Ultrasmall Rh nanoparticles decorated on carbon nanotubes with encapsulated Ni nanoparticles as excellent and pH-universal electrocatalysts for hydrogen evolution reaction

摘要

Synthesis of Rh-based material with low loading as efficient and pH-universal electrocatalyst for hydrogen evolution reaction (HER) remains challenging. Here, ultrafine and well-dispersed Rh nanoparticles (NPs) (1.92 nm in diameter) were synthesized and fixed on nitrogen (N)-doped carbon nanotubes with encapsulated nickel NPs (Rh/Ni@NCNTs) by a simple and sustainable strategy without any organic solvents, capping agents, and reducing agents. Rh/Ni@NCNTs with a low Rh loading of 2.84 wt% exhibited an outperforming catalytic activity with overpotentials of 14, 26, and 45 mV at 10 mA cm(-2) in 1.0 M KOH, 1.0 M PBS, and 0.5 M H2SO4, respectively. Moreover, Rh/Ni@NCNTs displayed a high turnover frequency (TOF) of 1.67 s(-1) at 100 mV in alkaline solution. The high HER performance should be attributed to the catalytically active nature of metal Rh, unique structure characteristics of Ni@NCNTs induced positive synergistic effects with the anchored Rh NPs, and metal Ni promoted N-rich feature of Rh/Ni@NCNTs. The NCNTs with ultrathin wrinkle graphitic carbon walls could efficiently wrap the as-synthesized ultrasmall Rh NPs, prohibiting their aggregations and leading to high stability and durability of Rh/Ni@NCNTs. The present study may open a new frontier for preparing high-dispersed and high-active HER catalyst.