ZrO2 Catalysts Research Articles

N2O Assisted Ethane Transformation into Ethylene Using NiO−CeO2−ZrO2 Catalysts

AbstractNiO−CeO2 and NiO−CeO2−ZrO2 catalysts have been synthesized, electrochemically characterized (Mott‐Schottky (MS) measurements and Electrochemical Impedance Spectroscopy), physicochemically characterized (by N2 adsorption, XRD, Transmission Electron Microscopy and XPS) and tested in the N2O assisted ethane oxydehydrogenation. The use of low Zr‐loadings (Zr/Ce=0.1 at. ratio) has led to the optimal results in the ethylene production, improving those obtained by the Zr‐free NiO−CeO2 catalyst. However, high Zr‐loadings have meant a decrease in the olefin production. The catalytic results obtained have been explained considering the amount of oxygen vacancies, the crystalline phases formed and, especially, the nature of the surface Ni species. Importantly, the use of N2O as an oxidizing agent leads to a remarkable improvement in the selectivity to the olefin compared to that obtained employing molecular O2. Then, for a given ethane conversion the selectivity to ethylene is ca. 15 points higher using N2O than using O2. Another additional positive aspect of this NiO−CeO2−ZrO2 catalyst is its high catalytic stability.

Kinetic investigation of dry reforming of methane reaction over Ni–Rh/ZrO2–Al2O3 catalyst using Langmuir-Freundlich isotherm

The study involved conducting kinetic measurements for the dry reforming of methane (DRM) over a Ni–Rh/Al2O3 (85%)-ZrO2(15%) catalyst under a wide range of operating conditions (temperature: 500–900 °C, total flow rate of the inlet feed: 50–100 mL/min). The support material was prepared using the sol-gel method, followed by impregnation of Ni–Rh catalyst on the incipient wetness of the Al2O3–ZrO2 support. The calcined, reduced and spent samples were characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), inductively coupled plasma atomic emission spectrometer (ICP-AES), N2 adsorption/desorption and CHNS analyzer, and tested for activity, yield and stability in DRM reaction. Furthermore, kinetic behavior of Ni–Rh/Al2O3–ZrO2 catalyst in DRM process was investigated by assuming DRM and reverse water-gas shift (RWGS) reactions take place on two kinds of different active sites. Experimental data were fitted using rate expressions based on the Langmuir-Freundlich (LF) isotherm for DRM and RWGS reactions. The activation energy for the DRM reaction was optimized at 43.62 kJ/mol, falling within the reported literature range of 24.73–108.9 kJ/mol. Statistical indices indicated that the kinetic model accurately predicted CO2 conversion compared to other responses, with an error of 12.054%. The computed and experimental trends for CH4 and CO2 conversions, H2 and Co yield in terms of temperature were similar with each other and the difference between the calculated and experimental trends was lower for conversions compared to yields.

Enhancement and sulfur poisoning mechanism of Ce doped ZrO2 catalyst in COS hydrolysis at low-temperature

In order to achieve efficient and longer-lifespan removal of carbonyl sulfide (COS), a high-performance catalyst for hydrolysis is needed urgently. In this study, Ce doped ZrO2 oxides are used to remove COS with or without H2O. The results showed that the doping of Ce significantly improves the removal of COS by ZrO2 and obtains a sulfur capacity of 155.4 mgS/g at 70 °C, but there is still accompanied by sulfur poisoning. The characterization reveals that CeO2 has a cubic phase, ZrO2 has a mixed phase of tetragonal and monoclinic, and Ce-doped Zr with different ratio of Ce/Zr forms a Ce-Zr solid solution. Ce and Ce-Zr oxides have Ce3+/Ce4+ pairs, adsorbed oxygen species and surface oxygen vacancies, while ZrO2 has adsorbed oxygen and surface oxygen vacancies, the presence of which can promote the dissociation of H2O and surface adsorption of COS. ZrO2 has abundant medium-strong basicity while CeO2 has abundant weak and strong basicity, and different proportions of Ce/Zr adjust the surface basic strength, basic amount and surface redox property of Ce-Zr solid solution, which changes the adsorption and hydrolysis of COS and H2O and related oxidation reactions on Ce and Zr, thereby changing the sulfur poisoning. Ce has abundant –OH groups, which can rapidly adsorb COS, leading to hydrolysis and direct oxidation of COS in the absence of H2O, while the OH groups on ZrO2 promote the hydrolysis of COS to H2S. Although suitable Ce-doped ZrO2 improves the removal efficiency of COS, it still inevitably leads to the sulfur poisoning, but the presence of Zr could change the sulfation degree of CeO2 and the Claus reaction.

