Supported Platinum Nanoparticles Research Articles

Supported Platinum Nanoparticles Catalyzed Carbon-Carbon Bond Cleavage of Polyolefins: Role of the Oxide Support Acidity.

Supported platinum nanoparticle catalysts are known to convert polyolefins to high-quality liquid hydrocarbons using hydrogen under relatively mild conditions. To date, few studies using platinum grafted onto various metal oxide (MxOy) supports have been undertaken to understand the role of the acidity of the oxide support in the carbon-carbon bond cleavage of polyethylene under consistent catalytic conditions. Specifically, two Pt/MxOy catalysts (MxOy = SrTiO3 and SiO2-Al2O3; Al = 3.0 wt %, target Pt loading 2 wt % Pt ∼1.5 nm), under identical catalytic polyethylene hydrogenolysis conditions (T = 300 °C, P(H2) = 170 psi, t = 24 h; Mw = ∼3,800 g/mol, Mn = ∼1,100 g/mol, Đ = 3.45, Nbranch/100C = 1.0), yielded a narrow distribution of hydrocarbons with molecular weights in the range of lubricants (Mw = < 600 g/mol; Mn < 400 g/mol; Đ = 1.5). While Pt/SrTiO3 formed saturated hydrocarbons with negligible branching, Pt/SiO2-Al2O3 formed partially unsaturated hydrocarbons (<1 mol % alkenes and ∼4 mol % alkyl aromatics) with increased branch density (Nbranch/100C = 5.5). Further investigations suggest evidence for a competitive hydrocracking mechanism occurring alongside hydrogenolysis, stemming from the increased acidity of Pt/SiO2-Al2O3 compared to Pt/SrTiO3. Additionally, the products of these polymer deconstruction reactions were found to be independent of the polyethylene feedstock, allowing the potential to upcycle polyethylenes with various properties into a value-added product.

Heterogeneous nanostructure anatase/rutile titania supported platinum nanoparticles for efficient photocatalytic degradation of methylene blue dyes

Efficient degradation of organic compounds in water is also challenge for wastewater treatment. Photocatalytic degradation based on multifunctional semiconductor materials has attracted great attention as a prospective method and is highly desirable. Here, we investigated the photocatalytic performance of Pt-supported TiO2 photocatalyst in different crystal structures (rutile, rutile/anatase, anatase) for degradation of methylene blue dye. The morphology and structural properties of TiO2 nanoparticles were tested using field emission scanning electron microscope (FESEM) and X-ray diffraction analysis (XRD) techniques. Moreover, the photocatalytic activities over noble metal supported anatase/rutile titania catalysts (Pd/TiO2, Pt/TiO2, and Ru/TiO2) were evaluated by degrading the methylene blue dye under solar light irradiation, and Pt/TiO2 contributed the highest decomposition efficiency within 20 min irradiation. A possible reaction mechanism for the catalytic oxidation of methylene blue was proposed.

Enhancing the durability of Pt nanoparticles for water electrolysis using ultrathin SiO2 layers

Using ALD to coat the Pt/CB electrocatalysts with an ultrathin layer of SiO2 can strongly reduce the Pt agglomeration and detachment during hydrogen evolution reaction in acidic conditions.

Poly (3, 4-propylenedioxythiophene)/Hollow carbon sphere composites supported Pt NPs to facilitate methanol oxidation reactions

