Photocatalytic Hydrogen Evolution Rate Research Articles

Insights from DFT and mechanistic analysis of surface-precision carbon self-doped porous g-C3N4 for enhanced visible light-driven hydrogen evolution

Substituting carbon for nitrogen in g-C3N4 enhances π-electrons activity and photocatalytic performance, despite the challenges posed by the higher electronegativity of nitrogen. We successfully achieved the substitution of C atoms for N atoms via the copolymerization of melamine and cytosine utilizing the Schiff base reaction, altering the g-C3N4 band structure from 2.74 to 2.49 eV and enhancing photoinduced electron reduction due to the introduction of −N-C = C- unit into the g-C3N4 network. The C-incorporated g-C3N4 extended the light-response range to 673 nm and improved the electron cloud density around the self-doping sites, significantly reducing the ΔGH* as indicated the DFT results, implying the efficient separation and migration of photoinduced carriers in g-C3N4. As anticipated, the photocatalytic hydrogen evolution (PHE) rate of the optimized C self-doped g-C3N4 was five and seven times higher than that of the pristine g-C3N4 under the full spectrum and the visible light (λ ≥ 400 nm), respectively. Moreover, g-C3N4-n also display superior activity (6.73, 4.48, 3.42, and 0.76 %) under the different wavelengths (λ = 420, 450, 480 nm, and 540 nm respectively). This report reveals a subtle atom-tailoring scheme to control carbon self-doping sites within the g-C3N4 framework, modulating its inherent electronic properties and photoactivity.

Synergy of atom doping and defect construction in marigold-like Zn3In2S6 for improved photocatalytic hydrogen production

Atom doping and defect construction are effective strategies to enhance the performance of photocatalysts. Herein, zirconium (Zr) doping and sulfur vacancies (Vs) are introduced on marigold-like Zn3In2S6 (Zr-ZIS-Vs) by controlling the amount of sulfur precursors and ZrCl4 via a one-pot hydrothermal process. Remarkably, the optimized Zr-ZIS-Vs catalyst exhibits excellent photocatalytic activity, giving a photocatalytic hydrogen evolution rate of 9.44 mmol g−1 h−1, which is 10.73, 4.39 and 2.37 times higher than pure Zn3In2S6 (ZIS, 0.88 mmol g−1 h−1), Zn3In2S6 with sulfur vacancies alone (ZIS-Vs, 2.15 mmol g−1 h−1), and Zn3In2S6 with Zr doping alone (Zr-ZIS, 3.98 mmol g−1 h−1). The apparent quantum efficiency (AQE) of Zr-ZIS-Vs achieves 27.15 % and 4.90 % at λ = 370 and 456 nm, respectively. Experimental results and theoretical simulations reveal the behavioral mechanisms of the deletion of S atoms and the tendency of Zr to replace In, indicating that the defective and reference strategies can narrow the band gap, provide abundant active sites, enhance the effective transport and separation of photogenerated carriers, and modulate the transfer of active sites to empirical site S atoms to achieve the synergistic thermodynamic and kinetic interactions, which effectively enhances the performance of photocatalytic hydrogen production.

2D Porphyrin-Based Covalent Organic Framework/PEG Composites: A Rational Strategy for Photocatalytic Hydrogen Evolution.

Two-dimensional porphyrin-based covalent organic frameworks (2D-por-COFs) have gained significant attention as attractive platforms for efficient solar light conversion into hydrogen production. Herein, we found that introducing transition metal zinc and polyethylene glycol (PEG) into 2D-por-COFs can effectively improve the photocatalytic hydrogen evolution performance. The photocatalytic hydrogen evolution rate of ZnPor-COF is 2.82 times higher than that of H2Por-COF. Moreover, ZnPor-COF@PEG has the highest photocatalytic hydrogen evolution efficiency, which is 1.31 times and 3.7 times that of pristine ZnPor-COF and H2Por-COF, respectively. The filling of PEG makes the layered structure of COFs more stable. PEG reduced the distortion and deformation of the carbon skeleton after the experiment of photocatalytic hydrogen evolution. The layered stacking and crystallization of 2D-por-COFs are also enhanced. Meanwhile, the presence of PEG also accelerates the transfer of excited electrons and enhances the photocatalytic hydrogen evolution activity. This strategy would provide valuable insights into the design of 2D-por-COFs as efficient solid photocatalysts for solar-driven hydrogen production. This article is protected by copyright. All rights reserved.

