Surface Polarity Induced Simultaneous Enhancement of Nanopore Accessibility and Metal Utilization in Metal and Nitrogen Co-Doped Carbon Electrocatalysts for CO2 Reduction

Theefficient utilization of active centers for the emerging classof metal (M) and nitrogen (N) co-doped carbon (M-N-C)catalysts remains a research hotspot for electrochemical synthesissuch as the reduction reactions of CO2, O-2,N-2, or functional groups in organic molecules. However,keeping sufficient accessibility to these active centers upon thermaltreatment at high temperatures can be challenging due to possiblenanopore blocking issues. To tackle this limitation, this work presentsa precise surface modulation approach based on a kind of porous carbonsupport with an ultrapolar surface, over which the unusual enhancementof nanopore accessibility and metal utilization is achieved. The strategyis well applicable to transition metals, precious metals, and rareearth metals. Experimental evidence revealed that the ultrapolar porewalls can be spontaneously wetted by hydrated metal ions. The unprecedentedwettability ensured a unique metal-support interaction, which notonly warrants the anchoring metal species in a dispersed manner butalso induces the development of transport nanopores by dynamical etchingof the polar carbon walls during thermal treatment. By this way, thisstrategy addresses the trade-off issue between metal utilization efficiencyand accessibility to the active centers for the M-N-Ctype catalysts.