Coal-Derived Carbon Support Regulates Interfacial Water Molecules toward Enhanced Alkaline Hydrogen Evolution on Platinum Nanoparticles.

Carbon-supported platinum (Pt) nanoparticles (NPs) are efficient electrocatalysts for the hydrogen evolution reaction (HER) but suffer from suboptimal kinetics in alkaline media. While restructuring interfacial water molecules offers a promising route to enhance alkaline HER, simple and effective strategies remain scarce. Here, we prepared Pt NPs on different carbon supports with varied compositions of oxygen-containing functional groups (OFGs) and explored the correlation between the HER activity and the OFG composition. Structural analyses confirm negligible effects of the support on the morphology, size, or electronic states of Pt NPs. However, in situ Raman spectroscopy reveals that OFGs, including carbonyl (C = O) and carboxyl (COOH) groups increase the proportion of interfacial free water molecules by reorganizing local hydrogen bonding. Meanwhile, a bituminous coal-derived carbon (bitu@C), featuring abundant OFGs, was developed as a functional support for Pt NPs. The Pt/bitu@C catalyst achieves a mass activity of 1.33 A mgpt -1 at an overpotential of 100 mV, significantly outperforming commercial carbon-supported counterparts, while exhibiting enhanced stability. This work highlights the critical role of OFGs in modulating water structures and provides a practical, coal-derived platform for engineering interfacial water molecules toward efficient alkaline HER kinetics.