Regular study of lanthanide oxides for boosting photocatalytic hydrogen production on ZnIn2S4 photocatalysts

Lanthanide oxides have potential advantages for photocatalytic hydrogen production. To systematically investigate the photocatalytic performance of lanthanide oxides on metal sulfides, a series of LnxOy/ZnIn2S4 (LnxOy/ZIS) were synthesized by hydrothermal method. Comprehensive characterization demonstrated that LnxOy synergistically improved the performance of ZnIn2S4 by extending light absorption, reducing contact interface resistance and enhancing carrier separation. The photocatalytic hydrogen evolution (PHE) rates of the LnxOy/ZIS photocatalysts were improved, which were 1.6–4.2 times higher than those of pure ZnIn2S4 (198.0 μmol g−1 h−1). The PHE rates of LnxOy/ZIS decreased with increasing lanthanide atomic number, and when the lanthanides contained variable valence ions, the PHE rates of LnxOy/ZIS were superior to those of neighbouring lanthanides. The heterojunction formed by LnxOy and ZnIn2S4 effectively promoted carrier separation. Lanthanide ions with unoccupied 4 f orbital were more likely to accept electrons and served as a hydrogen adsorption site for further hydrogen reduction. Multivalent ions could also promote the migration of electrons and generate oxygen vacancies to inhibit the recombination of carriers. In conclusion, for ZnIn2S4, lanthanide oxides are promising candidates to improve the performance of PHE. This study provides guidance on the selection of appropriate lanthanide oxides for the construction of efficient sulphur-based heterojunction photocatalysts.

Sulfur vacancy-induced 1T-MoS2 co-catalyst loaded on Zn3In2S6 for simultaneous promoting photocatalytic hydrogen evolution and pollutant degradation

In the field of photocatalytic hydrogen evolution, Zn3In2S6 has caught tremendous attention because of its suitable band gap and outstanding stability. However, the lower number of active sites as well as lower efficiency of photoproduced carrier separation restricted its further application. Introducing co-catalysts and structural defects are effective methods to solve the above problems. In this paper, Zn3In2S6 loaded metal phase MoS2 to construct flower-shaped spherical catalysts 1T-MoS2/Zn3In2S6 (M/ZIS6) with abundant sulfur vacancies. The visible-light-driven photocatalytic hydrogen evolution rate of 2.4 % M/ZIS6 was 8.71 mmol∙g−1·h−1, which far exceeded those of pure Zn3In2S6 (0.80 mmol∙g−1·h−1) and 2.4 % Pt/Zn3In2S6 (3.86 mmol∙g−1·h−1). Moreover, 2.4 % M/ZIS6 simultaneously displayed the excellent photocatalytic degradation performance toward acid orange 7 (AO7) in the hydrogen evolution reaction process. Co-catalyst metal phase 1T -MoS2, abundant sulfur defects, and a large and dense contact interface between 1T -MoS2 and Zn3In2S6 mainly contributed to the enhanced photocatalytic performance of 2.4 % M/ZIS6. This work provided a potential concept to construct efficient photocatalysts with noble metal-free co-catalyst for bifunctional applications.

Changeable Active Sites by Pr Doping CuSA-TiO2 Photocatalyst for Excellent Hydrogen Production.

Photocatalytic water splitting for clean hydrogen production has been a very attractive research field for decades. However, the insightful understanding of the actual active sites and their impact on catalytic performance is still ambiguous. Herein, a Pr-doped TiO2-supported Cu single atom (SA) photocatalyst is successfully synthesized (noted as Cu/Pr-TiO2). It is found that Pr dopants passivate the formation of oxygen vacancies, promoting the density of photogenerated electrons on the CuSAs, and optimizing the electronic structure and H* adsorption behavior on the CuSA active sites. The photocatalytic hydrogen evolution rate of the obtained Cu/Pr-TiO2 catalyst reaches 32.88mmolg-1h-1, 2.3 times higher than the Cu/TiO2. Innovatively, the excellent catalytic activity and performance is attributed to the active sites change from O atoms to CuSAs after Pr doping is found. This work provides new insight for understanding the accurate roles of single atoms in photocatalytic water splitting.

