CoS₂‑MoS₂ Nanoflower\nArrays for Efficient Hydrogen Evolution Reaction in the Universal\npH Range

Abstract

To\nexplore, highly active electrocatalysts are essential for water\nsplitting materials. Polyoxometalates (POMs) have drawn interesting\nattention in recent years due to their abundant structure and unique\nelectrocatalytic properties. In this study, by using a POM-based precursor\nCo2Mo10, novel bimetallic sulfide (CoS₂-MoS₂) nanocomposites are rationally designed and synthesized under hydrothermal\nconditions. The incorporation of Co²⁺ to the host electrocatalyst\ncould effectively increase the exposure of active sites of MoS₂. Compared to pure MoS₂, the CoS₂-MoS₂ nanocomposite exhibited a perfect hydrogen evolution reaction\n(HER) ability, for it merely requires overpotentials of 120 and 153\nmV for 10 mA cm^–2 working current density toward\nthe HER in 1 M KOH and 0.5 M H₂SO₄ electrolyte\nsystems, respectively. Additionally, the nanocomposite exhibited outstanding\nchemical stability and long-term durability. This study presents a\nnovel strategy that utilizes POMs to enrich the exposed edge sites\nof MoS₂, resulting in the preparation of efficient electrocatalysts.