Browsing by Author "Harshini, H."

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A Negative Effect of Niobium-Doped Ceria on Soot Oxidation Activity‡
(John Wiley and Sons Inc, 2022) Patil, S.S.; Naik, S.; Ramesh, M.D.; Harshini, H.; Prasad Dasari, H.P.
Niobium-doped ceria catalysts were synthesized to study soot oxidation activity. X-Ray diffraction (XRD) and Raman analysis of the samples revealed the presence of a fluorite structure of CeO2 for all the doped samples. The T50 temperature of the pure CeO2 sample was more significant than that of bare soot. The high catalytic activity of the CeO2 catalyst can be attributed to the low crystallite size, high facet ratio, and the large Brunauer-Emmett-Teller (BET) surface area as compared to Nb-doped samples. The activation energy calculated by both Ozawa and KAS methods were found to be low for CeO2 when compared to Nb-doped samples. CeO2 resulted in better soot oxidation activity with low activation energy. © 2022 Wiley-VCH GmbH
Ceria-samarium binary metal oxides: A comparative approach towards structural properties and soot oxidation activity
(Elsevier B.V., 2018) Anjana, A.P.; Geethu, J.; P, M.R.; Prasad Dasari, H.P.; Lee, J.-H.; Harshini, H.; Bhaskar Babu, G.U.
Binary metal oxides of CeO2-Sm2O3 (CSx, x varies from 10 to 90 mol%) along with pure CeO2 and Sm2O3 were synthesised successfully by the EDTA-Citrate method. From XRD, Raman spectroscopy and UV–vis DRS results, the whole composition of metal oxides exist in three phases: (fluorite phase (F) (CS10-CS30), bi-phase (fluorite (F) + cubic (C)) (CS30-CS90) and cubic phase (C) (Sm2O3)). For CSx samples, the calculated band gap energy values obtained from the UV–vis DRS results were in between 3.0–5.1 eV and fluorite phase samples (CS10–CS30) displayed lower band gap energy values (3.04–3.07 eV) than compared to the samples in other phases. Similarly, from XPS analysis, fluorite phase samples (CS10–CS30) showed higher surface oxygen vacancy concentration than compared to samples in other phases. Catalytic activity for soot oxidation is carried out on CSx samples, and the T50 temperature is in between 480–540 °C. Fluorite phase samples (CS10 CS30) showed higher surface area, lower degree of agglomeration, lower band gap energy, higher oxygen vacancy concentration and better catalytic activity for soot oxidation. Among all the CSx samples, CS10 sample displayed highest surface area (38 m2/g), lowest degree of agglomeration (0.36), lowest band gap energy (3.04 eV), highest oxygen vacancy concentration (64%) and highest soot oxidation activity (T50 = 480 °C). The order of the soot oxidation activity of CSx samples followed the same trend of band gap energy values. © 2018 Elsevier B.V.
Diesel soot oxidation over Mn–Pr–Ce oxide catalysts: structural changes and the impact of Mn doping
(Royal Society of Chemistry, 2025) Patil, S.S.; Prasad Dasari, H.P.; Shirasangi, R.; Harshini, H.
The soot oxidation activity of manganese-doped ceria-praseodymium catalysts, synthesized via solution combustion synthesis, was evaluated. The analyses performed with XRD and Raman spectroscopy indicated that the Mn-doped CP catalysts displayed the typical fluorite structure of CeO2. The addition of Mn to CP led to a reduction in crystallite size from 14 nm to below 10 nm. The F2g Raman active mode of fluorite-structured Ce and the oxygen vacancies resulting from the addition of Mn and Pr (bands B 560 cm–1 to 580 cm–1) were consistently observed across all Mn-doped CP catalysts. 15 and 20 Mn-CP exhibited an additional secondary phase identified as Mn2O3. The analysis of BET surface area and BJH pore size revealed that the Mn-doped CP catalysts exhibited both micro and mesoporous characteristics. The H2-TPR and O2-TPD profiles indicated enhanced reducibility resulting from the incorporation of Mn and Pr into CeO2-doped catalysts. The improved T50 (365 ± 1 1C) for the 5 Mn-CP catalytic system is primarily due to its increased specific surface area of 45 m2 g–1 and the presence of active surface adsorbed oxygen species identified in the XPS and O2-TPD studies. 5 Mn-CP exhibited the lowest activation energy value compared to all other Mn-doped catalysts. © 2025 The Author(s)
Dilatometer studies on LAMOX based electrolyte materials for solid oxide fuel cells
(Elsevier Ltd, 2021) Das, A.; Lakhanlal, u.; Shajahan, I.; Prasad Dasari, H.P.; Saidutta, M.B.; Harshini, H.
