Support effect and confinement effect of porous carbon loaded tin dioxide nanoparticles in high-performance CO2 electroreduction towards formate

Leveraging the interplay between the metal component and the supporting material represents a cornerstone strategy for augmenting electrocatalytic efficiency, e.g., electrocatalytic CO2 reduction reaction (CO2RR). Herein, we employ freestanding porous carbon fibers (PCNF) as an efficacious and stable support for the uniformly distributed SnO2 nanoparticles (SnO2PCNF), thereby capitalizing on the synergistic support effect that arises from their strong interaction. On one hand, the interaction between the SnO2 nanoparticles and the carbon support optimizes the electronic configuration of the active centers. This interaction leads to a noteworthy shift of the d-band center toward stronger intermediate adsorption energy, consequently lowering the energy barrier associated with CO2 reduction. As a result, the SnO2PCNF realizes a remarkable CO2RR performance with excellent selectivity towards formate (98.1%). On the other hand, the porous carbon fibers enable the uniform and stable dispersion of SnO2 nanoparticles, and this superior porous structure of carbon supports can also facilitate the exposure of the SnO2 nanoparticles on the reaction interface to a great extent. Consequently, adequate contact between active sites, reactants, and electrolytes can significantly increase the metal utilization, eventually bringing forth a remarkable 7.09 A/mg mass activity. This work might provide a useful idea for improving the utilization rate of metals in numerous electrocatalytic reactions. Formate with ultrahigh selectivity and mass activity could be obtained in CO2 electroreduction via constructing highly efficient and fully exposed SnO2 sites throughout porous carbon nanofibers as well as support effect. [Display omitted]