Dicyandiamide-assisted synthesis of N-doped porous CoMn–Nx@N–C carbon nanotube composites via MOFs as efficient trifunctional electrocatalysts in the same electrolyte

Abstract

The development of low-cost, long-term stability, and good oxygen reversible catalytic reaction (ORR/OER) and hydrogen evolution (HER) activity under the same electrolyte concentration of electrocatalytic materials has an important role in the construction of large-scale applications and more valuable sustainable energy systems. Among them, the representative CoMn–Nx@N–C-900-0.2 showed good ORR/OER/HER catalytic activity in 0.1 M KOH alkaline electrolyte, specifically manifested by its half-wave potential E = 0.84 V in the ORR test, which was better than that of commercial Pt/C. The total oxygen electrode activity index of OER/ORR was E = 0.79 V, and it also showed good HER performance. When the current density was 10 mA cm⁻², the operating potential was E = −0.266 V. The synergistic effects of the CoMn bimetallic alloy, tubular layered porous structure, which exposed more active area and various nitrogen species such as CoMn–Nx, were the main reasons for the improvement of the trifunctional catalytic performance of electrocatalytic materials. The synthesis strategy and analysis of the electrocatalyst performance provide a new reference for the development of multifunctional materials with high catalytic performance.