S-scheme g-C3N4/TiO2/CFs heterojunction composites with multi-dimensional through-holes and enhanced visible-light photocatalytic activity

A novel multi-dimensional through-holes structure of g-C3N4 with adjustable pore size was prepared by controlling the mass ratio of oxamide (OA, structure guiding agent) to urea during one-step calcination process, and a break-rearrangement mechanism was explored. Then, a series of porous g-C3N4/TiO2 (CT) composites with uniformly deposited TiO2 nanoparticles were prepared based on the multi-dimensional framework by a facile hydrothermal method. The results show that a new S-scheme heterojunction with multi-dimensional through-channel structure was obtained, which is particularly desired for enhancing the visible-light utilization, reducing the carrier recombination rate and enhancing redox capacity. The CT composite obtained at hydrothermal treatment time of 2 h has a specific surface area of 180.15 m(2) g(-1), which shows high degradation capability (99.99%) for tetracycline hydrochloride (TC center dot HCl) under 350 W Xe lamp irradiation for 90 min. In addition, CT nanostructures was in-situ growth on carbon fiber (CFs), the degradation rate constant is 0.1566 min(-1), and 90% of the degradation efficiency can be maintained even after 5 consecutive cycles. It is expected to provide an effective reference for solving the problems of recovery difficulty and low reuse rate of powder photocatalytic materials.

Automated summary

A novel multi-dimensional through-holes structure of g-C3N4 with adjustable pore size was prepared by controlling the mass ratio of oxamide to urea. Porous g-C3N4/TiO2 composites with uniformly deposited TiO2 nanoparticles were also successfully prepared. These composites exhibit a new S-scheme heterojunction with multi-dimensional through-channel structure, which enhances visible-light utilization and improves photocatalytic performance.