Platinum Nanocatalysts Research Articles

Edge sites dominate the hydrogen evolution reaction on platinum nanocatalysts

Edge sites dominate the hydrogen evolution reaction on platinum nanocatalysts

One-step liquid-phase synthesis of platinum nanocatalysts supported on carbon fiber substrates and their electrochemical characterization

Highly dispersed Pt nanoparticles supported on polyacrylonitrile-based carbon fiber substrates were prepared using a one-step liquid-phase process. Nanoparticles were grown on the fiber surface via electric resistance heating of the substrate in ethanol solutions containing a platinum-based organometallic complex as the nanoparticle precursor. After the synthesis, Pt nanoparticles were formed on the surface in highly dispersed states. Electrochemical characterization of the Pt nanoparticles was conducted using the substrates directly after synthesis. The Pt nanoparticles were electrochemically active and exhibited superior methanol oxidation properties.

Mesoporous silica-supported platinum nanocatalysts for colorimetric detection of glucose, cholesterol, and C-reactive protein.

Noble metal nanoparticles decorated on a catalyst support with a large specific surface area can exhibit enhanced catalytic activity. To this end, a synthetic method to heterogeneously and evenly nucleate platinum nanoparticles (Pt NPs) onto mesoporous silica nanoparticles (MSNs) is developed. The obtained Pt NP-modified MSNs (Pt-MSNs) are characterized as a thin layer of 3 nm-sized Pt NPs densely assembled on the MSN surface, by which the throughput of the peroxidase-like activity of Pt-MSNs is greatly improved. The utility of Pt-MSNs in colorimetric detection of analytes is validated for two different assay schemes. Firstly, colloidally dispersed Pt-MSNs are employed as a peroxidase-mimic in a two-step cascade reaction to quantitate glucose/cholesterol based on the amount of H2O2 produced by glucose/cholesterol oxidase. Secondly, detection of C-reactive protein (CRP) is conducted on a solid substrate by adopting a sandwich immunoassay format. Detection limits are estimated to be 20 μM, 55 μM, and 3.9 pM for glucose, cholesterol, and CRP, respectively.

Electrochemical Evolution of Fuel Cell Platinum Nanocatalysts on Carbon Nanotubes at the Atomic Scale

Electrochemical Evolution of Fuel Cell Platinum Nanocatalysts on Carbon Nanotubes at the Atomic Scale

The effect of initial temperature and external heat flux on the H2 and CO production by biomass gasification using molecular dynamics simulation

Biomass is a fuel produced from organic matter, and a renewable and sustainable energy source used to generate electricity or other forms of energy. From an environmental point of view, biomass includes all materials found in nature. This resource can be a suitable alternative to fossil resources. Biomass is based on carbon particles, H2, O2, N2, and many other atoms, such as alkali metals and heavy metals. In this research, the changes in the number of H2, carbon monoxide (CO) molecules created, and combustion efficiency (CE) inside the simulation box, using molecular dynamics (MD) simulation in the presence of 10 % platinum nanocatalyst with different initial temperatures (Temp) (1800, 1850, 1900 and 2000 K) and different external heat fluxes (EHF) (1, 2, 3 and 5 W/m2) were evaluated. The results show that as the Temp increased from 1800 to 2000 K, the number of H2 and CO molecules increased from 586 to 165 to 614 and 199, respectively. Besides, CE increased to 70% with the Temp increase to 2000 K. Furthermore, increasing the EHF from 1 to 5 W/m2, the number of H2 and CO molecules decreases from 589 to 170 to 603 and 180, respectively, and the CE increases to 69 % with the EHF increasing to 5 W/m2. It is expected that by examining the effects of system Temp and EHF, and the presence of nanocatalysts, the production of the number of H2 molecules will reach the highest efficiency.

