Boron doped C3N5 for photocatalytic nitrogen fixation to ammonia: The key role of boron in nitrogen activation and mechanism

Compared to g-C3N4, g-C3N5 can harvest more visible light and prolong the lifetime of photogenerated carriers, and exhibited a more excellent NH3 yield under visible light. A new catalyst boron doping g-C3N5 (B-C3N5) was prepared by a simple one-step calcination for photocatalytic nitrogen fixation. B-C3N5 achieved the NH3 yield up to 421.18 μmol h−1 g−1. Raman and ESR analysis reveal that the B tend to occupy the C vacancies in C3N5, which effectively improve the charge transfer capability and optimize band structure of B-C3N5. The B sites display perfect performance for N2 adsorption and activation to generate NH3. The intermediates of NRR process are identified by in-situ DRIFTS and a reaction mechanism is proposed to reveal the role of the B − O − H during the N2 adsorption, activation, and reduction process.