Enhancing the electrocatalytic performance of SnX 2 (X = S and Se) monolayers for CO 2 reduction to HCOOH via transition metal atom adsorption: a theoretical investigation.

Exploring highly efficient, stable, and low-cost electrocatalysts for CO reduction reaction (CRR) can not only mitigate greenhouse gas emission but also store renewable energy. Herein, CO electroreduction to HCOOH on the surface of SnX (X = S and Se) monolayer-supported non-noble metal atoms (Fe, Co and Ni) was systematically investigated using first-principles calculations. Our results show that Fe, Co and Ni adsorbed on the surface of SnX (X = S and Se) monolayers can effectively enhance their electrocatalytic activity for CO reduction to HCOOH with low limiting potentials due to the decreasing energy barrier of *OOCH. Moreover, the lower free energy of the *OOCH intermediate on the surface of TM/SnX (X = S and Se) monolayers verifies that the electroreduction of CO to HCOOH prefers to proceed along the path: CO → *OOCH → *HCOOH → HCOOH. Interestingly, SnX (X = S and Se) monolayer-supported Co and Ni atoms prefer the HCOOH product with low CRR overpotentials of 0.03/0.01 V and 0.13/0.05 V, respectively, showing remarkable catalytic performance. This work reveals an efficient strategy to enhance the electrocatalytic performance of SnX (X = S and Se) monolayers for CO reduction to HCOOH, which could provide a way to design and develop new CRR catalysts experimentally in future.