Improving the activity of the oxygen evolution reaction on TiN4–CoN4 embedded carbon nanotubes via boron atom doping and applying uniaxial strain

Abstract

Designing high-efficiency electrocatalysts for the oxygen evolution reaction (OER) is important, which is the bottleneck of the water splitting reaction due to the sluggish kinetics and substantial overpotential involved in the four-electron transfer reaction. Herein, we systematically investigate boron-doped TiN₄–CoN₄ moieties anchored on carbon nanotube substrates (TiN₄–CoN₄/CNT) using systematic density functional theory (DFT) simulations. Our computational analysis demonstrates thermodynamically favorable boron incorporation across nine distinct doping sites (B1–B9), with formation energies ranging from 0.66 to 2.44 eV and robust binding energies stabilized below −8.53 eV. Remarkably, strategic boron positioning at the B8 site dramatically reduces the theoretical OER overpotential from 0.47 V to 0.41 V, outperforming the benchmark values of conventional noble-metal catalysts. The enhancement of catalytic activity can be attributed to the significant upward shift of the d-band center of the B8 site. Notably, applying a −5% uniaxial strain further reduces the overpotential to 0.32 V through coordinated lattice distortion-induced charge redistribution. This work establishes a new design paradigm for achieving strain-engineered bimetallic catalysts, providing atomic-level insights into synergistic doping and strain effects for advanced energy conversion systems.