Poly(benzoquinone-pyrrole)-MoS2─A Class of 2D Organic–Inorganic Hybrid Layered Catalysts for Electrochemical Hydrogen Generation

Abstract

Hydrogen is attractive as a clean fuel as it can be produced directly from water and electricity (electrochemical hydrogen evolution reaction, one of the half-cell reactions in water electrolyzers) and creates the same products (water and electricity) when utilized in a fuel cell. Electrocatalysts are often used to accelerate the kinetics of these reactions, which led to a bloom in the field of electrocatalyst research to search for an efficient, stable, and cost-effective material. Hybrid organic–inorganic 2D electrocatalysts are presented in the current studies, which were prepared by combining two different class of 2D-layered materials: poly(benzoquinone-pyrrole) polymer (BQ-Py polymer) as the organic counterpart and MoS₂ as the inorganic counterpart. The hybrid composite catalysts (named BQ-Py-MoS₂_NS_US and BQ-Py-MoS₂_hyd) exhibit efficient HER activities with high durability in both acidic (aqueous 0.5 M H₂SO₄) and simulated seawater (3.5 wt % of aqueous NaCl) solutions. The studies also reveal some kinetic parameters for electrochemical HER, where it is observed that only 100 mV of extra overpotential is required for the hydrothermally formed hybrid composite to achieve 10 mA cm^–2 of current density as compared to the state-of-the-art HER catalyst (40 wt % Pt–C). This opens up an avenue to develop organic–inorganic hybrid composite catalysts for various electrochemical reactions.