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. RuO 2 nanoplates are generated within thin films of poly(hydroxyethyl methacrylate) (PHEMA) spincast on Ni foam, through mild thermal annealing. RuO 2 -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 costeffective and scalable strategies for the generation of hydrogen fuel.

An In Situ Fabricated Hydrogel Polymer – Palladium Nanocomposite Electrocatalyst for the HER: Critical Role of the Polymer in Realizing High Efficiency and Stability

“…We have demonstrated earlier, a facile and simple in situ protocol for the generation of Pd nanowires inside a polymer thin film; [19] the process involved the reduction of Pd 2+ precursor by the hydroxyl groups on the poly(vinyl alcohol) matrix and a crystal‐to‐crystal transformation. The advantages of using insulating, but hydrogel polymer thin films for the encapsulation of electrocatalyst nanoparticles, and the high efficiency and stability of the resulting nanocomposite based catalytic electrode for the water splitting reactions, have also been reported from our laboratory [20,21] . Swelling of the hydrogel and confinement of the aqueous electrolyte within it are the key factors behind the utility of these matrices, opening up extensive options of nanocatalyst‐polymer combinations for the working electrodes, and overcoming the otherwise singular choice of Nafion as the binder [22,23] .…”

“…The advantages of using insulating, but hydrogel polymer thin films for the encapsulation of electrocatalyst nanoparticles, and the high efficiency and stability of the resulting nanocomposite based catalytic electrode for the water splitting reactions, have also been reported from our laboratory. [20,21] Swelling of the hydrogel and confinement of the aqueous electrolyte within it are the key factors behind the utility of these matrices, opening up extensive options of nanocatalyst-polymer combinations for the working electrodes, and overcoming the otherwise singular choice of Nafion as the binder. [22,23] We have also shown recently that the polymer matrix can play an active role in enhancing the electrocatalytic efficiency through an optimal redox cycling; however, no in situ synthesis of the nanocatalyst could be exploited in that work on a Prussian Blue analogue -chitosan nanocomposite (KCoFe-CS), and the final overpotentials obtained were modest.…”

Hydrogel Polymer–PBA Nanocomposite Thin Film-Based Bifunctional Catalytic Electrode for Water Splitting: The Unique Role of the Polymer Matrix in Enhancing the Electrocatalytic Efficiency

“…We have demonstrated the proof of concept of using hydrogel polymerbased nanocomposites in this context; 23 though electrically insulating, the polymer matrix swells confining the electrolyte within, leading to efficient electrocatalysis. 24 In order to probe the wider scope of this concept and additional advantages of the polymer matrix, we have now explored the effectiveness of catalytic electrodes based on the nanocomposite thin films of PBAs and hydrogel polymers coated on suitable conducting substrates, in the HER and OER reactions. A matter of specific interest is to probe the potential utility of the polymer in exploiting the well-known propensity of PBAs to form hollow and framework structures, 25−28 which could further promote the electrocatalytic activity.…”

“…However, for catalytic electrode fabrication, the choice in terms of the polymer has been largely limited to Nafion. , It is therefore critical to explore alternate options that can reduce the cost, enhance the stability, and expand the scope of application. We have demonstrated the proof of concept of using hydrogel polymer-based nanocomposites in this context; though electrically insulating, the polymer matrix swells confining the electrolyte within, leading to efficient electrocatalysis . In order to probe the wider scope of this concept and additional advantages of the polymer matrix, we have now explored the effectiveness of catalytic electrodes based on the nanocomposite thin films of PBAs and hydrogel polymers coated on suitable conducting substrates, in the HER and OER reactions.…”

Core-Shell AgNWs@Ni(OH)2 Nanowires Anchored on Filter Paper for Efficient Hydrogen Evolution Reaction

“…[6][7][8][9][10][11] Electrochemical water splitting is widely perceived as a promising technology for industrializing hydrogen production in the future. 12,13 The process of electrochemical water splitting consists of hydrogen evolution reaction (HER) at the cathode and oxygen evolution reaction (OER) at the anode. 14 It is known that platinum (Pt) and Pt-based materials are the most effective electrocatalysts for the HER.…”