Electrochemical and catalytic conversion of CO2 into formic acid on Cu-InO2 nano alloy decorated on reduced graphene oxide (Cu-InO2@rGO)

Abstract

The catalytic and electrochemical hydrogenation of CO₂ offers the option of a carbon-neutral cycle for sustainable energy and synthesis of value-added chemicals. The synthesized noble metal-free Cu-InO₂@rGO nanocomposite has been characterized by various techniques such as scanning electron microscopy (SEM) confirming the spherical shape of Cu-InO₂ nanoalloy embedded on rGO, the average size calculated by high resolution-transmission electron microscopy (HR-TEM) shows Cu-InO₂ (∼ 4 nm) alloy is on rGO surface (∼100 nm). The XRD pattern confirms the Face centered cubic (FCC) crystal structure of Cu-InO₂@rGO, and Furrier transform- Infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses of Cu-In-O exist in the nanomaterials. The linear sweep voltammetry (LSV) demonstrates an ultra-low potential of −0.9 V vs. SCE. The bulk electrolysis on Cu-InO₂@rGO electrocatalyst demonstrated at a potential of −1.1 V vs. SCE to reach HCOOH with a Faradic yield of 76.10%. Electrochemical CO₂ reduction on Cu-InO₂@rGO is responsible for the variation of adsorption of CO₂ intermediates due to controlled selectivity and inhibiting the formation of H₂ and CO. In catalytic hydrogenation used as the same catalyst was found, an excellent yield towards HCOOH is 5.5 mmol. Current studies have highlighted the enhancement in activity along with selectivity for product formation could be due to having a capable active interface from electrocatalysts for low cost and proficient production of fuels.