Porous two-dimensional CuSe@BiOI isotype heterojunction with highly exposed (1 0 2) facets for efficient photoelectrocatalytic CO2 reduction and photodetection

Using photoelectrochemical technology to construct efficient photoelectric materials has aroused extensive research interest. In this study, we propose a two-dimensional porous CuSe@BiOI isotype heterojunction photocathode for CO 2 reduction to formic acid. The heterojunction was constructed by the epitaxial growth of high-quality oriented BiOI nanosheets onto the porous CuSe framework. The CuSe framework as a template to ensure the formation of the (1   0   2) facets of BiOI and the isotropic charge transport characteristics of the (1   0   2) surface greatly improve the efficiency of charge separation and transfer. This CuSe@BiOI isotype heterojunction electrode can efficiently reduce CO 2 to formic acid with a selectivity of up to 80.5 % in 0.5 M potassium bicarbonate aqueous solution. Meanwhile,   the performance of the photodetector based on CuSe@BiOI heterostructure is 6.97 × 10 11 Jones and a response rate of 87.13 mA W −1 . This finding provides a new approach to designing stable heterojunction photoelectrocatalysts with isotropy.