Enhanced molecular oxygen activation via K/O interfacial modification for boosted electrocatalytic degradation over a broad pH range

Molecular oxygen activation plays an important role in the electrocatalytic degradation of recalcitrant pollutants. And the key lies in the tailoring of electronic structures over catalysts. Herein, carbon nitride with K/O interfacial modification (KOCN) was designed and fabricated for efficient molecular oxygen activation. Theoretical screening results revealed the possible substitution of peripheral N atoms by O atoms and the location of K atoms in the six-fold cavities of g-C3N4 framework. Spectroscopic and experimental results reveal that the existence of K/O promotes charge redistribution over as-prepared catalysts, leading to optimized electronic structures. Therefore, optimized oxygen adsorption was realized over 8 % KOCN, which was further converted into superoxide and singlet oxygen effectively. The rate constant of 8 % KOCN (1.8 × 10-2 min−1) reached 2.2 folds of pristine g-C3N4 (8.1 × 10-3 min−1) counterpart during tetracycline degradation. Moreover, the high electron mobility and excellent structural stability endow the catalyst with remarkable catalytic performance in a broad pH range of 3–11.