scholarly journals Platinum Nanoparticle Inclusion into a Carbonized Polymer of Intrinsic Microporosity: Electrochemical Characteristics of a Catalyst for Electroless Hydrogen Peroxide Production

Nanomaterials ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 542 ◽  
Author(s):  
Robert Adamik ◽  
Naiara Hernández-Ibáñez ◽  
Jesus Iniesta ◽  
Jennifer Edwards ◽  
Alexander Howe ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Surface Area ◽  
Hydrogen Oxidation ◽  
Pt Nanoparticles ◽  
Bet Surface Area ◽  
Electrochemical Characteristics ◽  
Platinum Nanoparticle ◽  
Nano Catalyst ◽  
The One ◽  
Intrinsic Microporosity

The one-step vacuum carbonization synthesis of a platinum nano-catalyst embedded in a microporous heterocarbon (Pt@cPIM) is demonstrated. A nitrogen-rich polymer of an intrinsic microporosity (PIM) precursor is impregnated with PtCl62− to give (after vacuum carbonization at 700 °C) a nitrogen-containing heterocarbon with embedded Pt nanoparticles of typically 1–4 nm diameter (with some particles up to 20 nm diameter). The Brunauer-Emmett-Teller (BET) surface area of this hybrid material is 518 m2 g−1 (with a cumulative pore volume of 1.1 cm3 g−1) consistent with the surface area of the corresponding platinum-free heterocarbon. In electrochemical experiments, the heterocarbon-embedded nano-platinum is observed as reactive towards hydrogen oxidation, but essentially non-reactive towards bigger molecules during methanol oxidation or during oxygen reduction. Therefore, oxygen reduction under electrochemical conditions is suggested to occur mainly via a 2-electron pathway on the outer carbon shell to give H2O2. Kinetic selectivity is confirmed in exploratory catalysis experiments in the presence of H2 gas (which is oxidized on Pt) and O2 gas (which is reduced on the heterocarbon surface) to result in the direct formation of H2O2.

scholarly journals Chemical modification of the polymer of intrinsic microporosity PIM-1 for enhanced hydrogen storage

Adsorption ◽  
2020 ◽  
Vol 26 (7) ◽  
pp. 1083-1091
Author(s):  
Mi Tian ◽  
Sébastien Rochat ◽  
Hamish Fawcett ◽  
Andrew D. Burrows ◽  
Christopher R. Bowen ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Surface Area ◽  
Hydrogen Adsorption ◽  
Sorption Properties ◽  
Bet Surface Area ◽  
Polymer Modification ◽  
Gas Sorption ◽  
Chemically Modified ◽  
Polymer Of Intrinsic Microporosity ◽  
Intrinsic Microporosity

Abstract A detailed investigation has been carried out of the pre-polymerisation modification of the polymer of intrinsic microporosity PIM-1 by the addition of two methyl (Me) groups to its spirobisindane unit to create a new chemically modified PIM-1 analogue, termed MePIM. Our work explores the effects of this modification on the porosity of PIM-1 and hence on its gas sorption properties. MePIM was successfully synthesised using either low (338 K) or high (423 K) temperature syntheses. It was observed that introduction of methyl groups to the spirobisindane part of PIM-1 generates additional microporous spaces, which significantly increases both surface area and hydrogen storage capacity. The BET surface area (N2 at 77 K) was increased by ~ 12.5%, resulting in a ~ 25% increase of hydrogen adsorption after modification. MePIM also maintains the advantages of good processability and thermal stability. This work provides new insights on a facile polymer modification that enables enhanced gas sorption properties.

scholarly journals Classification of Platinum Nanoparticle Catalysts using Machine Learning

2020 ◽  
Author(s):  
Amanda J. Parker ◽  
George Opletal ◽  
Amanda Barnard
Keyword(s):  
Machine Learning ◽  
Hydrogen Oxidation ◽  
Pt Nanoparticles ◽  
Structure Property ◽  
Metallic Nanoparticle ◽  
Platinum Nanoparticle ◽  
Nanoparticle Catalysts ◽  
Structure Property Relationships ◽  
Multi Stage

Computer simulations and machine learning provide complementary ways of identifying structure/property relationships that are typically targeting toward predicting the ideal singular structure to maximise the performance on a given application. This can be inconsistent with experimental observations that measure the collective properties of entire samples of structures that contain distributions or mixture of structures, even when synthesized and processed with care. Metallic nanoparticle catalysts are an important example. In this study we have used a multi-stage machine learning workflow to identify the correct structure/property relationships of Pt nanoparticles relevant to oxygen reduction (ORR), hydrogen oxidation (HOR) and hydrogen evolution (HER) reactions. By including classification prior to regression we identified two distinct classes of nanoparticles, and subsequently generate the class-specific models based on experimentally relevant criteria that are consistent with observations. These multi-structure/multi-property relationships, predicting properties averaged over a large sample of structures, provide a more accessible way to transfer data-driven predictions into the lab.