Π‐Bridge Modulations in D–π–A Conjugated Microporous Polymers to Facilitate Charge Separation and Transfer Kinetics for Efficient Photocatalysis

AbstractThe burgeoning field of conjugated microporous polymers (CMPs) has generated widespread interest due to their potential as photocatalysts for hydrogen production from water. Nevertheless, their photocatalytic performance is sometimes hindered by inadequate charge separation and transfer, coupled with rapid charge recombination. Herein, a strategy to enhance photocatalytic performance via the customization of π‐bridges through the modulation of heteroatoms in a series of donor‐π‐acceptor (D‐π‐A) CMPs is proposed. This affords optimized energy levels and improved charge separation and transfer, thus boosting photocatalytic efficiency. Among various heteroatom substitutions, S‐doped CMP (10 mg) demonstrates the highest photocatalytic hydrogen evolution rate of 203 µmol h−1 (AQY450nm = 7.4%) under visible light irradiation. Subsequent experimental analysis reveals its superior photocatalytic performance can be largely related to its minimized exciton binding energy, facilitated charge transfer efficiency, and impeded charge recombination among these heteroatom‐doped D‐π‐A CMPs. This research paves the way for the rational design and modification of organic semiconductors for advanced solar‐driven photocatalysis by promoting charge separation and transfer.

Conical porous hollow g-C3N4 charge separation with high efficiency for enhancing visible-light photocatalytic activity

The performance of the photocatalysts is influenced by factors such as electron generation ability, charge separation rate, and active sites distribution. In this study, needle-shaped precursors were prepared through low-temperature supramolecular self-assembly, and conical porous hollow carbon nitride (PHCN) was obtained after high-temperature pyrolysis. The PHCN not only possesses a thin-walled porous structure but also contains nitrogen defects embedded in its structure, which synergistically enhance the efficiency of photogenerated charge separation and provide more reactive sites. The DFT calculations showed that nitrogen defects and Pt-loading synergistically optimize the intermediate reaction process of graphitic carbon nitride (g-C3N4). PHCN had excellent photocatalytic degradation of tetracycline hydrochloride (TCH) and Rhodamine B (Rh B). The photocatalytic hydrogen evolution rate of PHCN was 20.0 times higher than that of bulk g-C3N4 (BCN). This study elucidated the relationship between crystallization rate and precursor morphology, as well as the influence of their physicochemical properties on photocatalytic performance. It also lays the foundation for constructing materials with nitrogen defects and special morphology through supramolecular self-assembly.

Surface vacancy engineering powered reverse cation exchange in preparing CuZnS hollow nanoboxs for efficient photocatalytic hydrogen evolution

The cation exchange technology plays a significant role in designing high-performance photocatalysts at atomic scale. However, the chemical kinetic energy barrier greatly limits the application of cation exchange strategies. Herein, an effective surface vacancy engineering powered reverse cation exchange strategy was exploited to realize energy-unfavored cation exchange reactions. Cu vacancies are created on the surface of Cu2-xS nanoboxs (Cu2-xS NBs), which are subsequently occupied by Zn2+ ions. A hollow CuZnS nanoboxs (CuZnS NBs) were successfully prepared for photocatalytic hydrogen evolution. The prepared CuZnS NBs has abundant interfacial Zn-S bonds, which promote interfacial charge transfer (IFCT) as a rapidly electron bridge. In particular, the photocatalytic hydrogen evolution rate of CuZnS NBs under visible light is 2.06 mmol·g−1·h−1, which is 5.9 times higher than that of Cu2-xS. The synthetic mechanism and photocatalytic mechanism of the CuZnS was investigated from experiment and theoretical calculations. The surface vacancy powered reverse cation exchange strategy offers a new opportunity for the rational tailoring new-generation photocatalysts at the atomic scale.

