Fu Dong, Fabre Bruno, Loget Gabriel, Mériadec Cristelle, Ababou-Girard Soraya, Cadot Emmanuel, Leclerc-Laronze Nathalie, Marrot Jérôme, de Ponfilly Quentin
Université Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR6226, F-35000 Rennes, France.
Université Rennes, CNRS, IPR (Institut de Physique de Rennes)-UMR6251, F-35000 Rennes, France.
ACS Omega. 2018 Oct 22;3(10):13837-13849. doi: 10.1021/acsomega.8b01734. eCollection 2018 Oct 31.
Silicon photocathodes coated with drop-casted {MoS}-based polyoxothiometalate assemblies are demonstrated to be effective for sunlight-driven hydrogen evolution reaction (HER) in acid conditions. These photocathodes are catalytically more efficient than that coated with the parent thiomolybdate incorporating an organic ligand, as supported by a higher onset potential and a lower overvoltage at 10 mA cm. At pH 7.3, the trend is inversed and the beneficial effect of the polyoxometalate for the HER is not observed. Moreover, the polyoxothiometalate-modified photocathode is found to be also more stable under acid conditions and can be operated at the light-limited catalytic current for more than 40 h. Furthermore, X-ray photoelectron spectroscopy and atomic force microscopy measurements indicate that the cathodic polarization of both photocathodes leads to the release of a large amount of the deposited material into the electrolyte solution concomitantly with the formation of mixed valence species {Mo(IV) Mo(III) O S } resulting from the replacement of S sulfido ligands in the cluster by oxo O groups; these combined effects are shown to be beneficial for the photoelectrocatalysis.
通过滴铸法涂覆基于{MoS}的聚氧硫金属酸盐组件的硅光电阴极，被证明在酸性条件下对阳光驱动的析氢反应（HER）有效。这些光电阴极在催化方面比涂覆有包含有机配体的母体硫代钼酸盐的光电阴极更有效，这由更高的起始电位和在10 mA cm下更低的过电压所支持。在pH 7.3时，趋势相反，未观察到聚金属氧酸盐对HER的有益效果。此外，发现聚氧硫金属酸盐修饰的光电阴极在酸性条件下也更稳定，并且可以在光限制催化电流下运行超过40小时。此外，X射线光电子能谱和原子力显微镜测量表明，两种光电阴极的阴极极化导致大量沉积材料释放到电解质溶液中，同时形成由簇中的硫代S配体被氧代O基团取代而产生的混合价态物种{Mo(IV)Mo(III)OS}；这些综合效应被证明对光电催化有益。