Direct methanol fuel cells (DMFCs) are thought of as portable, sustainable, and non-polluting energy devices. The exploration of efficient and affordable catalysts for the methanol oxidation reaction (MOR) is significant for the industrial application of DMFCs. In this study, nitrogen-doped hollow carbon spheres (HCS) derived from polydopamine were proposed for the catalyst support for platinum nanoparticles (Pt NPs) for serving as the anode catalyst for DMFCs, and a composite support material was fabricated by in-situ oxidation of 3,4-ethylenedioxythiophene (ProDOT) with HCS to get core-shell structured poly(3,4-propylenedioxythiophene) (PProDOT)-embellished hollow carbon spheres (HCS) (PProDOT/HCS) for further improving the catalytic activity for supported catalyst. The results indicated that the platinum (Pt) on the surface of HCS was well dispersed, and the Pt became smaller and more evenly distributed with the introduction of PProDOT. Simultaneously, the Schottky junction formed between PProDOT and Pt NPs contributes to enhanced charge transfer and catalytic activity of the catalyst. Notably, the core-shell structure of the ternary catalyst, its excellent charge transfer capability, and the interaction between platinum and the support contribute to its high electrocatalytic activity. Electrochemical tests demonstrated that the PProDOT/HCS/Pt catalyst exhibited a mass activity of 1169.6 mA mg−1Pt for methanol oxidation in acidic electrolytes, surpassing the activity of the HCS/Pt catalyst (472.4 mA mg−1Pt) and commercial Pt/C (281.0 mA mg−1Pt).

Synthesis of Pt decorated manganese oxide (MnO2/Mn5O8) nanorods and their catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol

α-MnO2 nanorods (NRs) were synthesized by microwave irradiation and used as supports for platinum nanoparticles by wet impregnation with Pt(acac)2 as precursor. XRD analysis revealed that the samples without platinum (sample MP0) and with 1 % platinum (sample MP1) contained tetragonal α-MnO2. Samples with 3 % (sample MP3) and 5 % (sample MP5) of platinum contained monoclinic Mn5O8 in addition to α-MnO2, with Mn5O8 dominating in sample MP5. Rietveld analysis showed that the lattice parameters of α-MnO2 increased slightly with Pt loading. SEM and STEM showed that higher Pt loadings resulted in shorter nanorods and different sizes and dispersions of PtNPs on their surface. XPS results showed a decrease in Pt(IV) and Pt(II) concentration with Pt loading, while Pt(0) increased. NEXAFS results showed the presence of Mn(II) in MP3 and MP5, which is consistent with XRD results detecting Mn5O8. The catalytic activity of the Pt/α-MnO2 nanorods was tested in the catalytic reduction of 4-nitrophenol to 4-aminophenol. MP1, with the lowest platinum content, exhibited the highest mass normalized rate constant kapp/mPt of 1.8 × 104 s−1 g−1. The study suggests that the presence of Pt(IV) is not a limiting factor for the catalytic reduction of 4-NP to 4-AP.

Optical hydrogen peroxide sensor for measurements in flow

An optical hydrogen peroxide (H2O2) sensor is presented. The sensor is based on catalytic degradation of H2O2 and the detection of produced oxygen (O2) with a phosphorescent sensor. A novel aspect of the sensor is removal O2 from the analyte solution in flow. This allows the use of a more sensitive O2 sensor. Thereby, a better resolution at lower H2O2 concentrations is achieved. Sensor spots are integrated in a flow-through cell, and H2O2 is measured in flow between 10 and 80 µL/min. The catalytic activities of previously reported catalyst are tested. RuO2 and silica supported platinum nanoparticles are applied in the sensor with limit of detections of 0.16 and 0.17 µM H2O2, respectively. The sensor can measure reliably between 1 and 200 µM H2O2. The concentration range can be extended to 1000 µM H2O2 by exchanging the O2 sensor. Interfering species (NaONOO, NaOCl, t-BuOOH, and ascorbic acid) are tested and show only minor cross-sensitivities. The sensor is applied at-line in a model batch reactor with glucose oxidase to showcase production of H2O2 from glucose.

