Porous Multiwalled Nanotube Networks Assembled By Anatase/Rutile Heterojunctions For Enhanced Photocatalytic Activity

Facing the sustainable development in the fields of energy and environment,there are still some challenges in traditional single-crystal titanium dioxide,such as the wide band gap and low photo-generated carrier separation efficiency,which limit its application.The construction of titanium dioxide heterojunctions on one-dimensional porous nanostructure,can achieve enhanced photo-response and efficient photo-generated carrier separation,which provides an important strategy for a potentially efficient photocatalyst.Inspired by the interwoven fiber networks of eggshell membrane(ESM)and their functions on biomineralization,a bio-genetic strategy combining with stepwise impregnation and calcination process,was applied to synthesize functional materials with interconnected nanotube networks,followed by the exploration on photocatalysis application.The main results are as follows:Firstly,layered Ti-impregnant coating is in-situ formed on the ESM fiber substrate in the impregnation process and anatase/rutile heterojunctions with perfect crystallinity and uniform size were obtained in the subsequent calcination.As such,the final ESM-morphic nanocomposites is characteristic of multilevel interconnected networks with heterogeneous porous multiwalled nanotubes.Secondly,the multilevel interconnected networks can not only endow the products with unique 1D electrochemical property along the longitudinal direction,but also enlarge the accessible surface area to 139.97 m²/g.Moreover,the heterogeneous Ti O₂ nanocrystalline unites on 1D nanostructure can facilitate the interfacial charge transfer to achieve higher light-excitation and charges separation efficiency.Thirdly,benefiting from the excellent light absorption capacity,long photo-carrier lifetime and large specific surface area,the 800-Ti O₂ achieves photocurrent response of 70.0?A/cm²,which is approximate 9 times of that for sample 900-Ti O₂(7.9?A/cm²).And the photocatalytic rate was 43%higher than that of commercial Degussa P25.Considering the significantly improved light response and photocatalytic performance,porous multiwalled nanotube networks of anatase/rutile heterojunctions should have a broad application prospect in environmental pollution control.