Bismuth Metal Porphyrin Framework Doped RuO2 Derived Bi2O3-RuO2@C Composites for Highly Selective CO2 Electroreduction

In electrochemical reduction of carbon dioxide (CO2RR), the design of electrocatalysts with high efficiency and selectivity is very important and challenging. In this paper, a ternary composite consisting of ruthenium dioxide and bismuth metal porphyrin-based organic framework (Bi-TCPP MOF)-derived bismuth trioxide and C skeleton has been proposed (denoted as Bi2O3-RuO2@C). Nanoscale RuO2 and Bi2O3 particles are uniformly distributed on the C skeleton. The precursor bismuth metal porphyrin-based organic framework restricts the localized growth of Bi2O3 in the framework, while the unique, highly-conjugated system anchors the doped RuO2 particles, resulting in a uniform distribution of both active sites and hole-enrichment centers. Meanwhile, the Bi-TCPP MOF-derived carbon skeleton has good electrical conductivity, and the macroporous structure also facilitates the gas transport, which leads to the synthesis of Bi2O3-RuO2@C as an electrocatalyst for CO2RR and exhibits excellent catalytic performance and high selectivity for electrocatalytic carbon dioxide reduction to methane (CO2-CH4). The peak Faraday efficiency of Bi2O3-RuO2@C for catalyzing the reduction of CO2-CH4 can reach 66.95% when the doped RuO2 content is 20%. Importantly, this work opens up new horizons for metal ratio regulation in constructing efficient catalytic systems derived from MOFs.