Defect-amplified selective photocatalysis for enhanced phenol degradation over glucose on sulfuric-acid-treated g-C3N4

Molecularly selective photocatalysis is essential for advanced water purification that targets specific pollutants while preserving coexisting beneficial substances. In a significant departure from the conventional view of graphitic carbon nitride (g-C 3 N 4 , GCN) as a non-selective photocatalyst, this study first reveals an “unrecognized intrinsic selectivity” of GCN for phenol degradation over glucose. To maximize this latent potential, we developed a “defect-amplified” strategy using sulfuric acid treatment to introduce precise nitrogen vacancies (GCN-S). Our results demonstrate a dramatic amplification of selectivity: while pristine GCN shows only marginal preference, the defect-engineered GCN-S achieves an exceptional 87.5% phenol degradation with minimal glucose loss (∼8.6%), representing a nearly 10-fold increase in selective performance. Mechanistic analysis confirms that nitrogen defects play a crucial role in promoting the generation of superoxide radicals, which are identified as the primary active species for phenol decomposition, while simultaneously suppressing the pathways that lead to glucose degradation. By establishing the novel concept of “defect-amplified selective photocatalysis,” this work provides a transformative paradigm for designing next-generation, high-selectivity photocatalysts for sophisticated environmental applications.