Dual-functional heterojunction catalyst for synergistic improvement in selectivity of CO2 electroreduction for continuous production of high-concentration liquid fuels over a broad voltage range

Continuous production of liquid fuels in high concentration via electrocatalytic CO 2 reduction (CO 2 RR) calls for high-selectivity electrocatalysts and advanced devices. Here we designed and constructed a dual-functional heterojunction catalyst with an in situ growth strategy. The dual-functional heterojunction catalyst could synergistically activate CO 2 and water (as confirmed via in situ spectroscopy and theoretical calculations), and therefore the catalyst displayed a high selectivity and activity for formate production. Equipped with this catalyst, our custom-built gas–membrane–liquid electrolytic cell could continuously produce formate with a concentration as high as 1.55–1.85 M over the voltage range from 2.8 to 3.4 V (reaching the maximum of 1.85 M at 3.1 V). For continuous production of high-concentration HCOOH via CO 2 RR, our system features a broad voltage window. The results of theoretical calculations and in situ spectroscopies collectively demonstrate that constructing dual-functional heterojunction catalyst that work in synergy is the key solution to improving the overall catalytic performance.