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.     

Efficient photocatalytic H2 evolution over Cu and Cu3P co-modified TiO2 nanosheet

Schottky junction and p-n heterojunction are widely employed to enhance the charge transfer during the photocatalysis process. Herein, Cu and Cu₃P co-modified TiO₂ nanosheet hybrid (Cu–Cu₃P/TiO₂) was fabricated using an in situ hydrothermal method. The ternary composite achieved the superior H₂ evolution rate of 6915.7 μmol g^?1 h^?1 under simulated sunlight, which was higher than that of Cu/TiO₂ (4643.4 μmol g^?1 h^?1) and Cu₃P/TiO₂ (6315.8 μmol g^?1 h^?1) and pure TiO₂ (415.7 μmol g^?1 h^?1). The enhanced activity can be attributed to the collaboration effect of Schottky junction and p-n heterojunction among Cu/TiO₂ and Cu₃P/TiO₂, which can harvest the visible light, reduce the recombination of charge carriers and lower the overpotential of H₂ evolution, leading to a fast H₂ evolution kinetics. This work develops a feasible method for the exploration of H₂ evolution photocatalyst with outstanding charge separation properties.     

The heterojunction construction of hybrid B-doped g-C3N4 nanosheets and ZIF67 by simple mechanical grinding for improved photocatalytic hydrogen evolution

In this study, B-doped g-C₃N₄ nanosheets (BCN) were prepared using a thermal-oxidative etching method, resulting in a semiconductor with a large specific surface area. The B-doping enhances the light absorption of graphitic carbon nitride(g-C₃N₄) and improves the photogenerated carrier lifetime. The optimal B-containing amount resuled in a hydrogen production rate of 1297 μmol g⁻¹ h⁻¹ for g-C₃N₄ nanosheets. Furthermore, zeolitic imidazolate framework (ZIF)67/BCN heterostructures were successfully obtained through simple mechanical grinding approaches. The BCN provided abundant active sites and contributed to excellent encapsulation on the surface of ZIF67. The obtained ZIF67/BCN photocatalyst displayed an H₂ evolution rate of 3392 μmol g⁻¹ h⁻¹, attributed to forming type-II heterojunctions between ZIF67 and BCN. Moreover, the BCN exhibited a higher conduction band (CB) potential with ZIF67 than CN, resulting in more efficient light-driven charge separation between ZIF67 and BCN and enhanced photocatalytic performance. This work provides a meaningful reference for improving the activity of g-C₃N₄ photocatalysts.     

Porous g-C3N4/TiO2 S-scheme heterojunction photocatalyst for visible-light driven H2-production and simultaneous wastewater purification

In this work, photocatalysts with a novel S-scheme heterojunction were fabricated by coupling MOF-derived TiO₂ with porous g-C₃N₄ (MTO/PCN). The S-scheme heterojunction with matching band gap possesses different advantageous properties, which can not only inhibit photo-generated charge recombination, but also reserve outstanding redox ability. As expected, superior hydrogen evolution efficiency of 40-MTO/PCN was obtained in a TEOA-containing aqueous solution and pure water, which were 5252.9 and 974.6 μmol h⁻¹ g⁻¹, respectively. Meanwhile, the hybrid can also serve as a bifunctional catalyst for H₂ generation (2137.3 μmol h⁻¹ g⁻¹) and organic contaminant removal (the RhB purification efficiency: 35.24%). This work furnishes a feasible method for devising bifunctional photocatalysts that can simultaneously produce hydrogen and purify wastewater to provide both energy-saving and environmental restoration functions.     

Construction of porous Ni2P cocatalyst and its promotion effect on photocatalytic H2 production reaction and CO2 reduction

Due to superior light absorption abilities, porous materials are suitable to be served in photocatalytic reactions. In this study, porous Ni₂P is target-constructed from porous Ni(OH)₂ nanoflower. Promotion effect of the porous Ni₂P as cocatalyst is confirmed on photocatalytic performance of Ni₂P/CdS composite. The constructed porous Ni₂P/CdS photocatalyst shows much higher photocatalytic H₂ evolution rate (111.3 mmol h⁻¹ g⁻¹) from water and much higher CO (178.0 μmol h⁻¹ g⁻¹) and CH₄ (61.2 μmol h⁻¹ g⁻¹) evolution rates from CO₂ reduction than non-porous Ni₂P/CdS photocatalyst. Characterizations including UV-Vis diffuse reflectance, photoluminescence, transient photocurrent response, electrochemical impedance and electron paramagnetic resonance are conducted to verify the role of porous Ni₂P cocatalyst. The slow photon effect derived from porous structure Ni₂P is found to improve light path and increase the absorption utilization of light. The enhanced photocurrent intensity and the lowered resistance of porous Ni₂P/CdS due to the formed heterojunctions indicate much rapid isolation of photogenerated electron-hole pairs and rapid charge transfer of electrons. The higher signal of ⋅O₂- radicals is detected in porous Ni₂P/CdS than non-porous Ni₂P/CdS, which result in the remarkable photocatalyst activities of porous Ni₂P/CdS. Reaction mechanisms over Ni₂P/CdS photocatalyst are illustrated with a Z-scheme charge transfer path.     

