A study on interfacial regulation and function mechanism of TiO2@CeO2 3D core-shell heterostructure for photocatalytic degradation of unsymmetrical dimethyl hydrazine

Unsymmetrical dimethylhydrazine (UDMH), as a high-energy liquid rocket fuel widely used for space launches, inevitably produces huge volumes of UDMH wastewater during use. As UDMH and its byproducts are both highly toxic, this poses a major threat to the ecological environment and human body, making it an urgent need to develop an efficient, environmentally friendly treatment for UDMH wastewater. Photocatalysis is well recognized for being less costly and more environmentally friendly, yet as traditional photocatalysts are usually available in the form of powder, the photogenerated carriers cannot be well separated or effectively recycled. In this study, a composite photocatalyst featuring a three-dimensional core-shell array structure consisting of a TiO 2 crystal seed layer, a TiO 2 nanorod array core and a CeO 2 nanoparticle shell is created over the surface of recyclable carbon fiber by means of layer-by-layer loading. The TiO 2 rutile/anatase phase heterointerface and TiO 2 /CeO 2 heterointerface allow efficient separation and migration of photogenerated electrons and holes in the three-dimensional space. Under simulated solar irradiation, our new structure degrades 100 mg/L UDMH wastewater by up to 97.3 % within 240 min. More importantly, it shows good reusability and recyclability. Our research offers a practicable option for the efficient degradation of UDMH wastewater.