Size Effect of Graphene Oxide on Graphene-Aerogel-Supported Au Catalysts for Electrochemical CO2 Reduction

Abstract

The lateral size of graphene nanosheets plays a critical role in the properties and microstructure of 3D graphene as well as their application as supports of electrocatalysts for CO2 reduction reactions (CRRs). Here, graphene oxide (GO) nanosheets with different lateral sizes (1.5, 5, and 14 µm) were utilized as building blocks for 3D graphene aerogel (GA) to research the size effects of GO on the CRR performances of 3D Au/GA catalysts. It was found that GO-L (14 µm) led to the formation of GA with large pores and a low surface area and that GO-S (1.5 µm) induced the formation of GA with a thicker wall and isolated pores, which were not conducive to the mass transfer of CO2 or its interaction with catalysts. Au/GA constructed with a suitable-sized GO (5 µm) exhibited a hierarchical porous network and the highest surface area and conductivity. As a result, Au/GA-M exhibited the highest Faradaic efficiency (FE) of CO (FECO = 81%) and CO/H2 ratio at −0.82 V (vs. a Reversible Hydrogen Electrode (RHE)). This study indicates that for 3D GA-supported catalysts, there is a balance between the improvement of conductivity, the adsorption capacity of CO2, and the inhibition of the hydrogen evolution reaction (HER) during the CRR, which is related to the lateral size of GO.

Visible‐Light‐Induced Photocatalytic Hydrogen Evolution Performance of Graphdiyne‐Alkyne Phosphating Mo–Metal‐Organic Frameworks Heterojunction

“…Compared with traditional carbon materials, GDY can provide a lot of active sites for reactions, and active interfaces with defined component structures can be selectively constructed. [ 16–18 ] It is precisely because of its unique charge distribution characteristics that GDY has the characteristics of high activity and high stability. Li et al [ 19 ] used GDY's unique network structure and graphene in potassium‐ion batteries, which exhibited good cycling stability.…”