Size effect of Rhodium nanoparticles supported on carbon black on the performance of hydrogen evolution reaction

Carbon black lacks nucleation sites on its surface, leading to poor stability of the loaded metallic nanoparticles. With an aim to modulate the metallic nucleation or the growth of metal nanoparticles, the CoP nanoparticles are served as the bridge to deposit Rhodium (Rh) nanoparticles on carbon black in this work. These on-site deposited Rh nanoparticles are uniform and feature controllable sizes. Their size effect on the performance of hydrogen evolution reaction (HER) is then revealed. The Rh nanoparticles with a size of ∼3.23 nm shows excellent HER activity such as the overpotential of only 3 mV at a current density of 10 mA cm−2, far surpassing other reported Rh-based catalysts. The integrated anion exchange membrane water electrolysis system using this catalyst delivers a cell voltage of 1.81 V at a current density of 1 A cm−2 and a charge transfer resistance of 0.299 Ω at 60 °C, which are smaller than those (1.84 V and 0.337 Ω) obtained using a commercial 20 wt% Pt/C-JM catalyst. This work provides a facile strategy to control the size of metallic nanoparticles with high dispersion on the intrinsic surface of carbon black for the design of advanced HER electrocatalysts.