraction peak was easily indexed as an orthorhombic structure. The values of the predicted crystallite sizes for the undoped NaTaO3, Ag-doped, and N-doped NaTaO3 nanoparticles are 61.03 nm, 48.9 nm, and 53.50 nm, respectively. Pure, Ag, and N doped NaTaO3 nanocubes were discovered to exhibit band gap energies of 3.62, 3.60, and 3.57 eV, respectively, based on the UV-Vis examination. Moreover, a Field Emission Scanning Electron Microscopy study confirmed the presence of cubic (3-D) shape. An HRTEM examination verified that the material is polycrystalline. The Ta, Na, N, and O are present at binding energies of 26.09, 1073, 405.7, and 526.6 eV, respectively, according to the XPS spectra. The pure, silver (Ag), and nitrogen (N) doped NaTaO3 photocatalysts have photocatalytic H2 evolution rates of 556 µmolh−1, 2834 µmolh−1 and 3266 µmolh−1, respectively. Without a co-catalyst, the maximal rate of H2 generation under UV light has not yet been attained for the N-doped NaTaO3 perovskite with its cubic (3-D) structure. Furthermore, even after three days, the improved photocatalyst demonstrates 87 % of photocatalytic activity in the reliability test.

Z-scheme ferrite nanoparticle/graphite carbon nitride nanosheet heterojunctions for photocatalytic hydrogen evolution

Visible light-driven photocatalytic water splitting has been considered one of the most promising sustainable approaches toward solar fuel production. As a substitute for metal oxide semiconductors, 2D graphitic carbon nitride (gCN) have been suffered a major challenge owing to its moderate bandgap (∼2.8 eV) and the synergistic effect of using spinel metal ferrites with a narrow bandgap (∼1.7 eV–1.9 eV) as a cocatalyst is promising to enhance solar energy conversion efficiency and stability. The as-synthesized gCN/copper ferrite (CFO) nanocomposites exhibit 10-fold augmentation in the photocurrent density (∼5 μA cm−2) compared with pure gCN. Remarkably, the gCN/CFO nanocomposites also exhibit 24 times increment in the rate of photocatalytic H2 evolution (∼488 μmol g−1) in contrast with pure gCN (∼20 μmol g−1 h−1). The amalgamation of gCN with metal ferrites has resulted in the development of direct Z-scheme heterojunction at the interface, facilitating the spatial separation of electrons and holes and boosting photocatalytic performance. Oxygen vacancies enhance the photocatalytic efficacy of the nanocomposites, as confirmed by X-ray photoelectron spectroscopy analysis. Moreover, the as-synthesized composites are highly stable in structure and morphology under light irradiation without considerable reduction in the catalytic performance over several cycles. Therefore, this work presents a facile approach using metal ferrites as co-catalysts to develop graphitic carbon-nitride-based photocatalysts for solar light-assisted green fuel generation.

Enhanced Light Absorption and Photo-Generated Charge Separation Efficiency for Boosting Photocatalytic H2 Evolution through TiO2 Quantum Dots with N-Doping and Concomitant Oxygen Vacancy.

Low-range light absorption and rapid recombination of photo-generated charge carriers have prevented the occurrence of effective and applicable photocatalysis for decades. Quantum dots (QDs) offer a solution due to their size-controlled photon properties and charge separation capabilities. Herein, well-dispersed interstitial nitrogen-doped TiO2 QDs with stable oxygen vacancies (N-TiO2-x-VO) are fabricated by using a low-temperature, annealing-assisted hydrothermal method. Remarkably, electrostatic repulsion prevented aggregation arising from negative charges accumulated in situ on the surface of N-TiO2-x-VO, enabling complete solar spectrum utilization (200-800 nm) with a 2.5 eV bandgap. Enhanced UV-vis photocatalytic H2 evolution rate (HER) reached2757µmol g-1 h-1, 41.6 times higher than commercial TiO2 (66µmol g-1 h-1). Strikingly, under visible light, HER rate was 189µmol g-1 h-1. Experimental and simulated studies of mechanisms reveal that VO can serve as an electron reservoir of photo-generated charge carriers on N-doped active sites, and consequently, enhance the separation rate of exciton pairs. Moreover, the negative free energy (-0.35 V) indicates more favorable thermodynamics for HER as compared with bulk TiO2 (0.66 V). This research work paves a new way of developing efficient photocatalytic strategies of HER that are applicable in the sustainable carbon-zero energy supply.

