Polo, AnnalisaDozzi, Maria VittoriaGrigioni, IvanLhermitte, CharlesPlainpan, NukornMoretti, LucaCerullo, GiulioSivula, KevinSelli, Elena2022-07-042022-07-042022-07-042022-06-1510.1002/solr.202200349https://infoscience.epfl.ch/handle/20.500.14299/188927WOS:000811096200001Mo6+ doping increases the photoelectrochemical performance of BiVO4 photoanodes in water oxidation. Herein, the underlying mechanisms is elucidated through a systematic structural, morphological, and photoelectrochemical investigation on photoelectrodes of pure and Mo6+ doped BiVO4 prepared by a novel multistep spin-coating deposition approach, leading to multilayer flat films with high optical transparency. Transient absorption spectroscopy in the nano- to microsecond time scale reveals a longer lifetime of photogenerated holes in the doped films. Besides confirming that Mo6+ ions improve the electron transport in the material bulk, impedance spectroscopy also reveals the crucial role of the dopant on the surface properties of BiVO4 photoanodes. The presence of intra-bandgap states, acting as traps of photogenerated charge carriers in pure BiVO4, is detected through the build-up of the interfacial surface state capacitance. The limited activity of pure BiVO4 in water oxidation is largely improved upon 3 at% Mo6+ incorporation, ensuring a more efficient charge carrier transport with respect to pure BiVO4, together with the beneficial passivation of its trap surface states.Energy & FuelsMaterials Science, MultidisciplinaryMaterials Sciencebismuth vanadatebulk charge transportimpedance spectroscopymolybdenum dopingphotoelectrochemistrysurface states passivationwater oxidationphotoelectrochemical water oxidationscanning electrochemical microscopydoped bivo4charge separationphotocurrent performancequantum efficienciescarrier dynamicssurface-statestandem cellstext::journal::journal article::research article