Size separation of Bi2WO6 nanolayers promoting electroreduction of carbon dioxide to formate

This work reports a facile procedure to regulate the size of Bi 2 WO 6 nanolayers by adjusting their Zeta potentials in aqueous dispersions. The as-resultant small-size Bi 2 WO 6 nanolayers have exhibited excellent structural characteristics like highly exposed metal active sites and large surface areas, which are favorable for converting CO 2 to formate. At the applied potential of −0.9 V (vs. RHE), the small-size Bi 2 WO 6 nanolayers have demonstrated the maximum FE of 82.3% with a current density of 106.1 mA cm −2 in a flow-type electrochemical cell. Further mechanism study had been achieved by using density functional theory (DFT) computations that highlight the potential-limiting step of CO 2 *➔ OCHO* that reveals the presence of *COOH intermediates adsorbed on the catalyst surface during the electrocatalysis process. • A general procedure has been demonstrated to regulate the size of two-dimensional nanolayers in aqueous dispersions. • The as-produced small-size Bi2WO6 nanolayers have exhibited excellent activities for converting CO2 to formic acid. • Density function theory (DFT) calculations highlighte the potential-limiting step of CO2*➔ OCHO* for CRR. • In situ Raman tests have been performed to probe the change of intermediates adsorbed on Bi2WO6 during CRR.