Synergistic spin regulation in Mn-CsPbBr₃ halide perovskite nanocrystals for efficient photocatalytic nitrogen reduction in nonaqueous media

Industrial ammonia (NH₃) production relies predominantly on the energy-intensive and environmentally unfriendly Haber–Bosch process, motivating the development of sustainable alternatives for green NH₃ synthesis. The photocatalytic nitrogen reduction reaction (N₂RR) driven by solar energy is a promising route under ambient conditions, but requires highly efficient photocatalysts. Although halide perovskite nanocrystals possess excellent optoelectronic properties, their application in the N₂RR remains limited by poor aqueous stability and inefficient N₂ activation. Herein, we report a spin-regulated, nonaqueous photocatalytic strategy using spin-driven Mn-doped CsPbBr₃ nanocrystals for the N₂RR under visible-light irradiation in ethyl acetate, where the nonaqueous environment effectively suppresses water-induced instability. Compared with pristine CsPbBr₃, Mn-CsPbBr₃ delivers higher NH₃ yields, reaching 175.83 µmol g⁻¹ under an external magnetic field. The enhanced performance originates from synergistic spin regulation, where Mn²⁺-induced spin polarization suppresses recombination, and magnetic-field-driven Zeeman splitting further accelerates charge separation and interfacial electron transfer. Spectroscopic and photoelectrochemical analyses consistently confirm that spin-regulated charge carrier dynamics, enabled by this synergistic strategy, govern the improved photocatalytic N₂RR performance. This work establishes a previously unexplored spin-assisted, nonaqueous perovskite photocatalytic pathway for nitrogen fixation and highlights synergistic spin regulation as an effective design principle for advancing solar-to-ammonia conversion systems.