High‐Performance Electrocatalysts for Hydrogen Evolution Reaction Using Flexible Electrodes Made up of Chemically Modified Polyester Films

Abstract

In this work we propose a simple methodology to fabricate monometallic nickel [Ni] and bimetallic silver‐nickel [Ag/Ni] deposited flexible, self‐supported electrodes using polyester (commonly used as overhead projector [OHP]) films. Monometallic Ni is deposited onto chemically modified OHP sheets using a simple electroless deposition process. Similarly bimetallic Ag/Ni coating is carried out by employing galvanic replacement reaction (GRR) of silver onto Ni coated polyester films. Structure, morphology, composition and crystalline phase characteristics of these monometallic and bimetallic deposited flexible electrodes are analyzed by using a variety of spectroscopic and microscopic techniques. Electrochemical characteristics corresponding to hydrogen evolution reaction (HER) are investigated by using linear sweep voltammetry (LSV), Tafel polarization and impedance spectroscopic studies. Effect of time duration associated with GRR on the structural morphology of resultant deposits and on their HER electrocatalytic activity is also investigated. These studies reveal that compared to monometallic Ni, bimetallic Ag/Ni deposited flexible electrodes exhibit enhanced electrocatalytic performance for HER due to strong synergistic effect of bimetallic heterostructures. Among the various electrodes investigated, bimetallic Ag/Ni coated flexible polyester films obtained through 5 minutes of GRR show a higher electrocatalytic activity for HER. These results provide a platform towards the development of alternative electrodes for HER using simple and affordable techniques that play a significant role for further advancement of alkaline water electrolysis.

Galvanic replacement reaction to prepare catalytic materials

“…Furthermore, the surfactants such as sodium dodecyl sulfate (SDS), t‐octyl phenoxy poly ethoxy ethanol (Triton X‐100), and cetyl trimethyl ammonium bromide (CTAB) increased the current density of HER, with SDS providing the highest HER activity of Pd–Cu bimetallic NPs. Thota et al reported that the HER activity of the bimetallic Ag/Ni heterostructures deposited on a flexible polyester film (overhead projector, OHP) could be optimized by varying the GRR time, resulting in different surface morphologies and varied ratios of silver and nickel within the deposit 101 . Compared to the monometallic Ni/OHP and Ag/OHP electrodes, the Ag/Ni/OHP electrodes prepared through 5 min of GRR exhibited the lowest onset potential of −75 mV.…”

“…Thota et al reported that the HER activity of the bimetallic Ag/Ni heterostructures deposited on a flexible polyester film (overhead projector, OHP) could be optimized by varying the GRR time, resulting in different surface morphologies and varied ratios of silver and nickel within the deposit. 101 the electrodeposited Co(OH) 2 was increased, the corresponding sample exhibited slower kinetics and increased charge transfer resistance.…”