Facile deposition of Pt nanoparticles on Sb-doped SnO2 support with outstanding active surface area for the oxygen reduction reaction

2018 ◽  
Vol 8 (10) ◽  
pp. 2672-2685 ◽  
Author(s):  
Rhiyaad Mohamed ◽  
Tobias Binninger ◽  
Patricia J. Kooyman ◽  
Armin Hoell ◽  
Emiliana Fabbri ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Surface Area ◽  
Pt Nanoparticles ◽  
Active Surface ◽  
Reduction Reaction ◽  
Active Surface Area

Synthesis of Sb–SnO2 supported Pt nanoparticles with an outstanding ECSA for the oxygen reduction reaction.

scholarly journals Synthesis and Gas-Permeation Characterization of a Novel High-Surface Area Polyamide Derived from 1,3,6,8-Tetramethyl-2,7-diaminotriptycene: Towards Polyamides of Intrinsic Microporosity (PIM-PAs)

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 361 ◽  
Author(s):  
Giuseppe Genduso ◽  
Bader Ghanem ◽  
Yingge Wang ◽  
Ingo Pinnau
Keyword(s):  
Surface Area ◽  
Gas Permeability ◽  
High Surface ◽  
High Surface Area ◽  
Gas Permeation ◽  
Bet Surface Area ◽  
Mixed Gas ◽  
Fractional Free Volume ◽  
Intrinsic Microporosity

A triptycene-based diamine, 1,3,6,8-tetramethyl-2,7-diamino-triptycene (TMDAT), was used for the synthesis of a novel solution-processable polyamide obtained via polycondensation reaction with 4,4′-(hexafluoroisopropylidene)bis(benzoic acid) (6FBBA). Molecular simulations confirmed that the tetrasubstitution with ortho-methyl groups in the triptycene building block reduced rotations around the C–N bond of the amide group leading to enhanced fractional free volume. Based on N2 sorption at 77 K, 6FBBA-TMDAT revealed microporosity with a Brunauer–Emmett–Teller (BET) surface area of 396 m2 g−1; to date, this is the highest value reported for a linear polyamide. The aged 6FBBA-TMDAT sample showed moderate pure-gas permeabilities (e.g., 198 barrer for H2, ~109 for CO2, and ~25 for O2) and permselectivities (e.g., αH2/CH4 of ~50) that position this polyamide close to the 2008 H2/CH4 and H2/N2 upper bounds. CO2–CH4 mixed-gas permeability experiments at 35 °C demonstrated poor plasticization resistance; mixed-gas permselectivity negatively deviated from the pure-gas values likely, due to the enhancement of CH4 diffusion induced by mixing effects.

scholarly journals Classification of Platinum Nanoparticle Catalysts using Machine Learning

2020 ◽  
Author(s):  
Amanda J. Parker ◽  
George Opletal ◽  
Amanda Barnard
Keyword(s):  
Machine Learning ◽  
Hydrogen Oxidation ◽  
Pt Nanoparticles ◽  
Structure Property ◽  
Metallic Nanoparticle ◽  
Platinum Nanoparticle ◽  
Nanoparticle Catalysts ◽  
Structure Property Relationships ◽  
Multi Stage

Computer simulations and machine learning provide complementary ways of identifying structure/property relationships that are typically targeting toward predicting the ideal singular structure to maximise the performance on a given application. This can be inconsistent with experimental observations that measure the collective properties of entire samples of structures that contain distributions or mixture of structures, even when synthesized and processed with care. Metallic nanoparticle catalysts are an important example. In this study we have used a multi-stage machine learning workflow to identify the correct structure/property relationships of Pt nanoparticles relevant to oxygen reduction (ORR), hydrogen oxidation (HOR) and hydrogen evolution (HER) reactions. By including classification prior to regression we identified two distinct classes of nanoparticles, and subsequently generate the class-specific models based on experimentally relevant criteria that are consistent with observations. These multi-structure/multi-property relationships, predicting properties averaged over a large sample of structures, provide a more accessible way to transfer data-driven predictions into the lab.

