Modulation of hydrogen evolution reaction (HER) activity in palladium catalyst through surface functionalization of carbon support

This study explores the use of interface engineering to develop efficient and stable electrocatalysts for electrochemical hydrogen production. The process involves the electrochemical immobilization of an ionic organic layer containing heteroatoms on a carbon support, which is subsequently used for metal electrodeposition. Specifically, the amino derivative, 2-(N-(3-aminophenyl)-N-methylsulfamoyl)ethylsulfate potassium, was grafted onto a carbon electrode by the electrochemical reduction of an in situ generated diazonium compound. Electrochemical and surface analyses confirmed the successful immobilization of an ionic layer containing nitrogen and sulfur. The generated surfaces were then used to host an electrochemically deposited palladium catalyst. The hybrid electrocatalyst exhibited significant HER activity and stability, with only 60 mV overpotential required to achieve a current density of 10 mA cm⁻², and 400 mV to reach 1 A cm⁻². This work presents a promising approach for the design of hybrid HER electrocatalysts through judicious surface functionalization of carbon supports.