Symmetry breaking induced local electron rearrangement to enhance photocatalytic tetracycline hydrochloride oxidation and hydrogen evolution of carbon nitride

[Display omitted] •A symmetry breaking strategy was achieved by a sample doping approach and used to overcome insufficient capacity of carbon nitride photocatalysts.•The obtained local electronic structural reconstruction resulted in the generation of an intermediate energy level.•The electronic structure rearrangement brings adsorption characteristic changes for H2O and O2 molecules, leading to the variation of free radicals’ generation.•A balance between light absorption properties and photocatalytic redox capacity is obtained. A symmetry breaking strategy was achieved by a sample doping approach and used to overcome the sluggish carrier transfer and insufficient light capture capacity of carbon nitride photocatalysts. The obtained local electronic structural reconstruction resulted in the generation of an intermediate energy level, which can regulate the band gap structure and boost the redox reaction progress. Furthermore, the DFT calculation results prove the electronic structure rearrangement brings adsorption characteristic changes for H2O and O2 molecules, leading to the variation of free radicals’ generation. Combing the advantages of band gap structure optimization and internal electron rearrangement, the phosphorus doped carbon nitride achieves a balance between light absorption properties and photocatalytic redox capacity, exhibiting stronger reduction capacity, high carrier separation efficiency, and optimized adsorption sites. Consequently, the phosphorus doped carbon nitride shows enhanced activities in photocatalytic tetracycline hydrochloride degradation (3.6-fold increase), peroxydisulfate activation (4.5-fold increase), and hydrogen generation (13.5-fold increase) compared to pristine carbon nitride. This research highlights the symmetry regulation strategy as a promising method for developing highly efficient multifunctional carbon nitride-based photocatalysts.