Lattice strain and interfacial engineering of a Bi-based electrocatalyst for highly selective CO2 electroreduction to formate

Surface strain tuning in a coupled heterostructure efficiently engineers the catalytic performance of heterogeneous catalysts by altering the electronic structures and boosting electron transport. Generally, Bi-based catalysts are more favorable than ZnO for CO2 electroreduction to formate, but Bi is much more costly than Zn. Herein, a new Bi2O2CO3/ZnO heterojunction catalyst with porous nanoplate morphology is synthesized through a hexadecyl trimethyl ammonium bromide-templated hydrothermal reaction for a highly efficient catalytic CO2 reduction reaction (CO2RR) to produce formate. The Bi2O2CO3/ZnO catalyst shows a maximum Faradaic efficiency of 92% for formate production at -1.0 V vs. reversible hydrogen electrode (RHE) and a large partial current density of -200 mA mg(Bi)(-1) at -1.2 V vs. RHE. More importantly, the mass activity of Bi2O2CO3/ZnO normalized by Bi mass is an approximately 3.1-fold enhancement over that of the pristine Bi2O2CO3 at -1.2 V vs. RHE. By coupling X-ray photoelectron spectroscopy and adsorption spectroscopy measurements, the charge transfer from the Zn atom to the Bi atom through a heterogeneous interface results in an electron-enriched Bi2O2CO3 surface, which facilitates CO2 capture and activation. Meanwhile, compressive stress produced on the catalyst surface helps optimize the adsorption energy of the reaction intermediate, synergistically enhancing the catalytic selectivity and activity of Bi2O2CO3/ZnO for electrochemical CO2 reduction to formate.