Defect-rich MnxOy complex Fe–Ni sulfide heterogeneous electrocatalyst for a highly efficient hydrogen evolution reaction.

Designing earth-abundant hydrogen evolution reaction (HER) electrocatalysts with superior performance and eminent stability is the key to the practical production of high purity hydrogen. In the present work, Mn oxides with various valence state complex Fe–Ni sulfide (Mn x O y @FNS) heterogeneous materials were successfully fabricated through a feasible two-step hydrothermal process and can be directly used as active and efficient HER electrodes in alkaline media. This binder-free and defect-rich catalyst barely requires 105 and 365 mV to achieve −10 and −500 mA cm−2, respectively. Profiting from the disordered structure and the efficient interfacial effects between Mn oxides and Fe–Ni sulfide (FNS), this heterogeneous catalyst reveals sufficient electroactive sites, ample active edges and optimal electroconductivity. Additionally, during the 20 h HER reaction, the Mn x O y @FNS electrode exhibits outstanding durability. • Interlaced and plicated nanostructure provides sufficient exposed edge. • The disordered structure in Mn x O y @FNS afford plentiful electroactive sites. • This binder-free and defect-rich Mn x O y @FNS needs 105 to attain −10 mA cm−2. • This electrocatalyst exhibits excellent HER stability. [ABSTRACT FROM AUTHOR]