Topotactic transformation to mesoporous Co3O4 nanosheet photocathode for visible-light-driven direct photoelectrochemical hydrogen generation

Developing p-type photocathodes for direct hydrogen generation is an attractive challenge in photo-electrochemical (PEC) water splitting. In this paper, we report a development of mesoporous Co3O4 nanosheet photocathodes for visible-light-driven direct PEC hydrogen generation. The mesoporous Co3O4 nanosheet was fabricated through an in-situ topotactic transformation from solid hexagonal Co (OH)(2) to porous spinel Co3O4. The specific surface area of the mesoporous Co3O4 nanosheet is extremely high as 112.8 m(2)/g. Under visible light irradiation, the peak photocurrent value of the mesoporous Co3O4 nanosheet photocathode in S2- hole scavenger solution is 37 folds enhancement compared to that in only supporting electrolyte. The specific surface area effect on the PEC performance was also investigated. This demonstration of mesoporous v nanosheet photocathode with high specific surface area could open up new opportunities for p-type metal oxide photocathodes in visible-light-driven direct PEC hydrogen generation. (C) 2014 Elsevier B.V. All rights reserved.