CdS-based Photocatalysts Research Articles

Synthesis of carbon dots with tailored heteroatomic structure for achieving ultrahigh effectiveness in persulfate activation

Carbon dots (CDs) are normally feature with zero-dimensional structure, excellent solubility, good biosafety, and exceptional photoelectronic properties, thus, awakening the homogeneous-like photocatalytic potency of CDs in peroxymonosulfate (PMS) activation can afford new idea for water body remediation. Herein, we presented a facile nitrogen and sulfur co-doping strategy for the development of high-performance CDs-based photocatalysts. Through the deep investigation on the structure-activity relationship, we proposed that the incorporated pyridinic N within CDs structure could serve as efficient Lewis basic sites for PMS confinement. Importantly, the co-existence of oxidized sulfur groups and specific nitrogen speciation (pyridine N and pyrrolic N) induced unique “push-pull” effect on the photogenerated carriers within the surface state of S,N co-doped CDs. The unique synergy sites and surface hydrophilic nature conferred the CDs exceptional photocatalytic effectiveness, presenting a remarkable PMS consumption ratio of 7.62 per gram of the CDs photocatalyst within just 20 min. Profited from the improved kinetics of interfacial reactions, the CDs-photocatalyzed oxidation system that consisted largely of sulfate radicals can completely degrade rhodamine B within 12.5 min, and hold great potential in long-term operation without needing to regenerate CDs catalyst.

Electrostatic Self-Assembly of CdS Quantum Dots with Co9S8 Hollow Nanotubes for Enhanced Visible Light Photocatalytic H2 Production.

CdS quantum dots (CdS QDs) are regarded as a promising photocatalyst due to their remarkable response to visible light and suitable placement of conduction bands and valence bands. However, the problem of photocorrosion severely restricts their application. Herein, the CdS QDs-Co9S8 hollow nanotube composite photocatalyst has been successfully prepared by loading Co9S8 nanotubes onto CdS QDs through an electrostatic self-assembly method. The experimental results show that the introduction of Co9S8 cocatalyst can form a stable structure with CdS QDs, and can effectively avoid the photocorrosion of CdS QDs. Compared with blank CdS QDs, the CdS QDs-Co9S8 composite exhibits obviously better photocatalytic hydrogen evolution performance. In particular, CdS QDs loaded with 30% Co9S8 (CdS QDs-30%Co9S8) demonstrate the best photocatalytic performance, and the H2 production rate reaches 9642.7 μmol·g-1·h-1, which is 60.3 times that of the blank CdS QDs. A series of characterizations confirm that the growth of CdS QDs on Co9S8 nanotubes effectively facilitates the separation and migration of photogenerated carriers, thereby improving the photocatalytic hydrogen production properties of the composite. We expect that this work will facilitate the rational design of CdS-based photocatalysts, thereby enabling the development of more low-cost, high-efficiency and high-stability composites for photocatalysis.

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

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

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.

Synergistic enhancement of photoelectrocatalytic activity and photostability in CdS photoanodes by ultrathin polydopamine layer

CdS-based photocatalyst and photoanode have recently drawn the attention of several investigators primarily in connection with its excellent visible light response in various catalytic reactions involving light, especially photoelectrochemical (PEC) water splitting. The present approach highlights the concept of constructing a biological functional layer incorporated for photochemical instable semiconductors for practical PEC applications. However, practical applications of CdS-based photoanodes are limited by rapid charge recombination and severe photo corrosion. This study introduces a novel approach to enhance reaction kinetics and stability. We present a CdS nanorod photoanode with an ultrathin layer of polydopamine (PDA), prepared through a conformal polymerization assembly process, which serves as a robust platform for subsequent assembly of hole cocatalysts FeOOH. The resulting sandwich structure of CdS/PDA/FeOOH photoanode demonstrates an incident to current efficiency (IPCE) of 7.1% at 420 nm and a photocurrent of 1.9 mA/cm2 at 1.23 V versus the reversible hydrogen potential (RHE). The integrated photoanode exhibits significantly prolonged photostability compared to CdS, CdS/PDA, and CdS/FeOOH photoanodes. The significance of this work lies in constructing a FeOOH structure (with hole extraction and consumption capabilities) on the CdS outermost layer using an easy-to-operate preparation process, thereby revealing the ability of PDA to enable the passage of photogenerated holes. The present approach highlights the concept of integrating biologically functional layers to stabilize photochemically unstable semiconductors for practical PEC applications.

