- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Carbon nanosheet facilitated charge separation and transfer between molybdenum carbide and graphitic carbon nitride toward efficient photocatalytic H2 production
摘要： Interfacial manipulation of nanostructured heterojunction photocatalysts to enhance charge separation and transfer is highly desirable to achieve a high photocatalytic activity. In this work, a well-designed non-noble-metal Mo2C@C/g-C3N4 heterostructure is constructed, in which the intercalated carbon nanosheets serve as a binder to form an excellent interfacial contact between Mo2C and g-C3N4. In addition, large quantities of carbon quantum dotsare found to be homogeneously embedded in the carbon nanosheets. The as-obtained Mo2C@C/g-C3N4 hybrid exhibits a remarkably improved photocatalytic H2 evolution rate of 52.1 μmol h?1 under visible-light irradiation (λ ≥ 420 nm) without co-catalyst, which is up to nearly 260 times higher than that of pristine g-C3N4 (0.2 μmol h?1) under the same conditions. The significant increase in photocatalytic activity mainly results from the fast charge migration and separation between Mo2C and g-C3N4 facilitated by the conducting carbon nanosheets as an efficient electron mediator. Moreover, the carbon quantum dots embedded in the carbon support also promotes solar energy utilization. This work highlights a feasible strategy to explore highly efficient photocatalysts via interfacial engineering on heterojunction composites.
关键词： H2 evolution,Photocatalysis,Water splitting,Carbon nitride,Heterojunction
更新于2025-09-04 15:30:14
-
Novel microreactors of polyacrylamide (PAM) CdS microgels for admirable photocatalytic H2 production under visible light
摘要： Cadmium sul?de, with its narrow band gap, can be used as a photocatalyst in the visible light region for the splitting of water, but its limited number of active sites and tendency to agglomerate are problematic for producing high yields of hydrogen. Therefore, an inverse emulsion polymerization method was used to fabricate polyacrylamide (PAM) microgels as a substrate to immobilize CdS nanoparticles (PAM-CdS). The PAM microgels not only immobilized the CdS nanoparticles, but also prevented aggregation. NeCd bonds in the PAM-CdS microgels facilitated electron transfer from the PAM to the CdS resulting in more electrons participating in the H2 production process. The electrostatic interactions between the PAM and CdS also hindered the recombination of electron-hole pairs. These PAM-CdS microgels exhibit admirable photocatalytic H2 production performance with a H2 production rate of up to 5.21 mmol h?1 g?1.
关键词： Visible-light water splitting,PAM microgels,CdS,Photocatalytic H2 production
更新于2025-09-04 15:30:14
-
CuO photoelectrodes synthesized by the sol–gel method for water splitting
摘要： CuO is an attractive photocatalytic material for water splitting due to its high earth abundance and low cost. In this paper, we report the deposition of CuO thin films by sol–gel dip-coating process. Sol deposition has attractive advantages including low-cost solution processing and uniform film formation over large areas with a fairly good control of the film stoichiometry and thickness. Pure CuO phase was obtained for calcination temperatures higher than 360 °C in air. The CuO photocurrents for hydrogen evolution depend on the crystallinity and the microstructure of the film. Values of ?0.94 mA cm?2 at pH = 8 and 0 V vs. RHE were achieved for CuO photoelectrodes annealed at 400 °C under air. More interestingly, the stability of the photoelectrode was enhanced upon the sol–gel deposition of a TiO2 protective layer. In this all sol–gel CuO/TiO2 photocathode, a photocurrent of ?0.5 mA cm?2 is achieved at pH = 7 and 0 V vs. RHE with a stability of ~100% over 600 s.
关键词： TiO2 protecting layer for CuO photoelectrode,Sol–gel,CuO photoelectrode,Water splitting
更新于2025-09-04 15:30:14
-
Carbonyl linked carbon nitride loading few layered MoS2 for boosting photocatalytic hydrogen generation
摘要： Pristine graphitic carbon nitride g-C3N4 materials, as a novel metal-free photocatalyst with moderate activity, have attracted intense interest. However, its fast photogenerated carriers recombination always induces a relative low performance. Herein, we for the first time report one new =C=O group linked g-C3N4 (CO-C3N4) through CO2-assisted thermal polymerization of urea. It is found that the edge =C=O groups work as the photogenerated electrons collection sites, and then promote the carriers separation. The visible-light phototatalytic hydrogen evolution performance of our synthesized samples shows 1.85 times higher than that of the reference g-C3N4. To get a considerable visible-light driven photocatalytic hydrogen generation, a new few layered MoS2 with a small size (ca. 20 nm) is prepared through a liquid exfoliation, and then is loaded onto the CO-C3N4. The optimal MoS2/CO-C3N4 sample gives the photocatalytic hydrogen evolution of 1990 and 1440μmol/(g*h) under the λ > 400 and λ > 420 illumination, higher than the reported values in literatures. The sample also shows a considerable excellent photocatalytic activity of 44.3 μmol/(g*h) under LED-600 condition.