An amphiphilic nitrogen-doped graphene prepared by ammonia cold plasma and its supported platinum nanocatalyst for aqueous-phase hydrogenation of cinnamaldehyde

Herein, a nitrogen-doped graphene (NPGR) with amphiphilic surface was efficiently synthesized by radio-frequency cold plasma under low vacuum, using ammonia as plasma source. NPGR supported platinum nanocatalyst (Pt/NPGR) was then prepared for aqueous-phase hydrogenation of cinnamaldehyde (CAL) and effects of nitrogen doping on the reaction were investigated. Results indicated the formation of a Pickering emulsion catalytic system, exhibiting the high catalytic performance. Apparent initial reaction rate constant (k) over it arrived at 1.07 h−1, higher than that over Pt catalysts supported on pristine graphene (Pt/ GR, 0.62 h−1) and graphene oxide (Pt/GO, 0.15 h−1), respectively. On the other hand, the selectivity to cinnamyl alcohol kept high (84%) at 95% CAL conversion. In addition, the catalyst showed good recyclability for the reaction. The high catalytic performance of Pt/NPGR in aqueous-phase CAL hydrogenation was thanks to the enhanced surface properties of graphene after doping a small amount of nitrogen in it.

Preparation of supported ultrafine platinum nanocatalysts by ethylene glycol assisted photochemical method and application of catalytic 4-NP

Ultrafine Pt nanoparticles (Pt/SWCNTs) supported on single-walled carbon nanotubes (SWCNTs) were prepared by a photochemical method assisted by ethylene glycol (EG) as a reducing agent without the addition of stabilizing agents. the application in the reduction of 4-Nitrophenol (4-NP) was also explored. XRD diffraction patterns show that the content of Pt (111) crystal planes is higher, which is beneficial for improving the catalytic activity of platinum nanoparticles. TEM results showed that Pt/SWCNTs-E3 prepared under Ultra Violet (UV) light irradiation had a small-size particle with an average particle size of about 2.2 nm. XPS results showed that the prepared Pt nanoparticles mainly existed in the form of Pt0. The catalytic performance test results showed that the Pt/SWCNTs prepared under the UV condition of 395 nm had the highest activity for catalyzing the reduction of 4-NP, and the apparent rate constant was k = 0.34 min−1, indicating that it had good catalytic activity. After seven cycles, the conversion rate remains about 83%, which has good reusability and stability. The results show that the aggregation of Pt intermediates can be effectively controlled by photo-induced and strong metal − support interaction (SMSI) to obtain ultrafine nanoparticles dominated by Pt0.

TEMAS: A Flexible Non‐AI Algorithm for Metrology of Single‐Core and Core‐Shell Nanoparticles from TEM Images

AbstractAn essential application of electron microscopy is to provide feedback to tune the fabrication of nanoparticles (NPs). Real samples tend to follow a size distribution commonly linked to the synthesis process used and in turn to their functional properties. This study presents an algorithm for measuring particle size distributions in electron microscopy images. State‐of‐the‐art methods based on Artificial Intelligence (e.g., Deep Learning) require extensive datasets of labeled images similar to those expected to be analyzed, and extensive supervised re‐training is often required for cross‐domain application. In contrast, the non‐AI algorithm described in this study is accurate and can be quickly set up for measuring new experimental images in different domains. The accuracy of the method is validated quantitatively and comparing graphical and descriptive statistics. Different size distributions are measured on images of platinum and gold nanocatalysts supported on carbon black, amorphous carbon, and titanium dioxide crystals. Also, images of platinum‐iron core‐shell NPs supported on thin amorphous carbon film are successfully analyzed. The limitation of evaluating different algorithms for NPs metrology is the lack of standards that different researchers can use as ground truth. In order to overcome this limitation, the images and the ground truth measurements presented here are shared as an open dataset.

Synthesis of Ultrafine Platinum Nanocatalysts by Ice‐photochemical Method and Their Application in Catalytic Degradation of 4‐nitrophenol

AbstractHere, uniformly dispersed ultrafine platinum nanocatalysts (Pt/C60) were synthesized on C60 by ice‐photochemical method using potassium chloroplatinate (K2[PtCl4]) as platinum source under the condition of low temperature, no stabilizer and reducing agent. X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR), X‐ray photoelectron spectroscopy (XPS) and Transmission electron microscopy (TEM) were used to study the composition and morphology of Pt/C60 catalyst. It was confirmed that Pt Ultra‐small Particles (Pt UPs) was loaded on C60 surface with high dispersion. The average particle sizes of the three samples obtained under different reaction conditions were 1.41±0.1 nm, 1.54±0.4 nm and 1.73±0.3 nm, respectively. The results show that the light‐induced effect and the ice lattice domain limiting effect in the frozen state effectively control the formation and growth of platinum clusters in the process of Pt2+ reduction to Pt0. The rate constants of the three samples were 0.89 min−1, 0.31 min−1, 0.19 min−1, respectively, showing high catalytic activity in the study of the catalytic performance of Pt/C60 degradation of 4‐nitrophenol (4‐NP) by Ultraviolet‐visible spectroscopy (UV‐Vis). This method provides a meaningful attempt for the study of green chemical synthesis method of platinum metal catalysts.

