Ordered hierarchical mesoporous anatase TiO2 from yeast biotemplates

A novel approach is proposed to prepare ordered hierarchical mesoporous TiO2 by using yeast cells as the template via biomimetic mineralization. The structure and the mophology were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), Raman spectra, high-resolution transmission electron microscopy (HRTEM), and N2 adsorption–desorption isotherms (NADI). The bio-templated TiO2 has a hierarchical pore structure mainly distributed at 4.7 nm and 11.3 nm. An air electrode fabricated using this hierarchical mesoporous TiO2 exhibited remarkable electrocatalytic activity for oxygen reduction reaction (ORR). Compared to the electrolytic manganese dioxide (EMD) air electrode employed commercially, a 90% higher catalytic reduction current was achieved for this mesoporous TiO2 electrode. It is supposed that the hierarchically mesoporous structure and ordered pore distribution play important roles in significantly reducing electrochemical polarization and improving mass transport of the air diffusion electrode. This simple and efficient approach could spread as a general way to prepare advanced mesoporous materials in mild condition.