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 (H/CO) ratio in a wide potential window via electrochemical carbon dioxide (CO) 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 (CoN) and nickel (NiNB) 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 H/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 H/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 H production and the Ni sites in CO production, as well as the preferred process for H evolution. This work provides a strategy in the construction of dual-site catalysts for efficient syngas production, which is significant for practical applications.