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

Abstract

Exploring sustainable, low-cost and high-performance nonnoble 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 longterm 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.

Iron, Cobalt, and Nickel Phthalocyanine Tri-Doped Electrospun Carbon Nanofibre-Based Catalyst for Rechargeable Zinc–Air Battery Air Electrode

“…During continuous 5 mA cm −2 charge and discharge cycles (10 min per cycle), the RZAB eventually stops working due the formation of isolating ZnO layer at the Zn electrode. The battery can be mechanically recharged by replacing the Zn electrode and electrolyte, after which the RZAB operation can be continued [ 38 , 47 ]. Round-trip efficiencies of 58 and 60% were calculated for FeCoNi-CNF and Pt-Ru/C air electrode-based RZAB, respectively, at the 15th and also at the 25th hour of operation, showing the good stability of both bifunctional electrocatalysts up to 31 h. For comparison, the round-trip efficiency with FeCoNi-CNF air electrode is higher compared to the NiCo 2 O 4 blended with N-doped graphene nanoribbon-based catalysts exhibiting 55% during 5 mA cm −2 cycling in an earlier investigation [ 66 ].…”

“…In addition to dual TM-embedded CNF catalysts employed for RZAB air electrode application [ 23 , 24 , 25 ], triple TM combination with various nanocarbon supports have been also investigated [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. A very appealing and effective approach to introduce TM-Nx active sites into nanocarbon catalysts is the inclusion of TM macrocyclic compounds (e.g., metal phthalocyanines (Pc) or porphyrins) [ 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ]. Different TM Pc compounds have been also found to be efficient ORR and OER bifunctional catalysts according to computational studies [ 43 ].…”