Strong base g-C3N4 with perfect structure for photocatalytically eliminating formaldehyde under visible-light irradiation

Solid strong base systems of g-C3N4 by inducing potassium (KC3N4) were constructed for photocatalytically decomposing HCHO. Characterization and theoretical calculation revealed that the formation of K-C and K-N perfected the π-conjugated structure of g-C3N4, which greatly enhanced the basicity, improve optical and electrical properties of g-C3N4. In the photocatalytic process, K-improved π-conjugated structure promoted HCHO adsorption, activation, completely oxidative decomposition under visible-light irradiation. Therefore, KC3N4 photocatalysts presented high efficiency in photocatalytic elimination of HCHO, and the optimal apparent rate reached 0.21 mol−0.17 L0.17 min−1 with 1.17 reaction order by promoting the reaction between active oxygen (OH and OH) and formate species under visible-light irradiation, which was 30 times of that (0.007 mol−0.17 L0.17 min−1) over pristine g-C3N4. These results may suggest a new way for probing the advanced solid strong base photocatalysts for eliminating volatile organic compounds.