Anion assisted completely reconfigured manganese oxides with optimal proton adsorption for boosting acidic hydrogen evolution reaction

The optimal proton adsorption design of non-noble metal based catalysts is critical to the realization of efficient hydrogen evolution reactions (HER) in acidic media, but it is also challenging. Herein, sulfur anion-assisted completely reconfigured MnOx (R-S-MnOx-CC) with self-supported nanostructure was prepared on carbon cloth by in situ phase transformation method. The reconfiguration process results in spinel-structured Mn3O4 which can enhance charge transport and expose more active sites through charge disproportionation. The theoretical calculation indicates that the reconfiguration can increase the electron state density of the Mn d band near the Fermi level, promote the right shift of the d-band center, enhance the electron transport capacity of the catalyst to achieve the optimal H+ adsorption. The R-S-MnOx-CC catalyst has excellent acidic HER performance with an overpotential of only 43 mV and 234 mV at 10 mA cm−2 and 400 mA cm−2, respectively, a low charge transfer resistance Rct (0.29 Ω) and stably maintained for 100 h without decay (∼300 mA cm−2). This strategy provides a feasible way to design efficient and stable non-noble metal-based electrocatalysts for the HER industrialization of proton exchange membrane (PEM) water electrolyzers.