LAUSR

Abstract Electrochemical hydrogen evolution reaction (HER) is a promising route to harvest high-purity hydrogen (H2). Efficient and selective energy transformations rely on the development of novel catalytic materials in terms of compositions and structures that survive under harsh conditions. This study focuses on a unique nanostructured CoMoS3 catalyst for HER under strong acidic and basic electrolyte. The morphologies of the catalysts are fine-tuned by altering reaction times in a hydrothermal reaction. Limited reaction time generates twisted thin-sheet CoMoS3 (12 h), which spins into a nanotube with an extended synthetic time (16 h). As the reaction time increases to 20 h, the CoMoS3 composite creates open-ended nanotubes, facilitating reactants to penetrate and react actively in the inner space of the nanotubes. Further, prolonged reaction time (24 h) results in the formation of the close-ended CoMoS3 nanotubes. We find out that the open-ended structure plays an important role in achieving fast kinetics as well as creating more active sites in HER reaction. The catalyst delivers a profound performance under both acidic and basic conditions, with overpotentials of 93 mV and 115 mV (at a current density of 10 mA/cm2) in the acidic and basic electrolytes, respectively. Moreover, it shows superior long-term durability in both solutions. This work will provide a great foundation for understanding the morphology effect with the same composited catalyst towards energy conversion reactions, not limited to HER.