Photocatalytic H2 Production Research Articles

Sulfated CeO2-TiO2 as H2 evolution photocatalyst: Synergic effects of heterojunction and sulfation on catalyst performance

SO42−/CeO2/TiO2 composite oxides are successfully fabricated via sol-gel method and impregnation process for photocatalytic H2 production. The characterization results from XRD, FTIR and TEM revealed that the heterojunctions were formed by the formation of Ti-O-Ce bond across the SO42−/CeO2/TiO2 interface, which was contributed significantly to separation of photo-generated carriers. Py-FTIR spectra and XPS results indicated that Lewis acid and Brønsted acid sites were formed over the surface of SO42−/CeO2/TiO2 composite, which was owing to SO42− coordinated to the metal on the sample surface. The induced Lewis acid sites could enhance the separation of photogenerated carriers, and Brønsted acid sites could provide protons for photocatalytic H2 production. In addition, the Lewis acidity could facilitate the shift of conduction band minimum to a more negative value, which improves the photocatalytic H2 production capacity of SO42−/CeO2/TiO2. The results of photocatalytic H2 production revealed that SO42−/CeO2/TiO2 composite exhibits superior photocatalytic activity compared to bare CeO2, TiO2 and CeO2-TiO2 composite. Notably, it achieves the average H2 yield rate of 6295.2 μmol·g−1 h−1 over a period of 5 h. Combine the results of spectra analysis and photocatalytic activity H2 evolution, it can be concluded that the synergetic effects of heterojunction structure of CeO2/TiO2 composite and acid impregnation promoted the photocatalyst activity.

Fast carrier separation induced by the metal-like O-doped MoS2/CoS cocatalyst for achieving photocatalytic and photothermal hydrogen production

Full solar-spectrum-driven hydrogen (H2) production from water-splitting is highly desirable but remains a great challenge. A heterojunction composite photocatalyst with a full-spectrum absorption range of up to 1020 nm was constructed by introducing 2D/2D metallic oxygen-doped MoS2/CoS (O-MC) nanosheets onto 1D Zn0.1Cd0.9S nanorods (ZCS NR) for photocatalytic and photothermal H2 production. Consequently, the optimal ZMC1.5 heterojunction exhibited a significantly improved H2 production activity of 95.5 mmol g−1 h−1 under 420 nm monowavelength irradiation, which is 13.84 times higher than that of pristine ZCS NR. Even under 1020 nm monowavelength irradiation, the catalyst also shows an expressive H2 generation rate of 0.202 mmol g−1 h−1. Moreover, it gives an apparent quantum yield (AQY) of 39.5% at 420 nm. Femtosecond transient absorption spectroscopy (Fs-TAS) results reveal the multiple intraband and interband excited-charge transitions in the partially occupied band of O-MC and interfacial electron transfer between O-MC and ZCS NR result in the enhancement H2 evolution rate. This study highlights the extended light absorption and special partially occupied energy bands of metallic cocatalysts, which hold great potential for the design and synthesis of efficient full solar-spectrum (UV–vis-NIR light) responsive photocatalysts.

Pd(II) coordination molecule modified g-C3N4 for boosting photocatalytic hydrogen production

The photocatalytic H2 production activity of polymer carbon nitride (g-C3N4) is limited by the rapid recombination of photoelectron-hole pairs and slow surface reduction dynamic process. Here, a supramolecular complex (named R-TAP-Pd(II)) was fabricated via self-assembly of (R)-N-(1-phenylethyl)-4-(4-(pyridin-2-yl)-1H-1,2,3-triazol-1-yl)benzamide (R-TAP) with Pd(II) and used to modify g-C3N4. In the R-TAP-Pd(II)@g-C3N4 composite photocatalyst, the spin polarization of R-TAP-Pd(II) can promote charge transfer and inhibit photogenerated carrier recombination, as confirmed by spectral tests and photoelectrochemical performance tests. Electrochemical tests and in situ X-ray photoelectron spectroscopy (XPS) tests proved that the Pd(II) ion in the R-TAP-Pd(II) molecule can serve as active sites to accelerate H2 production. The R-TAP-Pd(II)@g-C3N4 presented a photocatalytic H2 generation rate of 1085 μmol g−1 h−1 when exposed to visible light, which was a about 278-fold increase compared with g-C3N4. This work finds a new approach to boost the photocatalytic efficiency of g-C3N4 via supramolecular self-assembly.

