Hydrogen production from the electro-oxidation of ammonia catalyzed by platinum and rhodium on raney nickel substrate

The optimization of a novel anode for the production of hydrogen via an ammonia alkaline electrolytic cell is presented. The novel anode was prepared by electrodeposition and contains Raney nickel, platinum, and rhodium in its catalytic layer. The platinum and rhodium layers were optimized by considering their influences on reaction kinetics and characterization by scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. It was demonstrated through electrochemical analysis that platinum and rhodium realized a synergistic catalytic effect on the oxidation of ammonia, showing higher activity than Pt-only electrodes with comparable catalyst loading. Hydrogen was successfully produced from a 1 M NH3/5 M KOH solution at 14.54 Wh/g H-2 at a current density of 2.5 mA/cm(2) by an anode containing 1 mg/cm(2) Rh and 10 mg/cm(2) Pt at ambient temperature and pressure. (c) 2006 The Electrochemical Society.