The impact of domain-driven and data-driven feature selection on the inverse design of nanoparticle catalysts

Incorporating practical considerations into machine learning can make predictions more actionable. However, researcher interventions in the learning process may have negative impacts on model performance, leading to a trade-off between accuracy and utility. In this paper we use multi-target machine learning to predict the structure of platinum nanocatalysts based on property indicators and develop intervention scenarios using ratios of data-driven (optimal) and domain-driven (preferable) variables during feature selection. We show that minor interventions to data-driven feature selection can be tolerated, and even improve model performance, but aggressive domain-driven feature selection degrades performance, even if the mapping function is perfectly balanced.

Low Platinum-Content Electrocatalysts for Highly Sensitive Detection of Endogenously Released H2O2.

The commercial viability of electrochemical sensors requires high catalytic efficiency electrode materials. A sluggish reaction of the sensor’s primary target species will require a high overpotential and, consequently, an excessive load of catalyst material to be used. Therefore, it is essential to understand nanocatalysts’ fundamental structures and typical catalytic properties to choose the most efficient material according to the biosensor target species. Catalytic activities of Pt-based catalysts have been significantly improved over the decades. Thus, electrodes using platinum nanocatalysts have demonstrated high power densities, with Pt loading considerably reduced on the electrodes. The high surface-to-volume ratio, higher electron transfer rate, and the simple functionalisation process are the main reasons that transition metal NPs have gained much attention in constructing high-sensitivity sensors. This study has designed to describe and highlight the performances of the different Pt-based bimetallic nanoparticles and alloys as an enzyme-free catalytic material for the sensitive electrochemical detection of H2O2. The current analysis may provide a promising platform for the prospective construction of Pt-based electrodes and their affinity matrix.

Development of Cathodes for Aluminum-Ion and Aluminum-Air Batteries Using Pulsed Electrodeposition

Electrical energy storage has emerged as a critical component in North America’s clean energy transformation. Vehicle electrification and integration of renewables such as wind and solar power into the grid have further underlined the importance of affordable, environmentally friendly energy storage platforms. Rechargeable batteries are now considered to be viable options for large-scale energy storage with lithium-ion and redox flow batteries leading the charge. Over the past decades, aluminum-ion batteries have experienced a renaissance on account of their high volumetric energy density, superior cycleability, enhanced stability and significant cost benefits compared with other commercially available secondary batteries. Aluminum-air batteries also hold significant promise as primary energy storage platforms, but they suffer from thermodynamics and kinetics hurdles, leading to inferior performance. To address these issues, researchers have focused on optimizing different cell components, including anodes, cathodes, and electrolytes.It is well established that nano-structuring battery components would markedly improve their short- and long-term performance by enhancing reaction kinetics. One of the major impediments to wide-scale commercialization of Al-ion batteries continues to be its inferior capacity and cycle stability compared with commercially available secondary batteries. Part of these issues can be ascribed to the failure of cathode materials currently being investigated and used. As for primary Al-air batteries, conventional air cathodes do not perform very well either; and there are many reasons as to why the incorporation of such air cathodes into Al-air batteries would lead to inferior performance or premature failure; the most important of which is low catalytic activity.To address a number of these issues, pulsed current electrodeposition was employed to deposit nano-catalysts such nickel, silver, platinum and oxides of manganese on different support materials, including carbon paper and cloth, titania nanotubes, and stainless steel and nickel meshes. The influence of various electrodeposition parameters, including peak current density, duty cycle, type of waveform and pulse frequency, on resulting layers were systematically investigated. In most cases, nanocatalysts about 2-40 nm in diameter were obtained. Various electrochemical tests were utilized to characterize the resulting layers. A simple mathematical model based on progressive nucleation also was developed to predict the influence of the aforementioned electrodeposition parameters on the resulting nano-catalyst layers. The model was further refined by considering all contributing factors towards growth current, including diffusion, ohmic and charge transfer phenomena as well as changing diffusion coefficients, during electrodeposition. According to the model, at high peak deposition current densities and low duty cycles (5% or less), the ramp-down waveform yielded the highest nucleation rates, confirming the experimental findings in which nanoparticles generated with the above waveform produced the smallest average grain size, ranging from 2-10 nanometer in diameter for platinum and silver nanocatalysts on carbon cloths and titania nanotubes, and 10-50 nm in diameter for nickel nanoparticles deposited on stainless steel and nickel meshes and titania nanotubes.