Surface plasmon resonance-mediated photocatalytic H2 generation.

The limited yield of H2 production has posed a significant challenge in contemporary research. To address this issue, researchers have turned to the application of surface plasmon resonance (SPR) materials in photocatalytic H2 generation SPR, arising from collective electron oscillations, enhances light absorption and facilitates efficient separation and transfer of electron-hole pairs in semiconductor systems, thereby boosting photocatalytic H2 production efficiency. However, existing reviews predominantly focus on SPR noble metals, neglecting non-noble metals and SPR semiconductors. In this review, we begin by elucidating five different SPR mechanisms, covering hot electron injection, electric field enhancement, light scattering, plasmon-induced resonant energy transfer, and photo-thermionic effect, by which SPR enhances photocatalytic activity. Subsequently, a comprehensive overview follows, detailing the application of SPR materials-metals, non-noble metals, and SPR semiconductors-in photocatalytic H2 production. Additionally, a personal perspective is offered on developing highly efficient SPR-based photocatalysis systems for solar-to-H2 conversion in the future. This review aims to guide the development of next-gen SPR-based materials for advancing solar-to-fuel conversion.

Selenium doping to improve internal electric field for excellent photocatalytic efficiency of g-C3N4 nanosheets

Graphitic carbon nitride is a promising photocatalyst to address environmental issues and energy applications. Herein, we develop an efficient defect-containing functionalized system of 2D selenium doped g-C3N4 porous nanosheets via one pot with two-step temperature for the first time. During heat treatment, Se-infused g-C3N4 nanosheets loosen stacking and form thinner nanosheets, which could effectively shorten the electronic path of charge migration. The introduction of nitrogen vacancies creates a midgap energy state below the CB, which improves the light-harvesting efficiency. Moreover, the dual effect of N vacancy and Se doping provides a driving force for the dissociation of excitons and achieves an effective spatial charge separation. High specific surface area (104.1 m2/g), suitable bandgap (2.65 eV), and good photocurrent response (0.45 µA cm−2) help to enhance the photocatalytic efficiency of 1-SeCN remarkably. Henceforth, high photocatalytic H2 production rate of 5441 µmol g−1 h−1 and CO evolution rate of 31.5 µmol g−1 h−1 verifies the effective Se doping enhances the photocatalytic efficiency of g-C3N4. Furthermore, DFT calculations are consistent with experimental results and this facile engineering strategy provides a scalable way to develop a novel, efficient g-C3N4-based photocatalyst for H2 production and CO2 reduction.

Boosting photothermal-assisted photocatalytic H2 production over black g-C3N4 nanosheet photocatalyst via incorporation with carbon dots

Although photocatalytic H2 production based on semiconductor materials has a wide potential application, it still facing challenges such as slow reaction kinetics or complex synthesis processes. To meet these challenges, the carbon dots loaded black g-C3N4 (CN-B-CDs) was synthesized by simple calcination method to achieve efficient photothermal-assisted photocatalytic H2 production. Photothermal imaging experiments confirmed the photothermal effect of CN-B and CDs as dual heat sources to increase the temperature of the composite system, thus improving the effective separation of photo-generated charges. In addition, multiple photocatalytic H2 production tests exhibited that CN-B-CDs photocatalysts not only have strong stability but also can accommodate a variety of complex water bodies, which displayed the potential for industrial application. This study combined the photothermal effect and the mechanism by which the CDs promote the charge transfer to design a new photocatalytic H2 production system and provided a new scheme for achieving efficient photothermal-assisted photocatalytic H2 production using carbon-based materials.