Direct Synthesis of Dimethyl Carbonate from Methanol and CO2 over ZrO2 Catalysts Combined with a Dehydrating Agent and a Cocatalyst

Zirconia nanocrystals as catalysts for the direct synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide have received significant interest recently. In this paper, three zirconia-based catalysts presenting different monoclinic and tetragonal phase contents are prepared and characterized by X-ray diffraction (XRD), N2 adsorption–desorption, transmission electron microscopy (TEM), and temperature-programmed desorption of NH3 and CO2 (NH3-TPD and CO2-TPD). The catalytic performances of these solids are evaluated in terms of DMC production. This production is low when using the bare zirconias, but it is significantly increased in the presence of 1,1,1-trimethoxymethane (TMM) playing the role of a dehydrating agent, which shifts the thermodynamic equilibrium. Moreover, the production of DMC is further improved by adding a second solid catalyst (cocatalyst), the molecular sieve 13X, to accelerate the hydration of TMM. Hence, the molecular sieve 13X plays a dual role by trapping water molecules formed by the reaction of DMC synthesis and providing strong acidic sites catalyzing TMM hydrolysis. To the best of our knowledge, the combination of two solid catalysts in the reaction medium to accelerate the water elimination to obtain higher DMC production from CO2 and methanol has never been reported.

The effect of supported metal Species on soot oxidation over PGM/CeO2-ZrO2

Abstract Herein is studied the soot oxidation over platinum group metal oxide/CeO2–ZrO2 (PGM/CZ) catalysts. The ability to capture gas-phase oxygen was in sequence of Ru/CZ > Rh/CZ > Ir/CZ > Pt/CZ > Pd/CZ. A soot oxidation test by TG-DTA showed that Ru/CZ, Rh/CZ, and Ir/CZ are highly active catalysts. It was found that there is a good correlation between the ability to capture gas-phase oxygen and soot oxidation activity. TEM observation revealed that soot oxidation mainly occurs at the interface between soot and CZ surfaces. The Ea values and soot oxidation test using labelled oxygen suggest that highly active catalysts oxidize soot by CZ lattice oxygen. For Ir/CZ, soot oxidation at 270 °C occurred due to the reduction by soot. Ru/CZ and Rh/CZ captured gas-phase oxygen spontaneously below 250 °C, resulting in soot oxidation at 270 °C. H2-TPR results suggest that the reactivity of lattice oxygen in the CZ surface, improved by PGM, is also related to soot oxidation activity. This suggests that the ability to capture gas-phase oxygen and the reactivity of lattice oxygen in the CZ surface determine the soot oxidation activity, and that Ru, Rh, and Ir have the effect of enhancing these properties.

Ni-Sr/TiZr for H2 from methane via POM: Sr loading & optimization.

Achieving remarkable H2 yield with significantly high H2/CO over Ni-based catalysts through partial oxidation of methane (POM) is a realistic approach to depleting the concentration of CH4 and using H2 and CO as synthetic feedstock. This study examined Ni catalysts on titania-zirconia for methane conversion via POM at 600 °C and atmospheric pressure. The addition of strontium to the catalyst was explored to improve its performance. Catalysts were characterized by X-ray diffraction, Raman-infrared-UV-vis spectroscopy, and Temperature-programmed reduction-desorption techniques (TPR, TPD). 2.5 wt% Sr addition induced the formation of the highest concentration of extreme basic sites. Interestingly, over the unpromoted catalyst, active sites are majorly generated by hardly reducible NiO species whereas upon 2.5 wt% promoted Sr promotional addition, most of active sites are derived by easily reducible NiO species. 45% CH4 conversion and 47% H2 yield with H2/CO = 3.5 were achieved over 2.5 wt% Sr promoted 5Ni/30TiO2 + ZrO2 catalyst. These results provide insight into the role of basic sites in enhancing activity through switching indirect pathways over direct pathways for POM. Further process optimization was carried out in the range of 10 000-22 000 SV, 0.35-0.75 O2/CH4, and 600-800 °C reaction temperature over 5Ni2.5Sr/30TiO2 + ZrO2 by using central composite design under response surface methodology. The optimum activity as high as ∼88% CH4 conversion, 86-87% yield of H2, and 2.92H2/CO were predicted and experimentally validated at 800 °C reaction temperature, 0.35O2/CH4 ratio, and 10 000 space velocity.

