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Visible-Light Overall Water Splitting by CdS/WO <sub/>3</sub> /CdWO <sub/>4</sub> Tricomposite Photocatalyst Suppressing Photocorrosion
摘要： Photocatalytic water splitting under visible light has attracted attention as a possible solution to the energy exhaustion problem. Hitherto, water splitting has been generally achieved using several oxynitrides, oxysul?des, and nitrides, and only a few studies report water splitting using cadmium sul?de (CdS) as a photocatalyst. A major reason for this is that CdS undergoes photocorrosion. In this study, we achieved an overall water splitting under visible light using a CdS/WO3/CdWO4 tricomposite photocatalyst. In the process, photocorrosion of CdS was suppressed by covering it with WO3 and CdWO4, and the oxidation reaction progressed in WO3 by the Z-scheme type photocatalytic reaction.
关键词： cadmium tungstate,tungsten oxide,photocorrosion,water splitting,cadmium sul?de,Z-scheme
更新于2025-11-19 16:51:07
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Encapsulated Cadmium Sulfide in Silicon Dioxide Porous Shells for Enhanced Photocatalytic Sustainability and Commendable Protection of Organic Carriers
摘要： The purpose of this study is to provide a solution to two troublesome problems on photocorrosion of cadmium sulfide (CdS) and photocatalysis damage to organic carrier. An encapsulation system of CdS in silicon dioxide (SiO2) porous shell can be constructed by following strategies: polypyrrole (PPy) layer is deposited on the surface of CdS nanoparticles via chemical redox polymerization; then the resulting PPy@CdS is covered by metasilicic acid (H2SiO3) with polyethylene glycol by sol–gel process, which originates from hydrolysis of tetraethyl orthosilicate; after removing PPy interlayers by calcination, CdS@void@SiO2 yolk–porous-shell nanospheres (YSNs) are fabricated. As expected, YSN nanoarchitecture is verified by transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) analysis. The tailored void can be tuned by the sacrificed layers of PPy. CdS@void@SiO2 YSNs exhibit excellent photostability with a considerably low level of Cd2+ concentration at <30 ppm, which is dropped down 18 times less than ≈520 ppm of CdS. CdS@void@SiO2 YSNs show good dye removal efficiency up to 99.5%, and commendable hydrogen evolution of 126.8 μmol g?1 h?1. More interestingly, the transparent and porous SiO2 shell in the YSNs has an impressive shielding to organic carrier. Our versatile YSNs have great potential to translate CdS photocatalyst to industrial-scale application because of its stability and nondestructivity.
关键词： cadmium sulfide,photocorrosion,carrier protection,sustainable photocatalysis,yolk–porous-shell
更新于2025-11-14 15:18:02
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Effective Photocatalytic Hydrogen Evolution by Cascadal Carrier Transfer in the Reverse Direction
摘要： Visible-light-responsive photocatalysts used in the highly efficient hydrogen production exhibit several disadvantages such as photocorrosion and fast recombination. Because of the potential important applications of such catalysts, it is crucial that a simple, effective solution is developed. In this respect, in this study, we combined SiC (β modification) and TiO2 with CdS to overcome the challenges of photocorrosion and fast recombination of CdS. Notably, we found that when irradiated with visible light, CdS was excited, and the excited electrons moved to the conduction band of TiO2, thereby increasing the efficiency of charge separation. In addition, by moving the holes generated on CdS to the valence band of SiC, in the opposite direction of TiO2, photocorrosion and fast recombination were prevented. As a result, in the sulfide solution, the CdS/SiC composite catalyst exhibited 4.3 times higher hydrogen generation ability than pure CdS. Moreover, this effect was enhanced with the addition of TiO2, giving 10.8 times higher hydrogen generation ability for the CdS/SiC/TiO2 catalyst. Notably, the most efficient catalyst, which was obtained by depositing Pt as a cocatalyst, exhibited 1.09 mmol g?1 h?1 hydrogen generation ability and an apparent quantum yield of 24.8%. Because water reduction proceeded on the TiO2 surface and oxidative sulfide decomposition proceeded on the SiC surface, the exposure of CdS to the solution was unnecessary, and X-ray photoelectron spectroscopy confirmed that photocorrosion was successfully suppressed. Thus, we believe that the effective composite photocatalyst construction method presented herein can also be applied to other visible-light-responsive powder photocatalysts having the same disadvantages as CdS, thereby improving the efficiency of such catalysts.