TS-1 zeolite encapsulated Pt clusters with enhanced electronic metal-support interaction of Pt−O(H)−Ti for nearly-zero-carbon-emitting photocatalytic hydrogen production from methanol

Photocatalytic H2 production from methanol is sustainable, yet challenges remain in avoiding carbon-containing gaseous by-products. Titanium silicalite-1 (TS-1) zeolite possesses attractive photocatalytic performance, but lack of modification strategies due to its microporous framework. Herein, we developed a pre-anchoring strategy to confine ultra-small Pt clusters inside TS-1 with ultra-low loading (0.2 mol%), in which Pt were anchored in Ti−OH nests by electronic metal-support interaction (EMSI). The optimal catalyst achieved a remarkable H2 generation rate of 63.2 mmol g–1 h–1 in CH3OH solutions, along with the production of high-value chemical HCHO as the oxidation product with 96.9% selectivity. Investigations reveal that the EMSI between Pt and Ti facilitated the selective decomposition of CH3OH to H2 and HCHO, leading to a nearly zero-carbon-emission process. Accordingly, we propose a light-driven carbon-negative "CO2→CH3OH→H2" route, coupling CO2 utilization and green H2 production with CH3OH as the intermediate, therefore offering a new perspective for "liquid sunshine".

Interlayer Potassium Single-Atom-Coordinated g-C3N4 for Significantly Boosted Visible Light Photocatalytic H2 Production.

In recent years, graphitic carbon nitride (g-C3N4) has attracted considerable attention because it includes earth-abundant carbon and nitrogen elements and exhibits good chemical and thermal stability owing to the strong covalent interaction in its conjugated layer structure. However, bulk g-C3N4 has some disadvantages of low specific surface area, poor light absorption, rapid recombination of photogenerated charge carriers, and insufficient active sites, which hinder its practical applications. In this study, we design and synthesize potassium single-atom (K SAs)-doped g-C3N4 porous nanosheets (CM-KX, where X represents the mass of KHP added) via supramolecular self-assembling and chemical cross-linking copolymerization strategies. The results show that the utilization of supramolecules as precursors can produce g-C3N4 nanosheets with reduced thickness, increased surface area, and abundant mesopores. In addition, the intercalation of K atoms within the g-C3N4 nitrogen pots through the formation of K-N bonds results in the reduction of the band gap and expansion of the visible-light absorption range. The optimized K-doped CM-K12 nanosheets achieve a specific surface area of 127 m2 g-1, which is 11.4 times larger than that of the pristine g-C3N4 nanosheets. Furthermore, the optimal CM-K12 sample exhibits the maximum H2 production rate of 127.78 μmol h-1 under visible light (λ ≥ 420 nm), which is nearly 23 times higher than that of bare g-C3N4. This significant improvement of photocatalytic activity is attributed to the synergistic effects of the mesoporous structure and K SAs doping, which effectively increase the specific surface area, improve the visible-light absorption capacity, and facilitate the separation and transfer of photogenerated electron-hole pairs. Besides, the optimal sample shows good chemical stability for 20 h in the recycling experiments. Density functional theory calculations confirm that the introduction of K SAs significantly boosts the adsorption energy for water and decreases the activation energy barrier for the reduction of water to hydrogen.

Construction of Inverse-Opal ZnIn2S4 with Well-Defined 3D Porous Structure for Enhancing Photocatalytic H2 Production.

