TiO 2 /BP/g-C 3 N 4 heterojunction photocatalyst for the enhanced photocatalytic degradation of RhB.

The efficiency of graphite carbon nitride (g-C 3 N 4 , CN) as a photocatalyst is limited due to its quick recombination of photogenerated carriers and layer re-stacking. To enhance its photocatalytic activity, a multi-heterojunction photocatalyst was developed using TiO 2 and black phosphorus (BP) coupled with CN through a liquid-phase ultrasonic method. The composite, TiO 2 /BP/CN, demonstrated a wider range of light response and higher photo-induced carrier separation efficiency. The presence of TiO 2 nanoparticles on CN nanolayers reduced interlayer stacking and increased specific surface area, thereby providing more reactive sites. As a result, the optimized TiO 2 /BP/CN composite demonstrated enhanced photocatalytic efficiency for the degradation of Rhodamine B (RhB), with a first-order kinetic constant of 2.8, 4.3, and 6.4 times that of CN, TiO 2 , and BP, respectively. Active substance capture experiments confirmed that superoxide radical (·O 2 ) was the primary reactive species. This study highlights the potential of the developed TiO 2 /BP/CN composite as a promising photocatalyst for environmental remediation applications.