Phenanthrenequinone-like moiety functionalized carbon for electrocatalytic acidic oxygen evolution

Developing a cheap, efficient, and stable oxygen evolution reaction (OER) material becomes the bottleneck of large-scale hydrogen production in acidic electrolytes. The design of high-efficiency anode materials largely relies on the accurate identification of active species. Here, we transform cheap graphite flake (GP) into phenanthrenequinone (PQ)-like moiety functionalized graphite (MEO-GP) via a mild electrochemical oxidation (MEO) treatment. MEO-GP exhibits superior acidic OER performance with an overpotential of 270 mV at 10 mA cm−2, outperforming other oxygen-containing groups of functionalized graphite. The combined results from multiple characterizations reveal that PQ-like moiety is the most active species for acidic OER. Theoretical calculations demonstrate that PQ-like moiety can significantly reduce reaction energy of the rate-determining step (O∗ to OOH∗) of OER by decreasing the adsorption energy of O∗, leading to the smallest theoretical overpotential of PQ-like moiety. This work provides molecular insight into the structural transformation of carbon materials under electrooxidation conditions.