The present study deals with the citrate complexion synthesis of LAMOX-based Solid Oxide Fuel Cell (SOFC) electrolyte materials (La1.8Dy0.2Mo2-xWxO9 (x = 0, 0.1, 0.2, 0.5, and 1), La1.8Dy0.2Mo2-xGaxO9 (x = 0.1 and 0.2), and La1.8Dy0.2Mo2-xVxO9 (x = 0.025, 0.05, 0.1, and 0.2)) and their characterization to understand the sintering behaviour and phase stability. From the dilatometer studies, the linear shrinkage and shrinkage rate of the LDMW (x = 0, and 0.1) showed better shrinkage than LM and LDM. Gallium addition (LDMG) and Vanadium addition (LDMV) showed a negative impact on shrinkage behaviour. In the temperature range of 500–580 °C, the abrupt change in shrinkage rate showed the transition of phase from ? to ? for the LM. The modification of LM to LDM, LDMW, and LDMV suppressed the formation of the ? phase. During thermal expansion behaviour study in the temperature range of 100–500 °C and 550–800 °C, the LM sintered pellet showed the coefficient of thermal expansion (CTE) values of 13.3 ? 10?6/°C and 21.6 ? 10?6/°C respectively. The LDM and LDMW sintered pellets showed the CTE values in the range of 14–15 ? 10?6/°C and 16–19 ? 10?6/°C, respectively. The relative density of the sintered pellets (1100 °C/5 h in air) (LM, LDM, LDMW, and LDMG (x = 0.1)) is found to be >90%. It provides the suitability of these materials for further investigation as electrolytes of SOFCs/SOECs. © 2020 Elsevier B.V.
Effect of Ag loading on praseodymium doped ceria catalyst for soot oxidation activity
(Springer, 2022) Govardhan, P.; Anjana, A.P.; Patil, S.S.; Prasad Dasari, H.P.; Harshini, H.; Shourya, A.
Silver-loaded praseodymium doped ceria (XAg/PDC) was synthesized by microwave-assisted co-precipitation and wetness impregnation. XRD confirms the fluorite structure of ceria without secondary phase, and Raman spectroscopy represents the increased generation of oxygen vacancies with Ag loading. The TEM analysis shows lattice fringes corresponding to both CeO2 and Ag on the surface. The BET and BJH analysis of catalyst confirms the high porosity accompanied by high surface area and pore diameter of 5Ag/PDC and 15Ag/PDC, making it more active for the oxidation reaction. From the XPS analysis the amount of surface Ce3+ concentration and the surface chemisorbed oxygen species (O2 2) is high for 5Ag/PDC and 15Ag/PDC, in line with XRD and Raman results. The soot oxidation T50 temperature follows the trend: 5Ag/PDC∼15Ag/PDC<10Ag/PDC<20Ag/PDC<0Ag/PDC. The Ag loading increased the surface reducibility of cerium ions and thus 5 wt% was optimized. © 2021, The Korean Institute of Chemical Engineers.
Effect of ionic radius on soot oxidation activity for ceria-based binary metal oxides
(John Wiley and Sons Ltd vgorayska@wiley.com Southern Gate Chichester, West Sussex PO19 8SQ, 2019) Anjana, A.P.; Prasad Dasari, H.P.; Harshini, H.; Babu, G.U.B.
CeO2 (C) along with binary metal oxides of Ce0.9M0.1O2-? (M = Sn, Hf, Zr, Gd, Sm, and La; CT, CH, CZ CG, CS, and CL) are synthesized using the EDTA–citrate method. Samples having an ionic radius smaller (CT, CH, and CZ) and larger (CG, CS, and CL) than Ce4+ are classified separately, and their soot oxidation activity is analyzed. The incorporation of dopant is confirmed from lattice constant variation in X-ray diffraction result. The critical descriptors for the activity are dopant nature (ionic radius and oxidation-state), single-phase solid solution, lattice strain, reactive (200) and (220) planes, Raman intensity ration (Iov/IF2g), optical bandgap, reducibility ratio, and surface oxygen vacancy. Smaller ionic radius, isovalent dopants (CH and CZ) create a defect site by lowering the optical bandgap along with improved surface oxygen vacancy concentration and thus enhanced soot oxidation activity. Aliovalent dopant with larger ionic radius shows the involvement of lattice oxygen in oxidation reaction by charge compensation mechanism. CL showed the highest activity amongst larger ionic radius samples. © 2019 Curtin University and John Wiley & Sons, Ltd.