Selective photocatalytic C-C coupling of benzyl alcohol into hydrobenzoin using Pt-deposited CdS nanosheets passivated with cysteamine.

Achieving high selectivity towards hydrobenzoin (HB) from photocatalytic carbon-carbon (C-C) coupling reaction of benzyl alcohol (BzOH) remains a challenge due to side competing reactions and subsequent conversions of HB into its derivatives. In this study, we have developed a high-performance CdS-based photocatalyst for synthesizing HB with precisely controlled surface properties and structure, achieving high selectivity for HB synthesis. We employed strategies such as cysteamine passivation and Pt deposition to address issues related to photogenerated charge trapping and recombination, thereby enhancing the photocatalytic capability of CdS. With optimized Pt/CdS NSs as the photocatalyst, we investigated the impact of the Pt/CdS heterostructure on intermediate reactions, which in turn altered product selectivity. Specifically, excessive Pt suppresses the electron-induced benzaldehyde-to-intermediate reaction by consuming electrons for the competing hydrogen evolution reaction (HER), leading to high selectivity toward benzaldehyde. In contrast, bare CdS without Pt suffers from insufficient charge supply for BzOH conversion due to the charge recombination issue, which promotes the subsequent conversion of HB to its derivatives. Notably, when Pt is precisely loaded to avoid dominant HER competition, the overall reaction rate increases, maintaining high selectivity towards HB and ensuring faster conversion of BzOH to HB rather than subsequent conversions of HB into its derivatives, thereby maximizing the HB yield. Subsequently, we have developed a photocatalyst that achieves a 93.4% conversion of 0.24 mmol BzOH with 85.3% selectivity toward HB under solar simulator irradiation (AM 1.5G). This work is expected to offer instructive guidance on rationally designing the photocatalyst for efficient C-C coupling reactions.

Effective photocatalytic hydrogen evolution by Ti3C2-modified CdS synergized with N-doped C-coated Cu2O in S-scheme heterojunctions

Photocatalytic hydrogen evolution through water splitting holds tremendous promise for converting solar energy into a clean and renewable fuel source. However, the efficiency of photocatalysis is often hindered by poor light absorption, insufficient charge separation, and slow reaction kinetics of the photocatalysts. In this study, we designed and synthesized a novel S-scheme heterojunction comprising Ti3C2 MXene, CdS nanorods, and nitrogen-doped carbon coated Cu2O (Cu2O@NC) core-shell nanoparticles. Ti3C2 MXene as a cocatalyst enhances the light absorption and charge transfer of CdS nanorods. Simultaneously, the core-shell Cu2O@NC nanoparticles establish a pathway for transferring photogenerated electrons and create a favorable band alignment for efficient hydrogen evolution. The synergistic effects of Ti3C2 MXene and Cu2O@NC on CdS nanorods result in multiple charge transfer channels and improved photocatalytic performance. The optimal hydrogen evolution rate of the Ti3C2-CdS-Cu2O@NC S-scheme heterojunction photocatalyst is 7.4 times higher than that of pure CdS. Experimental techniques and DFT calculations were employed to explore the structure, morphology, optical properties, charge dynamics, and band structure of the heterojunction. The results revealed that the S-scheme mechanism effectively suppresses the recombination of photogenerated carriers and facilitates the separation and migration of photogenerated electrons and holes to the reaction sites. Furthermore, Ti3C2 MXene provides abundant active sites essential for accelerating the surface H2-evolution reaction kinetics. The Cu2O@NC core-shell nanoparticles with a large surface area and high stability are closely adhered to CdS nanorods and establish an S-scheme internal electric field with CdS nanorods to drive charge separation. This investigation provides valuable insights into the rational design of CdS-based photocatalysts, enabling efficient hydrogen production by harnessing the robust kinetic driving force provided by the S-scheme heterojunctions.

Evidence for an Interface of Hybrid Cocatalysts Favoring Photocatalytic Hydrogen Evolution Kinetics.

