Computational Design of Copper doped Indium for electrocatalytic Reduction of CO2 to Formic Acid. Issue 22 (11th September 2020) - Sun, Wenli
Abstract: Electrochemical reduction of CO2 to formic acid is crucial to achieve a low carbon cycle and mitigate the energy crisis. Density functional calculation is deemed to be an important method for designing highly efficient catalysts for CO2 electrochemical reduction (CO2 ER). Cu−In alloy is mostly reported to show an increasing selectivity of reducing CO2 to CO, however the performance of CO2 ER over In with tiny amount of Cu doping and the influence of trace Cu to the reaction are rarely researched. Here, The CO2 ER mechanism over In and trace Cu doped In (denoted as Cu−In) catalysts are theoretically investigated. Additionally, the relative reduction pathways and Gibbs free energies of the key intermediates ( * COOH and HCOO * ) are calculated, which show that Cu−In can produce formic acid more efficiently since Cu−In surface prefers to adsorb HCOO* to form formic acid and decrease the production of CO. Additionally, the theoretical calculation is verified by experimental results. The designed Cu−In catalyst (containing 1.55 wt % Cu) shows a high Faraday efficiency of 70 % for formate in CO2 saturated 0.5 M NaHCO3 electrolyte, which is much better than pure In (56 %). Abstract : Catalyst design : Density functional calculations indicate that (101) surface of trace Cu doped In (Cu−In) is more likely to adsorb HCOO* to produce formate in CO2 electrochemical reduction than (101) surface of pure In. Moreover, when verifying theoretical calculation with experiments, the as‐prepared Cu−In catalyst shows higher Faradaic efficiency for formate (70 %) in CO2 reduction than pure In (56 %), which corresponds well with the calculation results.