Novel Graphitic Carbon Nitride/Co-B-P Nanocomposites with Significantly Enhance Visible-Light Photocatalytic Hydrogen Production from Water Splitting

As a promising metal-free photocatalyst for hydrogen (H2) production through water splitting under visible-light irradiation, graphitic carbon nitride (g-C3N4) photocatalysts decorated with CoBP was prepared via simple ultra sonification. This paper highlights the structures of the photocatalysts, their stability, rate of hydrogen evolution and the mechanism of charge transfer within the photocatalysts. The prepared C3N4/CoBP nanocomposite photocatalysts were characterized by using X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy and UV–visible (UV–vis) diffuse reflectance spectroscopy. After detailed analysis, the C3N4/CoBP nanocomposite photocatalysts showed excellent photocatalytic performance, which was due to the formation of the heterostructured hybrids of g-C3N4 and CoBP. The effects of C3N4/CoBP nanohybrids on H2 evolution were evaluated. The effects improved with increasing load of CoBP until the optimal level (5 wt% CoBP with visible-light irradiation at λ ≥420 nm). The maximum and remarkable photocatalytic H2 evolution rate of 51.68 μmol h−1 was achieved, which was 3.8 times that obtained from pure g-C3N4. Moreover, the C3N4/CoBP heterostructured nanohybrids demonstrated extremely high photostability and recyclability for H2 evolution after visible light illumination. The composite hybrid accelerated the separation and transfer of photogenerated charge carriers and subsequently suppressed charge recombination. Conclusively, this study offered an opportunity for the design and synthesis of highly stable and efficient C3N4/CoBP nanocomposite photocatalysts for energy conversion and utilisation.

Facile construction of MoS2 decorated CdS hybrid heterojunction with enhanced hydrogen generation performance

Promoting the charge separation to improve photocatalytic performance of semiconductor photocatalysts is very important in the field of artificial photosynthesis. Here, a novel MoS2/CdS 2D–2D ultrathin nanosheet heterostructure was fabricated via a one-pot solvothermal route. The obtained 2D–2D MoS2/CdS nanojunction has not only provided large contact areas, but also shortened the charge transport distance, resulting in significantly enhanced photocatalytic H2 evolution property. The composites that were synthesized were examined using X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Transmission electron microscope (TEM), UV-vis diffuse reflectance spectra (DRS), Photoluminescence (PL) and X-ray photoelectron spectra (XPS) analysis. By optimizing the 2D MoS2 amounts in the heterojunction, the 5 wt.% 2D/2D MoS2/CdS heterojunction displayed the maximal photocatalytic H2 evolution rate of 4449 μmolh−1g−1 under visible light irradiation in the presence of lactic acid as the sacrificial reagent, which was 6 times higher than that of pristine 2D CdS. Based on the photoelectrochemical and photoluminescence spectra tests, it could be deduced that the charge separation and transfer of 2D/2D MoS2/CdS heterojunction was tremendously improved, and the recombination of photoinduced electron-hole pairs was effectively impeded. Moreover, the 2D MoS2 was used as a cocatalyst to provide the abundant active sites and lower the overpotential for H2 generation reaction. The current work would offer an insight to fabricate the 2D/2D heterojunction photocatalysts for splitting H2O into H2.

Ice-Templated Synthesis of Atomic Cluster Cocatalyst with Regulable Coordination Number for Enhanced Photocatalytic Hydrogen Evolution.

Supported metal catalysts have been exploited in various applications. Among them, cocatalyst supported on photocatalyst is essential for activation of photocatalysis. However, cocatalyst decoration in a controllable fashion to promote intrinsic activity remains challenging. Herein, a versatile method is developed for cocatalyst synthesis using an ice-templating (ICT) strategy, resulting in size control from single-atom (SA), and atomic clusters (AC) to nanoparticles (NP). Importantly, the coordination numbers (CN) of decorated AC cocatalysts are highly controllable, and this ICT method applies to various metals and photocatalytic substrates. Taking narrow-band gap Ga-doped La5Ti2Cu0.9Ag0.1O7S5 (LTCA) photocatalyst as an example, supported Ru AC/LTCA catalysts with regulable Ru CNs have been prepared, delivering significantly enhanced activities compared to Ru SA and Ru NPs supported on LTCA. Specifically, Ru(CN = 3.4) AC/LTCA with an average CN of Ru─Ru bond measured to be ≈3.4 exhibits excellent photocatalytic H2 evolution rate (578µmol h-1) under visible light irradiation. Density functional theory calculation reveals that the modeled Ru(CN = 3) atomic cluster cocatalyst possesses favorable electronic properties and available active sites for the H2 evolution reaction.

