Transition Metal Ruthenium-Loaded Nitrogen-Doped Mesoporous Carbon as an Efficient Hydrogen Evolution Catalyst

Ruthenium-supported nitrogen-doped mesoporous carbon, referred to as Ru/NC-T (with T indicating the pyrolysis temperature), was prepared via a strategically designed combination of hydrothermal treatment and subsequent pyrolysis, with the objective of producing an electrocatalyst exhibiting high activity and stability for the hydrogen evolution reaction (HER). In this synthesis, p-phenylenediamine-a small organic molecule characterized by high nitrogen content and excellent solubility in absolute ethanol-served simultaneously as the nitrogen source and a coordinating ligand. It forms stable complexes with ruthenium, which subsequently undergo polymerization with formaldehyde to yield a uniform metal-organic coordination polymer. This polymeric precursor ensures a homogeneous distribution of ruthenium species and introduces abundant nitrogen functionalities into the carbon framework upon pyrolysis. Extensive structural analyses, including X-ray diffraction (XRD), transmission electron microscopy (TEM), and nitrogen adsorption-desorption measurements, indicated that the resulting Ru/NC-T materials exhibit a well-developed mesoporous structure with high specific surface area, finely dispersed ruthenium nanoparticles, and controllable nitrogen doping levels. Such features facilitate efficient mass and electron transport and provide numerous accessible active sites, which are essential for enhanced catalytic performance. Electrochemical tests revealed that the Ru/NC-T catalysts demonstrate outstanding HER performance in acidic environments, characterized by low overpotentials, high current densities, and excellent long-term durability. The synergistic interaction between ruthenium nanoparticles and the nitrogen-doped carbon matrix, along with the electronic modulation imparted by different nitrogen species, plays a key role in boosting catalytic efficiency. This work offers valuable guidance for the rational design of high-performance transition metal-based electrocatalysts, emphasizing the significance of controlled metal-nitrogen coordination, mesoporous architecture, and electronic structure tuning. Moreover, the facile synthesis route presented here is versatile and can be adapted to other noble or non-noble metal systems, providing a promising strategy for developing efficient, durable, and cost-effective electrocatalysts for sustainable hydrogen generation.