Hybrid cocatalysts have great application potential for improving the photocatalytic hydrogen evolution performance of semiconductors. The interfaces between components of hybrid cocatalysts make a great contribution to the improvement, but the associated mechanisms remain unclear. Herein, we prepared and tested three comparative CdS-based photocatalysts with NiS, NiS/Ni9S8, and Ni9S8 as the cocatalysts separately. The emphasis is placed on investigating the effect of the NiS/Ni9S8 interfaces on the photocatalytic hydrogen evolution performance of CdS. NiS/Ni9S8 exhibits a higher ability than NiS and Ni9S8 in making CdS a more active photocatalyst for water splitting. It shows that NiS, NiS/Ni9S8, and Ni9S8 perform similarly in terms of promoting the charge transfer and separation of CdS based on steady-state and time-resolved photoluminescence studies. At the same time, the linear sweep voltammetry and electrochemical impedance spectroscopy tests combined with the density functional theory calculations reveal that the component interfaces of NiS/Ni9S8 enable us to lower the water splitting activation energy, the charge-transfer resistance from the cocatalyst to sacrificial agent, and hydrogen adsorption Gibbs free energy. It is evidenced from this work that component interfaces of hybrid cocatalysts play a vital role in accelerating the dynamics of hydrogen evolution reactions.

Augmented photocatalytic water splitting performance of CdS nanorods encased with Co-C@WS2 nanostructures

Hydrogen production via photocatalytic water-splitting process is a favourable and eco-friendly technique which addresses the energy-environmental issues. However, the development of affordable, highly efficient as well as stable photocatalysts continues to be a challenging task. Here, we propose a photocatalyst based on CdS nanorods that are coupled with WS2 nanosheets and metal-organic framework (MOF) derived Co-C nanostructures to promote photo-assisted H2 evolution in the aqueous medium. The experimental outcomes demonstrate that the fabricated nanocomposite is highly active to produce H2 at a rate of 214.96 mmol. g−1. h−1, indicating highest values among CdS-based photocatalysts. Additionally, the nanocomposite displayed an excellent long-term stability for 40 h. Overall, the present work introduces a photocatalytic system devoid of noble-metals, illustrating the functionalities of MOF-derived materials along with 2D transition metal dichalcogenides for accelerating the H2 evolution rate of semiconductor photocatalysts.

Ohmic-functionalized type I heterojunction: Improved alkaline water splitting and photocatalytic conversion from CO2 to C2H2

A hollow dodecahedron-shaped N-doped carbon (N-C) coated with CoSe2 nanoparticles are fabricated via MOF-derived self-sacrificing strategy based on Kirkendall Effect. By coupling with CdS nanodots, the optimal Ohmic-type functionalized type I heterojunction CdS/N-C/CoSe2 (CCE50) exhibits a significant photocatalytic hydrogen evolution reaction (PHER) rate of 19317.3 μmol h−1 gcat−1 that is 15.7 and 33.7 folds higher than type I CdS/N-C heterojunction (1230.3 μmol h−1 gcat−1) and pure CdS respectively, and successfully transfers the source of photo-corrosion to obtain stable PHER for 5 cycles. Moreover, the CCE50 in alkaline media (pH = 12) achieves a 1.6-fold PHER rate higher than that in the original triethanolamine (TEOA) aqueous solution (pH≈8), where electron paramagnetic resonance (EPR) result shows that it is attributed to the accumulation of O2–. The effective PHER rate can be attributed to the synergistic effect of higher light absorption in hollow CCE50 with multiple scattering and the introduction of Ohmic contact. Besides, the successful conversion from CO2 to C2H2 under 80 kPa CO2 pressure is detected firstly on CdS-based photocatalyst (the conversion rate is 2.8 μmol h−1 gcat−1) without other C1 or C2 gas products. EPR, in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) tests, Kelvin Probe Force Microscopy (KPFM) and density functional theory calculations, etc. have illustrated and verified the photocatalytic mechanism for Ohmic contact-enhancing type I heterojunction, which promotes hydrogen production in alkaline media and C2H2 generation from CO2.

Research progress on synthetic and modification strategies of CdS-based photocatalysts

Research progress on synthetic and modification strategies of CdS-based photocatalysts

Photocatalytic Production of Syngas from Biomass.

