Influence of Ni2+ on OER kinetics and photoluminescence properties of ZnSnO3 nanoparticles

Abstract

Ni2+ doped ZnSnO3 nanoparticles (NPs) were synthesized using Aloe vera mediated solution combustion method, followed by an investigation into their luminescence and oxygen evolution reaction properties. The Bragg reflections of ZnSnO3: Ni(1–9 mol%) NPs revealed a cubic structure, with the addition of the dopant inducing lattice strain and resulting in peak shifting towards higher angles. No impurity-related peaks were observed. The estimated crystallite size and optical band gap decrease (3.1–2.94 eV) with an increase in dopant concentration. The surface morphology consists of irregular-sized and shaped NPs with hallows. The EDAX spectra show the purity of the sample. Photoluminescence emission spectra were recorded at a 230 nm excitation wavelength, where intense blue emission observed at 482 nm was attributed to a direct transition between the conduction band edge and the valence band edge, corresponding to the direct recombination of free excitons. Another satellite peak observed at 525 nm can be attributed to oxygen deficiency. Moreover, the nanoparticles exhibited outstanding performance in oxygen evolution reaction studies, showing low over potentials between 300 and 318 mV, a minimal Tafel slope of range 63–72 mV dec−1, and stable electrochemical behavior over 12 h at a current density of 23 mA/cm2. These results highlight their effectiveness as electrocatalysts.