Electrocatalytic oxygen reduction reaction (ORR) and CO2 reduction reaction (CO2RR) are at the heart of fuel cells and converting greenhouse gas CO2 into value-added fuels, respectively. However, sluggish kinetics rates of ORR/CO2RR and lack of efficient catalysts impede large-scale applications of these clean-energy technologies. Although heteroatoms-doped mesoporous carbons (MPCs) are suggested to be promising candidates for ORR/CO2RR owing to intriguing features including numerous edge locations, large interfacial area and porous channel, facile preparation of MPCs with efficient dopants to enable high performance remains a great challenge. Herein, we proposed a new self-growth-templating concept for the fabrication of three-dimensional (3D) N,P,Co-doped MPCs frameworks, which was achieved through simply pyrolyzing Vitamin B12 in NaCl assemblies-enclosed nanoreactors. The route realizes the controllable formation of mesoporous templates, elimination of the templates, as well as in situ doping of N,P,Co into MPCs in the one-step calcination process. The resultant MPCs are characterized by 3D carbon honeycombs, large-sized mesopore (about 30 nm), high surface area (1036 m2 g−1), and dense distribution of the N,P,Co dopants. The highly mesoporous architecture not only enhances mass transportation but also provides the 3D electrocatalyic surface to expose highly active N,P,Co-induced dopants. These features endow MPCs with excellent activity toward oxygen reduction (half-wave potential of 0.85 V, kinetic-limiting current density of 51 mA cm−2 at −0.71 V) and CO2 reduction (onset overpotential of 190 mV, CO Faradaic efficiency of 62%), coupled with high electrochemical stability. This N,P,Co-doped MPCs with excellent performance for ORR and CO2RR will contribute to the development of new materials for fuel cells and CO2 electro-conversion. More importantly, the developed self-constructing concept is a major breakthrough in the fabrication of MPCs, which is also believed to potentially bring an innovation on the methodology for synthesizing other advanced mesoporous materials beyond carbon for the broad applications.

Functional mesoporous carbon frameworks for efficient electrocatalytic oxygen and carbon dioxide reduction reaction

255th National Meeting (2018)

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