A study on interfacial regulation and function mechanism of S-scheme 001-TiO2/CeO2 two-dimensional charge-separation Interface for photocatalytic degradation of unsymmetrical Dimethylhydrazine

Abstract

Unsymmetrical dimethylhydrazine (UDMH), as a high-energy liquid rocket fuel widely used for energy liquid rocket fuel, inevitably produces huge volumes of UDMH wastewater during use. As UDMH and its byproducts are both highly toxic, this poses a severe threat to ecological environment and human health, making it an urgent need to develop an efficient, environmentally friendly treatment for UDMH wastewater. Photocatalytic technology has emerged as a research hotspot in the field of water pollution control owing to its low cost and eco-friendliness. In this study, a (001) facet-dominated 001-TiO₂/CeO₂ S-scheme heterojunction was constructed via a solvothermal-photoassisted method, effectively achieving primary carrier separation. Under simulated solar irradiation, this structure achieved a 98.7 % degradation efficiency for 100 mg/L UDMH wastewater within 140 min, with degradation rate constants 3.8 times and 5.5 times higher than those of 001-TiO₂ and P25, respectively. To address the challenge of recovering powdered photocatalysts, this study immobilized the nanopowders using a silver conductive adhesive, creating a two-dimensional conductor interface for electron transport and a nanoparticle structure for hole retention, thereby enabling secondary carrier separation. Under simulated solar irradiation, this immobilized structure achieved a 75.1 % degradation efficiency for 100 mg/L UDMH wastewater within 420 min. More importantly, it demonstrated excellent reusability and recyclability. This study provides a practical and feasible approach for the efficient degradation of UDMH wastewater.