Johnson Matthey Highlights
Johnson Matthey Highlights
A selection of recent publications by Johnson Matthey R&D staff and collaborators
Robust Continuous Synthesis and in situ Deposition of Catalytically Active Nanoparticles on Colloidal Support Materials in a Triphasic Flow Millireactor
W. K. Wong, J. T. Y. Chin, S. A. Khan, F. Pelletier and E. C. Corbos, Chem. Eng. J., 2022, 430, (4), 132778 LINK https://doi.org/10.1016/j.cej.2021.132778
A triphasic flow millireactor for catalytic nanoparticle synthesis and facile in situ deposition onto colloidal support materials is presented. Colloidal deposition was chosen because it allows nanoparticles with complex shapes and compositions to be deposited on the support material. In comparison to batch-synthesised nanoparticles, those generated by flow synthesis demonstrated greater quality and consistency. The method is shown to be effective when using different support materials, including alumina, ceria and titania. The technique’s versatility is also demonstrated for various nanoparticle types, such as tri-/bi-/mono-metallics.
Comparison Between the Thermal and Plasma (NTP) Assisted Palladium Catalyzed Oxidation of CH4 using AC or Nanopulse Power Supply
F. De Rosa, C. Hardacre, W. G. Graham, G. McCullough, P. Millington, P. Hinde and A. Goguet, Catal. Today, 2022, 384–386, 177 LINK https://doi.org/10.1016/j.cattod.2021.04.015
A palladium supported alumina catalyst was used to investigate the combustion of methane using three systems (thermocatalytic, plasma and plasma-catalyst). To compare the three systems, the authors looked for the presence of a synergistic effect between the heterogenous catalyst and the plasma. The specific input energy of each system was also examined. The plasma systems were shown to be less efficient than the thermal process. When an AC power supply was used, no synergistic effect was found for the plasma systems. However, a nanopulse power supply demonstrated more promise. When using a nanopulsed operation, energy requirements were reduced for both heterogenous and homogeneous configurations.
Gas-Phase Isomerisation of m-Xylene on Isoreticular Zeolites with Tuneable Porosity
N. Remperová, J. Přech, M. Kubů, K. Gołąbek, J. F. Miñambres, M.-F. Hsieh, A. Turrina and M. Mazur, Catal. Today, 2022, 390–391, 78 LINK https://doi.org/10.1016/j.cattod.2021.11.044
The ADOR approach was used to synthesise aluminium-containing isoreticular zeolites with controllable pore sizes. The zeolites were used to study catalytic performance in gas-phase m-xylene isomerisation. The authors investigated phase purity, the crystallinity and interlayer distances, aluminium content, textural properties of prepared materials and their crystals morphology. Comparisons were made with standard ZSM-5 zeolite. IPC-2 (10- and 12-ring channels) exhibited the highest conversion and p-xylene yields. A drop in selectivity was observed in the presence of extra-large, 14-ring channels, a consequence of xylene disproportionation.
Evaluation Of Water States in Thin Proton Exchange Membrane Manufacturing using Terahertz Time‐Domain Spectroscopy
D. F. Alves-Lima, X. Li, B. Coulson, E. Nesling, G. A. H. Ludlam, R. Degl’Innocenti, R. Dawson, M. Peruffo and H. Lin, J. Membr. Sci., 2022, 647, 120329 LINK https://doi.org/10.1016/j.memsci.2022.120329
The unique structure of perfluorinated sulfonic-acid ionomers (used as materials in proton exchange membranes) supports their chemical/mechanical and water properties. An understanding of these properties is imperative for creating optimal membranes. The authors used terahertz time-domain spectroscopy to resolve molecular water states and retention properties inside Nafion membranes (Figure 1). They also developed a parametric-based algorithm for data analysis. The technique was applied to industrially relevant thin ionomers (13–70 μm), and results were reinforced by prior demonstrations and conventional gravimetric analysis. The method showed sensitivity to membranes prepared under different processing conditions.
Biotechnological Synthesis of Pd-based Nanoparticle Catalysts
C. Egan-Morriss, R. L. Kimber, N. A. Powell and J. R. Lloyd, Nanoscale Adv., 2022, 4, (3), 654 LINK https://doi.org/10.1039/D1NA00686J
Palladium nanoparticles supported on microbial cells (bio-Pd) offer a more sustainable alternative to palladium nanoparticles generated via conventional chemical synthesis. However, the intrinsic activity and selectivity of bio-Pd needs to be enhanced to make it commercially viable. Bacteria, such as dissimilatory metal-reducing bacteria, have historically been used to produce bio-Pd. Recently, bio-bimetallic nanoparticles have been introduced, which can significantly enhance the catalytic properties of bio-Pd. To further enhance these properties, bio-Pd can be integrated into biocatalytic processes using systems biology. In this review, the authors examine enzymatic metal reduction processes that can be bioengineered to control the shape, size and cellular location of bio-Pd to improve its catalytic properties.
