Substitution of Zinc(II) in Nickel(II) Oxide as Proficient Copper-Free Catalysts for Selective CO2 Electroreduction

In the present study, we have synthesized nanocrystalline Zn-substituted-NiO (Ni<inf>1-x</inf>Zn<inf>x</inf>O, where x = 0.05 and 0.1) catalysts by solution combustion method and utilized for CO<inf>2</inf> electroreduction. X-ray diffraction (XRD) and field-emission scanning electron microscopy coupled with energy-dispersive spectroscopy (FESEM-EDS) characterizations showed pure crystalline phase of NiO with bulk doping of Zn²⁺ over NiO lattices. Their ionic interaction and synergetic effect influences the redox electrochemistry of NiO. Zn substitution increases the hydrocarbon selectivity with FE% up to 47% for C<inf>2</inf>H<inf>4</inf> and CH<inf>4</inf> at-1.4 V. While ZnO alone is known to produce CO and NiO is inactive for CO<inf>2</inf> electroreduction. However, their solid solution reduces CO<inf>2</inf> with high efficiency and enhanced hydrocarbon selectivity due to Ni²⁺ and Zn²⁺ ionic interaction.