Effects of N,S doping on a graphene oxide aerogel for adsorption and photocatalytic reduction of carbon dioxide

Abstract

Solar photocatalytic reduction of carbon dioxide (CO₂) based on graphene derivatives has received increasing attention due to its cost-effectiveness and unique performance in addressing climate and energy issues. However, in most of the studies, graphene derivatives were mainly used as co-catalysts and their own photocatalytic ability was neglected. In this study, heteroatom doping and morphology modulation were applied to synergistically optimize the structure and properties of graphene oxide (GO), that is, a N and S co-doped three-dimensional graphene oxide aerogel (N,S-GOA) was constructed and applied to the adsorption and photocatalytic reduction of CO₂. N,S-GOA efficiently converted CO₂ to carbon monoxide (CO) under visible light irradiation without sacrificial agents or co-catalysts, demonstrating its role as a standalone photocatalyst. The co-doping of N and S resulted in a porous structure with increased specific surface area, aiding CO₂ adsorption and product diffusion. Furthermore, the unique structural properties and synergistic effects of N and S co-doping increased the defect density and prolonged the lifetime of the photogenerated electrons, thus improving the overall catalytic activity. This study provides a new strategy for the design of a high-surface-area and multi-active-site GO-based three-dimensional aerogel photocatalyst and highlights its application in CO₂ adsorption and photocatalytic reduction.