Monotonically increasing relationship between conversion selectivity from CO2 to CO and the interface area of Cu-Ag biphasic electrochemical catalyst

Abstract

Besides composition, the electrochemical CO2 reduction reaction (CO2RR) is also very sensitive to the structure of catalyst due to the complex intermediates. In this paper, a series of Cu-Ag biphasic catalysts with a similar average value of unimodal phase size distribution were synthesized. The phase interface area of the biphasic catalyst can be manipulated by the element ratio due to the unimodal phase size distribution. The catalytic performances of Cu-Ag biphasic catalysts for CO2RR to CO were studied and it is found the conversion selectivity heavily depends on the phase interface area. The maximum phase interface makes the original inert copper catalyst have excellent electrochemical performance. A high FECO of 80.25% was attained with a partial current density of − 4.88 mA cm−2 at − 0.9 V vs RHE in Cu50Ag50 and the FECO was almost not attenuated within 25 h. The catalytic performances are even better than those of Ag100 catalyst. The paper enlightens another way to reduce the dependence of electrochemical catalyst on noble metals. The phase interface can be further increased with less noble metal element proportion, for the methodology of this paper ignores the thickness of the phase.