Visible-light Photocatalytic Hydrogen Production Research Articles

Efficient visible light photocatalytic green hydrogen production from Dy2O3 combined with nitrogen-deficient g-C3N4

The efficient construction of heterojunction photocatalysts has a crucial significance in achieving the decomposition of water for hydrogen generation. This work successfully prepared nitrogen-deficient g-C3N4 (ND-g-C3N4) and combined it with dysprosium oxide (Dy2O3) through high-temperature calcination to create a type II heterojunction photocatalyst (Dy2O3/ND-g-C3N4). Notably, under visible light, the Dy2O3/ND-g-C3N4 photocatalyst demonstrated impressive hydrogen production rates in both ethylene glycol and glucose solutions. Specifically, the photocatalyst achieved H2 generation rates of 463.256 and 510.305 μmol⋅g−1⋅h−1 in ethylene glycol and glucose solutions, respectively. And the quantum yield could be up to 21.76% and 23.96%, respectively. Furthermore, the photocatalytic reforming of glucose for H2 production yielded valuable intermediate products. The f-shell layer in the Dy2O3 had a significant function in enhancing photocatalytic hydrogen production efficiency. This improvement was attributed to the ability of the f-shell layer to capture excited electrons, thereby decreasing the rate of recombination of exciton pairs.

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.

Self-doped zinc-mediated ZnIn2S4 microflowers towards optimized visible-light photocatalytic hydrogen production

Doping is a favorable strategy for modifying the performance of ZnIn2S4 (ZIS). However, the doped heteroatoms are prone to be the sites of carrier complexation. According to the coordination structure and the bond order relationship in hexagonal ZIS, we synthesized Zn self-doped ZIS as an efficient hydrogen evolution reaction (HER) photocatalyst by one-step hydrothermal method. By adjusting the content of Zn in the reaction precursor, the excess Zn competes with In and S to form a tetrahedral coordination structure. The doping of Zn in the In-S tetrahedron makes the conduction band shift negatively, which is conducive to the redox reaction. Moreover, the transfer rate of electrons and holes is accelerated, which is beneficial to inhibit the recombination of electron-hole pairs. The optimized Zn-doped ZIS exhibits enhanced HER efficiency of 10.8 mmol/g/h under visible light, which is 2.9 times higher than that of the pristine ZIS.

Construction of an all-organic S-scheme heterostructure based on PEDOT immobilized g-C3N4 nanosheets by electrostatic self-assembly with enhanced visible-light photocatalytic hydrogen production

Inspired by photosynthesis in nature, exploring all-organic S-scheme heterojunction photocatalysts for efficient H2 production is of great significance in addressing energy shortage issues. In this paper, poly(3,4-ethylenedioxythiophene) (PEDOT) immobilized g-C3N4(CN) nanosheets were constructed by an electrostatic self-assembly strategy to obtain an all-organic S-scheme heterojunction, significantly enhancing the visible-light photocatalytic H2 production performance of g-C3N4. The optimized 5PEDOT/CN exhibits the highest H2 production rate of 3.15 mmol g−1h−1, a 31.5-fold enhancement over pristine CN. According to the staggered energy band positions of two components and the results of electron spin resonance tests, the S-scheme heterojunction electron-transfer mechanism is confirmed, which greatly facilitates the spatial charge separation and retains the strong reducing ability of high-energy potential electrons for efficient photocatalytic H2 production. Based on the results of FT-IR spectra, XPS spectra, fluorescence spectra, hydroxyl radical tests and time-resolved photoluminescence spectra, it is confirmed that the significantly improved photocatalytic activity is mainly attributed to the enhanced charge separation by the S-scheme heterojunction and the tightly contacted interface dependent on N···S interactions in PEDOT immobilized CN nanosheet heterojunctions, along with the enhanced visible-light absorption ability. This work presents a novel approach to the design and fabrication of all-organic S-scheme heterojunction photocatalysts for solar-light-driven energy production.

Excellent visible-light photocatalytic hydrogen production efficiency: Hollow-structured TiO2/CdS/Au or hollow-structured TiO2/Au/CdS ternary heterojunction nanocomposites?

