In-situ assemblage of Fe–V–P/graphene aerogel based on prussian blue analogue as a high-performance electrocatalyst for oxygen evolution reaction

Abstract

The carbon scaffold with high conductivity is suitable to enhance the catalytic activity of prussian blue analogues (PBAs) in oxygen evolution reaction (OER) of water splitting. Herein, a two-step strategy is developed to synthesize Fe–V–P/graphene aerogel based on prussian blue analogue (Fe–V–P/GA) electrocatalysts, which possess dense arrangement of anomalous octahedron structure. In the vanadium-modified PBAs (FeV–PBAs), Fe/V with a series of different molar ratios has been investigated and when the molar ratio of Fe/V is 1:1, the catalyst achieves a fairly high specific surface area expressed by the double-layer capacitance of 5.29 mF cm−2 and requires overpotentials of only 234.0 and 314.3 mV to attain the benchmark current density of 10 and 50 mA cm−2 during OER process. Besides, the catalyst owns satisfactory stability and the current density remains almost constant during stability tests lasting up to 70 h. As revealed via electrochemical kinetics analysis and the spectroscopic measurement, embellished FeV–PBAs not only lead to larger tangible area, more accessible sites and higher durable stability, but also provide formation of high valence state of iron and vanadium species, strong modification of electronic state and faster kinetics. This study provides a novel mode of thinking to consummate the design of 3D construction so as to boost the catalytic effect of transition metal catalysts for efficient oxygen evolution.