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Prasad, D. Hari,Park, S. Y.,Ji, H.-I.,Kim, H.-R.,Son, J.-W.,Kim, B.-K.,Lee, H.-W.,Lee, J.-H. AmericanChemical Society 2012 The Journal of Physical Chemistry Part C Vol.116 No.5
<P>In this study, Ce<SUB>0.65</SUB>Zr<SUB>0.25</SUB>RE<SUB>0.1</SUB>O<SUB>2−δ</SUB> (RE = Tb, Gd, Eu, Sm, Nd, Pr,and La)solid solutions were successfully prepared by the glycine-nitrateprocess and tested for CO oxidation activity. The X-ray diffractionresults confirmed the formation of complete Ce<SUB>0.65</SUB>Zr<SUB>0.25</SUB>RE<SUB>0.1</SUB>O<SUB>2−δ</SUB> solid solutions.The Raman spectroscopy measurements suggested the presence of oxygenvacancies due to defective structure formation and further evidencedthe formation of solid solution. The high-resolution transmissionelectron microscopy observations showed the nanocrystalline natureof the solid solutions. From X-ray photoelectron spectroscopy analysisit was revealed that the cerium, terbium, and praseodymium are presentin +3 and +4 oxidation states. The UV–vis diffuse reflectancespectroscopy indicated that the Pr<SUP>3+</SUP> ions in the Ce<SUB>0.65</SUB>Zr<SUB>0.25</SUB>Pr<SUB>0.1</SUB>O<SUB>2−δ</SUB> system provoked a significant increase in the Ce<SUP>3+</SUP> fractionon the surface. H<SUB>2</SUB> temperature-programmed reduction measurementsshowed an enhanced surface reduction at much lower temperatures forCe<SUB>0.65</SUB>Zr<SUB>0.25</SUB>Pr<SUB>0.1</SUB>O<SUB>2−δ</SUB> sample compared to others, indicating increased oxygen mobilityin these samples, which enable the enhanced oxygen diffusion at lowertemperatures. Significantly high CO oxidation activity is exhibitedby Ce<SUB>0.65</SUB>Zr<SUB>0.25</SUB>Pr<SUB>0.1</SUB>O<SUB>2</SUB> solid solution.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2012/jpccck.2012.116.issue-5/jp207107j/production/images/medium/jp-2011-07107j_0007.gif'></P>
Hari Prasad Uppara,Sunit Kumar Singh,Nitin Kumar Labhsetwar,Mudiyaru Subrahmanya Murari,Harshini Dasari 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.7
The synthesis of binary mixed oxide Ce-Hf (CH), ternary mixed oxide Ce-Hf-Ru (CHR), and Ce-Hf-Mg (CHM) has been attempted using the PVP-assisted sol-gel method. The structural and surface morphology of the prepared catalysts were investigated and studied for the generation of superoxides (O2 )/peroxides (O2 2) species and availability of lattice oxygen (O) during soot oxidation reactions. The successfully incorporated Hf4+/Mg2+ into ceria (CH, CHM) enhances the redox potential sites on nano-flake morphology, thus produces more oxygen vacancies (□). However, Ru4+/Hf4+ was not doped into the ceria structure in CHR catalyst; it showed lesser structural distortions generating fewer oxygen vacancies. In addition, it was observed that better performing catalysts should possess lower oxidation temperature and be catalytically stable. Indeed, the ternary oxide CHR featured excellent catalytic properties when compared with the others. However, CHM was found structurally and catalytically stable with self-regenerative capability even after the repeated soot oxidation experiments. Thus, the possible soot oxidation mechanism has been proposed on the prepared catalysts.
( Kannapu Hari Prasad Reddy ),( Youna Park ),( Jihyeon Song ),( Young-kwon Park ) 한국공업화학회 2021 공업화학 Vol.32 No.4
Catalytic ozonation of methyl ethyl ketone (MEK) has been examined over mesoporous MnOx/Al<sub>2</sub>O<sub>3</sub> (MA) catalysts developed by a solvent deficient method using two different manganese precursors including manganese chloride (C) and manganese sulfate (S) at room temperature. The maximum catalytic activities of MA with C (MEK removal efficiency and ozone decomposition of 98.4 and 93.7%, respectively) were higher than those of MA with S (MEK removal efficiency and ozone decomposition of 96 and 68%, respectively). Also the catalytic stability of MA with C was much higher than that of MA with S. The physico-chemical properties of catalysts are well correlated with the activity results, which confirmed that fine dispersion of MnOx species with high ratios of Mn<sup>3+</sup>/Mn<sup>4+</sup> and more acid sites are attributed to the higher catalyst stability for the MA-C catalyst.