Separation of hot electrons and holes in Au/LaFeO3 to boost the photocatalytic activities both for water reduction and oxidation

Construction of plasmon-based nanostructures is an effective way to enhance the photocatalytic activities of semiconductor photocatalysts for water-splitting. However, the synergistic effect of plasmon-related hot electrons and holes for water splitting in the plasmon-hybrid photocatalyst is rarely considered. Herein, we construct a plasmon-based Au/LaFeO₃ composite photocatalyst to investigate the complex roles of hot electrons and holes for solar water splitting. Benefiting from the formation of Schottky junction and surface plasmon resonance effect of the Au nanoparticles, the synthesized photocatalyst exhibits an excellent photocatalytic activity for each half-reaction of water splitting, and the rates for H₂ and O₂ generation are obtained as high as 202 μmol g⁻¹ h⁻¹ and 23 μmol g⁻¹ h⁻¹, respectively. Moreover, an in-depth investigation reveals that the improved hydrogen evolution is caused by the hot electron injection from Au to LaFeO₃, and the hot holes in Au induced by the separation of hot charges can initiate the water oxidation directly on the surface of gold. Thus, this work provides a new insight into the synergistic effect of plasmon-related hot electrons and holes for boosting the photocatalytic reactions.     

Performance of amine-modified CdS-D@ZIF-8 nanocomposites for enhanced photocatalytic H2 evolution

The exploration of an efficient photocatalyst for H₂ evolution directly from water splitting is highly desirable due to the current environmental and energy situation. The present work successfully used a solvothermal method to synthesize organic-inorganic CdS-diethylenetriamine (CdS-D) nanorods (NRs). The amine-modified CdS-D@ZIF-8 nanocomposite materials were prepared using the self-assembly method with different ZIF-8 nanocrystals (NCs) weight ratios. At λ ≥ 420 nm wavelength, the optimized CdS-D@ZIF-8 (CZ-2) nanocomposite with 5.0 wt% loading of ZIF-8 NCs showed the highest performance of 2293.9 μmol g⁻¹ h⁻¹ H₂ evolution and an apparent quantum yield (AQY) of 4.95%. The CZ-2 nanocomposite's activity was 114.69, 5.25, and 1.32 times higher than that of ZIF-8 NCs (20.0 μmol g⁻¹ h⁻¹), CdS-D NRs (436.4 μmol g⁻¹ h⁻¹) and 1.0 wt% Pt/CdS-D (1737.3 μmol g⁻¹ h⁻¹), respectively. The cyclic photostability of the prepared CZ-2 nanocomposite remained unchanged after six consecutive cycles. The UV-DRS, electrochemical measurements, and Mott-Schottky (MS) analysis were performed to explain the band edge positions for CdS-D NRs and ZIF-8 NCs. The detailed S-scheme charge transfer mechanism of the as-prepared catalysts was also studied using the density functional theory (DFT). This work provides vital information for the controllable synthesis of ZIF-8-modified S-scheme nanocomposites for solar energy utilization.     

Hydrogen evolution using CdWO4 modified by BiFeO3 in the presence of potassium iodide; a combination of photocatalytic and non-photocatalytic water splitting

