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

Abstract

The presence of multiple active sites and hetero-junction on a multicomponent hetero-structured catalyst would exhibit modest hydrogen binding strength and charge transfer, as well as redistribution during interaction withthe 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 underalkaline environment. Preformed NixB seed and Fe3O4 phases were codeposited on a g-CN layer. Post-catalytic characterization studies indicatedfacet 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 studyshowed almost unaltered current density over ~50h at 150 mV, only 7.0%current loss over 50h. The reactivity and stability can be attributed to the synergistic interaction within metal centers and the carbon support with a largesurface area.