Confinement of SnCu_xO_2+x Nanoclusters in Zeolites for High-Efficient Electrochemical Carbon Dioxide Reduction

Electrochemical reduction of carbon dioxide (CO2RR) to methane has achieved impressive Faradaic efficiencies of over 40% with copper-based catalysts including Cu2O, copper-silver alloys and others. Although copper-based catalysts work effectively in the CO2RR, they suffer from a major disadvantage: low selectivity of desired products due to the difficulty of regulating the intermediate coverage on the catalyst surface. Here, this work presents new SnCuxO2+x nanocluster electrocatalysts encapsulated in purely siliceous MFI zeolites (coded as SnCuxO2+x@MFI) for a high-efficient CO2RR. This allows the formation of *CO intermediates in the channels of zeolites, which further undergoes a multi-step protonation process to generate methane, a very attractive feature for Li-CO2 batteries that use the CO2RR catalyst as the cathode. The obtained SnCu1.5O3.5@MFI catalyst possesses a desired catalytic performance with the Faradaic efficiency of CO2 reduction to methane at 66.6 +/- 3.2% in a 0.1 m KHCO3 electrolyte. Using the SnCu1.5O3.5@MFI as a cathode within a Li-CO2 battery, this work achieves a full discharge specific capacity of 23 000 mAh g(-1) at a cut-off voltage of 2.0 V (vs Li+/Li) and an operational life over 100 cycles at 1000 mAh g(-1) cutoff specific capacity. This novel confinement catalyst offers a viable pathway to develop efficient CO2RR and Li-CO2 batteries with attractive properties for practical applications.