关键词： water splitting,CO-C3N4,MoS2,photocatalysis,H2 generation
更新于2025-09-04 15:30:14
-
Potential Application of Metal–organic frameworks for Photocatalytic Water Splitting
摘要： These days, the environmental pollution and energy shortage are the crucial global issues. Therefore, replacing the renewable source of energy with the fossil fuels is the most promising approach to solve the aforementioned problems. Hydrogen is an attractive source energy because of its high energy density and its combustion by-product is only water. Hydrogen production through photosplitting of water over a semiconductor based photocatalyst is a desirable approach to diminish the global energy and environmental problems. However, its low solar conversion efficiency and finding suitable photocatalyst still remain as the main challenge for this system. Recently metal–organic frameworks (MOFs) have received great attention for the photocatalytic hydrogen production due to their large surface to volume ratio, design flexibility, and well-defined porosity. In this short review, we focus on the previous studies on the various types of MOFs based photocatalyst in the solar hydrogen production system. The main intention of review is to highlight the importance of coupling molecular approaches of catalyst design with materials science strategies in the improvement of MOFs based photocatalysts, which will undoubtedly lead to a very bright future for photocatalytic water.
关键词： Solar Energy,Photocatalytic Water Splitting,Metal–organic frameworks,Hydrogen Production,Renewable Energy
更新于2025-09-04 15:30:14
-
Mixed-Phase (2H and 1T) MoS2 Catalyst for a Highly Efficient and Stable Si Photocathode
摘要： We describe the direct formation of mixed-phase (1T and 2H) MoS2 layers on Si as a photocathode via atomic layer deposition (ALD) for application in the photoelectrochemical (PEC) reduction of water to hydrogen. Without typical series-metal interfaces between Si and MoS2, our p-Si/SiOx/MoS2 photocathode showed efficient and stable operation in hydrogen evolution reactions (HERs). The resulting performance could be explained by spatially genuine device architectures in three dimensions (i.e., laterally homo and vertically heterojunction structures). The ALD-grown MoS2 overlayer with the mixed-phase 1T and 2H homojunction passivates light absorber and surface states and functions as a monolithic structure for effective charge transport within MoS2. It is also beneficial in the operation of p-i-n heterojunctions with inhomogeneous barrier heights due to the presence of mixed-phase cocatalysts. The effective barrier heights reached up to 0.8 eV with optimized MoS2 thicknesses, leading to a 670 mV photovoltage enhancement without employing buried Si p-n junctions. The fast-transient behaviors via light illumination show that the mixed-phase layered chalcogenides can serve as efficient cocatalysts by depinning the Fermi levels at the interfaces. A long-term operation of ~70 h was also demonstrated in a 0.5 M H2SO4 solution.
关键词： pinch-off effect,molybdenum disulfide,photoelectrochemical water splitting (PEC),p-i-n heterojunction,atomic layer deposition (ALD)
更新于2025-09-04 15:30:14
-
ALD of Space-Efficient SnO2 Underlayers for BiVO4 Host-Guest Architectures for Photoassisted Water Splitting
摘要： Bismuth vanadate (BiVO4) is promising for solar-assisted water splitting. The performance of BiVO4 is limited by charge separation for >70 nm films or by light harvesting for <700 nm films. To resolve this mismatch, host-guest architectures use thin film coatings on 3D scaffolds. Recombination, however, is exacerbated at the extended host-guest interface. Underlayers are used to limit this recombination with a host-underlayer-guest series. Such underlayers consume precious pore volume where typical SnO2 underlayers are optimized with 65-80 nm. Here we examine conformal and ultrathin SnO2 underlayers with low defect density produced by atomic layer deposition (ALD). This shifts the optimized thickness to just 8 nm with significantly improved space-efficiency. The materials chemistry thus determines the dimension optimization. Lastly, we demonstrate host-guest architectures with an applied bias photon-to-charge efficiency of 0.71%, a new record for a photoanode absorber prepared by ALD.
