Efficient solar-driven nitrogen fixation over an elemental phosphorus photocatalyst
Photocatalytic ammonia synthesis from nitrogen (N2) and water under ambient conditions is emerging as an intriguing alternative to the energy-consuming and CO2-emitting Haber-Bosch process. However, photocatalytic N2 fixation is seriously handicapped by the difficulty in N2 activation, underlining the importance of developing efficient earth-abundant photocatalysts for nitrogen reduction reaction (NRR). Herein, this work reported a breakthrough in the development of elemental NRR photocatalyst. Prepared by a facile sublimation-deposition method, nano-sized crystalline red phosphorous (RP) was loaded on photo-inactive SiO2 nanospheres, in which RP was modified by in situ formed carbon material. The obtained hybrid catalyst (denoted as SiO2/C-RP) was proved to be endowed with marked activity in photocatalytic N2 fixation, achieving an NH3 yield of 0.73 μmol h−1 with 20 mg of catalyst in 40 mL pure water, which greatly outperformed the crystalline bulk RP. Such remarkably improved photocatalytic activity stems from the synergetic effect of the enhanced surface area, light absorption, water dispersibility and charge separation performance. This work would shed light on future design of the earth-abundant, non-toxic and scalable photocatalysts for nitrogen fixation.