Rapid solventless microwave preparation of small-size RuSe2@CNT catalysts: unlocking noble metal selenides for enhanced alkaline seawater hydrogen evolution

Ru-based catalysts represent promising Pt alternatives due to their decent hydrogen adsorption energy and cost advantages. However, their practical application is hindered by sluggish hydrogen evolution reaction (HER) kinetics and insufficient active site exposure in alkaline media. Herein, this work innovatively developed rapid solventless microwave heating method to synthesize small-size ruthenium selenide (RuSe 2 ) nanoparticles loaded on the carbon nanotube (CNT) surface. This microwave reaction accomplishes ultrafast transformation (100 s) to generate RuSe 2 nanoparticles (~ 3 nm in diameter), representing one of the fastest synthetic routes for transition metal selenides. By benchmarking the HER activity, RuSe 2 @CNT exhibits excellent activity in 1.0 M KOH, requiring an overpotential of 26 mV to achieve 10 mA cm − 2 , which is better than Ru@CNT (63 mV) and the commercial Pt/C (33 mV). Moreover, RuSe 2 @CNT exhibits outstanding HER activity with an overpotential of merely 66 mV at 10 mA cm − 2 , while demonstrating remarkable stability in natural alkaline seawater media. The demonstrated microwave selenization mechanism opens new possibilities for engineering ultrafine metal chalcogenides for marine energy applications.