Subrahmanya Hari Prasad Peri 대한공간정보학회 2023 Spatial Information Research Vol.31 No.4
The present study investigates the possible association between major air pollutants and COVID-19. We hypothesized that the post-lockdown surge in air pollution is the major cause of the increment in COVID-19 cases and deaths. The statistical results showed that pollutant concentrations of PM2.5 (20%), PM10(24%), SO2 (12%), and O3 (19%) were raised. So, we attempted to quantify the relative risk due to all major air pollutants by fitting generalized additive models. The results suggest that the pollution concentration escalated the COVID-19 cases and deaths. The pooled study suggests that for every 10 μg/m3 increment in pollutant concentration, an increment of COVID-19 cases is observed for PM2.5 (3%), PM10 (1%), SO2 (7.7%), and O3 (10%). Similarly, there is an increment in COVID-19 deaths for PM2.5 (2.8%), PM10 (1%), SO2 (4.5%), and O3 (7.2%). The spatial maps of relative risk revealed the most vulnerable regions due to each pollutant, thus steering the policymakers to implement region-specific mitigation strategies.
KANNAPU HARI PRASAD REDDY,Jyothi Yadagiri,Surendar Moogi,Eilhann E.Kwon,Su Shiung Lam,박영권 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.94 No.-
In this study, conversion of n-propanal to produce 2-methyl-2-pentenal (C6 compound, a fuel rangeprecursor) was carried out using AMW-SBA-15 catalyst synthesized from activated marble waste (AMW)consisting mainly of Ca2+ and Mg2+ ions. AMW-SBA-15 catalysts with different weight ratios of AMW/Si(6, 12, and 18 wt. %) were prepared using single step sol-gel method. The catalytic activities wereexamined using afixed bed continuous reactor over temperature ranging from 350 425 C underatmospheric pressure. The 12AMW-SBA-15 catalysts showed superior catalytic performance with npropanalconversion of 75 % and C-6 compound selectivity of 81 % at 375 C without the need ofdeactivation for 12 h. To elucidate the structure-activity relationship, all catalysts were characterizedusing a variety of techniques. The superior performance of 12AMW-SBA-15 was ascribed to the highsurface area and smaller particle size as well as the high hydrophobicity, which controlled the hydrationof Ca2+/Mg2+ ions during the reaction.
Chemical synthesis and characterization of CexZr1-xO2 powders by a modified solgel method
D.Hari Prasad,이종호,이해원,김병국,박종성 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.6
CexZr1-xO2 (x = 1, 0.7, 0.4, 0.2, 0) solid solution powders were successfully synthesized by a modified sol-gel method using a simple metal nitrate precursors as sources for cerium and zirconium which do not contain any hazardous and explosive precursor materials. X-ray diffraction (XRD) and Raman spectroscopy analyses revealed the formation of a solid solution depending on the ratio of the two oxides. In the modified sol-gel method, the composition range of the solid solution was wider than that from other methods. When the content of ZrO2 in the compound of CexZr1-xO2 was increased, the crystal structures were maintained as the cubic fluorite structures up to 60mol% of ZrO2 and the cubic phase was still predominant upto 80 mol% of ZrO2. A decrease in the crystallite size and an increase in the BET surface area were observed along with an increase of the Zr content in CexZr1-xO2 solid solutions. The powder morphologies were also investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis.
Control of phosphoric acid induced volume change in clays using fly ash
Chavali, Rama Vara Prasad,Reddy, P. Hari Prasad Techno-Press 2018 Geomechanics & engineering Vol.15 No.6
Volume changes of soils induced by inorganic acids cause severe foundation and superstructure failures in industrial buildings. This study aimed to assess the potential of fly ash to control volume changes in soils under acidic environment. Two soils such as black cotton soil predominant with montmorillonite and kaolin clay predominant with kaolinite were used for the present investigation. Both soils exhibited an increase in swelling subjected to phosphoric acid contamination. Ion exchange reactions and mineralogical transformations lead to an increase in swelling and a decrease in compressibility in black cotton soil, whereas phosphate adsorption and mineral dissolution lead to an increase in swelling and compressibility in case of kaolin clay. Different percentages of Class F fly ash obtained from Ramagundam national thermal power station were used for soil treatment. Fly ash treatment leads to significant reduction in swelling and compressibility, which is attributed to the formation of aluminum phosphate cements in the presence of phosphoric acid.