Two ternary heterojunction composites, namely hollow-structured TiO2/CdS/Au and hollow-structured TiO2/Au/CdS, were successfully synthesized by preparing hollow-structured TiO2 first, followed by the deposition of Au and CdS (with different deposition sequences), respectively. In these two composites, hollow-structured TiO2 nanotubes provide 1D structure with large specific area, which facilitate the immobilization of CdS and Au nanoparticles and the transfer of electrons. CdS is visible-light responsive and Au nanoparticles can improve photocatalytic efficiency by the formation of schottky barrier and surface plasmon resonance effect (SPR). The structures and phases, morphologies, surface and optical properties of the two composites were systematically characterized. TiO2/CdS/Au ternary heterojunction composite has efficient light absorption ability and excellent performances in photocatalytic hydrogen generation (up to 3600 μmol h−1 g−1), which is more than 4 times higher than that of TiO2/Au/CdS (800 μmol h−1 g−1). Therefore, in this way, we present a promising strategy to construct hybrid photocatalysts for hydrogen production.

In situ photodeposition of loaded Co–MoSx for promoting visible-light g-C3N4 photocatalytic hydrogen production performance

The Co–MoSx can efficiently catalyze H2 evolution reaction under visible light.

A Novel Synthetic 3D Interconnected Porous Carbon-Rich Graphitic Carbon Nitride for Boosting Visible Light Photocatalytic Hydrogen Production and Dye Contaminant Degradation

The use of photocatalysis to address environmental pollution and energy shortage is an attractive choice. Herein, we successfully synthesized a novel 3D interconnected porous carbon-rich g-C3N4 catalyst via facile thermal polymerization to enhance photocatalytic hydrogen production and photodegradation of dye contaminants. Enhanced hydrogen evolution (1956.23 μmol g−1 h−1) and photocatalytic RhB degradation (96.74%) efficiency were achieved with the as-obtained catalysts. Based on the photocatalytic experimental data and characterization analyses, an enhancement mechanism was proposed. The 3D interconnected porous structure endowed the g-C3N4 with numerous active sites and a large specific surface area, and the carbon modification facilitated the separation and transfer of the photoinduced charge carriers. Nanoshape engineering and the carbon-rich structure showed a synergetic effect in increasing photocatalytic performance. This study offers an applicable methodology for the exploitation of an economical catalyst to alleviate environmental pollution and energy shortages.

Modified Metal Organic Frameworks Supported Ni Single Atom Catalyst for Enhanced Photocatalytic Hydrogen Evolution Reaction