Hydrogen Reconversion from Ammonia through Anion Exchange Membrane Electrolysis

Nitrogen-based compounds, especially ammonia, is a promising alternative for the storage and transport of renewable hydrogen over long distances [1]. Considering ammonia as a hydrogen carrier will require studying the conversion (ammonia to hydrogen) and reconversion steps (hydrogen to ammonia). The reconversion of ammonia can take place through electrolysis under alkaline conditions [2] and needs the development of more efficient catalysts. For this, we started studying the electro-oxidation of ammonia in an anion exchange membrane electrolyser over platinum-based and PGM free electrodes with KOH as electrolyte. We have prepared several catalysts, carbon supported platinum, platinum-iridium, and nickel nanoparticles using the polyol technique. Commercial carbon supported platinum nanoparticles was used as catalyst for the cathodes. Catalyst coated substrates (CCS) were then prepared by spraying a catalytic ink over stainless-steel fiber paper for the anode side. The formulation of the ink requires optimizing parameters such as the type of ionomer (nafion, sustanion) and the ratio of ionomer to carbon. Anodes obtained have been assembled with anion exchange membranes and commercial cathodes for ammonia electro-oxidation in single cell. We have compared the performance of these different membrane electrodes assemblies (MEAs) to commercially available ones integrating nickel-iron-cobalt based anodes. The performance of MEAs was analyzed based on polarization curves, cyclic voltammograms and impedance spectroscopy data. Different testing conditions were investigated by varying the ammonia concentration from 0.1 to 1 M, the temperature from 25 °C to 60°C, and the KOH concentration from 0.1 to 5 M.

Correlation between the Electrochemical Durability of Pt/C Catalysts and the Surface Functional Groups of the Support Carbon

Herein, we report the effects of the catalyst support surface chemical/physical state of commercially available high-surface-area carbons on the electrochemical performance of Pt/C electrocatalysts synthesized using carbons as the support for platinum nanoparticles (Pt-NPs). A series of Pt/C electrocatalysts were synthesized through a microwave-assisted polyol process. The support carbons and the Pt/C catalysts were characterized for their structural characteristics including crystallinity, microstructure (morphology and particle size distribution), physical surface area, porosity, thermal behavior, and surface chemical state. Evaluation of the electrocatalytic performances and durability parameters of the Pt/C catalysts was performed through cyclic voltammetry and an accelerated stress test (AST). The results showed that the support carbons have similar physical properties except for the amounts and types of oxygen-containing surface functional groups. The Pt/C catalysts supported on the carbon with a higher surface oxygen content were found more durable during the AST, as compared to their corresponding counterparts supported on the carbon with a lower surface oxygen content. This was attributed to the presence of oxygen functional groups that may function as the active sites for the nucleation of new Pt-NPs, hence inhibiting Ostwald ripening to some extent. This study provides valuable catalyst support selection criteria and synthesis parameters at different pressures.

Ti3C2 MXene supporting platinum nanoparticles as rapid electrons transfer channel and active sites for boosted photocatalytic water splitting over g-C3N4

Two-dimension (2D) MXene materials have increasingly attracted attentions in improving the photocatalytic conversion of solar-to-chemical energy over graphitic carbon nitride (g-C3N4). In this work, Pt nanoparticles modified few-layer Ti3C2 MXene sheet (MXene@Pt) was successfully prepared by chemical reduction, which was used as efficient co-catalysts to enhance the photocatalytic hydrogen evolution over porous g-C3N4 (PCN). The high work function of MXene@Pt and the tight 2D/2D interfacial contact between MXene@Pt and PCN significantly promoted the transfer and separation of photogenerated electron-hole. Besides, the MXene@Pt could enhance the light-harvesting of PCN and provide plentiful active sites for hydrogen evolution reaction. The hydrogen evolution activity of optimum 2D/2D MXene@Pt modified PCN (PCN/MPt-5) composite was dramatically enhanced, even higher than that of equal Pt mass modified PCN. Besides, overall water splitting was realized via a two-electron pathway with H2O2 and H2 generation. This work may provide the fabrication strategy for developing MXene-based co-catalyst in photocatalysis.

Controlled Growth of Platinum Nanoparticles on Amorphous Silica from Grafted Pt-Disilicate Complexes.

