Active site of the Pt electrodes modified with purine bases for hydrogen evolution reaction in alkaline solution

The hydrogen evolution reaction (HER) on Pt electrodes can be activated by controlling the hydrophilic/hydrophobic structure in the electric double layer (EDL). Identifying the factors governing the HER activity is essential for developing practical electrocatalysts. In this study, we investigated the HER activity of the Pt electrodes modified with purine bases. With increasing purine coverage, the HER activity of purine-modified Pt(110) increased linearly to 4.2 times higher than that of the unmodified surface. X-ray diffraction analysis indicated that the water molecules interacting with the purine were precisely located in the missing rows of the reconstructed Pt(110). These water molecules facilitated hydrogen donation to the topmost Pt atoms to activate the HER. We additionally attempted to activate the HER by the purine modification on the Pt stepped surface of commercial Pt/C. The purine modification and the oxidative roughening of Pt/C increased the activity by 3.2 times compared to that of untreated and unmodified Pt/C. • Purine-modified Pt(110) enhances HER activity by 4.2-fold. • HER of purine-modified Pt(110) modified increases linearly with purine coverage. • Hydrogen bonding structure surrounding purine promote the diffusion of OH − and improve HER. • Purine modification of Pt/C with (110) structure improved HER activity by 3.0-fold.