Bio-inspired NiO/ZrO2 mixed oxides (NZMO) for oxygen evolution reactions: from facile synthesis to electrochemical analysis

Official URL: https://dx.doi.org/10.1002/jctb.7246

Background: Earth's abundant natural materials can be exploited for their potential in producing economically viable and sustainable electrocatalysts for clean energy generation. Herein, we employed a low cost and environmentally benign synthesis approach using plant extract as capping agent to synthesize bimetallic NiO/ZrO2 (nickel/Zirconiu mixed oxides; NZMO), and then studied their electrocatalytic properties. Results: The synthesized material was characterized for its elemental, compositional and morphological feature elucidation. The phytocapping agents were probed by Fourier transform infrared spectroscopy (FTIR) and gas chromatography–mass spectroscopy (GC–MS) which confirmed the active contribution of phytocompounds in synthesis as capping and stabilizing agents. Elemental and X-ray photoelectron spectroscopic (XPS) analysis manifested the presence of Ni, Zr and O content with morphological elucidations representing well-defined structures. The synthesized material was systematically investigated for electrocatalytic performance towards an oxygen evolution reaction (OER). Electrochemical testing showed that the NZMO exhibits remarkable enhanced catalytic activity with 0.39 V overpotential value and 72 mV dec−1 Tafel value at an existing density of 10 mA cm−2, which is comparable to that of precious metal catalysts. Conclusion: Experimental investigation demonstrates that the remarkable OER performance of NZMO could be attributed to intrinsic catalytic properties originating as a result of binary materials. Moreover, the organic compounds involved in the synthesis mechanism also could be the major contributors in terms of provision of active sites due to protons. Thus, the present work presents a promising electrocatalytic material using mixed metal oxides and paves a novel path toward the green synthesis of binary oxides with improved electrocatalytic performance.