Interlayer Charge Transfer Over Graphitized Carbon Nitride Enabling Highly-Efficient Photocatalytic Nitrogen Fixation

Abstract

Exploiting cost-effective, high-efficiency, and contamination-free semiconductors for photocatalytic nitrogen reduction reaction (N₂RR) is still a great challenge, especially in sacrificial-free system. On basis of the electron “acceptance–donation” concept, a boron-doped and carbon-deficient g-C₃N₄ (B_xCvN) is herein developed through precise dopant and defect engineering. The optimized B₁₅CvN exhibisted an NH₃ production rate of 135.3 µmol h⁻¹ g⁻¹ in pure water with nine-fold enhancement to the pristine graphitic carbon nitride (g-C₃N₄), on account of the markedly elevated visible-light harvesting, N₂ activation, and multi-directional photoinduced carriers transfer. The decorated B atoms with coexistent occupied and empty sp³ hybridized orbitals are theoretically proved to be in charge of the increase of N₂ adsorption energy from –0.08 to –0.26 eV and the change in N₂ adsorption model from one-way to two-way end-on pattern. Noticeably, the elaborate coordination of doped B atoms and carbon vacancies greatly facilitated the interlayer interaction and vertical charge migration of B_xCvN, which is distinctly revealed through the charge density difference calculations. The current study provides an alternative groundbreaking perspective for advancing photocatalytic N₂RR through the targeted configuration of the defect and dopant sites.