Co‐N‐doped hierarchically ordered macro/mesoporous carbon as bifunctional electrocatalyst toward oxygen reduction/evolution reactions

Abstract

Exploring progressed activity and stability, electrocatalyst toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), has been the most considerable factor in extensive commercialization of metal-air batteries and fuel cells. Herein, Co/N co-doped 3D hierarchical porous bifunctional oxygen electrocatalyst was synthesized using F127 as soft template and PMMA nanosphere as hard template to build hierarchically ordered macro/mesoporous porous nanostructure. The as-obtained macro/mesoporous CoN doped carbon endowing its 3D ordered hierarchical porosity and satisfactory surface area, leading to superior performance for ORR, OER, and rechargeable Zn-air battery. For ORR, the catalyst showed superior ORR activity with an attractive half-wave potential of 0.85 V (vs RHE), remarkable methanol tolerance, and robust long-term stability under alkaline electrolyte. For OER, the assynthetized electrocatalyst exhibited low overpotential of 1.67 V (vs RHE) under the current density of 10 mA/cm 2. Moreover, the Zn-air battery assembled from the hierarchical porous catalyst displayed a high peak power density of 146 mW/cm 2 .

Air Electrodes for Flexible and Rechargeable Zn−Air Batteries

“…Consequently, adjusting the microtopography of carbon‐based materials with specific meso‐/microporous structures gained much attention in recent years. [ 179 ] Silica or polystyrene templates were adopted to achieve structure controlling and obtain pertinent porosity during pyrolysis. [ 180 ] The surface area and total pore volume were improved with a remarkable macropore distribution, as reported by several studies.…”

Supporting critical raw material circularity – upcycling graphite from waste LIBs to Zn–air batteries

“…This process leads to the formation of N-C and M-Nxtype bonds, which are recognized as active sites for the ORR and the OER. [31][32][33][34][35][36][37][38] In addition to nitrogen species, metal nanoparticles encapsulated by carbon or metal oxides are wellknown OER active centres. [39][40][41][42] The ability to catalyse both oxygen reactions, good capacity, and long-term stability are required characteristics for promising bifunctional oxygen electrocatalysts that could be applied in rechargeable Zn-air batteries (ZABs) as air cathode catalyst materials.…”

N‐rich mesoporous carbon supported CoNC and FeNC catalysts derived from o‐phenylenediamine for oxygen reduction reaction

“…Gong and colleagues successfully found that N-doped vertical carbon nanotube arrays have good ORR catalytic activity, which provided an alternative basis for the development of non-metal heteroatom-substituted porous carbon catalysts. 30 Meng et al 31 obtained macro/mesoporous Co-N-doped carbon endowing its 3D ordered hierarchical porosity and satisfactory surface area, which lead to superior performance. It is well known that M/N/C structured electrocatalysts facilitate oxygen adsorption, subsequent reduction and provide more active sites, include pyrrolic N, pyridinic N and graphitic N species.…”