With dwindling fossil fuels and rising concern about their impacts on climate, electrochemical reduction of CO2 has attracted researchers’ attention as it has the potential to utilize the abundant greenhouse gas in the Earth’s atmosphere and store intermittent energy from solar panels and wind turbines in chemical bonds. A commercially viable catalyst for CO2 electroreduction should meet the cost-effective requirement while possessing high efficiency and selectivity. Experimental studies showed that tin oxides (SnOx) have the ability to selectively convert CO2 to formate (HCOO-), although the reaction mechanism is not clear with respect to the nature of active sites and the process occurs at prohibitively high overpotentials (~1 V). The goal of this study is to understand the reaction mechanism of CO2 electroreduction on SnOx and leverage that knowledge to design metal/SnOx composite catalysts with superior activity. In this poster, we will discuss the reaction mechanism of CO2 reduction on SnOx obtained from first-principles density functional theory calculations and molecular dynamics, focusing on the competing pathways leading to the production of CO, H2, and HCOO-. We found that the outcome of CO2 electroreduction on SnOx is highly dependent on its surface structure, which can explain a wide range of faradaic efficiencies for formate production on SnOx reported in different studies. By engineering the lattice strain of SnOx by forming Ag/Sn alloys, we illustrated that the electrocatalytic reactivity can be further optimized for formate production, while the CO formation is not affected.

Engineering metal/SnOx interfaces for electrochemical CO2 reduction

253rd National Meeting (2017)

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