Hydroxylated carbon nanotube/carbon nitride nanobelt composites with enhanced photooxidation and H2 evolution efficiency

Hydroxylated multi-walled carbon nanotubes modified with a carbon nitride nanobelt (HCNT/CNN) were successfully fabricated by using combined solvothermal and ultrasonic methods to improve both tetracycline hydrochloride (TC) degradation and H2 evolution. The well-designed photocatalysts exhibited a wide light absorption range, low photoluminescence (PL) intensity, high photocurrent, and small electrochemical impedance spectroscopy (EIS) arc; these properties significantly enhanced the overall photocatalytic efficiency. At the optimal loading of HCNT (0.05 wt%), the resulting HCNT/CNN exhibited the highest TC photocatalytic degradation rate, and the H2 production rate reached 175.5 μmol g−1 h−1. Compared to the multi-walled carbon nanotube modified carbon nitride nanobelt, the TC photocatalytic degradation rate and H2 production rate of HCNT/CNN increased by factors of 3 and 4.2, respectively. This significantly enhanced performance can be ascribed to the formation of hydrogen bonds between HCNT and CNN, which facilitates the electron transfer from the CNN to the HCNT surface, thereby accelerating the separation of photogenerated charge carriers. Moreover, the possible mechanism of the improved photocatalytic performance for the HCNT/CNN composites was proposed. This study provides the guidance for the design of novel carbon nitride nanobelt-based photocatalysts for wastewater purification and H2 evolution.