Electrochemical CO₂ Reduction on SnO: Insights into C₁ Product Dynamic Distribution and Reaction Mechanisms

Abstract

The precise synthesis of desirable products from the electrochemical CO2 reduction reaction (CO2RR) remains challenging, primarily due to unclear structure–activity relationships under in situ reaction conditions. Recognized by their cost-effectiveness and nontoxic nature, Sn-based materials are extensively utilized in CO2RR to produce valuable chemicals. Notably, our large-scale data mining of the experimental CO2RR literature reveals a significant trend: SnO2-based electrocatalysts primarily generate HCOOH, while SnO-based counterparts demonstrate the ability to produce both HCOOH and CO in comparable quantities. Furthermore, our findings indicate that SnO remains underexplored in terms of its surface speciation and structure–activity relationships for the CO2RR compared to SnO2-based materials. Addressing these issues is crucial in the field of electrocatalysis, as understanding them will not only clarify why SnO uniquely influences the distribution of C1 products but also provide insights into how to precisely control electrocatalytic processes for targeted product synthesis. Herein, we employed a constant-potential method combined with surface coverage and reconstruction analyses to simulate the energetics of CO2RR intermediates and to elucidate the dynamic distribution of C1 products on the in situ resting surface of SnO under typical CO2RR conditions. Our analysis of surface coverage and reconstruction effectively identifies the active surface of SnO involved in the CO2RR. Furthermore, comparative simulations between pristine and reconstructed SnO surfaces reveal how electrochemistry-induced oxygen vacancies direct C1 product distribution. By addressing these critical issues, we aim to advance electrocatalysis and contribute to chemical production from CO2, stimulating future exploration of structure–activity relationships and reaction conditions in other electrocatalytic systems.