Downsizing metal nanoparticle catalysts to form single-atom catalysts (SACs) has proven to be one of the best ways to enhance the catalysts’ activity and selectivity1-2 due to their unique characteristics such as nearly 100% atom utilization and well-defined active sites.3 However, the broad application of SACs in catalytic reactions is limited by their poor stability as they possess high surface energy and thus tend to aggregate and form nanoclusters or nanoparticles.4 To address this challenge, various supports such as metal oxides, carbon materials, and porous materials are widely used to stabilize the SACs.5 Metal organic frameworks (MOFs), a class of porous crystalline materials, have proven to be an ideal candidate to support SACs owing to their high surface area, high porosity, and abundant potential anchoring sites.6 It has been shown that immobilizing SACs on MOFs, which forms MOF supported SACs, can integrate the unique properties of SACs and MOFs and led to remarkable catalytic activity, selectivity, and stability toward various catalytic reactions.6-8 Application of MOF supported SACs in photocatalysis, organic linkers of metal-organic frameworks act as photosensitive units,9 However most pristine metal-organic frameworks possesses poor light absorption properties due to wide band gap.9To enhance the light harvesting properties of the metal organic framework its organic linker is functionalized.10-11 In my poster presentation, I will present my work where post-synthetic modification of UiO-66-NH2 MOF linker with 3,4,9,10 perylene tetracarboxylic dianhydride (PDA) an organic molecule with broad absorption edge,12and immobilization of Ni single atom catalyst on the zirconium cluster of the MOF was done. This resulted in enhanced optical properties and charge separation efficiency which was proved by a combination of UV-visible spectroscopy (UV-Vis), photoelectrochemical techniques, and X-ray absorption spectroscopy (XAS). Observed photophysical effects posed by the modifications of the UiO-66-NH2 were evaluated by photocatalytic hydrogen generation.References Yan, J.; Kong, L.; Ji, Y.; White, J.; Li, Y.; Zhang, J.; An, P.; Liu, S.; Lee, S.-T.; Ma, T., Single atom tungsten doped ultrathin α-Ni (OH) 2 for enhanced electrocatalytic water oxidation. Nature communications 2019, 10 (1), 1-10.Jiao, L.; Jiang, H.-L., Metal-organic-framework-based single-atom catalysts for energy applications. Chem 2019, 5 (4), 786-804.Qiao, B.; Wang, A.; Yang, X.; Allard, L. F.; Jiang, Z.; Cui, Y.; Liu, J.; Li, J.; Zhang, T., Single-atom catalysis of CO oxidation using Pt1/FeO x. Nature chemistry 2011, 3 (8), 634-641.Xia, C.; Qiu, Y.; Xia, Y.; Zhu, P.; King, G.; Zhang, X.; Wu, Z.; Kim, J. Y.; Cullen, D. A.; Zheng, D., General synthesis of single-atom catalysts with high metal loading using graphene quantum dots. Nature chemistry 2021, 13 (9), 887-894.Wu, J.; Xiong, L.; Zhao, B.; Liu, M.; Huang, L., Densely populated single atom catalysts. Small Methods 2020, 4 (2), 1900540.Huang, H.; Shen, K.; Chen, F.; Li, Y., Metal–organic frameworks as a good platform for the fabrication of single-atom catalysts. ACS Catalysis 2020, 10 (12), 6579-6586.Qu, W.; Chen, C.; Tang, Z.; Wen, H.; Hu, L.; Xia, D.; Tian, S.; Zhao, H.; He, C.; Shu, D., Progress in metal-organic-framework-based single-atom catalysts for environmental remediation. Coordination Chemistry Reviews 2023, 474, 214855.Szilágyi, P.; Rogers, D.; Zaiser, I.; Callini, E.; Turner, S.; Borgschulte, A.; Züttel, A.; Geerlings, H.; Hirscher, M.; Dam, B., Functionalised metal–organic frameworks: a novel approach to stabilising single metal atoms. Journal of Materials Chemistry A 2017, 5 (30), 15559-15566.He, J.; Wang, J.; Chen, Y.; Zhang, J.; Duan, D.; Wang, Y.; Yan, Z., A dye-sensitized Pt@ UiO-66 (Zr) metal–organic framework for visible-light photocatalytic hydrogen production. Chemical communications 2014, 50 (53), 7063-7066.Elcheikh Mahmoud, M.; Audi, H.; Assoud, A.; Ghaddar, T. H.; Hmadeh, M., Metal–Organic Framework Photocatalyst Incorporating Bis(4′-(4-carboxyphenyl)-terpyridine)ruthenium(II) for Visible-Light-Driven Carbon Dioxide Reduction. Journal of the American Chemical Society 2019, 141 (17), 7115-7121.Hendrickx, K.; Joos, J. J.; De Vos, A.; Poelman, D.; Smet, P. F.; Van Speybroeck, V.; Van Der Voort, P.; Lejaeghere, K., Exploring lanthanide doping in UiO-66: a combined experimental and computational study of the electronic structure. Inorganic Chemistry 2018, 57 (9), 5463-5474.Yu, H.; Joo, P.; Lee, D.; Kim, B. S.; Oh, J. H., Photoinduced Charge‐Carrier Dynamics of Phototransistors Based on Perylene Diimide/Reduced Graphene Oxide Core/Shell p–n Junction Nanowires. Advanced Optical Materials 2015, 3 (2), 241-247.

Boosting photocatalytic H2 production performance over perovskite/CdS quantum dots S-scheme photocatalyst

Layered perovskite materials are thought to be excellent photocatalysts. However, which always fails to absorb visible light. In this paper, CdS quantum dots and Ni2+ were incorporated into the interlayer of layered calcium niobate perovskite KCa2Nb3O10 to achieve an efficient visible-light photocatalytic hydrogen production, which was prepared by direct cation exchange reaction and a sulfurization process. The X-ray photoelectron spectroscopy and HRTEM mapping confirmed that the substituted CdS QDs and Ni2+ are mainly located at the interlayer edges and interlamination. The performance was increased with the increase of the interlayered Ni content. The obtained sample KCNO/CdS-Ni-50 exhibited a photocatalytic H2 evolution rate of 5.21 mmol•h−1•g−1 without noble metals as co-catalysts, about 670 times higher than that of pristine KCa2Nb3O10. The highly efficient photocatalytic activity and stability can be ascribed to the S-scheme heterojunction structure, in which the sites for redox reaction were separated in space to inhibit the photo-generated electron-hole recombination.

