We studied the electrochemical synthesis of NH3 on Fe–CuS/C catalysts in an alkaline aqueous solution under ambient conditions. The metal chalcogenide catalyst is active in the nitrogen reduction reaction (NRR) for approximately 45 min with an NH3 production yield of 16 μg h–1 cm–2 at −0.4 V RHE, while it decomposes to CuO. The rapid degradation of the catalyst hinders the precise investigation of the NH3 production activity in longer time measurements. Herein, the electrochemical NH3 production rate is enhanced with increased overpotentials when the degradation effect is mitigated in the measurement, which was difficult to observe in the NRR reports. In the Tafel analysis, the exchange current density, heterogeneous rate constant, and transfer coefficient of the Fe–CuS/C catalyst on the NRR were estimated. When the electrode degradation is mitigated, one of the best NH3 production activities among the reported metal sulfide electrochemical NRR catalysts is obtained, which is 42 μg h–1 cm–2 at −0.6 VRHE.

Electrodeposited single-crystalline PbCrO4 microrods are highly active toward photoelectrochemical water oxidation.

Electrochemical water splitting is the most promising pathway to produce high-purity hydrogen to alleviate global energy crisis. This reaction demands inexpensive, efficient and robust electrocatalyst for its commercial use. Herein, we demonstrate an effective, facile and scalable method for the synthesis of cerium doped Ni3Fe nanostructures as an electrocatalyst for oxygen evolution reaction (OER) by following simple chemical bath deposition route. The different molar ratios (3, 6 and 12 mM) of cerium in the chemical bath were used to study its effect on the structural and the electrochemical properties of the Ni3Fe nanostructured films. Doping of cerium contents induced variations in the morphology of deposited Ni3Fe nanostructures. The optimized electrocatalyst Ni3Fe/Ce-6 yielded high surface area catalyst nanosheets uniformly deposited on three-dimensional conductive scaffold to ensure increase in the exposure of doped Ni3Fe catalytic sites with high electrical conductivity. As a result, this earth-abundant electrocatalyst affords high OER performance with a small overpotential of 310 mV versus reversible hydrogen electrode (RHE) at 10 mA cm-2 and retains good stability up to ~ 10 h in alkaline electrolyte. This scalable strategy has great potential in future advancement of efficient and low-cost electrocatalysts for their large-scale application in energy conversion systems.                     KEY WORDS: Oxygen evolution, Electrocatalyst, Ni3Fe nanostructures, Cerium, Alkaline electrolyte   Bull. Chem. Soc. Ethiop. 2020, 34(2), 353-363 DOI: https://dx.doi.org/10.4314/bcse.v34i2.12