Ultrafine Si nanowires/Sn3O4 nanosheets 3D hierarchical heterostructured array as a photoanode with high-efficient photoelectrocatalytic performance

Constructing a high performance three-dimensional (3D) semiconductor photoelectrode for photoelectrocatalytic hydrogen (H-2) production by water splitting is a promising method to resolve the current energy and environmental issues. Here, a ultrafine Si nanowires/Sn3O4 nanosheet (SiNWs/Sn3O4) 3D hierarchical heterostructured photoanode was synthesized via a facile approach with a metal-assisted chemical etching step following an in situ hydrothermal synthesis process. The ultrafine SiNWs/Sn3O4 3D hierarchical heterostructured photoanode exhibits significantly enhanced photoelectrochemical activity, and its photocurrent density is 8 times higher than that of single phase structures of SiNWs. This increase of catalytic activity may be attributed to the enhancement of the full-spectrum light absorption, decrease of the photocarrier recombination rate and a low transmission resistance at the catalyst/electrolyte interface. This work provides a novel design for preparing highly efficient Si based 3D heterostructured catalysts for the production of clean energy.