Nitrogen and sulfur incorporated chitosan-derived carbon sphere hybrid MXene as highly efficient electrocatalyst for oxygen reduction reaction

Abstract

The quest for non-precious electrocatalysts through biomass for energy applications has attracted keen interest, but optimization for fuel cells remains challenging. Herein, we have developed a nitrogen and sulfur-anchored MXene hybrid chitosan-derived carbon sphere (N,S-MXC) reporting for the first time as a novel oxygen reduction reaction (ORR) electrocatalyst. Interestingly, as the mass ratio of MXene to Chitosan varied by (1:2, 1:1, and 2:1), the microstructures of the as-prepared catalysts changed, which drastically influenced the corresponding ORR performance. Notably, when the mass ratio was maintained to be 1:2, Ti₃C₂ nanoparticles were dispersed on the surface of the biomass carbon core shell. They created multimodal porous morphology that helps to facilitate faster electron transfer, resulting in a high onset-potential of 0.89 V and limiting current density of −4.2 mA/cm² as well as excellent durability with minimum half-wave potential loss of 2.3 mV after 5000 cyclic voltammetry (CV) cycles than benchmark Pt/C. In addition, the corresponding catalyst also possessed robust stability of 87.47 % and an excellent methanal poisoning tolerance effect in an alkaline medium. In a nutshell, this work paves the pathway for converting sea animal waste to develop porous carbon as supporting material for fuel cells that directly or indirectly support achieving carbon neutrality.