Abstract
Bio-hierarchical TiO2-based porous structures (denoted as morph-TiO2) with N and La co-doping (denoted as N-La-morph-TiO2) are successfully synthesized via a facile one-pot reaction by using butterfly wings as bio-template and surfactant as co-template. Due to the novel dual-template strategy, the well-aligned 3D bio-hierarchical porous structures in combination with N-La codoping not only modify the band structure of TiO2 to make it more responsive to visible light, but also increase the surface area and lead TiO2 to have enhanced photocatalytic activity for methyl orange (MO) degradation under UV and/or visible light illumination as compared with P25 TiO2 and pristine TiO2. The optimized N-La-morph-TiO2 nanostructures present a narrow pore size distribution with an average pore diameter of 8.7 nm and a high specific surface area (196 m2 g−1), which is nearly four times that of P25 TiO2. The enhanced photocatalytic activity is attributed to the combination of the doped inorganic elements, the fine hierarchical and well-aligned porous nanostructures as analyzed by SEM, TEM, XPS, BET, UV–vis absorption and photodegradation tests. The promotional mechanisms and principles reported in this work are believed to have great significance in heterogeneous photocatalysis.