The conversion of solar energy into hydrogen using photocatalysts is a pivotal solution to the ongoing energy and environmental challenges. In this study, inverse opal (IO) ZnIn2S4 (ZIS) with varying pore sizes is synthesized for the first time via a template method. The experimental results indicate that the constructed inverse opal ZnIn2S4 has a unique photonic bandgap, and its slow photon effect can enhance the interaction between light and matter, thereby improving the efficiency of light utilization. ZnIn2S4 with voids of 200 nm (ZIS-200) achieved the highest hydrogen production rate of 14.32 μ mol h-1. The normalized rate with a specific surface area is five times higher than that of the broken structures (B-ZIS), as the red edge of ZIS-200 is coupled with the intrinsic absorption edge of the ZIS. This study not only developed an approach for constructing inverse opal multi-metallic sulfides, but also provides a new strategy for enriching efficient ZnIn2S4-based photocatalysts for hydrogen evolution from water.

Enhanced photocatalytic H2 production activity by loading Ni complex on flower-like MoS2 nanomaterials

BackgroundExploring efficient H2-production photocatalysts is very important for converting solar energy to chemical energy. Some approaches were developed to prevent the recombination of photogenerated electron-hole pairs, ultimately enhancing the photocatalytic H2 production activity. Methods3D flower-like MoS2 nanomaterials were surface-modified by the Ni complex as the redox mediator to make the composite photocatalysts. This work investigated the effect of zeta potential on the Ni-complex loading, charge separation, and photocatalytic H2 production activity of MoS2. Significant findingsThe Ni-complex with central cation can be loaded on MoS2 with negative zeta potential due to the columb attraction force. The photogenerated carriers can transfer from MoS2 to the central Ni ion of the complex due to the ligands-stabilized multiple oxidation states of Ni, leading to suppressed charge recombination. The FE-TEM mapping and XPS confirm the loading of Ni complex. The photoluminescence, photocurrent response, and EIS tests confirm the improved photoinduced charge separation of the Ni complex-modified photocatalyst. The flower-like microstructure of MoS2 provides a large specific surface area and high light absorption. The H2 production activity of MoS2-Ni complex photocatalyst (3320 μmol g−1 h−1) is higher than that of the pristine MoS2 photocatalyst (2576 μmol g−1 h−1).

P-doped ultrathin g-C3N4/In2S3 S-scheme heterojunction enhances photocatalytic hydrogen production and degradation of ofloxacin

In this work, ultrathin lamellar g-C3N4/In2S3 S-scheme heterojunctions doped with P were synthesized by urea recrystallization and investigated to see which ratio was more favorable for photocatalysis. The P doping formed a new Fermi energy level and reduced the forbidden bandwidth. The ultrathin lamellar structure facilitated rapid charge transfer, and the formation of S-scheme heterojunction, the presence of the interfacial electric field, and band bending effectively separated strong redox-capable electron-hole pairs, thus significantly improving the photocatalytic performance. Among the prepared materials, the 50UP-C3N4/In2S3 photocatalyst with 50 % UP-C3N4 mass fraction showed optimal photocatalytic H2 production performance, with a hydrogen production rate of 12,387 μmol h−1 g−1. Moreover, it showed good performance in photocatalytic degradation, with a degradation efficiency of up to 90.2 % of ofloxacin after 120 min of light exposure. This article provided a new perspective on the synthesis of other photocatalysts with carbazide-based S-scheme heterojunction structures.

Deep insight into regulation mechanism of band distribution in phase junction CdS for enhanced photocatalytic H2 production

An in-depth understanding of structure-activity relationship between the phase constitution and solar-to-hydrogen (STH) conversion efficiency is conducive to guiding the optimization route of targeted photocatalyst candidates, further establishing advanced photocatalytic systems. Herein, based on the concept of phase engineering, we encompassed the crystalline phase of CdS and achieved precise regulation of phase proportion as well as phase boundary width in the phase junction for the first time. The above cooperative effect not only modifies energy band distribution for sufficient redox potentials, but also guarantees the reverse migration orientation of photogenerated carriers in phase junction, thereby endowing photocarriers with a prolonged lifetime. Compared to pure cubic or hexagonal phase (72.6 or 101.1 μmol h−1 g−1), this CdS system with optimized phase junction demonstrates an improved photocatalytic hydrogen evolution activity of 1.04 mmol h−1 g−1 and favorable stability without cocatalyst assistance, which mainly stems from an efficient protons reduction process interacting with long-lived photogenerated electrons. This research explores the mechanism behind phase regulation and its relationship with junction capability, providing a powerful strategy to manipulate crystal phase distribution and paving a feasible avenue for other phase-dependent photocatalysts towards rational design of heterostructures based on different phases in solar energy conversion field.

