Negative-Valent Platinum Stabilized by Pt─Ni Electron Bridges on Oxygen-Deficient NiFe-LDH for Enhanced Electrocatalytic Hydrogen Evolution

Abstract

The unique hydrogen adsorption characteristics of negatively charged platinum play a crucial role in enhancing the electrocatalytic hydrogen evolution reaction. However, atomically dispersed Pt atoms are typically anchored to the support through non-metallic atom bonds, resulting in a high oxidation state. Here, atomically dispersed Pt atoms are anchored in oxygen-deficient NiFe-LDH. Electron transfer between Pt and NiFe-LDH occurs primarily through Pt─Ni bonds rather than the conventional Pt─O bonds. Oxygen vacancies in the NiFe-LDH promote additional electron transfer from Ni to Pt, thereby reducing the valence state of Pt and enhancing hydrogen adsorption. Meanwhile, the elevated valence state of Ni increases the catalyst's hydrophilicity and reduces the energy barrier for hydrolysis dissociation. This catalyst demonstrates remarkably low overpotentials of 4 and 9 mV at 10 mA cm⁻² in 1 m KOH and 1 m KPi, respectively. Additionally, its mass activity is 51.5 and 23.7 times higher that of Pt/C, respectively. This study presents a novel strategy for enhancing electrocatalytic performance through the rational design of coordination environments and electronic structures in supported metal catalysts.