Novel heterogeneous structure of BiFeO₃–CdWO₄ with different molar ratios was applied for the photocatalytic hydrogen evolution in a self-designed externally UV/visible irradiated photoreactor in the presence of potassium iodide. The photocatalysts were synthesized by simple hydrothermal method and characterized by XRD, FE-SEM-mapping, TEM, UV–Vis DRS, PL, EIS, transient photocurrent and Mott-schottky techniques to identify the structural, optical and photoelectrochemical properties. The slope of Mott-schottky plots confirmed the p-type and n-type conductivity of the synthesized BiFeO₃ and CdWO₄, respectively. The p-n heterojunctions exhibited more efficiently light absorption, charge separation and electron mobility relative to the pure photocatalysts. We observed that coupling 40 mol% BiFeO₃ with CdWO₄ provided the best photocatalytic performance of hydrogen evolution, 268.90 μmol h⁻¹.g_cat⁻¹ from distilled water and 379.43 μmol h⁻¹.g_cat⁻¹ from 0.05 M KI aqueous solution. Iodine species increased H₂ evolution efficiency because of taking part in the charge transfer processes, either by scavenging excited holes or by direct reduction of H⁺ to H^• under UV irradiation. Fermi level equilibrium in the p-n heterojunction suggests the best interparticle charge transfer mechanism explaining how photoinduced electrons with superior energy states and desirable lifetime can be supplied to reduce H⁺ to H^•.     

Facile fabrication of mesoporous In2O3/LaNaTaO3 nanocomposites for photocatalytic H2 evolution

The incorporation of In₂O₃ nanoparticles on mesoporous La_0.02Na_0.98TaO₃ photocatalysts is very interesting for promoting the H₂ production under UV illumination in the presence of [10%] glycerol as a hole scavenger. It is demonstrated that an outstanding mesoporous In₂O₃/La_0.02Na_0.98TaO₃ photocatalyst can be constructed by incorporating In₂O₃ nanoparticles (0-2 wt%) and mesoporous La_0.02Na_0.98TaO₃ nanocomposites for highly promoting photocatalytic H₂ evolution. The maximum yield of H₂ ~ 2350 μmol g⁻¹ was obtained over mesoporous 1%In₂O₃/La_0.02Na_0.98TaO₃ nanocomposite. The mesoporous 1%In₂O₃/La_0.02Na_0.98TaO₃ nanocomposite exhibited further enhancement H₂ production, in which the rate of H₂ evolution can be as high as 235 μmol g⁻¹ h⁻¹, 435 times higher than those of mesoporous La_0.02Na_0.98TaO₃. The results showed that the 1%In₂O₃/La_0.02Na_0.98TaO₃ photocatalyst possesses high stability and durability for H₂ evolution by implying almost no photoactivity reduce after five cycles for 45 h continuous illumination. The measurement of photoluminescence spectroscopy, transient photocurrent spectra and UV- diffuse reflectance spectra for all synthesized samples exhibited that the promoted H₂ production is mainly explained by its effective electron-hole separation and broaden photoresponse region due to its compositions and structures of the obtained heterostructures.     

Fabrication of hollow g-C3N4@α-Fe2O3/Co-Pi heterojunction spheres with enhanced visible-light photocatalytic water splitting activity

For the first time, g-C₃N₄@α-Fe₂O₃/Co-Pi heterojunctional hollow spheres were successfully fabricated via thermal condensation method followed by solvothermal and photo-deposition treatment, which showed excellent photocatalytical property. Except for the Z-scheme charge transfer between α-Fe₂O₃ and g-C₃N₄, the Co-Pi could further reduce the combination of photogenerated electrons and holes as a hole storage agent, resulting in remarkably enhanced visible-light photocatalytic water splitting activity with the H₂ production rate of 450 μmol h⁻¹g⁻¹, which is 15.7 times higher than that of g-C₃N₄. Moreover, the photocatalytic activity of the prepared ternary hollow photocatalysts showed almost no significant weakness after five cycles, which indicated their good performance stability. The as-prepared g-C₃N₄@α-Fe₂O₃/Co-Pi also possessed good activity for overall water splitting with the hydrogen production rate reaching 9.8 μmol h⁻¹g⁻¹. This synthesized g-C₃N₄@α-Fe₂O₃/Co-Pi composite is expected to be a promising candidate for water splitting.     

Facile fabrication of nickel/porous g-C3N4 by using carbon dot as template for enhanced photocatalytic hydrogen production

Ni/porous g-C₃N₄ was prepared by high temperature thermal polymerization process using carbon dots as soft template and photodeposition. With nickel nanoparticles supported as co-catalyst, the hydrogen evolution reaction (HER) activity of the photocatalyst has been significantly enhanced under visible light, which is up to 1273.58 μmol g⁻¹ h⁻¹, superior to pristine g-C₃N₄ (4.12 μmol g⁻¹ h⁻¹). This is attributed to the inhibited recombination of photogenerated electron-hole pairs and the much better electron transport efficiency. The formed porous structure of carbon nitride could facilitate light utilization and together with nickel nanoparticles, better charge separation can be realized which are proved by the photoluminescence, time-resolved photoluminescence spectra, transient photocurrent measurements and electrochemical impendence spectroscopy. This work provides a useful route to obtain less expensive and efficient photocatalyst containing no noble metals for hydrogen production.     