关键词： CdS,photocorrosion,hydrogen production,TiO2,photocatalysts,SiC,fast recombination
更新于2025-09-23 15:21:21
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Incorporating graphene quantum dots to enhance the photoactivity of CdSe-sensitized TiO2 nanorods for solar hydrogen production
摘要： This work demonstrated that the incorporation of graphene quantum dots (GQDs) can greatly improve the photoelectrochemical (PEC) efficiency of CdSe-sensitized TiO2 nanorods (TiO2/CdSe), a TiO2-based visible light-responsive photoelectrode paradigm, for solar hydrogen production. For TiO2/CdSe, the accumulated holes at CdSe may induce photocorrosive oxidation to decompose CdSe, deteriorating the long-term stability of photoelectrode and degrading the PEC performance. With the introduction of GQDs, the delocalized holes can further transfer from CdSe to the GQDs, which eases the hole accumulation at the CdSe sites, thus retarding photocorrosion. Compared to the binary TiO2/CdSe photoanode, the ternary TiO2/CdSe/GQDs photoanode displays higher photocurrent and better photostability toward PEC hydrogen production. This superiority can be attributed to vectorial charge transfer and enhanced reaction kinetics provided by the introduction of GQDs. The findings from this work highlight the importance of the introduction of GQDs as a potential solution to the photocorrosion issue of chalcogenide-sensitized semiconductor photoelectrodes.
关键词： photocorrosion,photoelectrochemical efficiency,solar hydrogen production,CdSe-sensitized TiO2 nanorods,graphene quantum dots
更新于2025-09-23 15:19:57
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Hematite films by aerosol pyrolysis: influence of substrate and photocorrosion suppression by TiO2 capping
摘要： Sn-doped hematite (Fe2O3) films were prepared by aerosol pyrolysis (AP) on fluorine doped tin oxide (FTO), titanium and stainless steel. Photoactive electrodes were obtained in all cases and the photosensitivity had an onset around 650 nm. Maximum incident photon to electron conversion efficiency (IPCE) was 0.3 at 300 nm for samples deposited on FTO. The Faradaic efficiency of the photocorrosion reaction was found to be 0.47 % for an unprotected FTO/hematite electrode in H2SO4. The Faradaic efficiency of this dissolution reaction decreased to 0.3 % for a hematite electrode covered with a 65 nm thick dip coated layer of TiO2, and to 0.17 % for a sample with a spray coated TiO2 layer, thus proving the beneficial role of TiO2 in protecting hematite against photocorrosion.
关键词： photocorrosion,aerosol pyrolysis,α-Fe2O3 / TiO2 electrodes
更新于2025-09-19 17:15:36
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Significant enhancement of stability for visible photocatalytic overall water splitting by assembling ultra-thin layer of NiO over Zn1-xCdxSX
摘要： Solar light driven water splitting into hydrogen and oxygen using visible light active photocatalyst has been considered as a clean, green, and renewable route to solar energy conversion and storage. Although Zn1-xCdxS catalyst shows comparatively higher activity for photocatalytic hydrogen generation under visible light irradiation, it suffers serious photocorrosion during the photocatalytic reaction. Deposition of protection layer over Zn1-xCdxS catalyst is believed to be an effective way to inhibit such photocorrosion. Nevertheless, seldom of protection layer exhibits satisfied catalytic properties for hydrogen evolution while presents good protection ability. In this work, a new Zn1-xCdxS photocatalyst has been developed for water splitting under visible light illumination by assembled an ultra-thin NiO layer over Zn0.8Cd0.2S via in-situ photodeposition method. By this strategy, NiO/Zn0.8Cd0.2S showed significant higher activity than Pt/Zn0.8Cd0.2S under same conditions without photocorrosion. The AQE of 0.66% for hydrogen evolution at 430 nm has been achieved and multi-cycle stability has been accomplished up to 12 hours without significant decay. Moreover, the strong electronic coupling between NiO layer and Zn1-xCdxS promoted efficient charge separation and migration.