Modulating oxygen vacancy of ZnO for visible-light driven photocatalytic H2 evolution via facile gas treatment approach

Photocatalytic hydrogen production through water splitting is one of the most promising approaches for sustainable and renewable energy source. In recent years, research on defect rich metal oxide semiconductors has increased tremendously. N-type semiconductor ZnO exhibits a wide direct band gap of 3.3eV, limiting the optical absorption at UV range, hindering the photocatalytic performance of pristine ZnO. Furthermore, short charge carriers life time can also decrease the efficiency for hydrogen evolution. In this report, crystal defect engineering via oxygen vacancy tailoring was conducted, narrowing the bandgap of ZnO, while creating interstitial defects that reduces the recombination rate of electrons and holes. ZnO was synthesized via hydrothermal method using zinc acetate dihydrate and sodium hydroxide as precursors before subjecting for conditional annealing for 30, 60, 90 and 120 min for 200 °C, 300 °C, 400 °C and 500 °C. A series of characterization techniques were used to authenticate the effects of oxygen vacancy in ZnO. Experimental studies revealed that ZnO annealed at 400 °C for 120 min exhibit the highest amount of hydrogen produced through photochemical reactions. Therefore, the degree of oxygen vacancies in ZnO semiconductor can be regulated through diligent control of annealing parameters. Specifically, finding the optimum annealing temperature and duration were the focus in this study that relates to its photocatalytic hydrogen evolution rate.

Synthesis of the composites of carbon quantum dots and metal organic framework and their application in hydrogen evolution

The Ti-MIL-125 metal-organic framework (MOF) functions as a nanoreactor, producing carbon quantum dots (CQDs) within its structure and forming CQD/MOF composites. Similarly, a Pt-CQD/MOF three-component composite is synthesized. Their properties, along with those of CQDs and MOF-free-CQDs (mf-CQDs) enclosed within the MOF, undergo assessment and comparison. Integrating CQDs and Pt minimally alters the MOF structure but reduces specific surface areas due to incorporation. The emitted wavelength of CQD/MOF (570 nm) differs from pristine CQDs (450 nm) and mf-CQDs (496 nm), indicating MOF influence on CQDs' growth and photoluminescence. HOMO and LUMO levels of CQDs/MOF, measured via ultraviolet photoelectron spectroscopy and low-energy inverse photoelectron spectroscopy, are more positive than those of the MOF, suggesting heterogeneous junction formation, aiding electron separation. CQD/MOF exhibits a modest photocatalytic hydrogen evolution rate of 20.4 μmol/g/h. Conversely, Pt-CQD/MOF significantly boosts the rate to 2213 μmol/g/h, underscoring Pt's pivotal catalytic role.

Donor-acceptor covalent organic framework/ZnIn2S4 core-shell structure S-scheme heterostructure for efficient photocatalytic hydrogen evolution

Covalent organic frameworks (COFs) show promising prospect as the photocatalysts with advantages of exceptional light adsorption capability, large specific surface area, and adjustable band structure. However, COFs usually suffer from severe recombination of photogenerated carriers. Therefore, there is an urgent demand to design effective COF-based heterostructures to enhance the separation of carriers. In this work, a porphyrin-based COF with electron donor-acceptor structure is synthesized via condensation polymerization by using 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (TAPPP) and N,N,N',N'-tetra(4-formylphenyl)benzidin (NFPBD) as the donor and acceptor, respectively. Subsequently, ZnIn2S4 (ZIS) are successfully in-situ grown on the surface of porphyrin-based COF, forming a novel core-shell structure. The in-situ synthesized ZIS with positive charges can be easily adsorbed on the negatively charged sites of the COF’s surface via the electrostatic interaction. This organic/inorganic hybrid COF-ZIS heterostructure exhibits a superior photocatalytic hydrogen evolution (PHE) rate of 695 μmol g−1 h−1, approximately three times higher than that of ZIS. The construction of COF-ZIS heterostructure plays an important role in enhancing the separation and transport of photogenerated carriers, which provides more electrons at the surface of ZIS to take part in proton reduction. Electron paramagnetic resonance spectra confirm the charge carriers transfer mode in the COF-ZIS heterostructure via an S-scheme mechanism. Moreover, upon loading Pt as the cocatalyst, the heterostructure achieves an effective PHE rate of 2711 μmol g−1 h−1 along with an exceptional stability. Additionally, the COF-ZIS heterostructure reaches up to 2.45% of apparent quantum efficiency at 400 nm. Notably, the average lifetime of the COF-ZIS heterostructure increases by 43.2% and 98.9% compared to that of ZIS and the COF individually, as observed through single-particle fluorescence spectroscopy. This work gives valuable inspiration into the building of donor-acceptor COF-based S-scheme heterostructures to achieve highly effective green energy conversion by aligning band structures.