ConspectusAs a renewable solar energy and carbon carrier, biomass exploration has received global attention. Photocatalytic valorization of biomass into fuels and chemicals is a promising and sustainable method for future chemical production. Photocatalysis has the potential to accomplish reactions under ambient conditions due to the unique reaction mechanisms involving photoinduced charge carriers and has recently been recognized as an efficient and feasible technology for biomass conversion. Biomass is widely used as sacrificial agent to scavenge holes in photocatalytic hydrogen evolution, and the carbon is eventually degraded to CO2 with a minor amount of CO. The generation of CO instead of CO2 is more economical and promising but also a challenge under photoreforming conditions.This is a new research direction, while until now there has still been the lack of a comprehensive review article to summarize and provide prospects for this topic. This Account will highlight our contributions in the research direction of the photocatalytic reforming of biomass into syngas (CO + H2). In 2020, we first reported the photocatalytic conversion of biopolyols and sugars into syngas by employing a defect-rich Cu-TiO2 nanorod photocatalyst and found that formic acid is a key intermediate to CO. Further study revealed that a facet-dependent electron-trapping state on anatase TiO2 will affect the photocatalytic dehydration activity for formic acid intermediates by regulating the electron transfer process during the reaction, and the selective generation of FA or CO from photocatalytic biomass reforming was achieved via exposing the (100) or (101) facets, respectively. Visible light-driven syngas generation was further achieved over a CdS-based photocatalyst. Sulfate modification of CdS ([SO4]/CdS) was constructed as the proton acceptor, thus efficiently facilitating the proton-coupled electron transfer process. Besides, we put forward an oxygen-controlled strategy to increase the CO generation rate without a significant decrease in CO selectivity via controlling the O2/substrate ratio. Based on this system, a Z-scheme CdS@g-C3N4 core-shell structure and CdO-CdS semicoherent interface were created to facilitate charge transfer and enhance the O2 activation, thus increasing the CO generation rate. Moreover, we also developed a photoelectrochemical approach to separately produce CO and H2 from biomass. Nitrogen doping of a hexagonal WO3 nanowire array was used to produce the photoanode. The built-in electric field generated via nitrogen doping promoted charge transfer, hence improving the efficiency of PEC reforming of biopolyols and sugars. This Account will systematically analyze the challenges in this research direction, the reaction route in the photocatalytic biomass reforming, and the factors affecting CO selectivity and give insight into the design of efficient photocatalytic systems.

CoP-Embedded Graphitic N-Doped C Nanosheets in Ohmic Contact with S-Deficient CdS Nanocrystals Triggering Efficient Visible-Light Photocatalytic H2 Evolution

Photocatalytic water splitting using semiconductor-based catalysts is a promising avenue to gain H2 fuel from renewable solar energy. Nonetheless, developing earth-abundant and visible-light-responsive photocatalysts for efficient H2 production still remains a huge challenge. In this work, unique two-dimensional hierarchitectures of S-deficient CdS integrated with ultrafine CoP nanocrystals embedding in graphitic N-doped C (CoP-CN) nanosheets are fabricated for the first time. Noticeably, the graphitic CN electron mediator not only enhances the photocatalytic stability of CdS/CoP-CN composites by protecting CoP from external corrosion but also induces the formation of an ohmic junction to boost electron extraction from CdS to CoP efficiently. Meanwhile, the S vacancies in CdS serve as electron traps to further enhance the separation of photogenerated carriers. Such unique CdS/CoP-CN hierarchical hybrid nanosheets exhibited an extraordinary visible-light-induced (λ > 400 nm) photocatalytic H2-evolving performance, delivering a high apparent quantum yield (26.3% at 420 nm) and an excellent H2 generation rate of 54.01 mmol·g–1·h–1, much superior to those of a CdS/CoP Schottky junction, Pt-loaded CdS, and a vast amount of CdS-based photocatalysts ever reported. In addition, the outstanding H2-evolving durability of CdS/CoP-CN composites was verified by cycling and long-term photocatalytic tests. The findings presented here are anticipated to enlighten the rational design and synthesis of highly active photocatalysts with an ohmic junction for application in energy and environment-related domains.

