Rare earth elements induced electronic engineering in Rh cluster toward efficient alkaline hydrogen evolution reaction

The unique electronic and crystal structures of rare earth metals (RE) offer promising opportunities for enhancing the hydrogen evolution reaction (HER) properties of materials. In this work, a series of RE (Sm, Nd, Pr and Ho)-doped Rh@NSPC (NSPC stands for N, S co-doped porous carbon nanosheets) with sizes less than 2 nm are prepared, utilizing a simple, rapid and solvent-free joule-heat pyrolysis method for the first time. The optimized Sm-Rh@NSPC achieves HER performance. The high-catalytic performance and stability of Sm-Rh@NSPC are attributed to the synergistic electronic interactions between Sm and Rh clusters, leading to an increase in the electron cloud density of Rh, which promotes the adsorption of H⁺, the dissociation of Rh-H bonds and the release of H₂. Notably, the overpotential of the Sm-Rh@NSPC catalyst is a mere 18.1 mV at current density of 10 mAcm^-2, with a Tafel slope of only 15.2 mV dec^-1. Furthermore, it exhibits stable operation in a 1.0 M KOH electrolyte at 10 mA cm^-2 for more than 100 h. This study provides new insights into the synthesis of composite RE hybrid cluster nanocatalysts and their RE-enhanced electrocatalytic performance. It also introduces fresh perspectives for the development of efficient electrocatalysts.