Renewable biomass based jet fuel: Aldol condensation of furfural with 3-pentanone over calcium zirconium mixed oxide catalyst

Furfural is a biomass-derived chemical that can be converted into different valuable chemicals using green processes. The current study deals with a highly efficient, robust, and selective solid catalyst for the aldol condensation of furfural and 3-pentanone to synthesize 1-furan-2-yl-2-methylpent-1-en-3-one under environmentally benign conditions. CaZr (different molar ratios of Ca and Zr) mixed oxide (MO) catalysts along with reference CaO and ZrO2 catalysts were prepared by the hydrothermal technique and investigated for the current reaction. Among all, CaZr (1:2) MO catalyst was found to be the best for the conversion of furfural due to its desirable basic strength with good surface area and reusability characteristics. Furfural conversion and 1-furan-2-yl-2-methylpent-1-en-3-one selectivity were found to be 94 % and 98 %, respectively, under optimized reaction conditions. Effect of various reaction parameters was studied carefully to achieve the maximum yield of the required product. Reaction mechanism and kinetics were developed. The reaction aligns with the LHHW mechanism, and the activation energy was determined to be 10.40 kcal/mol.

Study on the reducible metal oxide carriers to regulate the catalytic reaction performance of CO2 with ethane

Aiming at the resource utilization of CO2 and the value-added catalytic conversion of ethane, different reducibility oxide carriers were used to study. Through catalytic reaction experiments, catalyst characterization and kinetic analysis, the interaction between reducible carriers and active metals and their regulation on the catalytic reaction performance of ethane with CO2 were revealed. Fe1.5Ni0.5/CeO2 has the highest ethylene selectivity of 87% near 650 °C, and is a good catalyst for the CO2-assisted ethane oxidative dehydrogenation to ethylene reaction. The strong interaction between the reducible CeO2 and ZrO2 carriers and active metals makes the Fe–O–Ce and Fe–O–Zr covalent bonds on the Fe1.5Ni0.5/CeO2 and Fe1.5Ni0.5/ZrO2 catalysts stronger than Fe–O–Ti and Fe–O–Al covalent bonds on Fe1.5Ni0.5/TiO2 and Fe1.5Ni0.5/γ-Al2O3 catalysts. The lattice oxygen on the reducible catalyst is more readily involved in the reaction. The strong interaction between the active metal and the carrier results in the reduction of the FeOx species and the formation of new active sites, resulting in a high reactivity of the catalyst. The mutually promoted redox cycle between the active species Fe3+/2+-Ni2+/0 and the reducible carrier variable metal Ce4+/3+ species improves the catalytic performance for the reaction of ethane awith CO2.

The structure–activity relationships of Rh/CeO2–ZrO2 catalysts based on Rh metal size effect in the three-way catalytic reactions

The structure–activity relationships of Rh/CeO2–ZrO2 catalysts based on Rh metal size effect in the three-way catalytic reactions

Hydrogen peroxide assisted oxidative liquefaction of alkaline lignin over cobalt-nickel loaded zirconia catalysts