Unique porous ZnS-CdS-CoSx Reuleaux triangle nanosheets: Highly promoted visible-light photocatalytic H2 evolution via synergistic effect of Z-scheme heterojunction and vacancy defects

Photocatalytic water-splitting employing Z-scheme semiconductor heterojunction is a promising avenue to realize the efficient conversion and storage of renewable solar energy because of its space-separated reduction and oxidation sites, effective charge separation and transportation, as well as the stronger redox abilities of photogenerated carriers. Nevertheless, the efficiency of Z-scheme photocatalysts is often weakened by the insufficient coupling of components due to the stepwise hybridization processes. In this work, unique ZnS-CdS-CoSx porous Reuleaux triangle nanosheets with intimate Z-scheme hetero-interface and S, Zn vacancies were produced by using Zn2Co3(OH)10·2H2O as the bimetallic precursor for subsequent sulfurization and Cd2+-exchange reaction. Noticeably, such a novel structure shows desirable features which suggest a promising photocatalyst for visible-light photocatalytic H2 evolution, including superior charge-separating capability enabled by the Z-scheme charge transfer and synergetic charge-trapping effect of S, Zn vacancies, excellent light-harvesting capacity, abundant S22− species as H2-evolving active sites, a large surface area, and good stability without obvious decline in activity after multiple cycling and long-term tests. The ZnS-CdS-CoSx heterojunction exhibits an outstanding visible-light-driven H2-evolving activity as high as 53.43 mmol·g−1·h−1, corresponding to a high apparent quantum efficiency of 30.8 % at 420 nm, far better than that of Pt-loaded CdS and a great deal of CdS-based photocatalysts reported in the literatures. The present work may shed new light on the designed synthesis of high-performance semiconductor heterojunction for sustainable solar utilization and environmental remediation.

A novel pathway toward efficient improvement of the photocatalytic activity and stability of CdS-based photocatalyst for light driven H2 evolution: The synergistic effect between CdS and SrWO4

It has been a research hot spot how to efficiently heighten the photocatalytic activity and stability of CdS-based photocatalysts for H2 evolution. Here, SrWO4/CdS nanoparticles which contained CdS/SrWO4 heterojunctions were prepared. Meanwhile, their photocatalytic performance and stability were investigated in detail for H2 evolution. At last, the photocatalytic mechanism of the SrWO4/CdS nanoparticles was discussed roughly. The results show that the photocatalytic performance of CdS can be heightened significantly due to introduction of SrWO4. The fastest evolution rate of H2 over the SrWO4/CdS nanoparticles is 392.5 μmol g−1 h−1, which is 5.8 times as high as that over the pure CdS nanomaterial. More interestingly, the SrWO4/CdS nanoparticles possess excellent stability. The evolution rate of H2 over the photocatalyst used 10 times can be up to 473 μmol g−1 h−1, which is the same as that over the once used sample, even is 37% higher than that over of the fresh one. In contrast, after used five times, the photocatalytic activity of the pure CdS nanomaterial is only 57% of that of the fresh sample. This study will supply a new idea for the design and development of highly stable and efficient CdS-based photocatalysts for H2 evolution in the future.

Recent Advances in Cadmium Sulfide-Based Photocatalysts for Photocatalytic Hydrogen Evolution

High-efficiency photocatalytic hydrogen evolution (PHE) relies on the development of inexpensive, stable, and efficient photocatalysts. Cadmium sulfide (CdS), as a typical binary metal sulfide, has attracted considerable research attention due to its negative conduction band position, narrow band gap for visible-light response, and strong driving force for PHE. However, the construction of CdS-based photocatalysts and the PHE rate still require improvement for practical applications. In this review, recent advances in CdS-based photocatalysts for PHE via water splitting are systematically summarized. First, the semiconductor properties of CdS, including the crystal and band structures, are briefly introduced. Afterward, the fundamental mechanisms of PHE using semiconductor photocatalysts via water splitting are discussed. Subsequently, the photoactivity of bare CdS with different morphologies and structures, CdS with cocatalyst loading, and CdS-based heterojunction photocatalysts are reviewed and discussed in detail. Finally, the challenges and prospects for exploring advanced CdS-based photocatalysts are provided.

