Amorphous oxygen-rich molybdenum oxysulfide Decorated p-type silicon microwire Arrays for efficient photoelectrochemical water reduction

• Autor(a) principal: Xiao-Qing Bao
• Data de Publicação: 2015
• Outros Autores: Petrovykh, D. Y., Alpuim, P., Stroppa, Daniel G., Guldris, Noelia, Fonseca, Helder, Costa, Margaret, Gaspar, Joao, Chuanhong Jin, Lifeng Liu
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/49828
• topic: Silicon microwire; Photocathode; Water reduction; Molybdenum oxysulfide; Hydrogen evolution reaction; Silicon nanostructure; Photoelectrochemical water splitting; Electrocatalysis; Ciências Naturais::Ciências Físicas

We report the fabrication of p-type silicon (Si) photocathodes consisting of well-ordered Si microwire (Si-MW) arrays coupled with non-precious and earth-abundant amorphous oxygen-rich molybdenum oxysulfide (MoOxSy) as both a hydrogen evolution catalyst and a passivation layer. The MoOxSyis conformally grown on the Si-MW surface through photo-assisted cyclic voltammetric (CV) deposition. By adjusting the cycle numbers of the CV deposition, Si-MW array electrodes with different MoOxSy catalyst loadings (Si-MWs@MoOxSy) have been obtained and comprehensively characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X- ray photoelectron spectroscopy (XPS), and Raman and Fourier-transform infrared spectroscopies. The photoelectrochemical performance of the Si-MWs@MoOxSycathodes toward water reduction is investigated and compared with that of platinum nanoparticle decorated Si-MW array electrodes (Si-MWs@PtNPs). An optimized Si-MWs@MoOxSyphotocathode is found to exhibit activity compar- able to that of the Si-MWs@PtNPs one, with a much better stability in acidic medium. In neutral electrolyte, Si-MWs@MoOxSyoutperforms Si-MWs@PtNPs in terms of both activity and stability. Given the low materials cost, easy and well-established electrode fabrication procedure, and high demonstrated photoelectrochemical performance, the Si-MWs@MoOxSyarrays reported here hold substantial promise for use as low-cost and efficient photocathodes for water reduction.