Electrochemical conversion of CO2 into more valuable chemical stocks is regarded as a promising pathway in the field of carbon neutral emission and energy storage. Tin oxides are one of the well-known catalysts to reduce CO2 into formic acid with high selectivity. Nevertheless, there are still deficiency in CO2 activation and selectivity tailoring towards HCOOH both from experimental and theoretical studies. Recently, oxygen vacancies have been regarded as a useful approach in intrinsic CO2 activation while are rarely applied in tin oxides. Therefore, construction of oxygen vacancies will definitely play a role in the initial CO2 activation for electrochemical CO2 reduction. DFT calculation demonstrated that N doping will reduce the oxygen vacancies formation energy and enhance charge density of Sn atoms. Inspired by the theoretical direction, we obtain N-doped SnO2 nanoparticle with abundant oxygen vacancies. As the Tafel slop of 83 mV dec-1 showed, accelerated CO2 activation is successfully achieved by oxygen vacancies and high charge density of Sn sites. Interestingly, N-doping further regulates the adsorption of *OCHO, *COOH and *H for high selectivity of HCOOH formation. Benefited from the above modulation, the obtained Ov-N-SnO2 catalysts exhibited 88% faradaic efficiency for HCOOH production, 93 % faradaic efficiency for C1 production, and low hydrogen evolution over a wild potential range. Both the experimental results and theoretical calculation reveal that the oxygen vacancies construction and N-doping of SnO2 catalysts could conduct as effective catalysts for electrochemical CO2 reduction. This study will also open an avenue for the rational design of novel and efficient catalysts towards CO2 electrochemical reduction.

Engineering SnO2 electrocatalysts for expedited CO2 activation and reduction

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.