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

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. A graphene oxide aerogel (GOA) can be used as a visible-light photocatalyst and CO2 adsorbent. N-doping increased the defect density and carrier separation ability, while S-doping improved the CO2 adsorption capacity.