International Journal of Hydrogen Energy, Vol.44, No.2, 605-617, 2019
Nano P zeolite modified with Au/Cu bimetallic nanoparticles for enhanced hydrogen evolution reaction
In the present study, the excellent catalytic performance of Au/Cu bimetallic nanoparticles based on nano P zeolite modified carbon paste electrode (Au/Cu-NPZ-CPE) as one of the most promising electrocatalyst toward hydrogen production is introduced. Herein, nano P zeolite is synthesized by using agriculture residues, stem sweep ash with purity approximately 80.205 wt% of SiO2 which provides attractive economically silica source for the preparation of inexpensive zeolite. For the preparation of Au/Cu-NPZ-CPE, ion exchange protocol followed by galvanic replacement reaction was employed to result Au/Cu embedded zeolite framework. By evaluating the electrocatalytic activity of proposed catalyst with linear sweep voltammetry and Tafel polarization, a low overpotential of 100 mV and high exchange current density (2.51 mA cm(-2)) are demonstrated which compares favorably to most previously reported electrocatalysts for hydrogen evolution reaction. Owing to the inherent porosity of synthesized nano P zeolite, it successfully prevents the aggregation of bimetallic nanoparticles which promotes the hydrogen evolution reaction. Particularly, low Tafel slope for offered catalyst (33 mV dec(-1)) demonstrates the acceleration of hydrogen evolution reaction kinetics owing to the increase in the number of accessible active sites. Tafel slope of Au/Cu-NPZ-CPE is 3, 5, 6, 6.5 and 7 times lower than that for Au-NPZ-CPE, Cu-NPZ-CPE, Au/Cu-CPE, NPZ-CPE and CPE, respectively, which shows the best electrocatalytic activity among other modified carbon paste electrodes. Furthermore, the corresponding long term stability test by chronoamperometry method indicates that the current density reaches to nearly 91% of its primary value (after 5500 s) which provides the favorable practical demands of the catalyst in hydrogen production. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.