Microwave Synthesis of Metallic Nanoparticles Supported on Porous Coordination Polymers: A Bi-functional Catalyst Design for CO2 Activation and Conversion

2011 ◽  
Vol 1312 ◽  
Author(s):  
Victor Abdelsayed ◽  
Yueying Fan ◽  
Todd Gardner
Keyword(s):  
Surface Area ◽  
Coordination Polymers ◽  
Metallic Nanoparticles ◽  
Pt Nanoparticles ◽  
High Energy ◽  
Catalyst Design ◽  
Bet Surface Area ◽  
Porous Coordination Polymers ◽  
Global Goal ◽  
Sorbent Materials

ABSTRACTThe efficient separation and conversion of CO2 from power plant flue gases remains a significant and far reaching global goal. Partially, because of the high energy cost associated with CO2 separation which makes technologies, such as amine scrubbing and conventional sorbent materials, less attractive. In this work we have used a microwave-assisted method to prepare Mg-based porous coordination polymers (MOF-74) with open metal sites. The material shows a high CO2 uptake at room temperature mainly due to the high binding energy between the open Mg site (in the coordination polymer) and the oxygen atom of the adsorbed CO2 molecule. Our results show that the microwave-based Mg-MOF-74 shows superior properties compared to thermally prepared samples such as higher surface area, crystallinity and CO2 uptake. Pt nanoparticles (<5-10 nm) were deposited on the Mg-MOF-74 as manifested from the TEM results. The Pt nanoparticles were uniformly dispersed across the sample with more aggregations at higher Pt loadings. Different techniques were used to characterize the materials such as (BET surface area, XRD, SEM, EDS, TEM and TGA). These materials function as a bi-functional catalyst and sorbent material with the Mg-MOF-74 material responsible for CO2 capture and supported Pt nanoparticles responsible for its catalytic activity.

scholarly journals Effect of tungsten carbide in carbon Pt catalyst support on electrochemical oxygen reduction in acid solution

2013 ◽  
Vol 67 (2) ◽  
pp. 303-311
Author(s):  
Maja Obradovic ◽  
Biljana Babic ◽  
Nedeljko Krstajic ◽  
Snezana Gojkovic
Keyword(s):  
Tungsten Carbide ◽  
Tungsten Oxide ◽  
Oxygen Reduction ◽  
Surface Area ◽  
Catalyst Support ◽  
Pt Nanoparticles ◽  
Cyclic Voltammogram ◽  
Xrd Pattern ◽  
Current Densities ◽  
Electrochemical Oxygen

Tungsten carbide was synthesized by calcination of carbon cryogel with embedded tungsten in a form of metatungstate. This material was used as a support for Pt nanoparticles. XRD pattern of W-C support indicates the presence of WC, W2C, and unreacted W, as well as graphitized carbon. According to the previous TEM analysis of W-C support, it contains particles with core-shell structure, where W particle was covered with the shell of a mixture of WC and W2C. The average Pt grain size calculated from XRD pattern was about 6 nm. Cyclic voltammogram of W-C support was recorded within potential range relevant for its application as a catalyst support in fuel cells. Pair of anodic/cathodic peaks close to the negative potential limit could be ascribed to the intercalation of hydrogen within hydrous tungsten oxide, which is always present on the surface of WC in aqueous solutions. Cyclic voltammogram of Pt/W-C indicated that tungsten oxide species are present on tungsten carbide shell as well as on the surface of Pt nanoparticles. Pt surface is only partially covered by hydrous tungsten oxide. Hydrogen intercalation in hydrous tungsten oxide is enhanced in the presence of Pt nanoparticles. Also, the presence of hydrated tungsten oxide leads to the decrease of OH chemisorbed on Pt surface. Stripping of underpotentially deposited copper was used for the assessment of Pt surface area and the specific surface area of Pt was estimated to 41 m2 g-1. Electrochemical oxygen reduction reaction was examined on the synthesized Pt/W-C catalyst and compared with the results on the commercial Pt/C catalyst. It was found that the current densities at Pt/W-C are almost double as those on Pt/C. The Tafel plots for both catalysts are characterized with two Tafel slopes: -0.060 V dec-1 at low current densities, and -0.120 V dec-1 at high current densities. From the rotational dependence of the reaction rate, it was found that oxygen reduction on both Pt/W-C and Pt/C follows the first order kinetics with respect to O2 and that four electrons are transferred per O2 molecule. The results show that the presence of tungsten carbide in support material i.e. hydrous tungsten oxide on Pt surface, leads to promotion of oxygen reduction on the Pt/W-C catalyst. It was assumed that oxophilic hydrated tungsten oxide hinders OH adsorption on Pt surface, thus increasing Pt surface area available for O2 adsorption and its electrochemical reduction.

