Boost Selectivity of HCOO- Using Anchored Bi Single Atoms towards CO2 Reduction.

Single atoms have been widely applied as efficient catalysts in various catalytic systems due to its high selectivity for certain products, which is induced by a uniform coordinate environment of active sites. Herein, it is demonstrated that Bi single atoms anchored on carbon black (Bi SAs/C) can serve as an efficient catalyst for CO2 electroreduction into formate (HCOO- ). During CO2 electroreduction, Bi SAs/C achieved a faradaic efficiency for HCOO- of 83.6 % at-1.1 Vversus reversible hydrogen electrode (V vs. RHE). Notably, the selectivity for HCOO- of Bi SAs/C was always higher than 95 % at all applied potentials. In addition, at-1.2 Vvs.RHE, the current density for HCOO- formation in thepresence of Bi SAs/C reached-12.0 mA cm-2 , which was 3.4 times as high as that (-3.5 mA cm-2 ) of BiOx clusters on carbon black (BiOx /C). Mechanistic studies revealed that Bi SAs/C facilitated the faradaic process and accelerated reaction kinetics in comparison with BiOx /C.