Patch-like, two dimensional WSe2-based hetero-structures activated by a healing catalyst for H2 photocatalytic generation

Patch-like, layered, WSe2-based hetero-structures are proposed for the photocatalytic water splitting achieving a photocurrent density for H2 evolution up to 5 mA cm−2. [Display omitted] •A general method for the synthesis of high surface area, 2D photo-catalysts is proposed for H2 generation.•Patch-like, WSe2-based, 2D hetero-structures are proposed as building blocks for the bottom-up fabrication of 2D photo-catalysts.•2D, WSe2-based hetero-structures include an ultrathin layer of healing catalyst and a rGO nanosheet.•Solar photocurrents up to 5 mA cm−2 were achieved demonstrating beneficial effect of nanostructuration. 2D photoactive materials may offer interesting opportunities in photocatalytic devices since they combine strong light absorption and shortening of charge carriers’ diffusion path. Because of their high surface defect concentration and the formation of a majority of edge/plane vs plane/plane contacts between the anisotropic building blocks, surface defect passivation and improvement of charge carrier transport are critical for the large development of high surface area, 2D photo-catalysts. Here, we propose a hetero-structure nanoporous network with a patch-like coating as high performance 2D photo-catalysts. The hetero-structured building blocks are composed of a photo-active WSe2 nanoflake in direct contact with both a conducting rGO nanosheet and an ultrathin layer of healing catalyst. The resulting nanoporous film achieves a H2 evolution photocurrent density up to 5 mA cm−2 demonstrating that the patch-like hetero-structures represent an effective strategy to simultaneously improve hole collection, defect passivation and charge transfer. These hetero-structures made of an ultrathin healing catalyst layer represent promising building blocks for the bottom-up fabrication of high surface area photocathodes particularly for 2D photo-catalysts displaying high defect concentration.