Enhanced electrocatalytic CO2 reduction to formic acid using nanocomposites of In2O3@C with graphene

In2O3 is an effective electrocatalyst to convert CO2 to formic acid (HCOOH), but its inherent poor electrical conductivity limits the efficient charge transfer during the reaction. Additionally, the tendency of In2O3 particles to agglomerate during synthesis further limits the exposure of active sites. Here we address these issues by leveraging the template effect of graphene oxide and employing InBDC as a self-sacrificing template for the pyrolysis synthesis of In2O3@C. The resulting In2O3@C/rGO-600 material features In2O3@C nanocubes uniformly anchored on a support of reduced graphene oxide (rGO), significantly enhancing the active sites exposure. The conductive rGO network facilitates charge transfer during electrocatalysis, and the presence of oxygen vacancies generated during pyrolysis, combined with the strong electron-donating ability of rGO, enhances the adsorption and activation of CO2. In performance evaluation, In2O3@C/rGO-600 exhibits a remarkable HCOOH Faradaic efficiency exceeding 94.0% over a broad potential window of −0.7 to −1.0 V (vs. reversible hydrogen electrode (RHE)), with the highest value of 97.9% at −0.9 V (vs. RHE) in a H-cell. Moreover, the material demonstrates an excellent cathodic energy efficiency of 71.6% at −0.7 V (vs. RHE). The study underscores the efficacy of uniformly anchoring metal oxide nanoparticles onto rGO for enhancing the electrocatalytic CO2 reduction performance of materials.