0D/1D heterostructure for efficient electrocatalytic CO2-to-C1 conversion by ultra-small cluster-based multi-metallic sulfide nanoparticles and MWCNTs

Abstract Rationally constructed catalysts for efficiently converting CO2 into valuable carbonaceous fuels like CO and formate via electrochemical process are promising for decreasing the excessive emission of CO2. Thus, electrocatalysts with a large turnover frequency (TOF) for CO and formate are highly desirable. To this end, multi-metallic nanoclusters (NCs) with unique electronic structure, large specific surface and abundant active sites are favorable theoretically. However, their structural complexity and challenging synthesis impede the application in CO2 electroreduction. Herein, negatively charged multi-metallic sulfide supertetrahedral NCs-based nanoparticles, containing Cu, Ga, In and Sn four metal components, were for the first time electrostatically self-assembled with positively charged multi-walled carbon nanotubes (MWCNTs) to fabricate a novel 0D/1D heterostructure that exhibits efficient CO2 electroreduction to C1 products (CO + HCOOH) with high Faradaic efficiency (FE) (>80%), excellent TOF (5974.62 h−1) and good long-term stability (12 h). Besides, a ratio-tunable syngas (CO + H2) (VCO/VH2: 0.1 ~ 2.73) and efficient electrochemical oxygen reduction reaction (ORR) could also be achieved for the hybrid catalyst. Comparative experiments figured out the favorable synergistic effects of co-existed Ga and In ions and enhanced interfacial charge-transfer were responsible for the promoted CO2 electroreduction activity.