Self-assembly synthesis of monodisperse BiVO4 nanosphere via a hybrid strategy for photoelectrochemical water splitting

Graphical Water Splitting : The synergistic effect of organic dehydration in esterification and inorganic precipitation of semiconductor with surfactant was proposed as a hybrid strategy to synthesize highly uniform monodisperse BiVO 4 nanosphere. The generated water in esterification provides the reverse micelle nanoreactor to precipitate BiVO 4 cluster, which then self-assembly aggregated to be BiVO 4 nanosphere. Furthermore, different nanoporous BiVO 4 photoanodes composing of BiVO 4 nanospheres were obtained by a simple drop-casting method for photoelectrochemical water splitting. Monodisperse semiconductor sphere holds great potential for a wide variety of application as a basic building block. Herein a binary oxide, BiVO 4 , with highly uniform monodisperse nanosphere of 125 nm diameter was primarily synthesized via a hybrid method with PVP assisted in organic solvent. After investigating the function of PVP and the emergence of esterification in solvent, we proposed a formation mechanism of amorphous BiVO 4 nanosphere, including the precipitation of BiVO 4 clusters in reverse micelles and the self-assembly aggregation of BiVO 4 clusters to be BiVO 4 nanospheres. The generated water in esterification provides a nanoreactor to precipitate BiVO 4 cluster, in return, the precipitation by using water catalyzes the process of esterification in ethanol with acetic acid. This hybrid reaction of inorganic BiVO 4 precipitate and organic esterification opens a novel avenue to couple nano inorganic chemistry with organic dehydration synthesis, achieving green chemistry for sustainable development. Furthermore, highly efficient nanoporous BiVO 4 photoanodes composed of BiVO 4 nanospheres for water splitting were obtained using a simple drop-casting method and optimized for their photocurrent density by calcination temperatures. This hybrid reaction strategy could be applied to synthesize other semiconductors with nanosphere toward novel low-cost structures and devices.