Acid-alkali assisted synthesis of white tremella-like g-C3N4 homojunction for photocatalytic degradation under visible light

Graphite nitride (g-C 3 N 4 ) photocatalyst has attracted tremendous attention because of its suitable visible light-driven band gap, facile synthesis from low-cost nitrogen­containing organic precursors, and high stability. To address the limitations of conventional single modification methods. Here, a novel homojunction photocatalyst was developed by combining defective g-C 3 N 4 (CNx) and flaked g-C 3 N 4 (CN) through alkali etching and acid stripping techniques. Compared to the conventional g-C 3 N 4 , the homojunction photocatalyst (CNx/CN) exhibited white tremella-like folds, and the homojunction structure allowed faster transfer and separation of electrons and holes in CNx/CN. Under the synergistic effect of morphological modulation and homojunction construction, CNx/CN exhibited excellent degradation performance (the degradation for MB is 94.2 %) in the degradation of methylene blue (MB) and showed excellent cycling stability after four cycling experiments. Furthermore, CNx/CN exhibited satisfactory practicality in several simulation experiments, including evaluations of pH, co-existing cations, and real water. This work provides a new strategy for constructing an efficient g-C 3 N 4 -based homojunction photocatalyst for practical application in contaminated water treatment.