Investigation of fluorescence characterization and electrochemical behavior on the catalysts of nanosized Pt-Rh/γ-Al₂O₃ to oxidize gaseous ammonia

Abstract

This work describes the environmentally friendly technology for oxidation of ammonia (NH₃) to form nitrogen at temperatures range from 423K to 673K by selective catalytic oxidation (SCO) over a nanosized Pt-Rh/γ-Al₂O₃ catalyst prepared by the incipient wetness impregnation method of hexachloroplatinic acid (H₂PtCl₆) and rhodium (III) nitrate (Rh(NO₃)₃) with γ-Al₂O₃ in a tubular fixed-bed flow quartz reactor (TFBR). The characterization of catalysts were thoroughly measured using transmission electron microscopy (TEM), three-dimensional excitation-emission fluorescent matrix (EEFM) spectroscopy, UV-Vis absorption, dynamic light-scattering (DLS), zeta potential meter, and cyclic voltammetry (CV). The results demonstrated that at a temperature of 673K and an oxygen content of 4%, approximately 99% of the NH₃ was removed by catalytic oxidation over the nanosized Pt-Rh/γ-Al₂O₃ catalyst. N₂ was the main product in NH₃-SCO process. Further, it reveals that the oxidation of NH₃ was proceeds by the over-oxidation of NH₃ into NO, which was conversely reacted with the NH₃ to yield N₂. Therefore, the application of nanosized Pt-Rh/γ-Al₂O₃ catalyst can significantly enhance the catalytic activity toward NH₃ oxidation. One fluorescent peak for fresh catalyst was different with that of exhausted catalyst. It indicates that EEFM spectroscopy was proven to be an appropriate and effective method to characterize the Pt clusters in intrinsic emission from nanosized Pt-Rh/γ-Al₂O₃ catalyst. Results obtained from the CV may explain the significant catalytic activity of the catalysts.

Keywords

ammonia (NH₃) / nanosized Pt-Rh/γ-Al₂O₃ catalyst / excitation-emission fluorescent matrix (EEFM) / selective catalytic oxidation (SCO) / tubular fixed-bed reactor (TFBR)

References

[1] Galloway J N, Townsend A R, Erisman J W, Bekunda M, Cai Z, Freney J R, Martinelli L A, Seitzinger S P, Sutton M A. Transformation of the nitrogen cycle: recent trends, questions, and potential solutions. Science, 2008, 320(5878): 889–892

[2] Cui X, Zhou J, Ye Z, Chen H, Li L, Ruan M, Shi J. Selective catalytic oxidation of ammonia to nitrogen over mesoporous CuO/RuO₂ synthesized by co-nanocasting-replication method. Journal of Catalysis, 2010, 270(2): 310–317

[3] Amblard M, Burch R, Southward B W L. A study of the mechanism of selective conversion of ammonia to nitrogen on Ni/γ-Al₂O₃ under strongly oxidizing conditions. Catalysis Today, 2000, 59(3-4): 365–371

[4] Wang W, Padban N, Ye Z, Andersson A, Bjerle I. Kinetic of ammonia decomposition in hot gas cleaning. Industrial & Engineering Chemistry Research, 1999, 38(11): 4175–4182

[5] Schmidt-Szałowski K, Krawczyk K, Petryk J. The properties of cobalt oxide catalyst for ammonia oxidation. Applied Catalysis A, General, 1998, 175(1-2): 147–157

[6] Liang C, Li W, Wei Z, Xin Q, Li C. Catalytic decomposition of ammonia over nitrided MoNx/α-Al₂O₃ and NiMoNy/α-Al₂O₃ catalysts. Industrial & Engineering Chemistry Research, 2000, 39(10): 3694–3697

[7] Hung C M. Decomposition kinetics of ammonia in gaseous stream by a nanoscale copper-cerium bimetallic catalyst. Journal of Hazardous Materials, 2008, 150(1): 53–61

[8] Brüggemann T C, Keil F J. Theoretical investigation of the mechanism of the selective catalytic oxidation of ammonia on H-form zeolites. Journal of Physical Chemistry C, 2009, 113(31): 13860–13876

[9] Zhang L, He H. Mechanism of selective catalytic oxidation of ammonia to nitrogen over Ag/Al₂O₃. Journal of Catalysis, 2009, 268(1): 18–25

[10] Wang Z, Qu Z, Quan X, Wang H. Selective catalytic oxidation of ammonia to nitrogen over ceria-zirconia mixed oxides. Applied Catalysis A: General, 2012, 411-412(1): 131–138

[11] Song S, Jiang S. Selective catalytic oxidation of ammonia to nitrogen over CuO/CNTs: the promoting effect of the defects of CNTs on the catalytic activity and selectivity. Applied Catalysis B: Environmental, 2012, 117-118(5): 346–350

[12] Hung C M, Lai W L, Lin J L. Removal of gaseous ammonia in Pt-Rh binary catalytic oxidation. Aerosol and Air Quality Research, 2012, 12(4): 583–591

[13] Hung C M. Preparation, properties and cytotoxicity assessment of nanosized Pt-Rh composite catalyst for the decomposition of gaseous ammonia. Advanced Materials Research, 2011, 160-162: 1285–1290

