Pd-SnO2 interface enables synthesis of syngas with controllable H2/CO ratios by electrocatalytic reduction of CO2

Electrochemical CO2 reduction reaction (eCO2RR) to syngas (CO + H2) is considered as a great potential and efficient way to abate carbon emissions and mitigate the depletion of fossil resources. Herein, a series of Pd-loaded SnO2 nanosheets catalysts (Pd-SnO2 NSs) are developed by photodeposition of Pd on the surface of SnO2 nanosheets. Due to the formation of the active Pd-SnO2 interface, the as-prepared Pd-SnO2 catalysts exhibit a suppressed eCO2RR to HCOOH pathway, thus realizing the faradaic efficiency of syngas close to 100%. The obtained optimal 4.3Pd-SnO2 catalyst exhibits high CO selectivity (78% FECO) and wide H2/CO ratio ranged from 4.2 to 0.28. Notably, the H2/CO ratio can be controlled easily by adjusting the applied potential. Moreover, the H2/CO ratio can maintain for more than 30 h. This work unfolds a promising candidate for earth-abundant Sn-based electrocatalysts for eCO2RR to syngas.