2D MOFs enriched g-C3N4 nanosheets for highly efficient charge separation and photocatalytic hydrogen evolution from water

Here we report a 2D-2D heterostructure of g-C₃N₄/UMOFNs photocatalysts via mechanical grinding two kinds of two-dimensional nanosheets of g-C₃N₄ nanosheets and UMOFNs, which exhibits enhanced H₂ evolution from water with simulated solar irradiation. g-C₃N₄ nanosheets are in close contact with UMOFNs, and there is a certain interaction between them, showing the effect of superimposition on the two-dimensional layer. The 2D-2D heterostructure offers a maximal photocatalytic hydrogen production activity of 1909.02 μmol g⁻¹ h⁻¹ with 3 wt% of UMOFNs, which is 3-fold higher than that of g-C₃N₄ nanosheets (628.76 μmol g⁻¹ h⁻¹) and 15-flod higher than that of bulk g-C₃N₄ (124.30 μmol g⁻¹ h⁻¹). The significant increasement of photocatalysis is due to 2D-2D heterostructure possessing a short charge transfer distance and large contact area between g-C₃N₄ and UMOFNs. The highly dispersed NiO, CoO and π-π bonds in UMOFNs of 2D-2D structure also promote charge transfer and enhance the photocatalytic activity.     

Potential Co-catalyst application of novel M3P2 (M=Zn,Cd) in photocatalytic hydrogen evolution reaction from water splitting

New noble-metal-free co-catalysts based on transition metal phosphides, Zn₃P₂ and Cd₃P₂, were fabricated and loaded on hetero-structure of BiFeO₃–CdWO₄ with the aim of promoting hydrogen evolution from water splitting without using sacrificial agent. The opto-electrochemical properties of the photocatalysts were investigated by various characterization techniques and it was observed that the co-catalyst loaded BiFeO₃–CdWO₄ exhibited better light harvestability, charge separation efficiency and charge mobility. The photocatalytic hydrogen productivity reached up to 572.81 μmol h⁻¹.g_cat⁻¹ h by loading 12 wt% Zn₃P₂ and 488.25 μmol h⁻¹.g_cat⁻¹ by loading 9 wt% Cd₃P₂ over BiFeO₃–CdWO₄. Zn₃P₂ and Cd₃P₂ have shown light absorption in visible to near IR region, thus they may also have the additional role of a photocatalyst other than being active sites for the photocatalytic reduction half-reaction. Loading the co-catalysts also resulted in multiplication of specific surface area which means an increase in the number of surface active sites. We observed a higher hydrogen productivity with lower photocatalytic rate by loaded Zn₃P₂ in compared with Cd₃P₂. This is attributed to the different photoresponsivity and band edge energy of the co-catalysts. The details of charge transfer mechanism between the host hetero-structure photocatalyst and loaded co-catalysts has been discussed.     

g-C3N4/CoAl-LDH 2D/2D hybrid heterojunction for boosting photocatalytic hydrogen evolution

In this work, a 2D/2D heterojunction composed of CoAl layered double hydroxide (LDH) and graphitic carbon nitride nanosheets (CNNS) was designed and fabricated for boosting photocatalytic hydrogen generation. The as-prepared 20 mol% CoAl-LDH/CNNS exhibited a remarkable photocatalytic hydrogen evolution rate of 680.13 μmol h⁻¹ g⁻¹, which was 21 times higher than that of pure CoAl-LDH (32.91 μmol h⁻¹ g⁻¹). The enhanced activity could be mainly attributed to its unique structure and high surface area. Distinct from ordinary heterojunction photocatalysts, two-dimensional (2D) heterojunctions with abundant 2D coupling interfaces and strong interfacial interaction could efficiently suppress the recombination of photo-induced charge carriers and shorten charge transmission distance. Particularly, compared with other concentrations, the increased surface area (138.70 m² g⁻¹) of 20 mol% CoAl-LDH/CNNS, which is 3.94 times of pure CNNS (35.48 m² g⁻¹), is more favorable for enhanced photocatalytic activity. Increasing the surface area of sheet-on-sheet heterostructure is an effective and novel strategy to facilitate the photocatalytic hydrogen evolution from water splitting.     

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.     

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.     

