Enriched active surface structure in nanosized tungsten-cobalt oxides electrocatalysts for efficient oxygen redox reactions

Abstract

Nanosized tungsten-cobalt oxide (WCoO-NP) electrodes were prepared using self-assembly template approach and their bifunctional electrocatalytic behaviour for the oxygen redox reactions was investigated. The texture, morphology, specific surface area, crystallinity, and electrocatalytic activity of the WCoO-NP were strongly associated with the W and Co content. The WCoO-NP materials contains 15 mol% of tungsten showed enhanced electrocatalytic behaviour, substantial shift in the OER onset potential of 190 mV, Tafel slope (92 mV/dec), ultra-low charge-transfer resistance, and current density of 30 mA cm−2 at 1.55 VRHE, which is more efficient catalyst than bare cobalt oxide nanoparticles (Co3O4-NP) counterpart and comparable to benchmark transition metal oxide electrocatalysts. The WCoO-NP materials exhibits long-term durability and good bifunctional electrocatalytic behaviour for both the OER and ORR, having ΔE (=EOER − EORR) of only 0.92 V which could be credited to the synergistic effect, enriched specific surface area, and improved electrical conductivity upon tungsten-doping. The WCoO-NP electrocatalysts prepared from earth-abundant materials are a promising candidate for high-efficiency OER and ORR applications.