Highly efficient photocatalytic nitrogen fixation using in situ sulfurized Z-scheme MIL-88B(Fe)/Fe3S4 heterostructure

Abstract

The photocatalytic nitrogen reduction reaction (NRR) represents a promising green pathway for ammonia synthesis under ambient conditions, offering a sustainable alternative to the energy-intensive Haber-Bosch process. Despite the potential of this approach, conventional photocatalysts often suffer from rapid charge recombination and inefficient N₂ adsorption/activation, which significantly limits their performance. To address these challenges, we herein report a controlled in-situ sulfurization strategy to construct a highly active MIL-88B(Fe)/Fe₃S₄ heterojunction. The in-situ sulfurization process ensures uniform distribution of the sulfur species within the composite, while the intimate interfacial contact between MIL-88B(Fe) and Fe₃S₄ facilitates efficient charge separation and transfer. The optimized catalyst demonstrates a remarkable photocatalytic nitrogen fixation rate of 68.57 μmol g⁻¹ after 2 h of irradiation, significantly outperforming both pristine MIL-88B(Fe) and Fe₃S₄ components. This work elucidates the critical role of the in-situ sulfurized Z-scheme MIL-88B(Fe)/Fe₃S₄ heterostructure in enhancing photocatalytic nitrogen fixation, providing a viable strategy for the rational design of highly efficient and durable NRR systems.