Steering the Electronic Microenvironment of Ruthenium Sites via Boron Buffering Enables Enhanced Hydrogen Evolution under a Universal pH Range

Abstract

Optimizing the microenvironment of active sites is crucial for enhancing the catalytic activity of the hydrogen evolution reaction (HER) across various pH conditions. Here, guided by theoretical predictions of boron (B)-doping’s electronic buffering effect on ruthenium (Ru) at the atomic scale, a highly efficient and universal-pH Ru-based HER electrocatalyst (Ru-NBC) by introducing B and nitrogen (N) into a carbon (C) matrix was designed. The Ru-NBC catalyst demonstrated exceptional HER activity, requiring overpotentials of 27, 40, and 68 mV in 1 M KOH, 0.5 M H₂SO₄, and 1 M phosphate buffer solution (PBS), respectively, to achieve a current density of 10 mA cm^–2. In situ Raman spectroscopy, ambient-pressure X-ray photoelectron spectroscopy, and potential of zero charge measurements revealed that B-doping modulates the local Ru microenvironment, restructuring the distribution balance of the interfacial water hydrogen-bond network within the electrochemical double layer and thereby facilitating water adsorption and dissociation. Density functional theory calculations further verified that the electronic buffering effect of B optimizes hydrogen adsorption in acidic media and water activation in alkaline conditions, resultantly contributing to the universal-pH HER performance. This study could provide guidance for the design of advanced electrocatalysts through modulation of the local microenvironment of active sites for energy storage and conversion.