Silver-Containing Metallo Hydrogel as a Nanocatalyst for Hydrogen Evolution

In recent years, non-noble-metal catalysts for hydrogen evolution have drawn significant attention. Silver (Ag) is more abundant in the Earth’s crust and relatively inexpensive, exhibits excellent thermal and electrical conductivity compared to other noble metals, and has rarely been considered as a potential electrocatalyst for hydrogen evolution. This piece of work demonstrates that a tripeptide-based amphiphilic gelator forms metallo hydrogels in the presence of metal ions such as Ag+, Ni2+, or Co2+ in phosphate buffer at pH 7.46. Morphological studies of metallogels reveal the nanofibrillar network structure. The silver-ion-containing metallogel can be photoreduced to form a hydrogel infused with silver nanoparticles and is confirmed by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) analysis. Interestingly, both the silver metallogel (Ag+) and the silver nanoparticle (Ag0) containing metallogel can catalyze hydrogen production from water. As a result, these silver nanoparticle-embedded nanofibers exhibit hydrogen evolution with an overpotential of 480 mV at a current density of 10 mA cm–2 having a Tafel slope of 252 mV dec–1, at a low electrochemical resistance in 0.5 M H2SO4 electrolyte, compared to other electrocatalysts under the same experimental conditions. Furthermore, this electrocatalyst has been witnessed to be highly stable during 2 h of chronoamperometric performance. This study highlights a promising avenue for utilizing a silver-containing metallo hydrogel as a nanocatalyst for water splitting, offering a clean and sustainable method for generating hydrogen as a green energy resource.