Amorphous-crystalline porous ruthenium selenide as highly efficient electrocatalysts for alkaline hydrogen evolution

Transition metal chalcogenides have garnered considerable attention as high-performance electrocatalysts for the hydrogen evolution reaction (HER). Enriching their structural properties through constructing a porous architecture and creating crystalline-amorphous interfaces holds promise for enhancing HER performance. In this study, porous RuSe2 electrocatalysts with varying crystallinities (i.e., amorphous, amorphous-crystal, and crystal) were synthesized using a straightforward hydrothermal method followed by a subsequent annealing process. Comparable experiments indicate that porous RuSe2-400°C, featuring a crystalline-amorphous structure, exhibited enhanced catalytic activity compared to its amorphous and crystalline counterparts. The porous architecture and interfacial sites between crystalline and amorphous phases in RuSe2-400°C not only integrate the critical factors of abundant unsaturated coordination sites and good electrical conductivity but also modify its surface electronic state, which can optimize the adsorption energies of reaction intermediates. As a result, the optimized samples displayed remarkable HER activity in an alkaline medium, showcasing an extremely low overpotential of 27 mV at 10 mA cm-2 and a Tafel slope of 39.8 mV dec-1. This study provides a platform for rationalizing high-perform porous electrocatalysts with rich amorphous/crystalline interfaces.