Synergistic phase and crystallinity engineering in cubic RuSe2 catalysts towards efficient hydrogen evolution reaction

The rational design and synthesis of electrocatalysts for hydrogen evolution reaction (HER) remain great challenges. Herein, cubic RuSe2 (c-RuSe2) electrocatalysts with different 1T phase ratios (ranging from 20.53% to 64.97%) and crystallinities (ranging from 1.72% to 89.10%) were developed by a fast and efficient microwave-assisted synthesis method. Remarkably, the c-RuSe2 calcined at 500 °C (RuSe2-500) with 45.46% 1T phase and 86.75% crystallinity exhibited a small overpotential of 29 mV at 10 mA cm−2 and a Tafel slope of 64 mV dec−1, close to the commercial Pt/C (31 mV, 53 mV dec−1) and better than most of the reported materials. The enhanced performance of RuSe2-500 could be attributed to the crystallinity, and the 1T phase content reached a certain equilibrium at 500 °C. Moreover, RuSe2-500 had the smallest charge transfer resistance, mainly due to its abundant active centers and excellent conductivity brought by the 1T phase, which were in favor of the HER kinetics and catalytic performance. This study explored the relationship between the ratio of the 1T phase and crystallinity in c-RuSe2, and gives a new pathway to improve the activity by synergistic regulation.