Atomic sulfur dissimilation remolding ZnIn2S4 nanosheets surface to enhance built-internal electric field for photocatalytic CO2 conversion to syngas

Abstract

The CO2 photoreduction of efficiency is severely limited by the sluggish charge kinetics and difficult CO2 adsorption and activation. In this paper, nonmetallic selenium (Se) doped into ZnIn2S4, whose surface were remolded by S atomic dissimilation. Density Functional Theory (DFT) calculated that Se atoms substituted surface sulfur (S) atoms of [In-S] surface layer. The excellent promotion for photoelectric properties of ZnIn2S4 with Se dopant benefitted for the adjusted surface properties. The built-internal electric field (B-IEF) was highly enhanced with S atomic dissimilation, which promoted charge separation of interlamination (between the [Zn-S], [S-In-S] and [In-S] layers) and achieved local electron polarization. Finally, ZnIn2S3.5Se0.5 showed the improved adsorption energy and lower activation energy, the performance for CO2 reduction was 1189.5 μmol·g−1·h−1 for CO and 801.6 μmol·g−1·h−1 for H2 (CO/H2: 3:2). This work reveals the relationship between surface/external modification and internal regulation of promoting photocatalytic performance of CO2 reduction.