Supported platinum nanoparticles are currently the most functional catalysts applied in commercial chemical processes. Although investigations have been performed to improve the dispersion and thermal stability of Pt particles, it is challenging to apply amorphous silica supports to these systems owing to various Pt species derived from the non-uniform surface structure of the amorphous support. Herein, we report the synthesis and characterization of amorphous silica-supported Pt nanoparticles from (cod)Pt-disilicate complex (cod = 1,5-cyclooctadiene), which forms bis-grafted surface Pt species regardless of surface heterogeneity. The synthesized Pt nanoparticles were highly dispersible and had higher hydrogenation activity than those prepared by the impregnation method, irrespective of the calcination and reduction temperatures. The high catalytic activity of the catalyst prepared at low temperatures (such as 150 °C) was attributed to the formation of Pt nanoparticles triggered by the reduction of cod ligands under H2 conditions, whereas that of the catalyst prepared at high temperatures (up to 450 °C) was due to the modification of the SiO2 surface by grafting of the (cod)Pt-disilicate complex.

Bacterial nanocellulose as green support of platinum nanoparticles for effective methanol oxidation

Bacterial nanocellulose, BNC, has emerged as a new class of nanomaterials recognized as renewable, biodegradable, biocompatible and material for versatile applications. BNC also proved as a perfect support matrix for metallic nanoparticle synthesis and appeared as suitable alternative for widely used carbon based materials. Following the idea to replace commonly used carbon based materials for platinum supports with the green and sustainable one, BNC appeared as an excellent candidate. Herein, microwave assisted synthesis has been reported for the first time for platinum nanoparticles supported on BNC as green material. Bacterial nanocelullose-platinum catalyst, Pt/BNC, was investigated by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), atomic force microscopy (AFM), X-ray diffractometry (XRD) and transmission-electron microscopy (TEM) analysis. The obtained results confirmed successful synthesis of new Pt-based catalyst. It was found that Pt/BNC catalyst has high electrocatalytic performance in methanol oxidation reaction. Green/sustainable catalytic system is highly desirable and provided by the elegant microwave assisted synthesis of Pt/BNC will pave the way for a larger scale application and expedite the market penetration of such fuel cells.

Fe-N-C Boosts the Stability of Supported Platinum Nanoparticles for Fuel Cells.

The poor durability of Pt-based nanoparticles dispersed on carbon black is the challenge for the application of long-life polymer electrolyte fuel cells. Recent work suggests that Fe- and N-codoped carbon (Fe-N-C) might be a better support than conventional high-surface-area carbon. In this work, we find that the electrochemical surface area retention of Pt/Fe-N-C is much better than that of commercial Pt/C during potential cycling in both acidic and basic media. In situ inductively coupled plasma mass spectrometry studies indicate that the Pt dissolution rate of Pt/Fe-N-C is 3 times smaller than that of Pt/C during cycling. Density functional theory calculations further illustrate that the Fe-N-C substrate can provide strong and stable support to the Pt nanoparticles and alleviate the oxide formation by adjusting the electronic structure. The strong metal-substrate interaction, together with a lower metal dissolution rate and highly stable support, may be the reason for the significantly enhanced stability of Pt/Fe-N-C. This finding highlights the importance of carbon support selection to achieve a more durable Pt-based electrocatalyst for fuel cells.

Effect of Pressure on Carbon monoxide Oxidation on Titania Supported Platinum Nanoparticles Catalyst

Thermographic testing methodology was developed to facilitate measurements of particle dimension and substrate influence in heterogeneous catalysts. A screening chip with several areas of less stress silicon nitride membranes which displays less heat conductivity and heat capacity was used. Heat produced during the reaction on catalysts deposited on membranes was established through IR camera which gave the value of the turn over frequency. Effect of pressure on CO conversion on titania supported Pt particles of different dimension was measured on 120 catalysts concurrently. The reaction was studied at various O2 and CO pressures at 170 ℃ and 240 ℃. At these temperature conditions, activity increased with increase of O2 and CO pressure, in agreement with previous reports.

