The doping and oxidation of 2D black and blue phosphorene: a new photocatalyst for nitrogen reduction driven by visible light

Abstract

The synthesis of NH₃ under ambient conditions using solar energy is the most attractive method of synthesis, and requires efficient and stable photo-catalysts with ultralow overpotentials, because a low overpotential ensures low energy consumption and a high yield of NH₃. Here, by using density functional theory calculations, the catalytic activity enhancements from B decoration and the oxidation of black and blue phosphorene for N₂ fixation photo-catalysis are predicted. The results show that the computed overpotentials (η_NRR) were 0.78 and 0.92 V through the end-on configuration of the B doped black phosphorene (B-B_lP) and blue phosphorene (B-B_eP), respectively. In addition, owing to the reduction of the band gap, decoration with B can greatly enhance the visible light and infrared light harvesting of B_lP and B_eP, guaranteeing them as ideal potential materials for the visible light reduction of N₂. The formation energy of B decoration and the ab initio molecular dynamics simulation results indicate that B-B_lP and B-B_eP are highly stable under ambient conditions (300 K). The oxidation of the B_lP and B_eP surfaces can also enhance the N₂ reduction reaction (NRR) performances using visible light driving, with the η_NRR values being 1.31 and 1.51 V through the end-on and side-on configurations, respectively. In summary, this work offers the opportunity for decorated phosphorene to act as a photo-catalyst for NH₃ production.