Decoupling photocatalytic nitrogen activation: Broad-spectrum ammonia synthesis in pure water via attenuated hole oxidation dynamics in intrinsically active Bi2O2Se

This study demonstrates a strategic paradigm in photocatalytic nitrogen fixation by engineering semiconductor hole oxidation dynamics to circumvent ammonium degradation. Diverging from conventional approaches focused on light absorption and carrier mobility enhancement, we develop a sacrificial agent-free system leveraging attenuated hole oxidation capacity to fundamentally suppress oxidative depletion of NH 4 + . Bi 2 O 2 Se (BOS) serves as an archetypal catalyst, revealing mechanistic correlations between weak hole oxidizing environments and nitrogen reduction efficiency. Experimental analyses confirm BOS's superior performance over traditional photocatalysts, attributed to its intrinsic capacity to prevent NH 4 + oxidation while enabling effective product enrichment. Remarkably, the catalyst maintains equivalent nitrogen fixation efficiency in ambient air and inert atmospheres, demonstrating exceptional oxygen compatibility. Furthermore, BOS exhibits panchromatic photon utilization extending into near-infrared regions (AQE = 0.12 % at 700 nm). The unmodified bulk-phase characteristics of BOS highlight its inherent catalytic superiority, challenging conventional modification-dependent catalyst design frameworks. This work establishes oxidation potential modulation as a critical determinant in photocatalytic nitrogen fixation while providing a material platform and conceptual blueprint for sustainable ammonia synthesis technologies.