Nickel centered metal-organic complex as an electro-catalyst for hydrogen evolution reaction at neutral and acidic conditions

In this study, we report the development of dihydropyrimidines substituted nickel electro-catalyst at mild conditions for hydrogen evolution reaction. The Biginelli type reaction was carried out to produce 4-(4-chlorophenyl)-3,4,5,6-tetrahydrobenzo[h]quinazoline-2(1H)-thi-one moiety. This was added with NiCl2 center dot 6H(2)O to synthesize Ni-quinazoline-2(1H)-thione catalyst. The prepared catalyst was characterized using UV-Vis, FT-IR, Mass, H-1 and C-13 NMR and SEM-EDX spectroscopy. It showed an excellent hydrogen evolution reaction (HER) activity. LSV polarization showed a low Tafel slope (34 mV/dec) nearly close to Pt/C (28 mV/dec) in neutral medium whereas a Tafel slope of 100 mV/dec was observed with 0.5M H2SO4 while Pt/C showed 50 mV/dec. Electrochemical impedance spectroscopy measured by applying -1.18 V in neutral medium showed two depressed semicircles whereas with 0.5M H2SO4 and -1.45 V applied voltage single half was observed. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.