scholarly journals Dependency of BET surface area on particle size for some granitic minerals

2011 ◽  
Vol 1 (1) ◽  
pp. 75-82 ◽  
Author(s):  
I. E. Dubois ◽  
S. Holgersson ◽  
S. Allard ◽  
M. E. Malmström
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Spent Nuclear Fuel ◽  
Fine Particles ◽  
Bet Surface Area ◽  
Crushed Material ◽  
Radionuclide Sorption ◽  
The One

AbstractIn order to assess the geochemical retention properties of rocks, which will be the final barrier for radionuclide transport to the biosphere in the case of a failed deep underground repository for spent nuclear fuel, radionuclide sorption experiments are usually made with crushed material. This raises the issue of extrapolating results obtained from laboratory experiments to the field scale. As sorption is generally related to the surface area of the geological material, it is then important to consider the dependency of the specific surface area on the particle size. In this work, BET surface area determinations of samples of different particle sizes are conducted on two minerals commonly found in granite: labradorite and magnetite. The results show a linear relationship between BET surface area and the inverse of the particle size, up to a certain particle size. Furthermore, results also show that the specific surface area for intact, larger pieces is much smaller than the one predicted by a linear extrapolation of results on crushed material. Therefore, extrapolation of BET area for fine particles to the field situation will lead to an overestimation of the surface area and thereby also the radionuclide sorption, if sorption coefficients are extrapolated as well. Also of importance is that these results show that sorption experiments on crushed material may dominantly reflect properties of new surface, created during the mechanically treatment of the samples.

scholarly journals A novel platinum-based nanocatalyst at a niobia-doped titania support for the hydrogen oxidation reaction

2011 ◽  
Vol 76 (8) ◽  
pp. 1139-1152 ◽  
Author(s):  
Nevenka Elezovic ◽  
Biljana Babic ◽  
Velimir Radmilovic ◽  
Ljiljana Gajic-Krstajic ◽  
Nedeljko Krstajic ◽  
...  
Keyword(s):  
Surface Area ◽  
Oxidation Reaction ◽  
Hydrogen Oxidation ◽  
Pt Nanoparticles ◽  
Active Surface Area ◽  
Real Surface ◽  
Hydrogen Oxidation Reaction ◽  
Rotating Disc ◽  
Doped Titania ◽  
Kinetics Of

The kinetics of the hydrogen oxidation reaction (HOR) was studied at Pt nanoparticles supported on niobia-doped titania (Pt/N-T). The catalyst support, with the composition of 0.05NbO2.5-?-0.995TiO2 (0<?<1), was synthesized by a modified sol-gel procedure and characterized by the BET and X-ray diffraction (XRD) techniques. The specific surface area of the support was found to be 70 m2 g-1. The XRD analysis revealed the presence of the anatase TiO2 phase in the support powder. No peaks indicating the existence of Nb-compounds were detected. Pt/N-T nanocatalyst was synthesized by the borohydride reduction method. Transmission electron microscopy revealed a quite homogenous distribution of the Pt nanoparticles over the support, with a mean particle size of about 3 nm. The electrochemical active surface area of Pt of 42?4 m2 g-1 was determined by the cyclic voltammetry technique. The kinetics of the HOR was investigated by linear sweep voltammetry at a rotating disc electrode in 0.5 mol dm-3 HClO4 solution. The determined value of the Tafel slope of 35 mV dec-1 and an exchange current density of 0.45 mA cm-2 per real surface area of the Pt are in good accordance with those already reported in the literature for the HOR at polycrystalline Pt and Pt nanocatalysts in acid solutions. This new catalyst exhibited better activity for the HOR in comparison with Pt nanocatalyst supported on Vulcan? XC-72R high area carbon.

Sign in / Sign up

Export Citation Format

Share Document