Investigation of Oxygen Reduction on Platinum Nanoparticles Deposited Onto Peat-Derived Carbon Carrier

Carbon supported platinum catalysts for proton exchange membrane fuel cell (PEMFC) applications have been studied intensively in the scientific community.1,2 The catalytic activity of the catalyst depends on the characteristics of the carbon support material3 and on the Pt depositing method4,5. The aim of the study was to investigate the oxygen reduction reaction (ORR) on Pt nanoparticles deposited on peat-derived carbon. The Pt nanoparticles were deposited on the carbon support material by three different methods using NaBH4 (NBH), ethylene glycol (EG) and isopropyl alcohol (IA) as a reducing agent.The studied materials were characterized using N2 sorption, X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Structure of the platinum nanocatalyst on carbon support was also studied using scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). For electrochemical characterization, the electrochemically active surface area (ECA) of the materials were measured in a three-electrode system (0,1 M HClO4) and in a completed PEMFC. The ORR kinetics of the materials were studied by the rotating disk electrode (RDE) method as well as in a PEMFC configuration.As a result, it was found that the higher the ECA of the material, the higher the catalytic activity. The catalytic activity of the synthesized materials increases in order: IA < NBH < EG. ECA of the materials increases in the same order. Also, the special surface area of the materials increases in the same order. The catalytic activities of the synthesized materials were compared to a commercial catalyst material, 60% Pt on HSA Ketjenblack. References O. Z. Sharaf and M. F. Orhan, Renew. sust. energ. rev., 32, 810–853 (2014).Y. Wang, K. S. Chen, J. Mishler, S. C. Cho, and X. C. Adroher, Appl. Energ., 88, 981–1007 (2011).S. Sharma and B. G. Pollet, J. Power Sources, 208, 96–119 (2012).S. Sepp et al., Electrochim. Acta, 203, 221–229 (2016).P. Valk et al., J. Electrochem. Soc., 165, F315–F323 (2018). Acknowledgements The author thanks the European Union Regional Development Fund for the financial support of the project TK141 “Innovative materials and high-tech equipment for energy recovery systems” (2014-2020.4.01.15-0011); the Estonian Research Agency project (personal research support group grant project No. PRG676) and the Estonian Energy Technology Program: SLOKT10209T “. Nanomaterials – research and applications (NAMUR)” project 3.2.0304.12-0397. The author also thanks the private limited company AuVe Tech.

A Systematic Investigation of Carbon Pretreatment for the Synthesis of Platinum Nano-Catalysts for Oxygen Reduction Reaction