Construction of 1D/0D CdS nanorods/Ti3C2 QDs Schottky heterojunctions for efficient photocatalysis

In this study, we present CdS nanorods/Ti3C2 QDs Schottky heterojunctions as highly efficient photocatalysts for excellent water splitting and photodegradation, where the Ti3C2 QDs as co-catalyst are firmly anchored on the surfaces of CdS nanorods by Polyethyleneimine (PEI). The enhanced hydrophilicity promotes the contact of the photocatalyst and water molecules owing to the introduction of PEI, accelerating the photocatalytic hydrogen evolution. Especially, the apparent quantum efficiency (AQE) can reach 32.1% and 26.2% at 450 and 500 nm, respectively, much higher than those of reported CdS-based photocatalysts. Additionally, the CdS nanorods/Ti3C2 QDs composite exhibits robust performance on the photodegradation of bisphenol A (BPA). The liquid chromatography-mass spectrometer (LC-MS) analysis demonstrates that BPA is oxidized to five byproducts firstly and then the rings are opened sequentially. Furthermore, femtosecond transient absorption (fs-TA) spectroscopy confirms that the formation of Schottky heterojunction between CdS nanorod and Ti3C2 QD, which promotes the migration and separation of photogenerated carriers, leading to the excellent photocatalytic activity. Our findings provide a rational design of heterogeneous photocatalyst with superior photocatalytic performance.

Peanut-chocolate-ball-inspired construction of the interface engineering between CdS and intergrown Cd: Boosting both the photocatalytic activity and photocorrosion resistance

Interface engineering can improve the charge separation efficiency and inhibit photocorrosion is an emerging direction of developing more efficient and cost-effective photocatalytic systems. Herein, we report the sulfur-confined intimate CdS intergrown Cd (CdS/Cd) Ohmic junction (peanut-chocolate-ball like) for high-efficient H2 production with superior anti-photocorrosion ability, which was fabricated from in-situ photoreduction of CdS intergrown Cd2SO4(OH)2 (CdS/Cd2SO4(OH)2) prepared through a facile space-controlled-solvothermal method. The ratios of CdS/Cd can be effectively controlled by tunning that of CdS/Cd2SO4(OH)2 which were prepared by adjusting the volume of reaction liquid and the remaining space of the reactor. Experiments investigations and density functional theory (DFT) calculations reveal that the CdS intergrown Cd Ohmic junction interfaces (with appropriate content Cd intergrown on CdS (19.54 wt%)) are beneficial in facilitating the transfer of photogenerated electrons by constructing an interfacial electric field and forming sulfur-confined structures for preventing the positive holes (h+) oxidize the CdS. This contributes to a high photocatalytic H2 production activity of 95.40 μmol h−1 (about 32.3 times higher than bare CdS) and possesses outstanding photocatalytic stability over 205 h, much longer than most CdS-based photocatalysts previously reported. The interface engineering design inspired by the structure of peanut-chocolate-ball can greatly promote the future development of catalytic systems for wider application.

Defected tungsten disulfide decorated CdS nanorods with covalent heterointerfaces for boosted photocatalytic H2 generation

Owing to their intrinsic and pronounced charge carrier transport when facing the formidable challenge of inhibiting severe surface charge recombination, one-dimensional (1D) CdS nanostructures are promising for advancing high-yield hydrogen production. We herein demonstrate an efficient strategy of boosting interfacial carrier separation by heterostructuring 1D CdS with defective WS2. This process yields solid covalent interfaces for high flux carrier transfer that differ distinctively from those reported structures with physical contacts. As a nonnoble cocatalyst, WS2 can accept photogenerated electrons from CdS, and the sulfur vacancies existing at its edges can effectively trap electrons as active sites for H2 evolution. Moreover, due to its strong negative property, the H+ from the aqueous solution can gather around WS2. WS2 possesses a lower reaction barrier than CdS, which expedites the kinetic process for the reaction. The optimized sample exhibits a high photocatalytic H2 evolution rate of 183.4 µmol/h (10 mg photocatalyst), which is as far as we know among the top in the records for CdS-based photocatalysts. We believe this present work will be inspiring in addressing the interfacial charge carrier transfer by constructing covalent heterointerfaces.

Boosting Hydrogen Evolution Performance of a CdS-Based Photocatalyst: In Situ Transition from Type I to Type II Heterojunction during Photocatalysis

Boosting Hydrogen Evolution Performance of a CdS-Based Photocatalyst: In Situ Transition from Type I to Type II Heterojunction during Photocatalysis