关键词： Overall water splitting,sulfide semiconductor photocatalyst with thin NiO catalytic layer,enhanced charge separation and migration,significant enhanced stability,anti-photocorrosion
更新于2025-09-19 17:15:36
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Respective construction of Type-II and direct Z-scheme heterostructure by selectively depositing CdS on {001} and {101} facets of TiO2 nanosheet with CDots modification: A comprehensive comparison
摘要： Directional deposition has always been a focus issue in the construction of specific heterostructure. Herein, for the first time, we have demonstrated that the CdS could be selectively deposited on {001} or {101} facets of TiO2 nanosheet, and two different charge transfer processes were formed. First, the selective deposition of CdS on {001} facets of TiO2 nanosheet ({001}TiO2/CdS) would form the Type-II heterostructure, which seriously weakened the redox ability of {001}TiO2/CdS and directly resulted in the low photocatalytic performance (4-Chlorophenol (4-CP), 61.92% in 40 min) and serious photocorrosion of CdS. In contrary, the selective deposition of CdS on {101} facets of TiO2 nanosheet ({101}TiO2/CdS) could construct direct Z-scheme heterostructure with significantly increased photocatalytic 4-CP degradation efficiency (96.12%), much higher than pristine TiO2 nanosheet (87.21%). The hybrids were further modified by carbon nanodots (CDots) ({101}TiO2/CdS/CDots) to enhance photocatalytic performance (99.84%). The obtained direct Z-scheme {101}TiO2/CdS/CDots showed excellent stability and anti-photocorrosion ability. The synergistic effect between TiO2 nanosheet, CdS and CDots was expounded through characterization analyses, and the photocatalytic reaction mechanism was proposed in detail. Toxicity assessment authenticated good biocompatibility and low cytotoxicity of {101}TiO2/CdS/CDots. Our discovery was expected to drive great advances in the use of TiO2 nanosheet for environmental remediation.
关键词： Toxicity,Selective CdS deposition,Z-scheme heterostructure,TiO2 nanosheet,Anti-photocorrosion
更新于2025-09-09 09:28:46
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TiO2 Nanowires-Supported Sulfides Hybrid Photocatalysts for Durable Solar Hydrogen Production
摘要： As the feet of clay, photocorrosion induced by hole accumulation has placed serious limitations on the widespread deployment of sulfides nanostructures for photoelectrochemical (PEC) water splitting. Developing sufficiently stable electrodes to construct durable PEC systems is therefore the key to the realization of solar hydrogen production. Here, an innovative charge transfer manipulation concept based on the aligned hole transport across the interface has been realized to enhance the photostability of In2S3 electrodes toward PEC solar hydrogen production. The concept was realized by conducting compact deposition of In2S3 nanocrystals on the TiO2 nanowires array. Under PEC operation, the supporting TiO2 nanowires functioned as an anisotropic charge transfer backbone to arouse aligned charge transport across the TiO2/In2S3 interface. Because of the aligned hole transport, the TiO2 nanowires-supported In2S3 hybrid nanostructures (TiO2-In2S3) exhibited improved hole transfer dynamics at the TiO2/In2S3 interface and enhanced hole injection kinetics at the electrode surface, substantially increasing the long-term photostability toward solar hydrogen production. The PEC durability tests showed that TiO2-In2S3 electrodes can achieve nearly 90.9 % retention of initial photocurrent upon continuous irradiation for 6 h, whereas the pure In2S3 merely retained 20.8 % of initial photocurrent. This double-gain charge transfer manipulation concept is expected to convey a viable approach to the intelligent design of highly efficient and sufficiently stable sulfides photocatalysts for sustainable solar fuel generation.
关键词： In2S3,interfacial charge dynamics,CdS,photocorrosion,solar hydrogen production
更新于2025-09-04 15:30:14
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Ta <sub/>3</sub> N <sub/>5</sub> /Co(OH) <sub/>x</sub> composites as photocatalysts for photoelectrochemical water splitting
摘要： Ta3N5 nanotubes (NTs) were obtained from nitridation of Ta2O5 NTs, which were grown directly on Ta foil through a 2-step anodization procedure. With Co(OH)x decoration, a photocurrent density as high as 2.3 mA cm?2 (1.23 V vs. NHE) was reached under AM1.5G simulated solar light; however, the electrode suffered from photocorrosion. More stable photoelectrochemical (PEC) performance was achieved by first loading Co(OH)x, followed by loading cobalt phosphate (Co–Pi) as double co-catalysts. The Co(OH)x/Co–Pi double co-catalysts may act as a hole storage layer that slows down the photocorrosion caused by the accumulated holes on the surface of the electrode. A “waggling” appearance close to the “mouth” of Ta2O5 NTs was observed, and may indicate structural instability of the “mouth” region, which breaks into segments after nitridation and forms a top layer of broken Ta3N5 NTs. A unique mesoporous structure of the walls of the Ta3N5 NTs, which is reported here the first time, is also a result of the nitridation process. We believe that the mesoporous structure makes it difficult for the nanotubes to be fully covered by the co-catalyst layer, hence rationalizing the remaining degradation by photocorrosion.
关键词： photoelectrochemical water splitting,photocorrosion,Co–Pi,Co(OH)x,mesoporous structure,Ta3N5 nanotubes
更新于2025-09-04 15:30:14