Facile construction of porous C-PDA@CN-ms core-shell heterostructures with superior photocatalytic H2 evolution

Building carbon nitride (CN)-based core shell heterostructures is an effective strategy to enhance the photocatalytic performance and stability by optimize the interface area and protect the CN core, respectively. Moreover, by fabricating the porous structures in core shells can further optimize the light absorption, charge separation, and mass transfer. Herein, we have constructed porous C-PDA–CN–ms core-shell heterostructures through a facile green molten salt (ms) sculpture the polydopamine (PDA) derived carbon (C-PDA) shells with CN core. In which, the C-PDA-CN core-shells arise from in situ polymerization of dopamine (DA) on the surface of melamine to form PDA@melamine coatings followed by thermal polycondensation. The molten salts at high-temperature act as a green fluid immersing in and out of C-PDA-CN core-shells to further produce porous structures. The 1 wt% C-PDA–CN–ms with porous core-shell structures display photocatalytic H₂ evolution rate of 3830 μmol h⁻¹ g⁻¹, which is 20.8 times enhancement of 1 wt% C-PDA-CN core-shells, even 73.6 times higher than that of pristine CN. It reveals that the porous and core-shell heterostructures endow C-PDA–CN–ms enhanced light absorption, various charge transport channels for improved charge carrier separation and transfer, contributing to the superior photocatalytic H₂ evolution performance. Our work opens a new window for the green construction of porous core-shell heterostructures of CN-based photocatalysts.     

Enhanced performance for photocatalytic hydrogen evolution using MoS2/graphene hybrids

A MoS₂/graphene hybrid (MSG) is synthesized by microwave hydrothermal method. Both of the charge transfer resistance and the photocurrent are tuned in graphene modified MoS₂ by enhancing photocatalytic nature, where the charge transfer resistance significantly decreases from 36,000 Ω–8.49 Ω and the photocurrent promotes from 0.29 mA cm^?2 to 16.47 mA cm^?2. In this article, the result reveals that the appropriate modification of graphene can reach the maximum yield of hydrogen gas. In addition, the appropriate conditions, such as the concentration of 0.32 M formic acid and the MoS₂ photocatalyst with 0.8 wt% graphene (MSG_0.8) dose of 0.013 g L^?1, can complete the outstanding photocatalytic hydrogen evolution, where the hydrogen evolution using MSG_0.8 composite photocatalyst has the maximum yield of 667.2 μmol h^?1 g^?1.     

Tuning the surface hydrophilicity of a C3N4 nanosheet for efficient photocatalytic H2 evolution coupled with microplastic degradation

Simultaneously realizing highly-efficient degradation of microplastics coupled with H₂ evolution is urgently demanded to solve the white pollution and energy shortage issues. Herein, we fabricate a series of fragmented hydrophilic homogeneous carbon nitride (TP-PCN) by terminating the polymerization of carbon nitride using iodide ions (I⁻), which acts as an invisible inhibitor by breaking the π-π bond to reduce the accumulation of ultra-thin layers in PCN to inhibit the polymerization. The H₂ evolution rate of resultant photocatalyst could reach 600.3 μmol g⁻¹ h⁻¹ in alkaline polyethylene terephthalate (PET) solution, exhibiting outstanding photocatalytic activity. Meanwhile, the PET was also degraded into small molecules, which were used in agricultural production, food processing and pharmaceuticals. The high photocatalytic activity of the TP-PCN photocatalyst can be ascribed to the promoted hydrophilicity and charge separation ability. This work supplies new insights for the design of functional photocatalysts and developing green technologies to solve environment pollution.     

Regulated effect of organic small molecular doped in carbon nitride skeleton for boosting photocatalytic hydrogen evolution

Organic small molecules doping in polymer carbon nitride (PCN) skeleton can dramatically improve photocatalytic performance owing to its effective regulation effect on molecular and electronic structure. Here, a new PCN-based photocatalyst is obtained via polymerization of urea with 1-benzyl-3-phenylthiourea (BPT). The doping effect of BPT in PCN skeleton directly adjusts the hybridization states and delocalization of molecular orbitals, so that the visible light harvest ability, adsorption capacity, charge separation efficiency and transfer kinetics are improved significantly. Consequently, the photocatalytic hydrogen evolution reaction (HER) rate reaches to 125.0 μmol h⁻¹ over the optimal PCN-BPT₁₅ photocatalyst, which is as 13.9 times as PCN (9.0 μmol h⁻¹). Noteworthily, a high apparent quantum efficiency (AQE) of 24.2% is achieved at 420 nm for photocatalytic HER. This work enriches the functionalized investigations of PCN-like photocatalysts by insight into regulated effect of organic small molecules in the skeleton for photocatalytic applications.