Stability and Degradation of Pt/C Catalysts Explored with IL-TEM

Industrial application of fuel cells, while, hopefully, inevitable, is still hindered by various aspects, one of them being the issue with oxygen reduction reaction (ORR) catalysts. Current state of the art platinum catalysts, while extraordinarily active, still have a long way to go when it comes to stability. In this work we have decided to tackle this problem by employing FW200 carbon black as a support for platinum nanoparticles. The carbon support was treated in 3000 °C to obtain highly ordered, graphitic structure. We’ve discovered that our catalyst, while initially exhibiting lower electrochemical surface area (ECSA) than it’s commercial, Vulcan-based counterpart, degraded with substantially slower rate than the industrial catalyst. We’ve came to that conclusion after subjecting the catalysts to accelerated degradation tests (ADT) on the rotating ring disk electrode in various potential ranges and performing ECSA and activity measurements during and after said tests. Additionally, to explore degradation mechanisms of the catalysts we’ve used identical localization transmission electron microscopy (ILTEM). This technique allows us to track the behaviour of each platinum nanoparticle, before and after electrochemical measurements, by performing ADT on TEM grids covered with catalyst. ILTEM experiments allowed us to prove, that the crystalline structure of graphitized FW200 hinders nanoparticles’ movement across the carbon support, leading to increased resistance to agglomeration. We used inductively coupled plasma optical emission spectroscopy to investigate platinum dissolution’s part in reducing catalyst activity by measuring the amount of platinum left in electrolyte after ADT. Lastly, we’ve investigated the influence of heat treatment in 3000 °C on the structure and electronic properties of the FW200 carbon black using Raman spectroscopy and X-ray photoelectron spectroscopy. Thorough electrochemical and structural study of platinum catalyst deposited on graphitized FW200 carbon black allowed us to confirm, that our material is highly competitive, in the terms of stability, to commercially available Vulcan-based catalysts. We also think that ILTEM, while exceptionally powerful, is still quite an underutilized technique and we would like to present how joint efforts of microscopists and electrochemists can push the boundaries of knowledge in ORR electrochemistry.

Carbon black‐heteroatom‐doped graphene aerogel hybrid supported platinum nanoparticles as electrocatalysts for oxidation of methanol and formic acid

Carbon black‐heteroatom‐doped graphene aerogel hybrid supported platinum nanoparticles as electrocatalysts for oxidation of methanol and formic acid

Surface modification of carbon fiber cloth by femtosecond laser direct writing technology

In this work, carbon fiber cloth is proposed by femtosecond laser direct writing technology (FLDWT) with different conditions. As consequence, series of laser-induced periodic surface structures (LIPSS) are constructed on the surface of carbon fiber cloth, and the hydrophobic property of carbon fiber cloth is changed dramatically, the contact angle of pristine carbon fiber cloth sharply decreases from 150.8° to 20.4°, which makes carbon fiber cloth successfully support platinum nanoparticles in a hydrophilic reaction environment.

(Digital Presentation) Durable Silica Nanosheets/Carbon Black Supported Catalyst for Proton Exchange Membrane Fuel Cells

