Ag-Embedded Laser-Induced Graphene as a Catalyst for the Oxygen Reduction Reaction in Alkaline Media.

Abstract

Oxygen reduction reaction (ORR) is a critical process in fuel cells, yet its slow kinetics necessitates efficient and cost-effective catalysts. Anion exchange membrane fuel cells (AEMFCs) offer a promising platform for ORR electrocatalysis, as the alkaline environment enables the use of non-precious metals and carbonaceous materials. Herein, we utilize a simple, solid-state, reagent-free, and one-step synthesis of silver nanoparticle-decorated laser-induced graphene (Ag@LIG) via direct CO₂ laser writing on a polyimide film coated with an edible silver leaf. The laser treatment simultaneously converts the polymer into a porous three-dimensional graphene network and incorporates metallic silver nanoparticles (∼5-50 nm) into the carbon matrix. X-ray photoelectron spectroscopy confirms the metallic nature of the incorporated silver and reveals a higher nitrogen content in Ag@LIG than in pristine LIG, with pyrrolic nitrogen as the dominant configuration. Electrochemical characterization demonstrates that Ag@LIG exhibits enhanced ORR activity compared to pristine LIG, with a ∼30 mV positive shift in onset potential and a predominantly four-electron pathway over the entire potential range, with low peroxide formation. This work highlights the potential of the solid-state laser approach for producing Ag-carbon hybrid electrocatalysts with promising ORR performance for alkaline fuel cells.