Hierarchical porous N-TiO2/carbon foam composite for enhancement of photodegradation activity under simulated sunlight

Nitrogen doped TiO 2 (N-TiO 2 ) photocatalyst was synthesized via sol-gel combined with low temperature reflux method using urea as nitrogen source. Hierarchical porous carbon foam (HPCF) with the characteristics of micro/mesopores and micron-sized macropores was made by steam activation of a new type of thin-walled carbon foam which was produced from the loose medium component of coal. N-TiO 2 /HPCF was synthesized by loading N-TiO 2 onto the HPCF via impregnation method. The synthesized catalysts were characterized by N 2 adsorption, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), diffuse reflection spectrometry (DRS) and photoluminescence spectroscopy (PL). Phenol was used as a simulated pollutant in wastewater to evaluate the photodegradation performances of naked TiO 2 , N-TiO 2 and N-TiO 2 /HPCF. The N-TiO 2 /HPCF composite removed 97 % of phenol in 2 h of simulated sunlight irradiation and displayed the highest photocatalytic activity, which was 4.9 times that of N-TiO 2 and 10.8 times that of naked TiO 2 . The enhanced activity of N-TiO 2 /HPCF can be ascribed to the combination of both extended visible light adsorption of N-TiO 2 and the concentrating effect brought by HPCF. This work demonstrates a facile approach to synthesis an inexpensive and efficient N-TiO 2 coated coal-based carbon foam for the treatment of wastewater. • Hierarchical porous carbon foam (HPCF) was prepared from coal loose medium component. • N-TiO 2 was synthesized by sol-gel process of TBOT followed by low-temperature reflux. • N-TiO 2 /HPCF exhibits high activity for degradation of phenol under simulated sunlight. • N-TiO 2 /HPCF has a good adsorption-photodegradation synergy.