Effect of morphology and oxidation state of nickel on diesel soot oxidation activity
(Elsevier Ltd, 2022) Vijay, M.P.A.; Patil, S.S.; Madhura, D.R.; Anjana, A.P.; Gouramma, P.; Prasad Dasari, H.P.; Arya, S.B.; Harshini, H.
NiO sample is synthesized using the EDTA citrate complex method and calcined at 600 °C/5 h. Ni sample was acquired by reducing NiO to Ni at 600 °C in 4% H2/N2 atmosphere. Its physicochemical properties were obtained by XRD and Raman spectroscopy analysis, where it confirmed the complete reduction of NiO to Ni. SEM and TEM micrographs revealed a drastic particle growth for the Ni, indicating NiO sintering during the reduction process and a considerable surface morphology change. Ozawa and KAS methods were used to calculate the mean activation energy (Ea) value. NiO displayed lower Ea than Ni. Hence, NiO showed better catalytic activity than Ni. © 2022
Effect of Nd-doping on soot oxidation activity of Ceria-based nanoparticles synthesized by Glycine Nitrate Process
(Elsevier B.V., 2019) Patil, S.S.; Prasad Dasari, H.P.; Harshini, H.
Neodymium-doped Ceria (NDC, Nd = 0, 1, 3, 5, 10, 20 and 30 mol %) catalysts were successfully synthesized by Glycine-Nitrate-Process (GNP) and tested for soot oxidation activity. For all NDC catalysts, XRD and Raman spectroscopy analyses showed a fluorite structure of ceria having an F2gRaman active symmetric breathing mode (O-Ce-O). 1NDC catalyst displayed better T50 temperature (427?C) followed by 0NDC (435?C), and 30NDC showed the highest T50 temperature (460?C). From XPS analysis, 1NDC and 0NDC catalysts showed a high amount of Ce3+ concentration and the surface-active oxygen species than compared to other NDC catalysts and thus, resulted in better soot oxidation activity indicating that the surface Ce3+ concentration and surface-active oxygen species play a key descriptor role in tuning the soot oxidation activity of NDC catalysts. © 2019 Elsevier B.V.
Effect of synthesis method on structural properties and soot oxidation activity of gadolinium-doped ceria
(Springer International Publishing kasia@cesj.com, 2018) Anjana, A.P.; Gadiyar, H.J.; Surendran, M.; Rao, A.S.; Prasad Dasari, H.P.; Harshini, H.; Babu, G.U.B.
Abstract: EDTA–citrate complex and solvothermal methods were adopted for the synthesis of gadolinium-doped ceria (GDC) (Ce0.9Gd0.1O2) solid solution, and the obtained GDC sample is tested for soot oxidation activity. Based on XRD results, it was evident that the reactive facet planes of {100} and {110} were highly intense [intensity ratio (%) of (200)/(100) (34.2%) and (220)/(111) (51.2%)] for GDC prepared by the EDTA–citrate method in comparison with the solvothermal method, and this highly intense reactive facet plane correlates to the lower energy for oxygen vacancy formation. Apart from the smaller crystallite size (10 nm) the GDC sample prepared by the EDTA–citrate method displayed lower band gap energy (2.99 eV), higher ratio of reducibility (45.45%) and lower binding energy (528.8 eV) for surface-adsorbed oxygen. The GDC obtained by EDTA–citrate method displayed a better soot oxidation activity (T50 = 468 °C) than compared to the GDC obtained by solvothermal method (T50 = 500 °C). The obtained results significantly show that the synthesis method plays a crucial role in controlling the structural properties and in enhancing the soot oxidation activity. © 2018, Institute of Chemistry, Slovak Academy of Sciences.
Isoconversional Kinetic Analysis and ANN-Based Prediction of Metformin Pyrolysis for Sustainable Waste Management
(American Chemical Society, 2025) Potnuri, R.; Lenka, M.; Sankar Rao, C.; Harshini, H.