Research toward the oxidative fractionation of lignin is gaining attention due to the selective breaking of a sub-aromatic unit of lignin's complex structure into monomeric phenolic. This study aims to investigate the liquefaction tendency of alkaline lignin by screening the synergistic effect of Co and Ni loaded on synthesized (syn) ZrO2 catalyst under the applied mild oxidative reaction conditions of molecular oxygen and hydrogen peroxide. Compared to the non-catalytic reaction (38.1 wt%), a significant improvement in the bio-oil yield (53.7 wt%) was obtained with the 5Co–5Ni/ZrO2-syn catalyst under the oxidative condition of molecular oxygen. However, only 44.3 wt% bio-oil was observed with commercial (com) 5Co–5Ni/ZrO2-com catalyst. The synergistic study of Co and Ni metal exhibited a diverse impact on the fractionation of lignin into respective product yields (bio-oil, gas, and char). Notably, adding a catalytic amount of hydrogen peroxide showed a remarkable improvement in liquefaction. The maximum bio-oil yield (72.1 wt%), and a maximum conversion (77.9%) were noticed with 0.5 mL H2O2 at 120 °C/30 min under the atmospheric molecular oxygen. The GC-MS analysis of bio-oil (5Co–5Ni/ZrO2-syn-HP) attributed to a high quantity of guaiacyl phenolic with a maximum proportion of benzaldehyde-3-hydroxy-4-methoxy (65.3%). The 5Co–5Ni/ZrO2-syn catalyst was also examined for the three catalytic cycles, which did not show any significant loss in product yield.

Co‐pyrolysis of cypress sawdust and green algae over Ni/ZrO2 catalyst: Syngas yield and carbon emission

AbstractIn order to promote syngas yield and reduce carbon emission, Ni loaded ZrO2 (Ni/ZrO2) catalysts were prepared for the co‐pyrolysis of cypress sawdust and green algae in a two stage fixed bed reactor. The syngas yield, syngas component, and carbon emission were investigated. The results showed that Ni/ZrO2 catalyst could obviously increase the combustible gas component in syngas. H2 content was increased from 7.5% (single component) and 8.12% (co‐pyrolysis) to 16.56% (catalytic pyrolysis). CO content was also increased from 19.62% (single component) and 19.46% (co‐pyrolysis) to 25.94% (catalytic pyrolysis). However the catalyst had a little effect on the syngas yield compared with single component pyrolysis and co‐pyrolysis. The pyrolysis temperature could make great influence on the carbon emission. The carbon emission reduction was increased from 33.32 to 234.25 g CO2 and from 105.94 to 369.23 g CO2, respectively for green algae and cypress sawdust.

Application of Silver-Iron Co-doped ZrO2 and TiO2 Bimetallic Catalysts in the Photodegradation of Pharmaceutics Pollutants and in Inhibition of Corrosion of Commercial X65 Steel

Application of Silver-Iron Co-doped ZrO2 and TiO2 Bimetallic Catalysts in the Photodegradation of Pharmaceutics Pollutants and in Inhibition of Corrosion of Commercial X65 Steel

A novel method for synthesis of nonylated diphenylamine by alkylation of diphenylamine with nonene over Fe-promoted SO42-/ZrO2 catalysts

As a green and efficient antioxidant, nonylated diphenylamine (NDPA) is of great significance to fields such as lubricants, synthetic rubber, and plastic. However, traditional catalysts for synthesizing NDPA still exhibit drawbacks of low efficiency, equipment corrosion, non-renewability, and environmental pollution. To overcome these challenges, a series of Fe-promoted SO42-/ZrO2 catalysts were successfully developed and employed for the first time in the alkylation of DPA and NON to synthesize NDPA in our present work. Both synthesis variables of catalysts and reaction conditions were well optimized. The as-synthesized NFe2.50S1.0Z catalyst possessed excellent catalytic performance with a high yield of mono- and di-nonyl-diphenylamine, as well as better reusability and stability than activated clay. After 5 reaction cycles, over 90 % of the catalytic activity could be recovered by the thermal treatment. These observations make the Fe-promoted SO42-/ZrO2 catalyst a promising candidate for industrials. Additionally, to systematically investigate and elucidate the promoting effects of Fe on sulfated zirconia catalysts, a thorough characterization of the physicochemical properties of these catalysts was conducted through various techniques, including XRD, SEM, TEM equipped with EDX, N2 adsorption-desorption isotherms, EA, ICP-OES, FT-IR, XPS, and NH3-TPD. The results indicated that the introduction of a small amount of Fe into the catalyst promoted the stabilization of T-ZrO2, smaller grain sizes, increased specific surface area, and strong acidity, which in turn positively affected the catalytic performance. In addition, a possible reaction mechanism of Fe-promoted SO42-/ZrO2 catalyst for catalyzing the alkylation of DPA with NON was proposed.

Tri-reforming of methane over Ni/ZrO2 catalyst derived from Zr-MOF for the production of synthesis gas.

