Controlling Selectivity for Efficient Nitrogen Photo‐Fixation Over Hydrogen Evolution using Anthracene‐Containing D–A Conjugated Polymers

ABSTRACT Donor–acceptor (D–A) structured organic photocatalysts have garnered considerable attention for artificial NH ₃ photosynthesis under ambient conditions. Nevertheless, their N ₂ photo‐fixation efficiency is constrained by insufficient chemisorption and selectivity towards N ₂ . Herein, we rationally designed a series of conjugated polymers with varying donor‐to‐acceptor molar ratios using anthracene and dibenzothiophene sulfone (BTSO) as electron‐donor and electron‐acceptor units. The production rate of the nitrogen reduction reaction (NRR) increases progressively with higher anthracene content. Notably, AnSO‐6, featuring a 1:1 donor‐to‐acceptor molar ratio, achieves a remarkable NH ₃ production rate of 1645.25 µmol g ⁻¹ h ⁻¹ under full‐spectrum irradiation without sacrificial agents. This enhancement stems from the superior N ₂ chemisorption capability, high electron transfer activity, and efficient charge separation endowed by the unique D–A structure. By contrast, the photocatalytic hydrogen evolution reaction (HER) exhibits an inverse trend, indicating the feasibility of tuning HER/NRR selectivity via donor‐to‐acceptor ratio adjustment. Additionally, the generality of the BTSO‐based D–A platform was validated by substituting anthracene with diverse electron donors, demonstrating broad applicability for efficient photocatalytic N ₂ fixation. This research establishes a promising approach to boost photocatalytic NH ₃ production and offers novel insights into modulating the equilibrium between NRR and HER through precise regulation of the donor‐to‐acceptor monomer ratio.