Pharmaceutical waste poses a growing environmental concern due to its persistence and potential ecological impacts, necessitating effective and sustainable management strategies. This study investigates the pyrolysis of metformin as a means to valorize pharmaceutical waste within a circular economy framework. Pyrolysis experiments conducted on 500 mg of metformin demonstrated the formation of liquid-phase products, characterized by GC–MS, which revealed a high concentration of the active pharmaceutical ingredient (API) alongside carbonaceous, nitro, and acidic compounds. Comprehensive thermogravimetric analyses at heating rates of 10, 20, 30, and 40 °C/min were performed to evaluate the thermal decomposition behavior. Kinetic parameters were determined using four isoconversional methods, namely KAS, FWO, Starink, and FRD, yielding average activation energies of 101.4, 105.8, 101.4, and 111.1 kJ/mol, respectively. Thermodynamic parameters (?G, ?H, and ?S) were also calculated to gain further insights into the decomposition process. Additionally, an ANN model was developed using temperature and heating rate as inputs to predict mass loss, achieving accurate estimations with an optimized architecture comprising two hidden layers. GC–MS analysis of the pyrolysis liquid identified a high concentration of the API, along with carbonaceous, nitro, and acidic compounds. These findings highlight the potential for API recovery and reuse, as well as the valorization of byproducts for energy or chemical synthesis. The potential recovery of APIs for reuse and the utilization of byproducts as fuels or chemical precursors underscore pyrolysis as a promising route for sustainable pharmaceutical waste management and circular economy integration. © 2025 The Authors. Published by American Chemical Society
Microwave assisted catalytic co-pyrolysis of banana peels and polypropylene: experimentation and machine learning optimization
(Royal Society of Chemistry, 2025) Rajpurohit, N.S.; Sinha, S.; Ramesh, R.; Sankar Rao, C.; Harshini, H.
The growing accumulation of agricultural and plastic waste poses serious environmental challenges, necessitating sustainable and efficient valorization strategies. This study investigates the microwave-assisted catalytic co-pyrolysis of banana peels and polypropylene, using graphite as a susceptor and potassium hydroxide as a catalyst. Experiments were conducted by varying biomass and plastic quantities and microwave power levels to study their effects on product yields and thermal performance. The process effectively converted waste materials into valuable products, with oil yield increasing with microwave power and optimized biomass-to-plastic ratios. The rate of mass loss and heating rate were found to significantly influence overall conversion efficiency. A support vector regression (SVR) model was developed to predict yields based on input parameters, achieving a coefficient of determination ranging from 0.81 to 0.99, which demonstrates the reliability of machine learning in capturing complex thermochemical behavior. 3D plots illustrated the nonlinear effects of process variables on yields. Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) analyses of char confirmed functional groups and crystalline phases, suggesting its suitability for applications like adsorbents or catalysts. Brunauer-Emmett-Teller (BET) analysis showed multilayer adsorption, while thermogravimetric analysis (TGA) highlighted distinct thermal degradation patterns of the feedstocks. These results affirm the promise of integrating experiments with ML for efficient waste-to-energy conversion. © 2025 The Royal Society of Chemistry.
Potential of CoMn2O4 spinel as soot oxidation catalyst and its kinetics thereof
(Nature Research, 2025) Rajagopal, R.; Patil, S.S.; Prasad Dasari, H.P.; Harshini, H.; Sundarabal, S.
Efficient catalysts for soot oxidation are critical for mitigating environmental pollution. In this study, CoMn2O4 spinel catalysts were synthesised using reverse co-precipitation and co-precipitation methods to evaluate their performance in soot oxidation and kinetic behaviour. All samples exhibited a tetragonal phase (XRD) and spherical morphology with rough surfaces (SEM). Raman spectroscopy confirmed structural disorder and oxygen vacancies, while XPS analysis revealed the presence of low-valence Mn ions, facilitating oxygen vacancy formation critical for soot oxidation. Additionally, the co-existence of Co and Mn ions contributed to a synergistic effect, enhancing the catalytic properties of the spinel structure. The reverse co-precipitation method produced a catalyst with a higher concentration of oxygen vacancies and active oxygen species among the samples. This sample demonstrated superior catalytic performance, achieving a T50% of 424 °C, low activation energy (153 kJ/mol) and pre-exponential factor (25 min? 1). Soot TPR analysis highlighted the role of catalyst reducibility, while thermogravimetric analysis revealed that activation energy and pre-exponential factors were influenced by surface composition. These findings provide valuable insights into the design of efficient catalysts for soot oxidation, emphasising the importance of synthesis methods and surface characteristics. © The Author(s) 2025.
Promotional effect of nickel addition on soot oxidation activity of Ce0.9Pr0.1O2 oxide catalysts
(Springer, 2020) Rajvanshi, K.; Patil, S.S.; Lakhanlal, u.; Prasad Dasari, H.P.; Saidutta, M.B.; Harshini, H.
