Unraveling the Function of Metal-Amorphous Support Interactions in Single-Atom Electrocatalytic Hydrogen Evolution.

Amorphization of the support in single-atom catalysts is a less researched concept for promoting catalytic kinetics through modulating the metal-support interaction (MSI). We modeled single-atom ruthenium (Ru ) supported on amorphous cobalt/nickel (oxy)hydroxide (Ru-a-CoNi) to explore the favorable MSI between Ru and the amorphous skeleton for the alkaline hydrogen evolution reaction (HER). Differing from the usual crystal counterpart (Ru-c-CoNi), the electrons on Ru are facilitated to exchange among local configurations (Ru-O-Co/Ni) of Ru-a-CoNi since the flexibly amorphous configuration induces the possible d-d electron transfer and medium-to-long range p-π orbital coupling, further intensifying the MSI. This embodies Ru-a-CoNi with enhanced water dissociation, alleviated oxophilicity, and rapid hydrogen migration, which results in superior durability and HER activity of Ru-a-CoNi, wherein only 15 mV can deliver 10 mA cm , significantly lower than the 58 mV required by Ru-c-CoNi.