Site-Selective d10/d0 Substitution in an S = ½ Spin Ladder Ba2CuTe1–xWxO6 (0 ≤ x ≤ 0.3)
C. Pughe, O. H. J. Mustonen, A. S. Gibbs, M. Etter, C. Liu, S. E. Dutton, A. Friskney, N. C. Hyatt, G. B. G. Stenning, H. M. Mutch, F. C. Coomer and E. J. Cussen, Inorg. Chem., 2022, 61, (9), 4033 LINK https://doi.org/10.1021/acs.inorgchem.1c03655
The hexagonal perovskite Ba2CuTeO6 has a spin ladder geometry of Cu2+ cations. The authors substituted Te6+ d10 by W6+ d0 in Ba2CuTeO6 to produce a Ba2CuTe1–xWxO6 solid solution (x = 0–0.3). The substitution of W6+ for Te6+ was nearly exclusively observed on the corner-sharing site within the spin ladder rather than the face-sharing site between ladders. The intraladder interactions (Jrung and Jleg) were shown to be directly tuned by site-selective doping. As W6+ increased, the system changed from a spin ladder to isolated spin chains. This was demonstrated by modelling the magnetic susceptibility data, which also showed that the relative intraladder interaction strength (Jrung/Jleg) was modified by the d0 orbitals.
Renewable Butadiene: A Case for Hybrid Processing via Bio- and Chemo-Catalysis
S. Rodgers, F. Meng, S. Poulston, A. Conradie and J. McKechnie, J. Cleaner Prod., 2022, 364, 132614 LINK https://doi.org/10.1016/j.jclepro.2022.132614
Technoeconomics and greenhouse gas emissions of renewable butadiene production using a hybrid biocatalytic route with black liquor were investigated and compared to two chemocatalytic routes using forestry residues and pulpwood. A novel aerobic gas fermentation platform was employed. Integrated supercritical water gasification and aerobic gas fermentation produces acetaldehyde, followed by chemocatalytic upgrading. One route passes through an ethanol intermediate, the other has propene as an intermediate. The hybrid bio/chemo-catalytic route was found to be profitable using the nominal technoeconomic inputs, producing a net present value of US$2.8 million and minimum selling price of US$1367 tonne−1.
Enzymatic Epoxidation of Long-Chain Terminal Alkenes by Fungal Peroxygenases
E. D. Babot, C. Aranda, J. Kiebist, K. Scheibner, R. Ullrich, M. Hofrichter, A. T. Martínez and A. Gutiérrez, Antioxidants, 2022, 11, (3), 522 LINK https://doi.org/10.3390/antiox11030522
Unspecific peroxygenases (UPOs) were explored to selectively epoxidise terminal alkenes. After optimisation of reaction parameters (cosolvent, cosubstrate and pH), UPOs from Cyclocybe (Agrocybe) aegerita, Marasmius rotula, Coprinopsis cinerea, Humicola insolens and Daldinia caldariorum were found to catalyse the epoxidation of long-chain terminal alkenes from C12:1 to C20:1. Alkenols and other hydroxylated derivatives of the alkenes were also formed. Peroxygenases therefore have potential as an interesting and green alternative to the existing technologies for epoxidising long-chain terminal alkenes.
A Cell Design for Correlative Hard X-ray Nanoprobe and Electron Microscopy Studies of Catalysts under in situ Conditions
J. E. Parker, M. Gomez-Gonzalez, Y. Van Lishout, H. Islam, D. Duran Martin, D. Ozkaya, P. D. Quinn and M. E. Schuster, J. Synchrotron Rad., 2022, 29, 431 LINK https://doi.org/10.1107/S1600577521013576
A specially developed system incorporating a commercially available gas-cell chip assembly within an X-ray nanoprobe beamline was used to investigate the redox behaviour of platinum nanoparticles supported on ceria under typical lean and rich diesel-exhaust conditions. The system may also be applied to a wide range of other solid–gas reactions. Complimentary in situ TEM and X-ray nanoprobe studies could be carried out under identical conditions. The same cell can be used and easily transferred between instruments, a major advantage which raises the possibility of studying the same particles under identical conditions (gas flow, pressure, temperature) using multiple techniques.
Intensified Liquid-Liquid Extraction of Biomolecules using Ionic Liquids in Small Channels
Y.-V. Phakoukaki, P. O’Shaughnessy and P. Angeli, Sep. Purif. Technol., 2022, 282, (B), 120063 LINK https://doi.org/10.1016/j.seppur.2021.120063
Intensified extraction of amino acid L-tryptophan from aqueous solution into an ionic liquid was carried out in small channels. The study demonstrated the possibility of replacing conventional organic solvents with ionic liquids. A mechanism is proposed for ionic liquid and extractant combination. Hydrodynamic properties of the liquid-liquid plug flow in small channels were investigated. High mass transfer coefficients in comparison to mixer-settlers and organic solvents, respectively, were found.