The present study investigates the promotional effect of Ni addition on soot oxidation activity of Ce0.9Pr0.1O2 oxide catalysts. A series of xNi-PDC (x= 0, 3, 5, 7, 10, 15, and 20 mol%) catalysts were synthesized by solution combustion synthesis method and characterized by XRD, Raman spectroscopy and TEM analysis. XRD and SAED patterns of the catalysts show cubic fluorite structure of ceria with an average crystallite size of 6–8 nm, and only 20Ni-PDC display NiO as a secondary phase. Raman spectra of xNi-PDC catalysts display an increase in oxygen vacancies. With a minimum addition of 10 mol% Ni to PDC, i.e., the 10Ni-PDC catalyst showed optimum soot oxidation activity (T50 = 360 °C) than compared to PDC and other Ni-PDC catalysts. Lattice strain and oxygen vacancies played a key descriptor role in showing better soot oxidation activity of the 10Ni-PDC catalyst. From the soot oxidation kinetic studies, the activation energy obtained by Ozawa plots for the 10Ni-PDC catalyst is 137 kJ/mol. © 2020, Institute of Chemistry, Slovak Academy of Sciences.
Solubility Limits of Ceria-Zirconia-Lanthana Solid-Solutions
(Elsevier Ltd, 2017) Abbas, Z.; Surendran, M.; Anjana, P.A.; Jidev, P.K.; Harshini, H.; Sudhakar Naidu, N.; Anandhan, S.; Bhat, K.U.; Bhaskar Babu, G.U.; Prasad Dasari, H.P.
We demonstrate, the solubility limits of Ceria-Zirconia-Lanthana (CZLa) solid-solutions with the increase in heat-treatment temperature from 600Â°C to 1300Â°C. CZLa nano-crystalline samples were successfully synthesized by EDTA-Citrate complex method and were characterized by Raman Spectroscopy (RS) and Transmission Electron Microscopy (TEM) analysis. With an increase in temperature, it is noticed that the solubility limit is decreased in CZLa system. At 600Â°C, a very good solubility is observed in CZLa system and is confirmed from RS analysis. At higher heat-treatment temperatures (1000 and 1300Â°C), with an increase in La content, Zr precipitated in the CZLa system and is confirmed from RS analysis. The reason for such kind of behavior in this CZLa system is clearly explained in this work. Â© 2017 Elsevier Ltd.
Soot Oxidation Activity of Redox and Non-Redox Metal Oxides Synthesised by EDTA–Citrate Method
(Springer New York LLC barbara.b.bertram@gsk.com, 2017) Anjana, A.P.; Prasad Dasari, H.P.; Lee, J.-H.; Harshini, H.; Babu, G.U.B.
Abstract: In the present study, redox (CeO2, SnO2, Pr6O11 and Mn3O4) and non-redox (Gd2O3, La2O3 ZrO2 and HfO2) metal oxides were successfully synthesised using the EDTA–citrate complexing method and tested for soot oxidation activity. The characterization of the metal oxides is carried out using FTIR, XRD, BET surface area, pore volume analyser, SEM and TEM. The redox nature and metal–oxygen bond information of the metal oxides are obtained from XPS analysis. In redox metal oxides, three critical parameters [lattice oxygen binding energy, reduction temperature and ?r (ionic size difference of the corresponding metal oxide oxidation states)] govern the soot oxidation activity. Among the redox metal oxide samples, Mn3O4 and Pr6O11 samples showed lower binding energy for oxygen (O?—529.4, 528.9 eV respectively), lower reduction temperature (T?—317 and 512 °C respectively) and have smaller ?r value (9 pm and 17 pm respectively). Thus, displayed a better soot oxidation activity (T50 = 484 and 482 °C respectively) than compared to other redox metal oxides. Among the non-redox metal oxides, HfO2 sample displayed higher BET surface area (21.06 m2/g), lattice strain (0.0157), smaller ionic radius (58.2 pm) and higher relative surface oxygen ratio (58%) and thus resulted in a significantly better soot oxidation activity (T50 = 483 °C) than compared to other non-redox metal oxides. Graphical Abstract: [Figure not available: see fulltext.]. © 2017, Springer Science+Business Media, LLC.
Soot Oxidation Kinetics on Nickel Oxide: Effects of Various Synthesis Techniques
(Pleiades Publishing, 2024) Patil, S.S.; Prasad Dasari, H.P.; Gouramma, P.; Harshini, H.