Organizing Photosensitive and Photothermal Single-Sites Uniformly in a Trimetallic Metal-Organic Framework for Efficient Photocatalytic Hydrogen Evolution.

Effective combination of the photosensitivity and photothermal propertyin photocatalyst is vital to achievethe maximum light utilization for superior photocatalytic efficiency. Herein, this work successfully organizes photosensitive Cd-NS single-sites and photothermal Ni-NS single-sites uniformly at a molecular level within a tailored trimetallic metal-organic framework. The optimized Ho6-Cd0.76Ni0.24-NS exhibits a superior photocatalytic hydrogen evolution rate of 40.06 mmol g-1 h-1 under visible-light irradiation and an apparent quantum efficiency of 29.37% at 420nm without using cocatalysts or photosensitizers. A systematical mechanism study reveals that the uniformly organized photosensitive and photothermal single-sites have synergistic effect, which form ultrashort pathways for efficient transport of photoinduced electrons, suppress the recombination of photogenerated charge carriers, hence promote the hydrogen evolution activity. This work provides a promising approach for organizing dual-functional single-sites uniformly in photocatalyst for high-performance photocatalytic activity.

Multishelled hollow CaTiO3 cubes decorated with Co0.2Cd0.8S nanoparticles for efficient photocatalytic H2 evolution via S-scheme charge transfer

Rationally designing S-scheme heterostructures with boosted charge separation efficiency and superior redox ability is regarded as an appealing strategy to conquer the shortcomings of mono-component and conventional heterojunction photocatalysts. Herein, a novel hierarchical S-scheme heterostructured photocatalyst was constructed by integrating Co0.2Cd0.8S nanoparticles on multishelled hollow CaTiO3 cubes to substantially improve the photocatalytic hydrogen production activity. An internal electric field (IEF) is formed at the heterojunction interfaces owing to the significant disparity in Fermi level (EF) between Co0.2Cd0.8S and CaTiO3, accompanied by the energy band bending, which enables the S-scheme charge transport route in the Co0.2Cd0.8S/CaTiO3 heterostructure, as verified by electron paramagnetic resonance and theoretical calculations. Benefiting from the boosted separation efficiency and superior redox capability of photocarriers within the constructed S-scheme heterostructure, the optimized Co0.2Cd0.8S/CaTiO3 sample exhibited a significantly improved photocatalytic hydrogen evolution rate of 8.13 mmol h−1 g−1, far exceeding that of mono-component counterparts and previously reported Co0.2Cd0.8S- or CaTiO3-based photocatalysts. This study is anticipated to inspire the strategic development of other economical and efficient S-scheme photocatalytic systems with enhanced H2 evolution activity.