[14] Hung C M. Application of Pt-Rh complex catalyst: feasibility study on the removal of gaseous ammonia. International Journal of Physical Sciences, 2012, 7(14): 2166–2173

[15] Hung C M. The study of catalytic oxidation ammonia reactivity using bimetallic PtRh particles as catalyst: electrocatalytic and electrochemical behavior. Advanced Science Letters, 2012, 8(1): 578–582

[16] Ohno T, Amirbahman A, Bro R. Parallel factor analysis of excitation-emission matrix fluorescence spectra of water soluble soil organic matter as basis for the determination of conditional metal binding parameters. Environmental Science & Technology, 2008, 42(1): 186–192

[17] Henderson R K, Baker A, Murphy K R, Hambly A, Stuetz R M, Khan S J. Fluorescence as a potential monitoring tool for recycled water systems: a review. Water Research, 2009, 43(4): 863–881

[18] Tang Z, Yu G, Liu D, Xu D, Shen Q. Different analysis techniques for fluorescence excitation-emission matrix spectroscopy to assess compost maturity. Chemosphere, 2011, 82(8): 1202–1208

[19] Anderson J A. Infrared study of CO oxidation over Pt-Rh/Al₂O₃ catalysts. Journal of Catalysis, 1993, 142(1): 153–165

[20] Choi J H, Park K W, Park I S, Nam W H, Sung Y E. Methanol electro-oxidation and direct methanol fuel cell using Pt/Rh and Pt/Ru/Rh alloy catalysts. Electrochimica Acta, 2004, 50(2-3): 787–790

[21] Stoyanovskii V O, Vedyagin A A, Aleshina G I, Volodin A M, Noskov A S. Characterization of Rh/Al₂O₃ catalysts after calcination at high temperatures under oxidizing conditions by luminescence spectroscopy and catalytic hydrogenolysis. Applied Catalysis B: Environmental, 2009, 90(1-2): 141–146

[22] Hung C M. Fabrication, characterization, and evaluation of the cytotoxicity of platinum-rhodium nanocomposite materials for use in ammonia treatment. Powder Technology, 2011, 209(1-3): 29–34

[23] Hu Z, Allen F M, Wan C Z, Heck R M, Steger J J, Lakis R E, Lyman C E. Performance and structure of Pt-Rh three-way catalysts: mechanism for Pt/Rh synergism. Journal of Catalysis, 1998, 174(1): 13–21

[24] Mulukutla R S, Shido T, Asakuru K, Kogure T, Iwasawa Y. Characterization of rhodium oxide nanoparticles in MCM-41 and their catalytic performances for NO-CO reactions in excess O₂. Applied Catalysis A: General, 2002, 228(1-2): 305–314

[25] Curtin T, Regan F O’, Deconinck C, Knűttle N, Hodnett B K. The catalytic oxidation of ammonia: influence of water and sulfur on selectivity to nitrogen over promoted copper oxide/alumina catalysts. Catalysis Today, 2000, 55(1-2): 189–195

[26] Sobczyk D P, de Jong A M, Hensen E J M, van Santen R A. Activation of ammonia dissociation by oxygen on platinum sponge studied with positron emission profiling. Journal of Catalysis, 2003, 219(1): 156–166

[27] Zhang S, Zhao Y. Facile preparation of organic nanoparticles by interfacial cross-linking of reversed micelles and template synthesis of subnanometer Au-Pt nanoparticles. Nano, 2011, 5(4): 2637–2646

[28] Larrivee E M, Elkins K M, Andrews S E, Nelson D J. Fluorescence characterization of the interaction of Al³⁺ and Pd²⁺ with Suwannee River fulvic acid in the absence and presence of the herbicide 2,4-dichlorophenoxyacetic acid. Journal of Inorganic Biochemistry, 2003, 97(1): 32–45

[29] Zhang Y, Geddes C D. Metal-enhanced fluorescence from thermally stable rhodium nanodeposits. Journal of Materials Chemistry, 2010, 20(39): 8600–8606

[30] Wu M L, Lai L B. Synthesis of Pt/Ag bimetallic nanoparticles in water-in-oil microemulsions. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2004, 244(1-3): 149–157

[31] Xu R. Progress in nanoparticles characterization: sizing and zeta potential measurement. Particuology, 2008, 6(2): 112–115

[32] Du H Y, Wang C H, Hsu H C, Chang S T, Chen U S, Yen S C, Chen L C, Shih H C, Chen K H. Controlled platinum nanoparticles uniformly dispersed on nitrogen-doped carbon nanotubes for methanol oxidation. Diamond and Related Materials, 2008, 17(4-5): 535–541

[33] Prasad K V, Chavdhari R V. Activity and selectivity of supported Rh catalysts for oxidative carbonylation of aniline. Journal of Catalysis, 1994, 145(1): 204–215

[34] Oliveira R T S, Santos M C, Nascente P A P, Bulhões L O S, Pereira E C. Nanogravimetric and voltammetric studies of a Pt-Rh alloy surface and its behavior for methanol oxidation. International Journal of Electrochemical Science, 2008, 3(8): 970–979

Acknowledgements

The authors would like to thank the National Science Council of China, for financially supporting this research under Contract No. NSC98-2221-E-132-003-MY3.

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2014 Higher Education Press and Springer-Verlag Berlin Heidelberg