Bimetallic Cu-Zn Co-Doped Porous N/C as Efficient Catalysts for Oxygen Reduction Reaction and Oxidation of 1,2-Propanediol

摘要

The development of non-precious metal catalysts toward oxygen reduction reaction (ORR) is essential for widespread application of fuel cells. Herein, bimetallic Cu-Zn co-doped porous N/C catalysts (Cu-Zn-N/C) with high N content were synthesized via a simple metal-organic framework (MOF)-derived method. The as-prepared Cu-Zn-N/C catalyst presents superior catalytic activity toward ORR with an onset potential of 0.90 V, a half-wave potential of 0.79 V, and a diffusion limiting current density of 5.82 mA cm(-2). It is found that Cu exists in three forms: one exists in Cu particles, and the others exist in Cu single atoms (either in high valence or in zero valence) that embedded in the carbon substrate. The evaporation of Zn atoms during the pyrolysis induces the pore structure of the carbon matrix, making it possible to support for the zero valent Cu atoms. In addition, as an efficient Cu-based catalyst for many applications, we show that the as-prepared catalyst can selectively oxidize 1,2-propanediol to lactic acid with 75.7 % selectivity at 82.8 % conversion.