Synthesis of black titanium dioxide/activated carbon composites for enhanced visible‐light photocatalytic properties

Abstract Black titanium dioxide (B-TiO2) formed by surface disorder engineering has attracted great attention due to its narrowed band gap, enhanced visible-light absorption, and various applications in photocatalysis, hydrogen production, photothermal conversion, etc. The hybrid of B-TiO2 with the other materials provides vast potential to improve it performance further. In this work, highly efficient visible-light-driven B-TiO2/activated carbon (AC) composite catalysts were synthesized by sol-gel method combined with argon heat treatment. The effect of AC content on the morphology, structure and optical properties of B-TiO2/AC was investigated. X-ray photoelectron spectroscopy (XPS) results showed a Ti-C- characteristic peak at 283.6 eV, which indicates the interaction between AC and B-TiO2. The photocatalytic experiments showed that the combination of 25wt% AC and B-TiO2 exhibited remarkable and stable photocatalytic performance for removing Rhodamine B (RhB). Particularly, under visible light irradiation (λ>420 nm), 82% of RhB was degraded within 60 minutes, which is 16% higher than B-TiO2 and 48% higher than white TiO2 (W-TiO2). Moreover, the RhB was degraded by 92% within 30 min under full-spectrum irradiation, which was 18% higher than B-TiO2 and 61% higher than W-TiO2. This work proposed a green and low-cost method for developing B-TiO2 based photocatalyst with improved performance.