Ligand-Driven Tuning of Adsorption Energy in Nanocrystals for High-Performance H2O2 Electrosynthesis

Abstract

Surface ligands modulate the electronic structure of nanocrystals (NCs); however, in catalytic applications, these ligands are often removed due to concerns about blocking active sites. We studied herein whether ligand functionality and a judiciously chosen degree of ligand coverage can precisely tune the adsorption energy of key intermediates on NC catalysts. Guided by density functional theory calculations, we introduced electron-withdrawing ligands at an optimized coverage on Ag2S NCs, achieving an ideal balance in intermediate adsorption strength (Delta G OOH* = 4.16 eV). This turned Ag2S NCs-intrinsically inactive for the two-electron oxygen reduction reaction-into efficient H2O2 electrocatalysts. When integrated onto oxidized carbon nanotube supports, these catalysts exhibited a stable H2O2 production of 161 mg cm-2 h-1 with a Faradaic efficiency of 84% at 300 mA cm-2 in neutral media. This ligand-driven tuning strategy opens new avenues to control and enhance the catalytic properties of NCs.