The enhancement of photocatalytic hydrogen production over Ag2WO4 modified g-C3N4 with Pt as cocatalyst

ABSTRACT The construction of heterojunction photocatalyst is an effective mean to improve the photoexcited electron–hole pair separation. The Ag2WO4-doped graphitic carbon nitride (g-C3N4, C3N4 for short) composite photocatalysts were fabricated by a simple calcination and in-situ depositing strategy. The composites were characterized by different techniques. The effects of Ag2WO4 content, type of scavengers, pH value of reaction solution and dose of scavenger on photocatalytic hydrogen (H2) generation were studied. It was found that the Ag2WO4 micro-nano particles were highly dispersed on the C3N4 surface. After doping Ag2WO4, the light absorption range of Ag2WO4-C3N4 material was broadened effectively from 440 nm to 448 nm, and the BET surface area of C3N4 was increased from 35.63 to 40.73 cm2·g−1, indicating that Ag2WO4 loading could provide some new BET surface areas. The binding energy of all elements in Ag2WO4-4/C3N4 was clearly shifted due to the charge transfer from C3N4 to Ag2WO4, implying a strong interaction between C3N4 and Ag2WO4. The photocatalytic H2 production rate of the optimized Ag2WO4-4/C3N4 was 6047.4 μmol·g−1·h−1, which was 2.04 and 171.8 times that of C3N4 and Ag2WO4, respectively. While Ag2WO4-4/C3N4 exhibited a poor H2 production performance in the absence of Pt co-catalyst (309.3 μmol·g−1·h−1), indicating the formation of heterojunction among Ag2WO4, C3N4 and Pt.

Optimization of Schottky barrier height and LSPR effect by dual defect induced work function changes for efficient solar-driven hydrogen production

Photocatalytic water splitting for hydrogen evolution provides a desired approach for sustainable clean energy. However, increasing the effective electron density for proton reduction remains a huge challenge due to the fast charge recombination kinetic. Herein, we propose an efficient strategy, based on manipulating the Schottky barrier height (SBH) and localized surface plasmonic resonances (LSPR) effect of Co-MoO2-x via dual defect (Co doping and oxygen vacancies) induced work function change, to achieve higher electrons density in plasmonic CdS/Co-MoO2-x@C Schottky junction photocatalyst for the first time. Through varying the Co heteroatom doping and oxygen vacancies in our Co-MoO2-x@C cocatalyst, we show adjustable SBH at the interface and tunable photothermal effect in CdS/Co-MoO2-x@C, which leads to inhibited energetic electrons backflow in metallic Co-MoO2-x to improve the electron density. Moreover, optimized electronic structure gives rise to a zero-approaching Gibbs free energy for intermediate state, enabling CdS/Co-MoO2-x@C with promoted intrinsic H2 evolution kinetics.Furthermore, the extended light absorption and elevated reaction temperature stemming from strong LSPR effect of Co-MoO2-x contribute to the decrease of apparent activation energy from 13.824 to 6.579 kJ/mol for H2 evolution. To this end, CdS/Co-MoO2-x@C-7 photocatalyst yields a full-spectrum driven photocatalytic H2 production rate of 89.95 mmol g−1h−1, surpassing most reported CdS-based photocatalyst. This study opens a new avenue toward construction of efficient broad-spectrum active photocatalyst.