Proton exchange membrane fuel cells (PEMFCs) which have high efficiency have attracted attention as one of the most promising energy conversion devices. Currently the catalysts in PEMFCs are mainly carbon supported noble metals where the support can afford the electron transport environment to improve catalyst efficiency and decrease catalyst loss by strengthening catalyst–support bonding [1]. Due to high electrical conductivity and surface area, carbon-based catalyst supports are widely used in PEMFCs. However, the high electric fields applied to the fuel cell can easily cause carbon corrosion and further accelerate catalyst loss.New alternative support materials are needed to reduce costs and increase the lifetime of PEMFC electrodes. Recently, silica-based supports such as silicon oxide [2, 3] and silicon carbide [4] have been considered feasible as catalyst supports due to efficient catalyst utilization and their resistance to carbon corrosion. As a silica-based material, hydrophilic silica nanosheets (SN) derived from cheap natural vermiculite [5] is for the first time to be combined with carbon black (CB) as a catalyst support in this work. SN-CB supported platinum (Pt) catalysts were prepared according to different weight ratios of SN and CB using a modified polyol reduction method [6]. After 18000-cycle accelerated stress test (AST), as shown in Fig. 1a and b, the electrochemical surface area (ECSA) of Pt/SN2-CB3 (the weight ratio of SN to CB is 2: 3) decays from 23.7 to 22.5 m2/g (only 4.8% degradation) compared to Pt/CB (25.8% degradation from 16.0 to 11.9 m2/g). Meanwhile, Pt/SN2-CB3 shows comparable initial onset potential (0.850 V) and high half-wave potential (0.654 V) compared to 0.881 V onset potential and 0.625 V half-wave potential for Pt/CB as shown in Fig. 1c and d. The half-wave potential of Pt/SN2-CB3 after AST test demonstrated the addition of SN into the support can result in a stable oxygen reduction reaction (ORR) durability. The possible reason why the ECSA, ORR activity and durability of SN-CB supported platinum catalysts are enhanced is that the synergic interactions among carbon, silica nanosheets and Pt nanoparticles may hinder carbon corrosion, Pt agglomeration and dissolution [2]. Different weight ratios between SN and CB and the functionalized SNs are currently being tested and the real fuel cell data will be presented. Reference [1] Y.-J. Wang, D.P. Wilkinson, J. Zhang, Noncarbon support materials for polymer electrolyte membrane fuel cell electrocatalysts, Chemical reviews, 111 (2011) 7625-7651.[2] P. Dhanasekaran, A. Shukla, S.V. Selvaganesh, S. Mohan, S. Bhat, Silica-decorated carbon-Pt electrocatalyst synthesis via single-step polyol method for superior polymer electrolyte fuel cell performance, durability and stack operation under low relative humidity, Journal of Power Sources, 438 (2019) 226999.[3] P. Dhanasekaran, S.V. Selvaganesh, A. Rathishkumar, S. Bhat, Designing self-humidified platinum anchored silica decorated carbon electrocatalyst for boosting the durability and performance of polymer electrolyte fuel cell stack, International Journal of Hydrogen Energy, 46 (2021) 8143-8155.[4] L. Dong, J. Zang, J. Su, Y. Jia, Y. Wang, J. Lu, X. Xu, Oxidized carbon/nano-SiC supported platinum nanoparticles as highly stable electrocatalyst for oxygen reduction reaction, International journal of hydrogen energy, 39 (2014) 16310-16317.[5] Z. Guo, J. Chen, J.J. Byun, R. Cai, M. Perez-Page, M. Sahoo, Z. Ji, S.J. Haigh, S.M. Holmes, High-performance polymer electrolyte membranes incorporated with 2D silica nanosheets in high-temperature proton exchange membrane fuel cells, Journal of Energy Chemistry, 64 (2022) 323-334.[6] Z. Ji, M. Perez-Page, J. Chen, R.G. Rodriguez, R. Cai, S.J. Haigh, S.M. Holmes, A structured catalyst support combining electrochemically exfoliated graphene oxide and carbon black for enhanced performance and durability in low-temperature hydrogen fuel cells, Energy, 226 (2021) 120318. Figure 1

Electrochemical Trends of Atomically Dispersed Metal-Nitrogen-Carbon Materials As Oxygen Reduction Reaction Catalysts and Active Supports

