In Situ-Fabricated Hydrogel Polymer - Semiconductor Nanocomposite Thin Film as a Highly Efficient and Robust Electrocatalyst for Hydrogen Evolution Reaction

Abstract

Development of simple and facile protocols for the fabrication of highly efficient and robust catalytic electrodes for water splitting reactions is of paramount interest in establishing clean energy generation strategies. We show that hydrogel polymer thin films, in spite of their insulating character, enable a unique solution of wide scope, combining the ease of in situ fabrication of the electrocatalyst and efficient application. RuO2 nanoplates are generated within thin films of poly(hydroxyethyl methacrylate) (PHEMA) spin-cast on Ni foam, through mild thermal annealing. RuO2-PHEMA affects efficient hydrogen evolution reaction (HER) in an alkaline medium, with a very low overpotential of 30 mV at a current density of 10 mA cm-2 and stability for 24 h at 40 mA cm-2 Faradaic efficiency is 99.6%, and the turnover frequency is 24.2 s-1 at 100 mV overpotential. Experiments with a range of polymers establish a clear correlation between the swelling characteristic of the polymer and the overpotential for HER. Efficient water splitting using a cell with both electrodes based on polymer-semiconductor nanocomposite thin films is also demonstrated. The novel catalytic electrode design offers abundant scope for developing cost-effective and scalable strategies for the generation of hydrogen fuel.