Multi‐Interface‐Modulated CoS 2 @MoS 2 Nanoarrays Derived by Predesigned Germanomolybdate Polymer Showing Ultrahighly Electrocatalytic Activity for Hydrogen Evolution Reaction in Wide pH Range

Abstract The development of non‐noble metal materials for efficient hydrogen evolution reaction (HER) in wide pH range is still a challenge at present. Herein, a predesigned polyoxometalate (POM)‐based metal–organic polymer {L 3 Co 2 · 6H 2 O}[H 3 GeMo 12 O 40 ] · 9H 2 O (L = 1,2,4‐triazole) is employed as bimetallic source together with thiourea converting to CoS 2 @MoS 2 on carbon cloth (CC) (abbreviated to CoS 2 @MoS 2 @CC) for the first time. Impressively, the CoS 2 @MoS 2 in the form of vertically interconnected nanoarrays with multiple interfaces are grown in situ on CC and act as electrodes directly for HER. The CoS 2 @MoS 2 @CC‐30h composite exhibits superb activity and long‐durability in both acidic and alkaline media. Low overpotential is achieved in 0.5 m H 2 SO 4 (65 mV) and 1.0 m KOH (87 mV) for 10 mA cm −2 versus RHE, which overmatch major MoS 2 ‐/POM‐based electrocatalysts. This work therefore may shed substantial lights on designing active and durable molybdenum‐based bi‐/polymetallic sulfide from variable POM‐based metal–organic polymers for electrocatalytic hydrogen evolution reaction in wide pH range.