Decorating graphdiyne on ultrathin bismuth subcarbonate nanosheets to promote CO₂ electroreduction to formate

Electrocatalytic reduction of CO₂ is one of the most attractive approaches for converting CO₂ into valuable chemical feedstocks and fuels. This work reports a catalyst comprising graphdiyne-decorated bismuth subcarbonate (denoted as BOC@GDY) for efficient electroreduction of CO₂ to formate. The BOC@GDY shows a stable current density of 200 mA cm^-2 at -1.1 V in a flow cell configuration, with a faradaic efficiency of 93.5% for formate. Experimental results show that the synergistic effect in BOC@GDY is beneficial for the CO₂ adsorption affinity, the reaction kinetics and the selectivity for formate. In addition, in-situ X-ray absorption and Raman spectroscopy indicate that the electron-rich GDY could facilitate the reduction from Bi(III) to Bi(0), thus leading to more active sites. We also demonstrate that the promoting effect of GDY in CO₂ electroreduction can be further extended to other metal catalysts. To the best of our knowledge, such general promoting functions of GDY for CO₂ electroreduction have not been documented thus far.