Dr Jawwad A Darr

Research Overview

Research of the Clean Materials Technology Group (about 10 researchers at present) is concerned with the application of green principles and clean technologies for the rapid and efficient syntheses of molecules or new inorganic materials. Our research is very multidisciplinary, covering chemistry, materials, high pressure engineering, supercritical fluids and automation. Dr Darr is currently leading two large EPSRC/industry funded consortia in nanomaterials discovery and scale-up engineering of nanomaterials, respectively. We are always happy to talk to potential collaborators who can complement our capabilities in materials syntheses and characterisation.

Link to Clean Materials Technology Group webpages

Continuous Hydrothermal Flow Synthesis (CHFS); A fast and continuous method for making inorganic nanoparticles

A batch hydrothermal reactor is great for crystallising inorganic materials, e.g. zeolites, complex oxides at relatively low temperatures and at high pressure; similar processes occur over hundreds of years, deep under the earths crust. The problems with batch hydrothermal reactions are really that they can be slow as the reactor has to heat up then cool down. In our CHFS, technique, we can make nanoparticle ceramics in a rapid and continuous manner in the space of minutes or seconds (uses supercritical water). The ability to rapidly precipitate crystalline inorganic materials can give access to kinetic phases or combinations of particle properties that are difficult to achieve using other more conventional methods.


Image of instant nano-HA nano-rods

We have developed several CHFS reactors (using supercritical water) for small and larger scale syntheses of highly crystalline inorganic nanomaterials (see above). To date, we have synthesised a large number of crystalline materials using the CHFS system. These include, doped nano-bioceramics,[1, 2] Co containing spinels,[3] Ceria-Zirconia solid solutions[4,5], hundreds of doped titanias, ZnO, nano-YSZ, La-Ni-O series of compounds,[6], precious metal nanoparticles, Magnetite nanoparticles, cermets, Nitrides, etc. We were recently awarded a large EPSRC consortium project to scale up the reactor and work with collaborators to assess applications of nanoceramics.

Figure Right. instant nano-HA nano-rods

High Throughput Nanoceramics Discovery [EPSRC Reference: EP/D038499/1]

Photo or a range of powdered materials

The current advancement of technology very much depends upon the discovery of new inorganic materials. In particular, when inorganic particles are very small, typically made up of a few hundred atoms (called nanomaterials), they can have unusual and exciting properties. The discovery of such nanomaterials is very much hampered by our inability to make these materials fast enough and then to be able to test them adequately for their properties. This large EPSRC funded consortium project is developing a new, faster and automated way of making (using CHFS technology) and discovering inorganic nanomaterials that can absorb sunlight (as an free energy source), and use this energy to split water into its constituents, hydrogen and oxygen (in a process known as photocatalysis). The hydrogen can then be used for powering cars or devices of the future.


Unknown image

The work on biomaterials ranges from porous alginate scaffolds for medical engineering applications[7,8] to drug delivery formulations,[9-11] surface modified bioceramics[12, 13] and nano-bioceramics.[1,2] The work as involved extensive use of sc-CO2 and sc-water, respectively.

Scale-up consortium [EPSRC Reference: EP/E040551/1]

This project seeks to move the existing laboratory scale CHFS system towards a x10 pilot scale-up (nano-powder production of up to 500g per 12h depending on variables). The proposed research will initially compare the ability to control particle characteristics of the CHFS system at the laboratory scale over a large range of process variables (flow rates, temperatures, pressures, etc), building full operational envelopes that will describe reactor variables versus particle properties for each material. The scale up quantities of nano-powders from the pilot plant will allow industrial partners to perform prototyping or comprehensive commercial evaluation of nano-powders in a range of applications which they have hitherto not been able to conduct due to lack of sufficient high quality material.

Supercritical fluids (SCFs); general information

Supercritical water and sc-CO2 have applications from solvents/reagents for transformation of organic molecules (oxidation, C-C- bond formation, etc) to depolymerisation and synthesis of crystalline ceramics, respectively. In many of these applications, the use of a SCF offers significant advantages such as in process control or enhanced kinetics of the reaction. If you are working in solid state, materials or organic chemistry and would like to know more about SCFs, feel free to contact us or see our group website for more information.