Abstract: Nickel oxide (NiO) nanoparticles were synthesized using four different methods: microwave co-precipitation (MCP), solution combustion synthesis (SCS), direct nitrate calcination (DNC), and the sol-gel process (SGP), incorporating organic additives such as glucose and fructose. X-ray diffraction and Raman spectroscopy analyses revealed that the NiO nanoparticles formed a face-centered cubic phase characterized by Ni–O bond stretching. The SCS method produced NiO nanoparticles with higher lattice strain, smaller crystallite size, and an increased facet ratio ({110}) compared to the other methods. Transmission electron microscopy indicated that the order of nano-agglomeration size for the NiO nanoparticles was DNC > MCP > SGP > SCS. The NiO nanoparticles synthesized via SCS, SGP and MCP exhibited irregular hexagonal shapes. Among the synthesized nanoparticles, those produced by the SCS method demonstrated the highest catalytic activity (T50 = 478°C), followed by DNC (T50 = 492°C), MCP (T50 = 495°C), and SGP (T50 = 538°C). A kinetic study was conducted to evaluate key parameters, including activation energy, preexponential factor, and reaction model. The experimental curves of soot conversion were compared with theoretical curves derived from the evaluated kinetic parameters. The NiO nanoparticles synthesized via SCS exhibited the highest kinetic activity with the enhanced reaction rate at lower temperatures. © Pleiades Publishing, Ltd. 2024.
Studies on the Solid Oxide Cell Perovskite Electrode Materials for Soot Oxidation Activity
(Springer, 2019) Shenoy, C.S.; Patil, S.S.; Govardhan, P.; Shourya, A.; Prasad Dasari, H.P.; Saidutta, M.B.; Harshini, H.
Solid oxide cell (SOC) perovskite electrode materials (BSCF (Ba0.5Sr0.5Co0.8Fe0.2O3-?), LSCF (La0.6Sr0.4Co0.2Fe0.8O3-?) and LSCM (La0.75Sr0.25Cr0.5Mn0.5O3-?)) were synthesised using microwave-assisted reverse-strike co-precipitation method and tested for soot oxidation activity. The calcined perovskite materials were characterized using FT-IR, XRD, SEM and BSE, BET and BJH and XPS analysis. The mean activation energy for soot oxidation was calculated from Ozawa plots at various heating rates (5, 10, 15 and 20 K/min) at different levels of soot conversions (T10 to T90) for BSCF, LSCM and LSCF perovskite materials and was around 133 ± 11.5, 138 ± 9.9 and 152 ± 7.2 kJ/mol, respectively. Irrespective of the heating rates, BSCF material showed the lowest T50 temperature than compared to other samples, and it is correlated to the presence of Fe3O4 as a secondary phase. © 2019, Springer Nature Switzerland AG.
Surface morphology and phase stability effect of Ceria-Hafnia (CHx) binary metal oxides on soot oxidation activity
(Elsevier B.V., 2018) Anjana, A.P.; Prasad Dasari, H.P.; Harshini, H.; Babu, G.U.B.
CeO2-HfO2 (CHx) binary metal oxides over whole composition range (0–100%) are synthesised using the EDTA-Citrate method and calcined at 600 °C/5 h. From XRD analysis, the sample series are classified as fluorite (F) phase for CH10-CH30, hybrid (F + M) phase for CH40-CH90 and monoclinic (M) phase for CH100 sample, respectively and the results were further confirmed using Raman spectroscopy. From SEM analysis, a clear surface morphology change is noticed for fluorite, hybrid and monoclinic phases of the CHx binary metal oxides. Further, Selected Area Electron Diffraction (SAED) analysis also confirmed the single and hybrid phases of CHx binary metal oxides. The soot oxidation for the CHx binary metal oxides displayed high catalytic activity for Fluorite phase (CH10 ? CH30) samples and a decrease in catalytic activity is noticed for the Hybrid phase (CH40 ? CH90) samples. The change in catalytic activity coincides with the change in the surface morphology and phase change for the CHx binary metal oxides. Among the Fluorite phase samples, CH10 sample displayed the highest catalytic activity (T50 = 430 °C) with higher surface area (29 m2/g), lower particle size (26 nm), lower degree of agglomeration (? = 2.8) higher surface oxygen concentration (44%). Isothermal-Time-on-stream (ITOS) analysis also showed that the CH10 sample can achieve T50 in a shorter time than compared to other CHx binary metal oxides. Surface morphology and phase stability can also play as key descriptors in screening CHx binary metal oxides for soot oxidation activity. © 2018 Elsevier B.V.