Cu, Co-Embedded N-Enriched Mesoporous Carbon for Efficient Oxygen Reduction and Hydrogen Evolution Reactions

摘要

Rational synthesis of hybrid, earth-abundant materials with efficient electrocatalytic functionalities are critical for sustainable energy applications. Copper is theoretically proposed to exhibit high reduction capability close to Pt, but its high diffusion behavior at elevated fabrication temperatures limits its homogeneous incorporation with carbon. Here, a Cu, Co-embedded nitrogen-enriched mesoporous carbon framework (CuCo@NC) is developed using, a facile Cu-confined thermal conversion strategy of zeolitic imidazolate frameworks (ZIF-67) pre-grown on Cu(OH)(2) nanowires. Cu ions formed below 450 degrees C are homogeneously confined within the pores of ZIF-67 to avoid self-aggregation, while the existence of Cu. N bonds further increases the nitrogen content in carbon frameworks derived from ZIF-67 at higher pyrolysis temperatures. This CuCo@NC electrocatalyst provides abundant active sites, high nitrogen doping, strong synergetic coupling, and improved mass transfer, thus significantly boosting electrocatalytic performances in oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). A high half-wave potential (0.884 V vs reversible hydrogen potential, RHE) and a large diffusion-limited current density are achieved for ORR, comparable to or exceeding the best reported earth-abundant ORR electrocatalysts. In addition, a low overpotential (145 mV vs RHE) at 10 mA cm(-2) is demonstrated for HER, further suggesting its great potential as an efficient electrocatalyst for sustainable energy applications.