The increasing concentration of CO2 and CH4 in the environment is a global concern. Tri-reforming of methane (TRM) is a promising route for the conversion of these two greenhouse gases to more valuable synthesis gas with an H2/CO ratio of 1.5-2. In this study, a series of Zr-MOF synthesized via the solvothermal method and impregnation technique was used to synthesize the nickel impregnated on MOF-derived ZrO2 catalyst. The catalyst was characterized by various methods, including N2-porosimetry, X-ray diffraction (XRD), temperature programmed reduction (TPR), CO2-temperature programmed desorption (CO2-TPD), thermo-gravimetric analysis (TGA), chemisorption, field-emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). Characterization results confirmed the formation of the Zr-MOF and nickel metal dispersed on MOF-derived ZrO2. Further, the tri-reforming activity of the catalyst developed was evaluated in a downflow-packed bed reactor. The various catalysts were screened for TRM activity at different temperatures (600-850°C). Results demonstrated that TRM was highly favorable over the NZ-1000 catalyst due to its desirable physicochemical properties, including nickel metal surface area (2.3 m2/gcat-1), metal dispersion (7.1%), and nickel metal reducibility (45%), respectively. Over the NZ-1000 catalyst, an optimum H2/CO ratio of ~ 1.6-2 was achieved at 750°C, and it was stable for a longer period of time.

Machine-Learning-Assisted Descriptors Identification for Indoor Formaldehyde Oxidation Catalysts.

The development of highly efficient catalysts for formaldehyde (HCHO) oxidation is of significant interest for the improvement of indoor air quality. Up to 400 works relating to the catalytic oxidation of HCHO have been published to date; however, their analysis for collective inference through conventional literature search is still a challenging task. A machine learning (ML) framework was presented to predict catalyst performance from experimental descriptors based on an HCHO oxidation catalysts database. MnOx, CeO2, Co3O4, TiO2, FeOx, ZrO2, Al2O3, SiO2, and carbon-based catalysts with different promoters were compiled from the literature. Notably, 20 descriptors including reaction catalyst composition, reaction conditions, and catalyst physical properties were collected for data mining (2263 data points). Furthermore, the eXtreme Gradient Boosting algorithm was employed, which successfully predicted the conversion efficiency of HCHO with an R-square value of 0.81. Shapley additive analysis suggested Pt/MnO2 and Ag/Ce-Co3O4 exhibited excellent catalytic performance of HCHO oxidation based on the analysis of the entire database. Validated by experimental tests and theoretical simulations, the key descriptor identified by ML, i.e., the first promoter, was further described as metal-support interactions. This study highlights ML as a useful tool for database establishment and the catalyst rational design strategy based on the importance of analysis between experimental descriptors and the performance of complex catalytic systems.

Plasma catalytic CO2 hydrogenation to methanol: The interaction between MnOx and ZrO2

AbstractPlasma catalytic CO2 hydrogenation to methanol over MnOx/ZrO2 catalyst was investigated in this work. A boosted methanol yield of 4.6 mg/h was obtained over MnOx/ZrO2 catalyst, while it was only 0.0 and 0.7 mg/h for ZrO2 and MnOx catalyst, respectively. The interaction between MnOx and ZrO2 was responsible for the enhanced methanol yield. It resulted in sufficient oxygen vacancy. The in situ DRIFT spectra was conducted to reveal the plasma catalytic CO2 hydrogenation to methanol reaction mechanism and the key intermediates of HCOO and CH3O species were determined. The sufficient oxygen vacancy promoted the formation of the key intermediates, especially the CH3O species.

Efficient conversion of lignin-derived phenols to cycloalkanes over bifunctional catalysts with low loading of ruthenium