In-doped Sn3O4 flower-like nanosheets for efficient visible-light photocatalytic hydrogen production

Improving photocatalytic activity is crucial for promoting photocatalytic hydrogen production. Element doping is a feasible strategy to accelerate carrier separation and migration rate. Herein, a simple one-pot hydrothermal process was used to create In doped Sn3O4 composite photocatalyst. It was demonstrated that the addition of In considerably raises the concentration of oxygen vacancy, which provides more unsaturated active sites, thus regulating the photocatalyst's electronic structure and surface properties, and promoting the carrier migration efficiency. Meanwhile, the light absorption range of samples after doping is redshifted, and the light absorption capacity is enhanced, which effectively improves the photocatalytic activity. Due to this, the optimal sample's average hydrogen production under visible light reached 22.83 μmol g−1 h−1, 4.5 folds more than that of Sn3O4, and shown good stability. This research presents a novel approach for the development of metal oxide photocatalyst with excellent activity and durability.

Facile strategy to fabricate NiTe2/g-C3N4 heterojunction photocatalyst with enhanced visible-light photocatalytic hydrogen production

Facile strategy to fabricate NiTe2/g-C3N4 heterojunction photocatalyst with enhanced visible-light photocatalytic hydrogen production

Single-Atom Cu Channel and N-Vacancy Engineering Enables Efficient Charge Separation and Transfer between C3N4 Interlayers for Boosting Photocatalytic Hydrogen Production

Polymeric carbon nitride (C3N4) has attracted great attention in photocatalysis due to its low-cost, visible-light response, and environment-friendly merits. However, the catalytic efficiency of pristine bulk C3N4 is severely limited by its poor photoinduced electron/hole pair separation and interlayer charge transport. Herein, single-atom Cu is bridged into C3N4 sheet interlayers through the thermal condensation of self-assembly supramolecules of Cu precursors and melamine–cyanuric acid monomers. Simultaneously, N vacancies are engineered into C3N4 only by gradient temperature. The single-atom Cu bridges serve as electron channels to promote photoinduced electron/hole pair separation and interlayer charge transport. The experimental results and calculations demonstrate that N vacancies break the symmetry of pristine C3N4, allowing more electrons to pass through the delocalized π-conjugated network of C3N4 to Cu sites, which facilitates charge transfer between C3N4 layers, resulting in more effective separation of electron/hole pairs, optimal charge distribution, and lower hydrogen evolution barrier. As a result, the photocatalyst at a stationary point with a 1 wt % Pt cocatalyst presents a high visible-light photocatalytic hydrogen production rate (11.23 mmol g–1 h–1), reaching a high apparent quantum yield of 31.60% at 420 nm. It is noted that the photocatalyst still exhibits a high hydrogen production rate of 605.15 μmol g–1 h–1 in the absence of the Pt cocatalyst.

Hydrothermally Synthesized Ag@MoS2 Composite for Enhanced Photocatalytic Hydrogen Production

Photocatalytic hydrogen production is a green, cost-effective, simple, and pollution-free technology for the supply of clean energy, which plays an important role in alleviating the fossil fuel crisis caused by exponentially grown energy consumption. Therefore, designing highly visible-light-active novel photocatalyst materials for photocatalytic hydrogen production is a promising task. The production efficiency of photocatalyst can be improved by using noble metals, which are useful for the effective transfer of charge carriers. This study highlights the synergistic effect of the noble co-catalyst Ag on MoS2 during the investigation of photocatalytic hydrogen production. The hydrothermal method was used for the preparation of an Ag-MoS2 composite, and their structural and morphological characterizations were carried out using different physiochemical characterization techniques. The Ag-MoS2 composite shows an enhanced visible light absorption capacity and photocatalytic hydrogen production rate, as compared to that of pure MoS2, which proves that Ag nanoparticles (NPs) can act as efficient co-catalyst materials for photocatalytic hydrogen production with an improved rate of hydrogen production. Along with this, a possible working mechanism was proposed for visible-light-driven photocatalytic hydrogen production using the Ag@MoS2 composite.

