Improved kinetics of reduction of alkaline water on the g‐CN‐supported transition metal oxide/boride hetero‐interface: A case study

• Published in: International journal of energy research Vol. 46; no. 11; pp. 14979 - 14993
• Main Authors: Jana, Jayasmita, Nivetha, Ravi, Diem, Huynh Ngoc, Van Phuc, Tran, Kang, Sung Gu, Chung, Jin Suk, Choi, Won Mook, Hur, Seung Hyun
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Inc 01-09-2022; Hindawi Limited
• Subjects: Alkaline water; Carbon; Carbon nitride; Catalysts; Charge transfer; Composite materials; Current density; Current loss; Electrode materials; Heavy metals; hydrogen evolution reaction; Intermediates; Iron oxides; Kinetics; multi‐valent iron oxide; Nickel; nickel boride; ternary composite; Transition metal oxides; water splitting kinetics
• ISSN: 0363-907X; 1099-114X
• DOI: 10.1002/er.8198

Summary
The presence of multiple active sites and hetero‐junction on a multi‐component hetero‐structured catalyst would exhibit modest hydrogen binding strength and charge transfer, as well as redistribution during interaction with the intermediates during the water reduction process. In this study, we synthesized a ternary iron oxide/nickel boride/graphitic carbon nitride (Fe3O4/NixB/g‐CN) composite as the electrode material for the reduction of water under alkaline environment. Preformed NixB seed and Fe3O4 phases were co‐deposited on a g‐CN layer. Post‐catalytic characterization studies indicated facet selective reactive sites for NixB and Fe3O4 during the reduction of water. The composite required 130 mV overpotential for 10 mA cm−2 current density. The Tafel slope value of 99 mV dec−1 indicated that the adsorption step might determine the rate of reaction. The long‐term chronoamperometric study showed almost unaltered current density over ~50 h at 150 mV, only ~7.0% current loss over 50 h. The reactivity and stability can be attributed to the synergistic interaction within metal centers and the carbon support with a large surface area.