Construction of low‐temperature limited‐domain carbon‐cured TiO ₂ three‐dimensional photocatalytic coating and its efficient cyclic degradation of methylene blue

BACKGROUND Photocatalytic technology holds significant potential for degrading organic dyes. However, the difficulty in recovering nanophotocatalysts and their tendency to cause secondary pollution severely hinder their industrial application. This study developed a confinement technique that successfully immobilized nano‐TiO 2 particles onto a foam ceramic substrate, forming a stable and highly efficient 3D porous photocatalytic coating (TiTC). The preparation process, reaction conditions, and reusability of TiTC were thoroughly investigated in this paper. RESULTS In the optimization of composition and processing, the TiTC‐10‐16 composition prepared via oxygen‐free calcination at 450 °C for 2 h demonstrated the best overall performance. It operates stably in methylene blue (MB) solutions with pH values ranging from 3–11 and concentrations between 50 and 200 mg · L −1 , with its response capability extending into the visible spectrum. After 10 consecutive cycles, the decay rate was 13.23%, and after 10 regeneration cycles, the decay rate was only 7.46%, demonstrating remarkable cycling stability. CONCLUSION The 3D pore structure of foam ceramics increases the contact area between the coating and MB. The porosity of the carbon coating both immobilizes nano‐ TiO 2 particles and provides pathways for photons to penetrate the coating and react with TiO 2 . Concurrently, the photosensitization effect of carbon significantly enhances catalytic performance. Through the synergistic effects of porous carbon immobilization, co‐reaction of internal and external TiO 2 , and photosensitization, the high efficiency and stability of TiTC are effectively improved, offering a novel pathway for developing highly efficient and stable catalysts.