Interfacial engineering of 0D/2D CoMn2O4 nanoparticles/CdS nanosheets p-n heterostructures for boosted photocatalytic H2 production and U(VI) reduction

Developing effective heterojunction photocatalysts that efficiently separate charge carriers and improve light-harvesting capabilities is crucial in addressing energy and environmental issues. Herein, a unique nanocomposite photocatalyst is constructed by attaching CoMn2O4 nanoparticles onto 2D CdS nanosheets for H2 production and U(VI) reduction. The optimized 2% CoMn2O4/CdS nanocomposite showcases the highest photocatalytic H2 production efficiency, 5.8 times higher than CdS nanosheets. Additionally, the U(VI) reduction rate constant of 2% CoMn2O4/CdS is 0.0192 min−1, approximately 1.9 folds over the pristine CdS (0.0101 min−1). The exceptional photocatalytic performance toward photocatalytic H2 evolution and U(VI) reduction reactions directly result from the electronic integration between CoMn2O4/CdS p-n heterojunction, facilitated by the efficient photoexcited charge separation. Feasible photocatalytic mechanisms are proposed through experimental analyses and theoretical calculations. This study provides a straightforward method for designing effective CdS-based heterostructured photocatalysts, contributing to the advancement of solar-to-H2 conversion and environmental abetment.

2D MoB MBene: An Efficient Co-Catalyst for Photocatalytic Hydrogen Production under Visible Light.

Highly active and low-cost co-catalysts have a positive effect on the enhancement of solar H2 production. Here, we employ two-dimensional (2D) MBene as a noble-metal-free co-catalyst to boost semiconductor for photocatalytic H2 production. MoB MBene is a 2D nanoboride, which is directly made from MoAlB by a facile hydrothermal etching and manual scraping off process. The as-synthesized MoB MBene with purity >95 wt % is treated by ultrasonic cell pulverization to obtain ultrathin 2D MoB MBene nanosheets (∼0.61 nm) and integrated with CdS via an electrostatic interaction strategy. The CdS/MoB composites exhibit an ultrahigh photocatalytic H2 production activity of 16,892 μmol g-1 h-1 under visible light, surpassing that of pure CdS by an exciting factor of ≈1135%. Theoretical calculations and various measurements account for the high performance in terms of Gibbs free energy, work functions, and photoelectrochemical properties. This work discovers the huge potential of these promising 2D MBene family materials as high-efficiency and low-cost co-catalysts for photocatalytic H2 production.

Microstructure regulation of Zn0.5Cd0.5S for enhancing the photocatalytic H2 production

As an excellent photocatalytic material, ZnxCd1-xS is widely used in photocatalytic H2 production due to its good visible light response and suitable band position. Based on our previous studies, this paper systematically studies the relationship of Zn0.5Cd0.5S (ZCS) material between microstructure and photocatalytic activity. By controlling the synthesized temperature, S sources and solvents, a series of ZCS nanomaterials with different morphology and crystalline phase have been prepared by hydrothermal, solvothermal and ion-exchange methods. When several sacrificial agents are added in photocatalytic H2 production, ZCS performs the highest activity synthesized by solvothermal method, about 12.15 mmol g−1 under 4 h’s visible light illumination. To explore the difference of ZCS samples in photocatalytic performance, many factors are considered, such as crystal size, crystallinity, separation of photogenerated charge carriers (PCCs), specific surface area and defect sites, which play important roles in the improving photocatalytic activity. This work provides a new direction for the design of photocatalyst from the microstructural regulation to achieve highly efficient activity.

