- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Metal oxide/(oxy)hydroxide overlayers as hole collectors and oxygen evolution catalysts on water splitting photoanodes
摘要： Solar-water-splitting provides a mechanism to convert and store solar energy in the form of stable chemical bonds. Water-splitting systems often include semiconductor photoanodes, such as n-Fe2O3 and n-BiVO4, which use photogenerated holes to oxidize water. These photoanodes often exhibit improved performance when coated with metal-oxide/(oxy)hydroxide overlayers that are catalytic for the water oxidation reaction. The mechanism for this improvement, however, remains a controversial topic. This is, in part, due to a lack of experimental techniques that are able to directly track the flow of photogenerated holes in such multicomponent systems. In this Perspective we illustrate how this issue can be addressed by using a second working electrode to make direct current/voltage measurements on the catalytic overlayer during operation in a photoelectrochemical cell. We discuss examples where the second working electrode is a thin metallic film deposited on the catalyst layer, as well as where it is the tip of a conducting atomic-force-microscopy probe. In applying these techniques to multiple semiconductors (Fe2O3, BiVO4, Si) paired with various metal-(oxy)hydroxide overlayers (e.g. Ni(Fe)OxHy and CoOxHy), we found in all cases investigated that the overlayers collect photogenerated holes from the semiconductor, charging to potentials sufficient to drive water oxidation. The overlayers studied thus form charge-separating heterojunctions with the semiconductor as well as serve as water-oxidation catalysts.
关键词： solar-water-splitting,water oxidation reaction,semiconductor photoanodes,photoelectrochemical cell,metal-oxide/(oxy)hydroxide overlayers
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