Controlled synthesis of Cr x -FeCo 2 P nanoarrays on nickel foam for overall urea splitting.

Urea splitting is a highly promising technology for hydrogen production to cope with the fossil energy crisis, which requires the development of catalysts with high electrocatalytic activity. In this article, Cr x -FeCo 2 P/NF catalysts were synthesized by hydrothermal and low-temperature phosphorylation and used in the overall urea splitting process. Cr 0.15 -FeCo 2 P/NF and Cr 0.1 -FeCo 2 P/NF exhibited excellent urea oxidation reaction (UOR) activity (potential of 1.355 V at 100 mA cm -2 ) and hydrogen evolution reaction (HER) activity (overpotential of 173 mV at 10 mA cm -2 ) in 0.5 M urea solution containing 1 M KOH. In the assembled Cr 0.15 -FeCo 2 P/NF//Cr 0.1 -FeCo 2 P/NF electrolytic cell, only a small voltage of 1.50 V is needed to reach 10 mA cm -2 . Density functional theory (DFT) calculation results demonstrate that an appropriate amount of Cr doping accelerates the kinetic performance of hydrogen production as well as improving the metallic properties of the electrode.