Construction of PCN-222 and Atomically Thin 2D CNs Van Der Waals Heterojunction for Enhanced Visible Light Photocatalytic Hydrogen Production.

Atomically thin two-dimensional (2D) CN sheets have attracted extensive attention in the field of photocatalysis because of their shorter diffusion path of photogenerated carriers and abundant surface reaction sites than bulk CN. However, 2D CNs still exhibit poor visible-light photocatalytic activity because of a strong quantum size effect. Here, PCN-222/CNs vdWHs were successfully constructed using the electrostatic self-assembly method. The results showed that PCN-222/CNs vdWHs with 1 wt.% PCN-222 enhanced the absorption range of CNs from 420 to 438 nm, which improved the absorption capacity of visible light. Additionally, the hydrogen production rate of 1 wt.% PCN-222/CNs is four times that of the pristine 2D CNs. This study provides a simple and effective strategy for 2D CN-based photocatalysts to promote visible light absorption.

The Green Box: Selenoviologen-Based Tetracationic Cyclophane for Electrochromism, Host–Guest Interactions, and Visible-Light Photocatalysis

The novel selenoviologen-based tetracationic cyclophanes (green boxes 3 and 5) with rigid electron-deficient cavities are synthesized via SN2 reactions in two steps. The green boxes exhibit good redox properties, narrow energy gaps, and strong absorption in the visible range (370-470 nm), especially for the green box 5 containing two selenoviologen (SeV2+) units. Meanwhile, the femtosecond transient absorption (fs-TA) reveals that the green boxes have a stabilized dicationic biradical, high efficiency of intramolecular charge transfer (ICT), and long-lived charge separation state due to the formation of cyclophane structure. Based on the excellent photophysical and redox properties, the green boxes are applied to electrochromic devices (ECDs) and visible-light-driven hydrogen production with a high H2 generation rate (34 μmol/h), turnover number (203), and apparent quantum yield (5.33 × 10-2). In addition, the host-guest recognitions are demonstrated between the green boxes and electron-rich guests (e.g., G1:1-naphthol and G2:platinum(II)-tethered naphthalene) in MeCN through C-H···π and π···π interactions. As a one-component system, the host-guest complexes of green box⊃G2 are successfully applied to visible-light photocatalytic hydrogen production due to the intramolecular electron transfer (IET) between platinum(II) of G2 and SeV2+ of the green box, which provides a simplified system for solar energy conversion.

Highly efficient visible-light photocatalytic hydrogen production using ZIF-derived Co9S8/N, S-CNTs-ZnIn2S4 composite

A hierarchical Co9S8/N, S-CNTs-ZnIn2S4 (CSCNs-ZIS) composite was reasonably constructed by grafting ZnIn2S4 nanosheets on the ZIF (67) derived Co9S8/N, S-doped carbon nanotubes for effective photocatalytic hydrogen production. The aggregated ZnIn2S4 nanosheets were uniformly wrapped on the surface of CSCNs, forming a hierarchical core–shell configuration, which effective inhibition of charge-carrier recombination. The CSCNs was adopted as an effective multi-component co-catalyst and further promoted photocatalytic hydrogen production performance. The H2 production rate of optimized CSCNs-ZIS composite reached 2409.2 μmol·h−1·g−1 and has high stability after three cycles. This work may inspire the design of a new noble-metal-free multi-component co-catalyst for sustainable H2 production.

Constructing metal-free heterophotocatalyst using two-dimensional carbon nitride sheets and violet phosphorene for highly efficient visible-light photocatalysis

Two-dimensional (2D) carbon nitride sheets (CNs) with nanoscale thickness have great potential in solar energy conversion owing to their intrinsic bandgap. However, their photocatalytic efficiency falls far below the practical requirements because the generated electron-hole pairs rapidly recombine. We construct a metal-free 2D p–n junction heterophotocatalyst from CNs and violet phosphorene (VP) using a simple electrostatic self-assembly method. The experimental results and density functional theory calculations show that the built-in electric field of the p–n junction promotes photogenerated carrier transport at the heterojunction interface, thereby promoting the separation of photogenerated electron-hole pairs. Under visible-light illumination, the visible-light photocatalytic hydrogen and CO production rates of the CNs/VP heterojunction were increased by 5.85 and 1.51 times, respectively, when compared to that of CNs. This study provides new insights into the design of metal-free heterogeneous photocatalysts with high catalytic activity.

