Designing cobalt-nickel dual-atoms on boron, nitrogen-codoped carbon nanotubes for carbon dioxide electroreduction to syngas.

Developing highly efficient electrocatalysts to produce syngas with a stable hydrogen/carbon monoxide (H2/CO) ratio in a wide potential window via electrochemical carbon dioxide (CO2) reduction is desperately required but still challenging. Herein, a dual-atomic site on boron, nitrogen-codoped carbon nanotubes (BCN) has been designed, containing both cobalt (CoN5) and nickel (NiN3B2) sites. Benefiting from the structure advantage and the bifunctional Co/Ni sites, such designed catalyst (CoNi-BCN) demonstrates remarkable performance for syngas production, achieving a stable H2/CO ratio of 1.5 over a broad potential window from -0.47 to -0.87 V vs. RHE. By tuning the Co/Ni molar ratio in CoNi-BCN, the H2/CO ratio can be adjusted from 0.5 to 2. In addition, this electrocatalyst exhibits outstanding stability within a long-term 20 h electrolyzing. Both experimental and theoretical calculation results confirm the primary role of the Co sites in H2 production and the Ni sites in CO production, as well as the preferred process for H2 evolution. This work provides a strategy in the construction of dual-site catalysts for efficient syngas production, which is significant for practical applications.