Asymmetrical Nd-O-Ru bridge active sites boost hydrogen evolution at large current densities

The development of hydrogen evolution reaction (HER) catalysts that combine high activity with high current density stability is an important step in promoting the scale-up preparation of green hydrogen in anion exchange membrane water electrolyzer (AEMWE). In this paper, we propose an asymmetrical “Nd−O–Ru” bridge active sites strategy in the rapid construction of rare earth metal oxides (M x O y , M = Nd, Ce) and ruthenium heterojunctions (M x O y @Ru/CNT, CNT stands for carbon nanotube) catalysts by a solvent-free microwave method. Experiments show that the catalyst exhibits excellent HER performance in alkaline media: driving 10 mA cm −2 and 1000 mA cm −2 only requires ultra-low overpotentials of 20 mV and 363 mV, and operates stably for 100 h at 1000 mA cm −2 . The combination of in situ Raman spectroscopy and theory calculations reveals that the p orbital of oxygen at the interface acts as an electronic bridge to mediate the coupling of the f orbital of Nd to the d orbital of Ru through “Nd−O–Ru” bridge enhancing the adsorption of water molecules while synergistically optimizing the free energy of hydrogen adsorption (ΔG H∗ ) and accelerating the kinetics of hydrolysis dissociation. Integrating this catalyst into the AEMWE yields current densities of 500 and 1000 mA cm −2 at voltages of 1.665 V and 1.806 V, respectively, thus offering a novel material design paradigm for industrial-scale water electrolysis. This study opens a new path for rational design of efficient energy conversion catalysts through orbital coupling engineering.