Hydrodeoxygenation (HDO) reactions are extensively employed in the conversion of biomass to advanced fuels, which rely heavily on bifunctional catalysts that contain both a metal component and an acidic component. A significant challenge in the development of HDO catalysts is the need to reduce costs while simultaneously enhancing catalytic efficiency. Here, a series of Ru@W/ZrO2 catalysts with an extremely low loading of Ru (0.5 wt%) were successfully synthesized using different Ru or W loading sequences and different Ru/W mass ratios. The catalysts were applied in the HDO reaction of lignin-derived phenols, and their physical and chemical characteristics were revealed by various characterization techniques, including XRD, H2-TPD, NH3-TPD, and XPS. The results suggest that the synthesis method with post-loading Ru leads to improved exposure and utilization of the low-loaded Ru, which effectively serves as the active sites for hydrogenation in catalytic reactions. Under the same reaction conditions, the bifunctional catalyst with post-loading of Ru achieved a complete conversion of phenol into cyclohexane, while the catalyst with simultaneous loading of Ru and W only yielded 42% of cyclohexane. In addition, the Ru/W ratios have also shown significant effects on the HDO performance of the catalyst. The catalyst exhibits the highest hydrogenation activity when the Ru/W ratio is 10, which is further supported by kinetic experiments. This study highlights the significance of the loading sequence of noble metals and the metal/acid ratio in the synthesis of highly active bifunctional catalysts, and also lays the groundwork for the efficient utilization of noble metals in biomass HDO conversion.

Unveiling the synergistic effects of pH and Sn content for tuning the catalytic performance of Ni0/NixSny intermetallic compounds dispersed on Ce-Zr mixed oxides in the aqueous phase reforming of ethylene glycol

The product distribution in aqueous phase reforming (APR) of polyols is closely tied to the catalytically induced feed cleavage mechanism. Strategic variations in catalyst composition and synergistic effects prompted by reaction conditions, such as pH, can be utilized to tune the product distribution of both liquid and gaseous phases. This study aimed to compare the physicochemical properties of various NixSny/Ce(Zr)O2 catalysts and their performance in batch tests during the APR of a 6%wt. ethylene glycol (EG) solution under both neutral and alkaline conditions. The results show that the progressive addition of tin strongly tunes the activity of the catalysts and the nickel-induced methanation reaction under neutral conditions, albeit decreasing feed conversions. In synergy with tin tuning, the alkaline environment boosts the process by increasing conversions and H2-yields while still minimizing methanation due to the alkali-induced process of Cannizzaro disproportionation of EG into glycolic acid with subsequent reforming thereof.

Multi-functional nanoscale ZrO2 catalysts for sustainable water treatment

This study aimed to synthesize highly reactive ZrO2 nanoparticles using a straightforward sol-gel method for addressing water contamination from hazardous metal ions and organic dyes. Structural and photocatalytic properties were assessed using X-ray diffraction (XRD), Fourier transmission Infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), and UV–visible absorption spectroscopy. XRD analysis confirmed the tetragonal crystal structure of ZrO2. Photodegradation experiments using Eriochrome Black T (EBT) as a model dye revealed nearly 99% degradation under natural sunlight. Investigations into catalyst loading, dye concentration, pH, and irradiation source were conducted. Preliminary tests demonstrated the adsorbent's efficacy in removing Ca2+ ions. Further process optimizations could significantly enhance the potential of this innovative adsorbent for extracting metal ions from complex effluents.

Size tuning of Pt nanoparticles on ZrO2: Optimizing catalytic performance for hydrogen evolution and water-splitting reactions - A DFT study

In heterogeneous catalysis, determining the optimal metal particle size is challenging due to the intricate relationship between particle size, electronic structure, and activity. Here, we investigate the size-dependent activity of Pt nanoparticle (PtNP)-based ZrO2 catalyst for hydrogen evolution reaction (HER) and water-splitting reaction (WSR) using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. By analyzing different Pt nanoparticle sizes (Pt4, Pt7, Pt11, P15, Pt19, and Pt25) supported on ZrO2, we determined their optimized geometries, and electronic structures, and calculated the hydrogen adsorption energies (ΔGH) for HER and activation energies barrier (Δ‡G) for WSR. The calculated results demonstrate that Pt11 is the optimal size for HER, exhibiting the lowest ΔGH (−0.066 eV), while Pt15 shows the lowest Δ‡G (0.24 eV) for WSR. The density of states (DOS) shows that the occupied Pt states fill the gap of ZrO2 (3.72 eV), significantly reducing the band gap (Eg) of the PtNP/ZrO2 composites. The most favorable configuration of the PtNP on ZrO2 for HER and WSR is determined to be a three-Pt-layer structure with rooflike edges which corresponds to a nanoparticle size of ∼0.70–1.55 nm for experiments. These findings can be regarded as an effort toward the design and optimization of metal-based oxide catalysts for renewable energy applications.