Cyanogroup functionalized sub-2 nm ultrafine Pt nanonetworks reinforce electrocatalytic hydrogen evolution in a broad pH range

Abstract

Surface functionalization is an effective way to improve the activity of electrocatalysts by adjusting the adsorption and desorption capacity of intermediate species on noble metal surfaces. Herein, density functional theory (DFT) calculations demonstrate that cyanogroup functionalization can effectively reduce the d-band centre (ε_d) of the Pt (111) plane, thus resulting in a hydrogen evolution reaction (HER) performance improvement. Cyanogroup functionalized Pt ultrafine nanonetworks (CN–Pt UNs, sub-2 nm) are synthesized via a facile one-pot heating method with high yield and abundant defects/grain boundaries as the highly active sites. Owing to the optimized Pt electronic properties and ultrathin network nanostructure, the overpotentials of CN–Pt UNs at 10 mA cm⁻² are merely 6 mV and 8 mV in 1 M HClO₄ and 1 M KOH, respectively, and are superior to those of commercial 20 wt% Pt/C in a wide pH range. This work offers a new perspective towards the rational design of noble metal catalysts for boosting electrocatalysis by surface cyanogroup functionalization.