Ruthenium and cobalt bimetal encapsulated in nitrogen-doped carbon material derived of ZIF-67 as enhanced hydrogen evolution electrocatalyst

Abstract

Due to the high price and low reserve of platinum (Pt) base precious catalysts, and non-noble metal catalysts are unable to catch up with the overpotential of Pt-based electrocatalysts, more and more attention has been paid to study low-noble metal catalysts. In this work, we report a highly active and steady electrocatalyst with ruthenium and cobalt bimetal encapsulated in nitrogen-doped carbon material derived of ZIF-67. ZIF-67 was firstly calcined under vacuum to form nitrogen-doped carbon containing the cobalt particles, and then made Ru atoms partly replaced some Co atoms to prepare the ruthenium and cobalt bimetal catalyst. The electrocatalyst is prepared with low loading Ru (3.5 wt%) and has an excellent hydrogen evolution reaction (HER) catalytic performance in acidic and alkaline medium. It displays the overpotential of only 23 mV at 10 mA cm−2 in alkaline solution, which even exceeds commercial 20 wt% Pt/C catalyst. Besides, the current density of the electrocatalyst is only reduced by less than 10% after continuous operation of 10,000 s, indicating excellent durability.