Phosphorus-Doped Single-Crystalline Quaternary Sulfide Nanobelts Enable Efficient Visible-Light Photocatalytic Hydrogen Evolution.

Facilitating charge separation and transport of semiconductors is pivotal to improving their solar-to-hydrogen conversion efficiency. To this end, manipulating the charge dynamics via element doping has attracted much attentions. Here, we doped phosphorus (P) into two-dimensional (2D) single-crystalline quaternary sulfide (SCQS) nanobelts, enabling significantly enhanced photocatalytic H2 production. By carefully studying the carrier dynamics after P doping, we found that the introduction of P leads to a narrowed band gap, inhibits the recombination of photogenerated carriers, and increases the electric conductivity, all of which contributed to their improved catalytic performance. Meanwhile, the inherited single-crystalline structure and exposed (0001) facet favors carrier transport and photocatalytic hydrogen production. It has been found that the P-doped Cu-Zn-In-S (CZIS) nanobelts exhibit a visible-light photocatalytic hydrogen production rate of 12.2 mmol h-1 g-1 without cocatalysts, which is 3.5-fold higher than that of pristine CZIS nanobelts. Moreover, the P doping strategy is proven to be common to other semiconductors, such as single-crystalline Cu-Zn-Ga-S (CZGS) nanobelts. Our work provides an efficient way to manipulate charge carriers and will help develop high-efficiency photocatalysts.

Boosting visible-light-driven photocatalytic H2 evolution of C/Znln2S4 hollow tubes by Ni doping

• A unique Ni doped CZIS photocatalyst was synthesized by a simply method. • Ni atoms partially replaced Zn atoms to form Ni/CZIS. • Ni/CZIS showed a high H 2 release capacity of 3537.04 μmol g -1 h −1 . • The good photocatalytic activity was attributed to Ni doping and special structure. An n-type nickel-doped carbon indium zinc sulfur (Ni/CZIS) hollow tube structure photocatalyst was synthesized for the first time through a simple solvothermal combination with an oil bath. Then it was characterized by a series of tests such as SEM, TEM, XRD, XPS, photoelectric properties and so on. The results showed that the addition of nickel acetate in the oil bath achieved uniform doping of nickel atoms and partially replaced the positions of zinc. The optimized Ni/CZIS material had lower overpotential, broadened the light absorption region, promoted photo-induced carrier separation and better hydrophilicity. Thus it showed an excellent visible-light photocatalytic hydrogen production rate (3035.75 μmol/g/h) and cyclic stability. In view of density functional theory calculations, Ni atomic doping narrowed the band gap width, changed the positions of the valence and conduction bands, and also generated a new hybridization level near the Fermi level. This energy level provided a new electronic channel for photo-generated electrons, facilitated the transfer of electrons and suppressed the recombination of carrier, thereby enhancing the photocatalytic hydrogen production performance.

Rationally designed 1D CdS/TiO2@Ti3C2 multi-components nanocomposites for enhanced visible light photocatalytic hydrogen production

The biggest challenging issue in photocatalysis is efficient separation of the photoinduced carriers and the aggregation of photo excited electrons on photocatalyst’s surface. Herein, one-dimensional (1D) CdS nanorod/2D TiO2@Ti3C2 MXene nanosheet heterojunctions with well-defined nanostructures and strong interfacial coupling are fabricated by facile one step hydrothermally-generated CdS nanorods on ultrathin 2D TiO2@Ti3C2 MXene nanosheets. the structural, morphological, optical and elemental composition of the photocatalysts were analyzed by X-ray diffraction, Raman, Scanning electron microscope, Transmission electron microscope, UV–vis absorption, Photoluminescence and X-ray photoelectron spectra analysis. H2 evaluation test was carried out under stimulated UV and visible light illumination using lactic acid as the hole scavenger. The results suggest that 1D CdS with TiO2@Ti3C2 composites showed higher H2 photocatalytic activity (3450 μmolg−1h−1) under UV light than compared with visible light (3115 μmolg−1h−1). The improved performance is due to conductive Ti3C2 MXene and 1D-CdS resulting in the increase of electron transfer efficiency. Besides, the 1D-CdS on the surface of TiO2@Ti3C2 composite enhances the Brunauer–Emmett–Teller surface area and boosts the density of active site.