Bismuth vacancies-enriched Bi4Ti3O12 nanosheets coated with UiO-66-NH2 for adsorption-combined piezocatalytic oxidation of HCHO

Catalytic oxidation of HCHO is often limited by the serious recombination of carriers in photocatalysts and the high cost of thermal catalysts based on precious metals. Herein, Bi4Ti3O12 nanosheets enriched with bismuth vacancies were synthesized and decorated by UiO-66-NH2 to obtain VBiTO@NU-66 for efficient removal of HCHO via piezocatalytic oxidation. The Bismuth vacancies in VBiTO enhanced the asymmetry of the crystal structure and introduced the atomic-level channels for energy and electron transfer. After loading UiO-66-NH2, the adsorption ability was substantially improved by the formation of Schiff-base covalent bonds between HCHO and –NH2. Under the joint action of adsorption and piezocatalysis, piezocatalytic oxidation rate of 300 mg/m3 HCHO by VBiTO@NU-66 was as high as 95.1% within 3 h, which was 6 times of that of pure BiTO nanosheets. This work offers a novel tactics for the efficient purification of gaseous environmental pollutants.