Bromine Atoms Decorated Pyene-based Covalent Organic Frameworks for Accelerated Photocatalytic H2 Production.

Designing materials with low exciton binding energy is an efficient way of improving the hydrogen production performance of COFs（Covalent Organic Frameworks. Here, it is demonstrated that the strategy of decorating bromine atoms on Pyene-based COFs can achieve elevated photocatalytic H2 evolution rates (HER = 13.61mmol g-1h-1). Low-temperature fluorescence and time-resolved fluorescence spectroscopy (TRPL) indicate that the introduction of bromine atoms can significantly suppress charge recombination. DFT (Density Functional Theory) calculation clarified that the C atoms adjacent to Br are the active sites with a reduced energy barrier in the process of formatting H intermediate species (H*). The modification strategy of Br atoms in COF furnishes a new medium for exploiting exquisite photocatalysts.

Photostability and visible-light-driven photoactivity enhancement of hierarchical C@ZnCdS/ZnS/MoS2

Zinc cadmium sulfide solid (Zn x Cd1−x S) related composites received great attention in photocatalytic hydrogen production because of their tunable bandgap and strong visible light absorption range. But sulfide-based metal materials commonly suffer from photo-corrosion issues. It is very important to construct the photocatalysts with high efficient activity and photostability for H2 production. Herein, we successively prepared ZnCdS/ZnS (ZCS/ZS) heterostructures, ZnCdS/ZnS/MoS2 (ZCS/ZS/M) heterostructures decorated ZCS/ZS with MoS2 quantum dots, then we obtained x-C@ZCS/ZS and x-C@ZCS/ZS/M heterostructures encapsulated ZCS/ZS and ZCS/ZS/M with carbon layer. The performance of the photocatalytic hydrogen production showed that sample 0.05-C@ZCS/ZS/M has a remarkable photocatalytic H2 evolution rate of 15.231 mmol·h−1·g−1 with noble metal-free co-catalysts. This rate was approximately 21 times higher than that of the pristine ZCS/ZS photocatalyst. The optimized sample reveals an excellent stability, without activity losses after 10 h. The improved photocatalytic activity can be attributed to the unique heterojunction structure formed by ZCS/ZS and MoS2. Additionally, the carbon films played a crucial role in providing excellent stability by spatially separating the sites for redox reactions, thereby inhibiting the recombination of photo-generated electron–hole pairs.

Periodic Macroporous ZnS-In2O3 heterojunctions based on double Z-scheme for improved photocatalytic performances on H2 evolution and Cr (VI) reduction

To achieve controllable transport of photogenerated carriers in heterojunctions and improve their photocatalytic performance, we construct a new type of periodic macroporous (PM) heterojunctions through the pyrolysis of the solid solution to obtain a number of alternating heterojunctions composed of ZnS and In2O3. The quantum wells can be constructed based on double Z-scheme in the alternating heterojunctions. This design restricts the degree of freedom of the carriers in the vertical direction, suppresses the recombination of photogenerated carriers, achieves their spatial separation, and thus improves the redox ability. The PM structure with efficient mass transfer in PM ZnS-In2O3 (PZI) enables photogenerated carriers to easily migrate to the surface. The photocatalytic H2 evolution rate and reduction of Cr (Ⅵ) of the PZI heterojunctions are considerably improved by the combined effects of the quantum wells and PM structures. This work proposes a novel idea for adjusting the transport process of photogenerated carriers and then improving photocatalytic performance.

Photothermal-Enhanced S-Scheme Heterojunction of Hollow Core-Shell FeNi2S4@ZnIn2S4 toward Photocatalytic Hydrogen Evolution.

