Titania-based, phosphorous-functionalized hybrids as photocatalysts for air purification

• Applicant: Professorin Dr.-Ing. Doris Segets
• Subject Area: Mechanical Process Engineering
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 392327370

• Final Report Year: 2023

Final Report Abstract

The aim of the project was to develop new functional photocatalysts with a deeper understanding of the surface behavior of titania nanoparticles and their doped or hybridized variations. Ta achieve this, two objectives were followed. Objective 1: Ta develop methods that enable a comparison of surface properties of different materials, here with a focus an titania. Hansen solubility/similarity parameters (HSP) have potential in understanding the adsorption behavior of organic compounds an titania photocatalysts. In this respect, a framework was developed that allows proper reporting of all information relating to method of HSP determination and the derived HSPs. Following the guidelines of the framework, a new method of HSP determination based an particle size distributions (PSDs) was developed and applied to titania synthesized from different procedures. Additionally, we validated the HSPs determined via the PSDs with a well-applied method in literature using integral extinctions (IE) for determining HSPs. We introduced additional considerations for enhancing the accuracy of the IE-based method and compared the two approaches for determining HSPs of P25 titania, carbon black and silicon/carbon composites. We reported that both methods gave similar HSPs for all three materials and showed the way future comparisons between methods of HSP determination could be done reliably. Objective 2: The second objective of the project was to apply the developed methods to predict liquid­ phase adsorption of technologically relevant pollutants such as Bisphenol A (BPA) and chloroform an different titania photocatalysts, e.g. synthesized by the Sun-group at SICCAS/Shanghai. We were able to identify that a larger HSP sphere radius determined through our routines could be directly related to adsorption efficiencies. A similar trend was observed in the adsorption of BPA an pristine titania and its composites with varying amounts of graphene where the 20% titania-graphene hybrid had the largest HSP diameter and BPA adsorption. Thus, and as an important conclusion, accurately determined HSPs can give valuable insights into in-situ adsorption behavior of titania powder dispersions. They can assist in choosing target molecules/compounds that have a proximity to the HSPs of a photocatalyst synthesized via a particular method. Beyond photocatalysis, further experimental confirmation could be done by using the predictive nature of HSPs in terms of interaction of particles with (so far untested) liquids once the investigated material's HSPs are known. This could assist in predicting aspects of material-solvent interaction such as choice of solvents for slurry preparation (e.g., electrode inks, pharmaceuticals, nanomedicine).

Publications

• Efficient adsorption and sustainable degradation of gaseous acetaldehyde and o-xylene using rGO-TiO2 photocatalyst. Chemical Engineering Journal, 349, 708-718.
  Lin, Wenjiao; Xie, Xiaofeng; Wang, Xiao; Wang, Yan; Segets, Doris & Sun, Jing
  
• Ultrastable photodegradation of formaldehyde under fluorescent lamp irradiation by anti-reflection structure SnS2/TiO2 composite. Journal of Photochemistry and Photobiology A: Chemistry, 364, 725-731.
  Lu, Guanhong; Xie, Xiaofeng; Wang, Xiao; Shi, Gansheng; Zeng, Qinglong; Segets, Doris & Sun, Jing
  
• Towards a framework for evaluating and reporting Hansen solubility parameters: applications to particle dispersions. Nanoscale Advances, 3(15), 4400-4410.
  Bapat, Shalmali; Kilian, Stefan O.; Wiggers, Hartmut & Segets, Doris
  
• Hansen parameter evaluation for the characterization of titania photocatalysts using particle size distributions and combinatorics. Nanoscale, 14(37), 13593-13607.
  Anwar, Osama; Bapat, Shalmali; Ahmed, Jalil; Xie, Xiaofeng; Sun, Jing & Segets, Doris
  
• Determination of Hansen Parameters of Nanoparticles: A Comparison of Two Methods Using Titania, Carbon Black, and Silicon/Carbon Composite Materials. Particle & Particle Systems Characterization, 40(11).
  Anwar, Osama; Amin, Amin Said; Amin, Adil; Kräenbring, Mena‐Alexander; Özcan, Fatih & Segets, Doris