Highly Selective Electrochemical Conversion of CO2 to HCOOH on Dendritic Indium Foams

CO2 electrochemical reduction is a potential technique to decrease the levels of CO2 emission but has been hindered by poor performance of electrocatalysts. In this work, electrochemical reduction of CO2 has been studied by using a needle-like porous Indium electrode, which was electrodeposited in aqueous electrolytes containing Cl- using the hydrogen bubble dynamic template. This novel electrode displayed improved electrocatalytic activity, enhanced conversion efficiencies and a lower onset potential (-0.76 V vs. RHE), which was 0.3 V less than the Indium foil electrode. Moreover, it exhibited enhanced faradaic efficiencies of 86 % for formate at -0.86 V vs. RHE and with a current density of 5.8 mA cm-2. This noteworthy excellent catalytic activity, is the result of a large electrochemical surface area and needle-like dendrite structures in the presence of Cl- salts. Utilization of the novel nanostructured electrocatalysts and understanding of the role of salts can contribute to the design of further improvements of CO2 reduction.