Topological insulator Bi2Te3 and graphene oxide synergistically enhance the photothermal effect and photocatalytic hydrogen evolution activity

Photothermal co-catalysis with the partial conversion of solar energy to thermal energy has the potential to overcome the current bottleneck of realizing efficient photocatalytic hydrogen production with zero artificial energy consumption. However, it is still challenging to design highly efficient photocatalysts that can make use of light and thermal energy synergistically. In this work, we successfully improved the photothermal effect and visible-light-catalyzed hydrogen evolution performance by constructing a novel heterojunction based on the topological insulator Bi2Te3 and graphene oxide (GO) synergistically modified with Zn0.67Cd0.33S. The photocatalytic hydrogen evolution rate of the 1.1 wt% Bi2Te3@0.05% GO@Zn0.67Cd0.33S heterojunctions reached 11.52 mmol/h/g (Apparent Quantum Yield of 21.7%), which was 12.9 times higher than that of pure Zn0.67Cd0.33S. Furthermore, the hydrogen production rate reached 71.79 mmol/h/g without cooling. The improved photocatalytic activity originated from the synergistic enhancement of visible-light absorption and the systematic enhancement of the photothermal effect by the Bi2Te3 and GO. In addition, the high electrical conductivity of Bi2Te3 and the high proton conductivity of GO not only increased the electron transfer rate but also synergistically mediated the acceleration of the hydrogen generation reaction. A strong built-in electric field is formed between Bi2Te3 and Zn0.67Cd0.33S, which greatly facilitates the efficient separation of photogenerated carriers. The obtained results illustrate a promising strategy for the development of efficient new photothermal catalysts.

Double S-scheme Cu2−xSe/twinned-Cd0.5Zn0.5S homo-heterojunctions with surface plasmon effects for efficient photocatalytic H2 evolution

The enhancement of charge separation and utilization efficiency in both the bulk phase and interface of semiconductor photocatalysts, as well as the expansion of light absorption range, are crucial research topics in the field of photocatalysis. To address this issue, twinned Cd0.5Zn0.5S (T-CZS) homojunctions consisting of wurtzite Cd0.5Zn0.5S (WZ-CZS) and zinc blende Cd0.5Zn0.5S (ZB-CZS) were synthesized via a hydrothermal method to facilitate the bulk-phase charge separation. Meanwhile, Cu2−xSe with localized surface plasmon resonance effect (LSPR) generated by Cu vacancies was also obtained through a hydrothermal process. Due to their opposite electronegativity, a solvent evaporation strategy was employed to combine Cu2−xSe and T-CZS by intermolecular electrostatic. After optimization, the photocatalytic hydrogen (H2) evolution rate of 5 wt% Cu2−xSe/T-CZS reached an impressive value of 60 mmol∙h−1∙g−1, which was 4.6 and 66.6 times higher than that of pure Cu2−xSe and T-CZS, respectively. Furthermore, this composites demonstrated a remarkable rate of 0.46 mmol∙h−1∙g−1 under near-infrared (NIR) wavelength (>800 nm). The enhanced performance observed in Cu2−xSe/T-CZS can be attributed to its unique and efficient double S-scheme charge transfer mechanism which effectively suppresses rapid recombination of electron-hole pairs both within the bulk phase and at the surface interfaces; this conclusion is supported by Density Functional Theory (DFT) calculations as well as electron paramagnetic resonance spectroscopy analysis. Moreover, incorporation of Cu2−xSe enables effective utilization ultraviolet visible-near infrared (UV–Vis-NIR) light by the composites while facilitating injection “hot electrons” into T-CZS for promoting photocatalytic reactions. This study provides a potential strategy for achieving efficient solar energy conversion through synergistic integration of non-stoichiometric plasmonic materials with photocatalysts with twinned-twinned structures.

Energy transfer enhanced photocatalytic hydrogen evolution in organic heterostructure nanoparticles via flash nanoprecipitation processing

Organic nanophotocatalysts are promising candidates for solar fuels production, but they still face the challenge of unfavorable geminate recombination due to the limited exciton diffusion lengths. Here, we introduce a binary nanophotocatalyst fabricated by blending two polymers, PS-PEG5 (PS) and PBT-PEG5 (PBT), with matched absorption and emission spectra, enabling a Förster resonance energy transfer (FRET) process for enhanced photocatalysis. These heterostructure nanophotocatalysts are processed using a facile and scalable flash nanoprecipitation (FNP) technique with precious kinetic control over binary nanoparticle formation. The resulting nanoparticles exhibit an exceptional photocatalytic hydrogen evolution rate up to 65 mmol g−1 h−1, 2.5 times higher than that single component nanoparticle. Characterizations through fluorescence spectra and transient absorption spectra confirm the hetero-energy transfer within the binary nanoparticles, which prolongs the excited-state lifetime and extends the namely “effective exciton diffusion length”. Our finding opens new avenues for designing efficient organic photocatalysts by improving exciton migration.

