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Nano-Catalyst Synthesized by Flame Spray Pyrolysis (FSP) for Visible Light Photocatalysis

Inturi, Siva Nagi Reddy
http://orcid.org/0000-0001-9483-6703
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511884949728835

Abstract Details

2017, PhD, University of Cincinnati, Engineering and Applied Science: Chemical Engineering.
The present dissertation work aims at developing of the photocatalysts which have significantly higher activity as well as stability in visible light. In our early steps we have developed a series of photocatalysts based on transition metals (M' = V, Cr, Fe, Co, Mn, Mo, Ni, Cu, Y, Ce, and Zr) incorporated TiO2 (Ti/M' = 20 atomic ratio) materials synthesized by a one-step liquid flame aerosol synthesis technique. Among all the catalysts tested, Cr-doped titania demonstrated a superior catalytic performance with a rate constant about 8-19 times higher than the rest of the metal-doped catalysts. We have optimized the Cr content in TiO2, the system with Ti/Cr atomic ratio 40 proven as a highly effective catalyst. Based on the characterization of the materials and reaction analysis, we proposed plausible reaction pathway for the catalytic activity under visible light conditions. Next, we studied the effect of leaching and stability of Cr-TiO2 nanoparticles synthesized by flame spray pyrolysis (FSP), co-precipitation, and sol-gel synthesis techniques. The leaching of the Cr into the liquid phase was found to be the primary cause of a reduction in the activity of the catalyst. We developed Si/Ti/Cr catalyst by FSP method which stabilizes and enhances the photocatalytic activity of the catalyst. Unlike the Cr/TiO2 systems, optimal flame-made Cr/Ti/Si catalyst established high efficiency under visible light, stability, and reusability without any Cr leaching even after five consecutive cycles. In the second half of the work, we successfully developed a novel rapid and continuous process for the synthesis of nitrogen-doped TiO2 (N-TiO2) with flame spray pyrolysis (FSP) equipment. The N incorporation into TiO2 by achieved by simple modification (addition of dilute nitric acid) in the precursor for the synthesis. The N atomic % in the range of 0.09 % to 0.15 % for the primary nitrogen source (nitric acid) has enhanced to remarkable 0.97 % when secondary N source was introduced. We also developed a model for the analysis of the effect of the synthesis conditions on the materials. We used the eulerian-lagrangian model to trace the particle formation and growth in the continuous fluid phase. The highest rate of phenol degradation was obtained for catalysts with secondary N source due to the increase in N content in the catalyst. The nitrogen was doped effectively and most nitrogen dopants are present in the chemical environment of (interstitial nitrogen) Ti-O-N and (substitutional nitrogen) O-Ti-N. The nitrogen doping concentration had an optimal value of 1.5 atomic % for the photocatalyst. Based on this we have also developed novel one-step synthesis route for S-doped TiO2 photocatalysts by flame spray pyrolysis (FSP) for visible light photocatalysis was developed. The as-synthesized S-modified titanium dioxide photocatalysts had sulfur (S6+) substituting for some of the lattice titanium atoms. This method is energy efficient, extremely simple, very effective, low cost, and could be effortlessly scaled up for large-scale fabrication. Our approach enables the synthesis of non-metal into metal/metal-oxide lattice by aerosol synthesis method without modifying the existing set-up.
Peter Panagiotis Smirniotis, Ph.D. (Committee Chair)
Anastasios Angelopoulos, Ph.D. (Committee Member)
Gregory Beaucage, Ph.D. (Committee Member)
Vesselin Shanov, Ph.D. (Committee Member)
Makram Suidan, Ph.D. (Committee Member)
409 p.
Chemical Engineering
Visible-Light Photocatalysis; Flame spray Pyrolysis; Doped-Titania; Photodegradation; Volatile Organic Compounds; Secondary Metal Contamination

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Citations

  • Inturi, S. N. R. (2017). Nano-Catalyst Synthesized by Flame Spray Pyrolysis (FSP) for Visible Light Photocatalysis [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511884949728835

    APA Style (7th edition)

  • Inturi, Siva Nagi Reddy. Nano-Catalyst Synthesized by Flame Spray Pyrolysis (FSP) for Visible Light Photocatalysis. 2017. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511884949728835.

    MLA Style (8th edition)

  • Inturi, Siva Nagi Reddy. "Nano-Catalyst Synthesized by Flame Spray Pyrolysis (FSP) for Visible Light Photocatalysis." Doctoral dissertation, University of Cincinnati, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511884949728835

    Chicago Manual of Style (17th edition)

ucin1511884949728835
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This open access ETD is published by University of Cincinnati and OhioLINK.