Facile Fabrication of Nitrogen, Phosphorus and Silicon Co-Doped Porous Carbon as an Efficient Oxygen Reduction Catalyst for Primary Zn-Air Battery

It is highly pleasurable but challenging to develop economical and efficient catalysts for accelerating the oxygen reduction reaction (ORR) endowed with sluggish kinetics involved in renewable energy conversion and storage systems such as Zn-air batteries. Herein, N, P and Si tri-doped porous carbon (SiN-PA900) catalysts was prepared by a simple one-step pyrolysis strategy using the mixture of the ionic liquid formed by phytic acid (PA) and N-methylimidazole and tetraethyl orthosilicate (TEOS) as N, P, Si and carbon sources, and the PA as pore-foaming agent. The resulting SiN-PA900 shows favorable catalytic activity toward ORR with an onset potential of 0.94 V versus RHE, half-wave potential of 0.81 V versus RHE, robust stability and excellent tolerance for methanol in alkaline medium, which are comparable to those of the commercial 20% Pt/C. More impressively, the assembled primary Zn-air battery employing the SiN-PA900 as cathode catalysts can achieve a peak power density of 181.4[Formula: see text]mW/cm2. Those encouraging properties could be attributed to a synergistic effect of the doped N, P and Si atoms in the carbon matrix, good surface wettability, high surface areas and hierarchical porous structures for sufficient contact and rapid transportation of the reactants in terms of composition and structures.