关键词： host-guest architectures,solar-assisted water splitting,atomic layer deposition,SnO2 underlayers,Bismuth vanadate
更新于2025-09-04 15:30:14
-
Ag?Au‐Bimetal Incorporated ZnO‐Nanorods Photo‐Anodes for Efficient Photoelectrochemical Splitting of Water
摘要： Plasmonic Ag(cid:0) Au/ZnO nanorods (ZNRs) based photo-anodes were synthesized using a simple electrochemical route and were then evaluated for photoelectrochemical (PEC) activity. The amalgamation of Ag and Au nanoclusters broadens the UV-Vis light absorption in the range of 400 nm to 650 nm. Ag(cid:0) Au/ZNRs photo-anodes had shown photo-current density of ~ 1.4 mA cm(cid:0) 2, at a bias of 0.75 V/SCE, which is ~ 3.1 times of bare ZNRs photo-anode. Bi-metallic Ag(cid:0) Au/ZNRs based photo-anode shows the maximum photo-conversion efficiency of 0.77 % at 0.5 V/SCE, under one sun illumination. Formation of hot electrons in Ag(cid:0) Au/ ZNRs photo-anodes can be partly held responsible for the enhanced PEC activity. Au/Ag core/shell morphology evolves when a thin layer of Ag is loaded on Au nanoparticles. For an in-depth analysis on Ag(cid:0) Au incorporated ZNRs based photo-anodes and its PEC activity, a detailed characterization was carried out using physico-chemical, spectral and microscopy techniques. The analysis shows that Au in direct contact with ZnO interacts mainly with oxygen vacancies present on surface of ZnO and Ag interacts with Au for an effective electron-hole segregation process at interface and electron storage occurs in metal nanoparticles. The results suggest bi-metal incorporated ZNRs based photo-anodes can be a prospective candidate for PEC water splitting application.
关键词： Water splitting,Incident photon to current conversion efficiency (IPCE),Bi-metal photo-anodes,Electrodeposition,PEC activity
更新于2025-09-04 15:30:14
-
Phase and Defect Engineering of MoS <sub/>2</sub> Stabilized in Periodic TiO <sub/>2</sub> Nanoporous Film for Enhanced Solar Water Splitting
摘要： Phase and defect engineering of the heterostructured MoS2@TiO2 nanoporous film is investigated to achieve a broad solar spectrum light absorption and high solar water splitting efficiency. The phase transition from the semiconducting 2H-MoS2 to the metallic 1T-MoS2 is achieved by a hydrothermal exfoliation treatment. Experimental studies elucidate that the solar water splitting activity is greatly improved by forming 1T-MoS2 along with increasing S-vacancies because of the significantly enhanced surface plasmon resonance. The mixed-phase MoS2@TiO2 film shows a high H2 yield rate of 308 μmol h?1 cm?2 and long-term durability for 30 h, which is superior to the state-of-the-art catalysts for solar water splitting. This study offers a universal and efficient avenue to rationalize the plasmonic catalysts for solar water splitting and other energy and environmental applications.
关键词： solar water splitting,defect engineering,MoS2,heterostructures,phase transitions
更新于2025-09-04 15:30:14
-
Enhancing Solar‐Driven Water Splitting with Surface‐Engineered Nanostructures
摘要： Functional nanoscale interfaces that promote the transport of photoexcited charge carriers are fundamental to efficient hydrogen production during photoelectrochemical (PEC) splitting of water. Here, the realization of a functional one-dimensional nanostructure achieved through surface engineering of hematite (α-Fe2O3) nanorods with a TiO2 overlayer is reported. The surface-engineered hematite nanostructure exhibits significantly improved PEC performance as compared to untreated α-Fe2O3, with an increase in the maximum incident photon-to-current efficiency (IPCE) of nearly 400% at 350 nm. While addition of the TiO2 overlayer did not alter the lifetime of photoexcited charge carriers, as evidenced from transient absorption spectroscopy, it is found that the presence of TiO2 could enhance oxygen electrocatalysis by interfacial electron enrichment, largely attributed to enhanced O(2p)(cid:1)Fe(3d) hybridization. Moreover, the interfacial electronic structure revealed from XANES measurements of the α-Fe2O3/TiO2 nanorods suggests that photoexcited holes in α-Fe2O3 may efficiently transfer through the TiO2 overlayer to the electrolyte while electrons migrate to the external circuit along the one-dimensional nanorods, thereby promoting charge separation and enhancing PEC splitting of water.
关键词： photoelectrochemical water splitting,titania,surface engineering,hematite,nanostructure
更新于2025-09-04 15:30:14