Herein, guided by the results of density functional theory prediction, the study rationally designs a hollow core-shell FeNi2S4@ZnIn2S4 (FNS@ZIS) Step-scheme (S-scheme) heterojunction for photocatalytic H2 evolution with photothermal-assisted. The hollow FNS spheres offered substrate for coating the ZIS nanosheets, which can inhibit ZIS nanosheets from agglomerating into pellet, enrich the active site, increase specific surfaces, and raise the light absorption. Notably, due to its excellent photothermal properties, FNS core generated heat unceasingly inside under visible-light irradiation and effectively prevent the heat loss of the reaction system, which increased the local temperature of photocatalysts and thus accelerated the charge migration. In addition, the S-scheme heterojunction construction via in situ growth has a tight interface, which can facilitate the separation and transfer of carriers and achieve high redox potential. Owning to the distinctive construction, the hollow core-shell FNS@ZIS S-scheme heterojunction show extraordinary stability and photocatalytic H2 evolution rate with 7.7mmolh-1g-1, which is ≈15.2-fold than pristine ZIS. Based on the double evidence of theoretical predictions and experimental confirmations, the photothermal effect and electron transfer mechanism of this innovative material are investigated in depth by the following infrared thermography technology and deep DFT calculations.

Co-optimization of g-C3N4 with prolonging exciton lifetime strategy and co-catalyst strategy for enhanced photocatalytic H2 evolution activity

In this work, the photocatalytic activity of g-C3N4 is co-optimized for the first time using a strategy of prolonging exciton lifetime and a co-catalyst strategy. Amorphous CoB nanoparticles are loaded on OCN-K-CN, which is an O, K doped g-C3N4 material with van der Waals heterojunctions inside. The optimized OCN-K-CN-CoB sample, containing 12 wt% CoB and 1.25% K2SO4 in precursors, show photocatalytic H2 evolution rate approximately 27 times higher than that of GCN. The mechanism of co-optimization is detailedly investigated through comparative experiments on light absorption, charge separation performance, and HER activity, with optimization strategy and CoB loading ratio as controlled variables. New roles of the two strategies have been revealed: "flux-limited reduction activity sites" for CoB and ''buffer-enhancer'' for OCN-K-CN. These new roles illustrate a hidden relationship between the optimizing effects of the two strategies and can explain a surprising advantage of this co-optimization: achieving near-optimal hydrogen evolution activity with significantly reduced co-catalyst loading ratio.

Controllable introducing C, N-defects and oxygen-doping on carbon nitride to tune electronic structure and boost photocatalytic hydrogen evolution

In this work, one-step pyrolysis of molten urea and formaldehyde was adopted to introduce O atom, C and N defects in polymeric carbon nitride (CN) for tuning its electronic structures. Results confirmed that the introduced C, N-defects and O dopant could increase the light absorption (440–640 nm) and suppressed the photogenerated charge recombination of CN. The calculated free energies for H* adsorption revealed that the intrinsic H2 evolution activity of C, N-deficient and O-doped CN increased. Accordingly, the optimal sample exhibited an excellent photocatalytic H2 evolution rate (HER) of 18.95 mmol g−1 h−1 in 10% triethanolamine solution under visible light irradiation (1% Pt as a cocatalyst), which was 6.7 times higher than that of traditional CN (2.83 mmol g−1 h−1). In addition, the HER and yield of benzaldehyde were 1.04 and 4.20 mmol g−1 h−1, respectively in 5% benzyl alcohol solution. This work provides a simple and effective strategy to tune the heptazine and electronic structure of CN for large increasing its photocatalytic activity.

Novel CdLa2S4/Ni2P photocatalyst with boosting H2 evolution: Heterostructures promote photogenic carrier interface separation

Metal sulfides, often exhibited excellent photocatalytic H2 evolution ability, has attracted more and more attention, whereas their industry applications were limited due to the photocorrosion. Therefore, the inhibition of photocorrosion is the key issue to promote the industrialization of metal sulfide catalysts. In this work, CdLa2S4 /Ni2P catalysts with satisfactory H2 evolution property were designed and synthesized. Catalyst with 15 % Ni2P dosage exhibited maximum photocatalytic H2 evolution rate as 1.143 mmolh-1g−1, which was 10 times higher than that of pure CdLa2S4. Such high catalytic efficiency maintained after 5 photocatalytic cycles. According to the results of transient photocurrent and photoluminescence, the heterojunction structure formed by Ni2P and CdLa2S4 improved the separation efficiency of photogenerated electron-hole pairs, thus prompted the H2 evolution ability and the catalyst stability. Further EPR results confirmed the existence of heterojunctions in the catalyst and proposed a possible reaction mechanism. The results show that the CdLa2S4/Ni2P composite photocatalyst has good visible light response and photochemical stability, and has broad application prospects in solar driven photocatalytic decomposition of water to hydrogen production.