Design and synthesis of TiO2/Ti3C2 composites for highly efficient photocatalytic removal of acetaminophen: The relationships between synthesis parameters, physicochemical properties, and photocatalytic activity

In this study, we report the potential of TiO2/Ti3C2 composite fabricated by oxidation of MXene for degradation of persistent organic pollutants. The effect of the synthesis conditions (time, temperature, and reaction envi-ronment) on the morphology, physicochemical properties, and photocatalytic activity was investigated. It was found that acetaminophen degradation was positively correlated with TiO2 content in the composite structure. Furthermore, the findings confirmed that the synthesis reaction environment strongly influenced the obtained materials photocatalytic activity. The TiO2/Ti3C2 composite obtained by solvothermal route in the presence of hydrochloric acid and ammonium fluoride exhibited the highest efficiency towards acetaminophen degradation than other composite materials, for which ACT removal reached 92 % within 60 min of irradiation under simulated solar light. The improved photocatalytic performance can be attributed to the presence of anatase-rutile polymorphs exposing highly active { 0 0 1} and { 1 0 1} facets coupled with MXene. Superoxide anion radicals and hydroxyl radicals played a major role in ACT degradation. Moreover, 3-hydroxyacetaminophen was detected as the first intermediate of ACT degradation, leading quickly to aromatic ring opening and production of aliphatic acids. Overall, this work provides an effective strategy for designing novel and efficient MXene-based photocatalysts for the degradation of emerging contaminants in water systems.