Fe-N Doped Peanut Shell Activated Carbon as a Superior Electrocatalyst for Oxygen Reduction and Cathode Catalyst for Zinc-Air Battery

Exploring sustainable, low-cost and high-performance non-noble metal (NNM) electrocatalysts as alternatives to Pt-based catalysts for oxygen reduction reaction (ORR) is crucial for the large-scale application of metal-air batteries and fuel cell technology. A new method for preparing ORR catalysts is to use biomass activated carbon supported transition metal. Biomass activated carbon has a highly porous structure which is beneficial to charge and energy transport. In this article, peanut shell activated carbon (PSAC) was prepared as a carrier and iron phthalocyanine (FePc) was the active component of the catalyst. Different mass ratios of the FePc and PSAC were selected for physical doping and then treated at a high temperature. The obtained catalyst FePc/PSAC-3/1 showed excellent ORR catalytic performance, the onset potential and the half-wave potential are 0.94 V and 0.85 V respectively, highly comparable to that of commercial Pt/C (20 wt% Pt) catalyst. FePc/PSAC-3/1 has good stability and better tolerance to the methanol crossover effect than the Pt/C catalyst in alkaline electrolytes. The product was further used as an air cathode to construct the Zn-air battery at the same time. The excellent recharge-ability was further evaluated by a 43 h long-term cycling test without noticeable deterioration for the voltage gap. This work demonstrates the great promise of developing new families of NNM ORR catalysts by the economical and sustainable process.