Bio-Inspired FeMo₂S₄ Microspheres as Bifunctional Electrocatalysts for Boosting Hydrogen Oxidation/Evolution Reactions in Alkaline Solution

Abstract

Developing robust and effectual nonprecious electrocatalysts for the bifunctional hydrogen oxidation and evolution reactions (HOR and HER) in alkaline electrolyte is of critical significance for the realization of future hydrogen economy but challenging. Herein, this work demonstrates a new routine for the preparation of bio-inspired FeMo2S4 microspheres via the one-step sulfuration of Keplerate-type polyoxometalate {Mo72Fe30}. The bio-inspired FeMo2S4 microspheres feature potential-abundant structural defects and atomically precise iron doping and act as an effective bifunctional electrocatalyst for hydrogen oxidation/reduction reactions. The FeMo2S4 catalyst presents an impressive alkaline HOR activity compared to FeS2 and MoS2 with the high mass activity of 1.85 mA·mg–1 and high specific activity as well as excellent tolerance to carbon monoxide poisoning. Meanwhile, FeMo2S4 electrocatalyst also displayed prominent alkaline HER activity with a low overpotential of 78 mV at a current density of 10 mA·cm–2 and robust long-term durableness. Density functional theory (DFT) calculations indicate that the bio-inspired FeMo2S4 with a unique electron structure possesses the optimal hydrogen adsorption energy and enhanced adsorption of hydroxyl intermediates, which accelerates the potential-determining Volmer step, thus promoting the HOR and HER performance. This work provides a new pathway for designing efficient noble-metal-free electrocatalysts for the hydrogen economy.

Fire‐retardant and high‐strength polymeric materials enabled by supramolecular aggregates

“…[35] A presentative example of supramolecular aggregate by Hbonding self-assembly is melamine cyanurate (MCA), which is built by melamine (MEL) and cyanuric acid. [36] Araby and coworkers [37] reported that the addition of 5.0 wt% MCA can increase the tensile strength and toughness of thermoplastic polyurethane (TPU) by 8.3% and 2.7%, respectively, owing to the formation of H-bonds between TPU chains and MCA. Furthermore, MCA is also known as a recyclable and environmentally friendly fire retardant due to the high contents of N element within its structure.…”

“…To counter this challenge, MCA is usually employed to combine with other materials to construct more efficient fire retardant via H-bonding interactions. [39] Araby and coworkers [37] developed MCA@α-ZrP as a novel hybrid fire retardant for TPU. The addition of 5.0 wt% MCA@α-ZrP reduces the peak heat release rate (PHRR) and total heat release (THR) of TPU by 49.7%, and 12.6%, respectively.…”

A tailored polyoxometalate-derived RuW/g-C3N4-based electrocatalyst for enhanced hydrogen evolution reaction

“…22–24 Recently, various well-defined composites of POMs have been reported as efficient electrocatalysts 25–28 as well as precursors for the hydrogen evolution reaction (HER). 29–32 The studies revealed that the presence of POMs assisted in inducing activity in an otherwise inactive counterpart via a synergistic effect. POMs incorporated into a 2D-carbon matrix also exhibited enhanced activity in energy applications as compared to the parent materials.…”

Indispensable Nafion Ionomer for High-Efficiency and Stable Oxygen Evolution Reaction in Alkaline Media

“…In comparison to acidic electrolysis, liquid alkaline electrolysis is a more well-developed technology. Alkaline electrolysis is less costly as it employs non-noble-metal electrocatalysts such as Ni, Co, Fe, Mn, and Mo. − Additionally, compared to that in the alkaline medium, significant corrosion can be observed in an acidic medium.…”