High photocatalytic performance for hydrogen production under visible light on the hetero-junction Pani-ZnO nanoparticles

The present work is devoted to the preparation of the hetero-junction of Polyaniline-Zinc oxide nanoparticles (Pani-ZnONps) and its photo-electrochemistry to assess its photo catalytic properties for the water reduction into hydrogen. The semiconducting characterization of the Pani-ZnONps synthetized by in situ chemical oxidative polymerization was studied for the hydrogen evolution reaction (HER) upon visible light illumination. The forbidden bands E-g (= 1.64 eV, Pani) and (3.20 eV, ZnONPS) were extracted from the UV-Visible diffuse reflectance data. The Electrochemical Impedance Spectroscopy (EIS) showed the predominance of the intrinsic material with a bulk impedance of 71 kU cm(2). The semi conductivity was demonstrated by the capacitance measurements with flat band potentials (E-fb = 0.7 and 0.3 V-SCE) and carriers concentrations (N-A = 1.77 x 10(19) and N-D = 4.80 x 10(20) cm(-3)) respectively for Pani and ZnONPS. The energetic diagram of the hetero-junction Pani-ZnONps predicts electrons injection from Pani to ZnONPS in KOH electrolyte. An improvement of 78% for the evolved hydrogen was obtained, compared to Pani alone; a liberation rate of 61.16 mmol g(-1) min(-1) and a quantum yield of 1.15% were obtained. More interestingly, the photoactivity was fully restored after three consecutive cycles with a zero-deactivation effect, indicating clearly the reusability of the catalyst over several cycles. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study focuses on the preparation of the Pani-ZnONps hetero-junction for photo catalytic water reduction into hydrogen. The results show that Pani-ZnONps exhibits good photo catalytic performance under visible light illumination and demonstrates excellent reusability.