Assembly of colloidal Cu nanoparticles and Ni–N–C nanocarbons to electrochemically boost cascade production of ethylene from CO2 reduction

Cu-based tandem catalysis provides an efficient route to boost production of C 2+ products for electrochemical carbon dioxide reduction (CO 2 RR), but colloidally synthesized Cu NPs are still less explored in tandem electrocatalyst design. A Cu-based tandem catalyst was constructed in hexane by assembling colloidal Cu NPs and Ni–N–C nanocarbon with tunable Cu NPs/Ni–N–C mass ratios, of which colloidal Cu NPs are homogeneously distributed over Ni–N–C nanocarbon. The Cu NPs/Ni–N–C tandem catalysts have been fully characterized by TEM, PXRD and XPS. In the H-type cell, the CO 2 RR contrast experiments verified that the optimized Cu NPs/Ni–N–C composite produced tandem effect in generating C 2 H 4 , benefiting from which a fourfold promotion in faradaic efficiency, and fivefold enhancement in partial current density were achieved compared to the reference Cu NPs/Vulcan carbon. Finally, the post-CO 2 RR Cu NPs/Ni–N–C catalysts were also measured by CV, EIS, TEM and XPS to further understand the change of tandem catalyst during CO 2 RR. Graphical abstract An efficient Cu-based tandem catalyst was designed by compositing colloidal Cu NPs and Ni–N–C nanocarbon, which boosts cascade production of C 2 H 4 from electrochemical carbon dioxide reduction.