Platinum-based catalysts currently remain the best option for polymer electrolyte membrane fuel cell (PEMFC) applications. Meanwhile, atomically dispersed metal-nitrogen-carbon (MNC) materials have been the frontrunner for platinum-group metal free catalysts for the oxygen reduction reaction (ORR)1. Considering that the platinum-based nanoparticles are preferably supported on carbonaceous materials, it would be intuitive to use MNC catalysts as a support for platinum nanoparticles to further increase the activity and performance of the catalyst layer in a PEMFC. In this work, we synthesized and investigated a series of MNC materials (Mn-N-C, Fe-N-C, Co-N-C, Ni-N-C, and Cu-N-C) using a previously described method2 to elucidate the electrochemical trends of possible interactions between the MNC materials as a support and standard Pt nanoparticles. Recent works3,4 have shown that combining MNC catalysts with Pt catalysts not only improves the activity of the overall composite catalyst, but also improves the stability of both counterparts. As shown in Figure 1, the supported Pt nanoparticles on MNC materials outperforms the same type of Pt nanoparticles when supported on an industry standard carbon.Reference Asset, T. & Atanassov, P. Iron-Nitrogen-Carbon Catalysts for Proton Exchange Membrane Fuel Cells. Joule 4, 33–44 (2020).Murphy, E. et al. Using Atomically Dispersed Bimetallic Active Sites to Probe the Nitrate Reduction Mechanism to Ammonia. ECS Meet. Abstr. MA2021-02, 1559 (2021).Ao, X. et al. Atomically dispersed Fe–N–C decorated with Pt-alloy core–shell nanoparticles for improved activity and durability towards oxygen reduction. Energy Environ. Sci. 13, 3032–3040 (2020).Qiao, Z. et al. Atomically dispersed single iron sites for promoting Pt and Pt3Co fuel cell catalysts: performance and durability improvements. Energy Environ. Sci. (2021). Figure 1

NaCl-Templated Ultrathin 2D-Yttria Nanosheets Supported Pt Nanoparticles for Enhancing CO Oxidation Reaction.

Morphology of support is of fundamental significance to the fabrication of highly efficient catalysts for CO oxidation reaction. Many methods for the construction of supports with specific morphology and structures greatly rely on controlling general physical and chemical synthesis conditions such as temperature or pH. In this paper, we report a facile route to prepare yttria nanosheet using NaCl as template to support platinum nanoparticles exhibiting higher CO oxidation activity than that of the normally prepared Pt/Y2O3. With the help of TEM and SEM, we found that Pt NPs evenly distributed on the surface of NaCl modified 2D-nanosheets with smaller size. The combination of XAFS and TEM characterizations demonstrated that the nano-size Pt species with PtxOy structure played an essential role in the conversion of CO and kept steady during the CO oxidation process. Moreover, the Pt nanoparticles supported on the NaCl templated Y2O3 nanosheets could be more easily reduced and thus exposed more Pt sites to adsorb CO molecules for CO oxidation according to XPS and DRIFTS results. This work offers a unique and general method for the preparation of potential non-cerium oxide rare earth element oxide supported nanocatalysts.

Optimization of platinum loading on partially fluorinated carbon catalysts for enhanced proton exchange membrane fuel cell performance

The role of partially fluorinated carbon (CFx) supported platinum nanoparticles as proton exchange membrane fuel cell (PEMFC) electrodes in a hydrogen fuel cell is investigated. CFx is employed as a platinum catalyst support via impregnation for oxygen reduction reaction (ORR) at various platinum loadings to determine the optimal loading for ORR and compared to the widely used (non-fluorinated) Vulcan Carbon (XC-72R). In half-cell testing, CFx catalysts display greater ORR kinetics at lower Pt loadings while XC-72R display higher kinetics at higher Pt loadings. PEMFC tests utilizing 30% wt-platinum on carbon supports as the cathode material reveal a 20% increase in fuel cell performance and an 11% decrease in charge transfer resistance for the CFx supported catalysts compared to that of the XC-72R supported catalysts. PEMFCs tests utilizing 10% wt-platinum on CFx supports as the anode catalyst display a 20% increase in power density compared to the XC-72R supported catalyst. Furthermore, utilizing CFx as the support for both anode and cathode electrodes display a 15% power density increase compared to XC-72R supported catalysts.