Molecular engineering in tunable crystallinity of 2D covalent organic frameworks for efficient photocatalytic hydrogen evolution

The strategy of molecular engineering has been employed to build the structure–property–activity relationship for covalent organic frameworks (COFs) with efficient photocatalytic water splitting for hydrogen production. However, previous reports focus on the impact of molecular design on COFs’ physicochemical properties, the crystallinity differences are usually ignored and related studies remain rare. Herein, we describe the preparation of a series of structurally related COFs with similar chemical compositions but have different numbers of nitrogen (N) atoms in the central aromatic ring via an efficient crystallization strategy using of 2,4,6-triformyl resorcinol (TFR). On one hand, the introduction of N atoms reduces π-π stacking interaction during the formation of framework, leading to a decrease in crystallinity. On the other hand, it contributes to enhancing the photocatalytic performance of the materials by varying the electronic structures. Consequently, our results revealed that the photocatalytic hydrogen evolution (PHE) rate is 61.22 mmol g−1 h−1 for COF-905-1N, significantly higher than COF-905-3N (40.60 mmol g−1 h−1) and COF-905 (26.23 mmol g−1 h−1). This study not only provide fundamental insights into formation mechanism of COFs, but also provide a practical approach to enhance COF-based photocatalytic performance.

The WO2.72/CdS0.25Se0.75-DETA nanocomposite with S-scheme heterojunction structures exhibits high efficiency and stable photocatalytic hydrogen evolution performance

Facing the global energy crisis, identifying impactful solutions is imperative. This research introduces the cutting-edge nanocomposites, WO3/CdS0.25Se0.75-Diethylenetriamine (Diethylenetriamine is abbreviated as DETA) with configurations of 20 %, 30 %, and 40 % WO3 (denoted as 20-WO/CSE, WO/CSE, and 40-WO/CSE), highlighted by its innovative S-scheme heterojunction. WO/CSE nanocomposite stands out in the realm of solar energy materials, achieving a superior photocatalytic hydrogen evolution rate of 16.7 mmol g−1h−1. Additionally, it exhibits exceptional corrosion resistance, maintaining performance integrity over four 12-hour testing cycles. The strategic incorporation of WO3 not only enhances the nanocomposite's photocatalytic efficiency but also underscores its potential in surpassing the capabilities of its individual constituents. Through theoretical calculations, the S-scheme heterojunction's effective charge transfer properties are confirmed, positioning this nanocomposite as a significant leap forward in addressing energy challenges through advanced solar energy materials and nanocomposites.

Construction of Ni2P modified N-doped TiO2 flower-like microspheres with rich 0D/2D heterojunctions for enhanced hydrogen evolution reaction

Ni2P nanocrystals modified N-doped TiO2 flower-like microspheres (Ni2P/N-TFMs) with rich 0D/2D heterojunctions were successfully synthesized via a facile hydrothermal-calcination route. The results indicate that N-TFMs are assembled by interlaced nanosheets with the thickness of only 3–8 nm, which provide abundant anchoring sites for the loading of Ni2P. Notably, the doping of N dopant effectively broadens the spectral response range of TFMs due to the formation of N 2p impurity energy level, and the formed 0D/2D heterojunctions between Ni2P nanocrystals and nanosheet units greatly facilitate the separation of photogenerated carriers and improve the photocatalytic reaction kinetic. Owing to the advantages in energy band structure and surface morphology, the synthesized 10Ni2P/N-TFMs composite exhibits a remarkably enhanced photocatalytic hydrogen evolution rate (0.368 mmol h−1 g−1) compared with commercial P25 TiO2 and N-TFMs under visible light irradiation, implying a wide application prospect of this kind of nanostructure in the field of green hydrogen production.