Hollow N-TiO2/MnO2 nanocomposite based yeast biomass for gaseous formaldehyde degradation under visible light

Abstract Synthesis of new hollow nano-composite photocatalysts based yeast biomass has been considered as a future innovation technology to control air pollution. This work demonstrates that a green, environmentally friendly, sustainable, and facile hydrothermal carbonization route of low-cost and renewable yeast biomass used to fabricate natural doping N-colloidal carbon spheres (NCSs) as a hard template for hollow N-TiO2/MnO2. The presence of natural doping nitrogen serves as a stabilizer and reductant. Hence, the yeast provided a solid frame with deposits nitrogen to form the hybrid N/yeast precursor. The resulting NCSs were obtained by hydrothermal method at 180 °C for 6 h. The characterization was performed using SEM, TEM, XRD, FTIR and N2 adsorption/desorption analysis. It was found that the findings fully retained the morphology of the yeast cells and the size of the hollow spheres was about 1.5–2 μm. The results of catalytic test showed that the new hollow nanosphere N-TiO2/MnO2 possessed a higher photodegradation activity for gaseous formaldehyde under visible irradiation than the commercial TiO2, due to their higher surface area (160 m2 g−1), hollow structure and superior reducibility. Its catalytic efficiency was attained to be more than 90%, which is about 10 times higher than that of the conventional catalyst TiO2–P25.