The synthesis of electrocatalysts for low- and high temperature fuel cells is dependent on many different factors that determine the activity of the produced catalysts. One important and highly underrepresented factor in literature are carbon pretreatments, which have a strong impact on the electrochemical activity of the produced catalyst. A web of science search showed that less than 1% of the articles working with the synthesis of Pt-based catalysts for the Oxygen reduction reaction (ORR) contain information on carbon pretreatments. In recent years no articles on the topic of carbon pretreatment for the synthesis of Pt-based ORR catalyst have been published.However, different forms (as powder, nano tubes, etc.) of carbon are commonly used as support material for Pt-based catalysts. Previous work has shown the importance of pretreatment of carbon supports to change the surface-active groups, enhancing the dispersion and reducing agglomeration of Pt-nanoparticles [1]. Oxidizing treatments are known to change the surface groups and decreasing the BET surface area [2]. Furthermore, carbon pretreatments can effectively reduce impurities present in as-purchased carbon [3].A systematic study of pretreatments of Vulcan XC72-R and Ketjen 300 have been carried out followed by the synthesis of supported Pt-nanoparticles using XPS, XRD, TEM, BET and RDE techniques. We found that the presence of sulfur in the surface strongly correlates with the ECSA of the supported Pt catalyst. This talk will elaborate on the effect of pretreatments on the carbon support, the synthesis of Pt nanoparticles and its impact on the resulting electrochemical performance: Compared to as received carbon, the Pt mass activity could be increased by a factor 4, exceeding the mass activity of comparable commercial Pt/C electrocatalysts.[1] Bimetallic Pt–Sn catalysts supported on activated carbon I. The effects of support modification and impregnation strategy - A. Erhan Aksoylu; M. Madalena A. Freitas; Jose L. Figueiredo[2] The effect of pretreatment of Vulcan XC-72R carbon on morphology and electrochemical oxygen reduction kinetics of supported Pd nano-particle in acidic electrolyte - Senthil Kumar, S. M.; Soler Herrero, Jaime; Irusta, Silvia; Scott, Keith[3] Effect of the carbon pre-treatment on the properties and performance for nitrobenzene hydrogenation of Pt/C catalysts - Torres, G. C.; Jablonski, E. L.; Baronetti, G. T.; Castro, A. A.; De Miguel, S. R.; Scelza, O. A.; Blanco, M. D.; Peña Jiménez, M. A.; Fierro, J. L.G. Figure 1

Photo-Cross-Linking Polymersome Nanoreactors with Size-Selective Permeability

The design of stable, inert, and permeable nanoreactors remains a challenge due to the additives required to create a cross-linked network, limiting their potential for catalysis. Polymersomes are nanovesicles self-assembled from amphiphilic block copolymers that can act as nanoreactors by encapsulating catalysts. A major restriction toward their use is their stability and reduced permeability. In order to overcome this, polymersome membranes can be cross-linked to retain their shape and function. Here, we report the synthesis of a PEG-b-P(S-co-4-VBA) polymer, which can self-assemble into polymersomes and subsequently be cross-linked using UV light. We demonstrate that these polymersomes are stable over a long period of time in various organic solvents, that incorporation of functional handles on their surface is possible, and that they are able to undergo reactions. Additionally, we show that co-assembly with up to 40% PEG-b-PS present results in the formation of pores in the membrane structure, which allows for the structure to be used as a nanoreactor. By encapsulating a platinum nanocatalyst, we are able to catalyze the depropargylation of a small coumarin substrate, which was able to enter and leave the porous nanoreactor.

Surface Microstructure Modulation Strategy to Design an Amphiphobic Platinum Nanocatalyst for Efficient Catalytic Oxidation of Hydrogen Isotopes

Surface Microstructure Modulation Strategy to Design an Amphiphobic Platinum Nanocatalyst for Efficient Catalytic Oxidation of Hydrogen Isotopes

Synthesis of layered double hydroxide-supported platinum nanocatalyst for highly efficient and selective hydrogenation of nitroaromatics

In this work, highly dispersed platinum nanoclusters (or single atoms) supported on layered double hydroxides (Pt/FeNi-LDHs, Pt/FeCo-LDHs, Pt/CoNi-LDHs) are synthesized. The as-prepared catalysts are used for the selective hydrogenation of nitroaromatics, the catalysts showed high activity, selectivity and stability. The as-synthesized catalysts are characterized by thermal-gravity (TG), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), high resolution TEM (HRTEM), scanning TEM (STEM), STEM-EDS elemental analysis and inductively coupled plasma emission spectroscopy (ICP-OES) methods, which prove that the Pt species are highly dispersed on the support. Take p-nitroacetophenone reduction as an example, the 0.4%Pt/FeNi-LDHs catalyst also shows excellent catalytic performance (conversion = 98.2%, turnover frequency (TOF) = 1100.5 h−1) and high selectivity to p-aminoacetophenone (93.8%) among these as-prepared catalysts even at low temperature (60 °C). Its excellent performance is probably due to the uniform distribution of the platinum species and the interaction of Pt–FeNi-LDHs conducive to the selective hydrogenation of –NO2 groups.

Platinum Nanocatalysts Supported on Defective Hollow Carbon Spheres: Oxygen Reduction Reaction Durability Studies.

