Heterostructured FeP4/CoP@NF as trifunctional electrocatalysts for energy-efficient hydrogen production

Abstract

The developing of efficient and cost-effective electrocatalysts for hydrogen evolution is of great significance to the development of hydrogen energy. It is believed that the efficient hydrogen generation of water cracking is restricted from the slow oxygen evolution reaction (OER) process. Consequently, it is highly recommended to find alternative anodizing to produce hydrogen to reduce electricity consumption. Urea oxidation reaction (UOR) is an alternative to the traditional anodic OER. In this paper, an electrocatalyst FeP4/CoP@NF-7.5 supported on nickel foam (NF) was designed by using a template-directed growth and low-temperature phosphating method. The FeP4/CoP@NF-7.5 with a rich interface gives it more active sites and enhances mass transfer and conductivity, possessing excellent catalytic performance against hydrogen evolution reaction (HER), OER and UOR in alkaline electrolyte. Thanks to the abundant interface and bimetallic synergy, the designed catalyst exhibits the overpotentials of 45 mV and 259 mV for HER and OER to transfer 10 mA cm−2. In addition, FeP4/CoP@NF-7.5 also possesses significant catalytic activity against UOR of 136 mV (j10) in 1 M KOH with 0.33 M urea, which provides another alternative to the low efficiency of OER through the reduction of hydrogen production costs. Finally, the overall water splitting test was undertaken in 1 M KOH containing/free of 0.33 M urea. Remarkably, only 1.43 V is required to drive on urea electrolyzer (j10 = 10 mA cm−2), while 1.52 V are gained on water electrolyzer. This paper lays the foundation for the developing of high-active transition bimetallic phosphide electrocatalysts for energy-saving hydrogen production.