Designing a highly selective and energy-efficient electrocatalyst to minimize the competitive hydrogen evolution reaction remains a challenge in electrochemical reduction of aqueous carbon dioxide. In this study, we report that doping of Pd with a small amount of Te can selectively convert CO2 to CO with a low overpotential. The PdTe/few-layer graphene (FLG) catalyst with a Pd/Te molar ratio of 1:0.05 displays a maximum CO Faradaic efficiency of 90% at -0.8 V (versus reversible hydrogen electrode, RHE), CO partial current density of 4.4 mA cm-2 and CO formation turnover frequency of 0.14 s-1 at -1.0 V (versus RHE), which are 3.7-, 4.3-, and 10-fold higher than Pd/FLG, respectively. Density functional calculations show that Te adatoms preferentially bind at terrace sites of Pd, thereby suppressing undesired hydrogen evolution, whereas CO2 adsorption and activation occurs on the high index sites of Pd to produce CO.
Revised: November 20, 2020 |
Published: January 14, 2018
Citation
Tao H., X. Sun, S. Back, Z. Han, Q. Zhu, A.W. Robertson, and T. Ma, et al. 2018.Doping Palladium with Tellurium for Highly Selective Electrocatalytic Reduction of Aqueous CO2 to CO.Chemical Science 9, no. 2:483-487.PNNL-SA-127588.doi:10.1039/C7SC03018E