The durability and long-term applicability of catalysts are critical parameters for the commercialization and adoption of fuel cells. Even though a few studies have been conducted on hollow carbon spheres (HCSs) as supports for Pt in oxygen reduction reactions (ORR) catalysis, in-depth durability studies have not been conducted thus far. In this study, Pt/HCSs and Pt/nitrogen-doped HCSs (Pt/NHCSs) were prepared using a reflux deposition technique. Small Pt particles were formed with deposition on the outside of the shell and inside the pores of the shell. The new catalysts demonstrated high activity (>380 μA cm−2 and 240 mA g−1) surpassing the commercial Pt/C by more than 10%. The catalysts demonstrated excellent durability compared to a commercial Pt/C in load cycling, experiencing less than 50% changes in the mass-specific activity (MA) and surface area-specific activity (SA). In stop-start durability cycling, the new materials demonstrated high stability with more than 50% retention of electrochemical active surface areas (ECSAs). The results can be rationalised by the high BET surface areas coupled with an array of meso and micropores that led to Pt confinement. Further, pair distribution function (PDF) analysis of the catalysts confirmed that the nitrogen and oxygen functional groups, as well as the shell curvature/roughness provided defects and nucleation sites for the deposition of the small Pt nanoparticles. The balance between graphitic and diamond-like carbon was critical for the electronic conductivity and to provide strong Pt-support anchoring.

Single‐Atom Molybdenum Engineered Platinum Nanocatalyst for Boosted Alkaline Hydrogen Oxidation

AbstractEngineering the surface electrochemistry at the atomic level can precisely and effectively manipulate the reactivity and durability of catalysts. Herein, a novel single‐atom fine‐tailoring strategy based on a highly hydrophilic Mo‐bifunctional promoter is proposed to greatly boost the hydrogen oxidation reaction (HOR) on Pt catalysts. The single‐atom Mo‐modified nanometer Pt anchored on porous N‐doped carbon (Mo‐Pt/NC) is developed via a pyrolysis–adsorption–reduction process. The designed Mo‐Pt/NC exhibits a remarkable mass‐specific kinetic current reaching 1584 mA mg−1Pt in 0.1 m KOH, which is nearly 11‐fold and fourfold higher than the activities of commercial Pt/C and Pt/NC counterparts respectively, and such extraordinary HOR behavior even exceeds those of documented Pt‐related catalysts. Electrochemical and spectroscopic studies indicate that hydrophilic Mo single‐atom sites can not only regulate the electronic microenvironment of Pt sites for attenuated H* adsorption, but they also serve as energetic H2O*‐adsorption promoters to jointly facilitate the HOR kinetics. Moreover, the anti‐CO poisoning capability of Mo‐Pt/NC is markedly enhanced by this Mo‐modified electronic effect. This work gives a significant guideline for the design of high‐performance HOR catalysts and other advanced catalysts.

Synthesis and Characterization of Mesoporous Silica Nanoparticles Loaded with Pt Catalysts

Coating the catalyst with a nanoporous layer has been demonstrated to be an effective approach to improve catalyst stability. Herein, we systematically investigate two types of core-shell mesoporous silica nanoparticles with a platinum nanocatalyst using a variety of characterization methods. One of the mesoporous particles has a unique amine ring structure in the middle of a shell (Ring-mSiO2/Pt-5.0/SiO2), and the other one has no ring structure (mSiO2/Pt-5.0/SiO2). Brunauer–Emmett–Teller/Barrett–Joyner–Halenda (BET/BJH) presented a similar surface area for both particles, and the pore size was 2.4 nm. Ultra-Small-Angle X-ray Scattering (USAXS)/ Small-Angle X-ray Scattering (SAXS) showed the size of mSiO2/Pt-5.0/SiO2 and Ring-mSiO2/Pt-5.0/SiO2 were 420 nm and 272 nm, respectively. It also showed that the ring structure was 30 nm above the silica core. Using high-resolution Transmission Electron Microscopy (TEM), it was found that the platinum nanoparticles are loaded evenly on the surface of the silica. In situ SAXS heating experiments and Thermogravimetric Analysis (TGA) indicated that the mSiO2/Pt-5.0/SiO2 were more stable during the high temperature, while the Ring-mSiO2/Pt-5.0/SiO2 had more change in the particle.