Hierarchical Ti3C2/BiVO4 microcapsules for enhanced solar-driven water evaporation and photocatalytic H2 evolution

Desalination processes frequently require a lot of energy to generate freshwater and energy, which depletes resources. Their reliance on each other creates tension between these two vital resources. Herein, hierarchical MXene nanosheets and bismuth vanadate (Ti3C2/BiVO4)-derived microcapsules were synthesized for a photothermal-induced photoredox reaction for twofold applications, namely, solar-driven water evaporation and hydrogen (H2) production. For this purpose, flexible aerogels were fabricated by introducing Ti3C2/BiVO4 microcapsules in the polymeric network of natural rubber latex (NRL-Ti3C2/BiVO4), and a high evaporation rate of 2.01 kg m−2 h−1 was achieved under 1-kW m−2 solar intensity. The excellent performance is attributed to the presence of Ti3C2/BiVO4 microcapsules in the polymeric network, which provides balanced hydrophilicity and broadband sun absorption (96 %) and is aimed at plasmonic heating with microscale thermal confinement tailored by heat transfer simulations. Notably, localized plasmonic heating at the catalyst active sites of the Ti3C2/BiVO4 heterostructure promotes enhanced photocatalytic H2 production evolved after 4 h of reaction is 9.39 μmol, which is highly efficient than pure BiVO4 and Ti3C2. This method turns the issue of water–fuel crisis into a collaborative connection, presenting avenues to collectively address the anticipated demand rather than fostering competition.

Bridging the gap between metallic MoO2 and ZnIn2S4 for enhanced photocatalytic H2 production

Noble metal-free cocatalysts have shown unprecedented potential in enhancing photocatalytic H2 evolution. However, it remains challenging to accelerate the carrier transfer rate by circuiting the substantial Schottky barrier between the metallic cocatalyst and the semiconductor. Herein, an in-situ carbonization strategy is used to accurately anchor MoO2 nanoparticles onto the surface of conductive carbon rods (MoO2/C), which serves as an efficient and stable metallic cocatalyst for ZnIn2S4 towards photocatalytic H2 evolution. The in-site derived carbon skeleton not only prevents the agglomeration of MoO2 nanoparticles thus enriching the active sites for H2 evolution, but also acts as conductor of photogenerated electrons to accelerate electron transfer. In addition, the formed Mo-S bonds at the interface provide additional electron transport channels for hierarchical core–shell MoO2/C@ZnIn2S4 (MO/C@ZIS) heterojunction. It is worth noting that the H2 evolution activity of the optimized MO/C@ZIS sample (2357 μmol·h−1·g−1) is 8.7 times higher than pure ZnIn2S4 (271 μmol·h−1·g−1), and also surpasses the activity of optimized Pt-modified ZnIn2S4 (2123 μmol·h−1·g−1). This work casts a new paradigm for the rational engineering of heterointerface between metallic cocatalysts and semiconductors towards fast electron transport and enhanced photocatalytic performance.

Synthesis of interfacial electric field-enhanced CdS/CdxZn1-xS/ZnO ternary heterojunction by lye dissolution etching mechanism for photocatalytic H2 production and CO2 reduction

The difficulty in fabricating a multifaceted composite heterojunction system based on CdxZn1-xS limits the enhancement of photocatalytic performance. In the present scrutiny, novel ZnO/CdxZn1-xS/CdS composite heterojunctions are successfully prepared by the alkaline dissolution etching method. The internal electric field at the interface of I-type and Z-scheme heterojunction improved the effective charge separation. The ZC 8 sample exhibits excellent photocatalytic performance and the H2 production efficiency is 15.67 mmol g−1 h−1 with good stability up to 82.9 % in 24-hour cycles. The performance of CH4 and CO capacity in the CO2RR process is 3.47 μmol g−1 h−1 and 23.5 μmol g−1 h−1, respectively. The photogenerated accelerated charge transport is then examined in detail by in situ X-ray photoelectron spectroscopy (ISXPS) and density functional theory (DFT) calculations. This work presents a new idea for the synthesis of CdxZn1-xS solid-solution-based materials and provides a solid reference for the detailed mechanism regarding the electric field at the heterojunction interface.