Selected Publications

Recent Continuous Hydrothermal flow Synthesis chemistry

  1. High Throughput Continuous Hydrothermal (HiTCH) Flow Synthesis of Zn-Ce Oxides; Unprecedented Solubility of Zn in the Nanoparticle Fluorite lattice. Suela Kellici, Kenan Gong, Tian Lin, Sonal Brown, Robin J. H. Clark, Martin Vickers, Jeremy K. Cockcroft, Vesna Middelkoop, Paul Barnes, James M Perkinsb Chris Tighe, and Jawwad A. Darr, Royal Society Philosophical Transactions A. in press 2010
  2. The Rapid Automated Materials Synthesis Instrument (RAMSI): Exploring the Composition and Heat-treatment of Nano-precursors Towards Low Temperature Red Phosphors Tian Lin, Suela Kellici, Kenan Gong, Kathryn Thompson, Julian R.G. Evans, Xue Wang and Jawwad A. Darr JOURNAL OF COMBINATORIAL CHEMISTRY in press 2010
  3. Middelkoop, V; Boldrin, P; Peel, M; Buslaps, T; Barnes, P; Darr, JA; Jacques, SDM. 2009. Imaging the inside of a Continuous Nanoceramic Synthesizer under Supercritical Water Conditions Using High-Energy Synchrotron X-Radiation. CHEMISTRY OF MATERIALS 21 (12):2430-2435.
  4. Weng, XL; Perston, B; Wang, XZ; Abrahams, I; Lin, T; Yang, SF; Evans, JRG; Morgan, DJ; Carley, AF; Bowker, M; Knowles, JC; Rehman, I; Darr, JA. 2009. Synthesis and characterization of doped nano-sized ceria-zirconia solid solutions. APPLIED CATALYSIS B-ENVIRONMENTAL 90 (3-4):405-415.
  5. Weng, XL; Cockcroft, JK; Hyett, G; Vickers, M; Boldrin, P; Tang, CC; Thompson, SP; Parker, JE; Knowles, JC; Rehman, I; Parkin, I; Evans, JRG; Darr, JA. 2009. High-Throughput Continuous Hydrothermal Synthesis of an Entire Nanoceramic Phase Diagram. JOURNAL OF COMBINATORIAL CHEMISTRY 11 (5):829-834.
  6. Wang, XZ; Perston, B; Yang, Y; Lin, T; Darr, JA. 2009. Robust QSAR model development in high-throughput catalyst discovery based on genetic parameter optimisation. CHEMICAL ENGINEERING RESEARCH & DESIGN 87 (10A):1420-1429.
  7. Boldrin, P; Hebb, AK; Chaudhry, AA; Otley, L; Thiebaut, B; Bishop, P; Darr, JA. 2007. Direct synthesis of nanosized NiCo2O4 spinel and related compounds via continuous hydrothermal synthesis methods. INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 46 (14):4830-4838.

Recent Photocatalysis

  1. Zhang, Z; Goodall, JBM; Brown, S; Karlsson, L; Clark, RJH; Hutchison, JL; Rehman, IU; Darr, JA. 2010. Continuous hydrothermal synthesis of extensive 2D sodium titanate (Na2Ti3O7) nano-sheets. DALTON TRANSACTIONS 39 (3):711-714, .
  2. Zhang, ZC; Brown, S; Goodall, JBM; Weng, XL; Thompson, K; Gong, KN; Kellici, S; Clark, RJH; Evans, JRG; Darr, JA. 2009. Direct continuous hydrothermal synthesis of high surface area nanosized titania. JOURNAL OF ALLOYS AND COMPOUNDS 476 (1-2):451-456.
  3. Kafizas, A; Kellici, S; Darr, JA; Parkin, IP. 2009. Titanium dioxide and composite metal/metal oxide titania thin films on glass: A comparative study of photocatalytic activity. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY 204 (2-3):183-190.
  4. Zhang, Z; Goodall, JBM; Morgan, DJ; Brown, S; Clark, RJH; Knowles, JC; Mordan, NJ; Evans, JRG; Carley, AF; Bowker, M; Darr, JA. 2009. Photocatalytic activities of N-doped nano-titanias and titanium nitride. JOURNAL OF THE EUROPEAN CERAMIC SOCIETY 29 (11):2343-2353.
  5. Thompson, K; Goodall, J; Kellici, S; Mattinson, JA; Egerton, TA; Rehman, I; Darr, JA. 2009. Screening tests for the evaluation of nanoparticle titania photocatalysts. JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY 84 (11):1717-1725.

Recent Biomaterials and Drug Research

  1. Moshaverinia, A; Roohpour, N; Darr, JA; Rehman, IU. 2009. Synthesis of a proline-modified acrylic acid copolymer in supercritical CO2 for glass-ionomer dental cement applications. ACTA BIOMATERIALIA 5 (5):1656-1662, .
  2. Moshaverinia, A; Roohpour, N; Darr, JA; Rehman, IU. 2009. Synthesis and characterization of a novel N-vinylcaprolactam-containing acrylic acid terpolymer for applications in glass-ionomer dental cements. ACTA BIOMATERIALIA 5 (6):2101-2108.
  3. Moshaverinia, A; Roohpour, N; Ansari, S; Moshaverinia, M; Schricker, S; Darr, JA; Rehman, IU. 2009. Effects of N-vinylpyrrolidone (NVP) containing polyelectrolytes on surface properties of conventional glass-ionomer cements (GIC). DENTAL MATERIALS 25 (10):1240-1247.
  4. Moshaverinia, A; Ansari, S; Moshaverinia, M; Roohpour, N; Darr, JA; Rehman, I. 2008. Effects of incorporation of hydroxyapatite and fluoroapatite nanobioceramics into conventional glass ionomer cements (GIC). ACTA BIOMATERIALIA 4 (2):432-440.
  5. Moshaverinia, A; Ansari, S; Movasaghi, Z; Billington, RW; Darr, JA; Rehman, IU. 2008. Modification of conventional glass-ionomer cements with N-vinylpyrrolidone containing polyacids, nano-hydroxy and fluoroapatite to improve mechanical properties. DENTAL MATERIALS 24 (10):1381-1390.
  6. Chaudhry, AA; Goodall, J; Vickers, M; Cockcroft, JK; Rehman, I; Knowles, JC; Darr, JA. 2008. Synthesis and characterisation of magnesium substituted calcium phosphate bioceramic nanoparticles made via continuous hydrothermal flow synthesis. JOURNAL OF MATERIALS CHEMISTRY 18 (48):5900-5908, .
  7. Gong, K; Rehman, IU; Darr, JA. 2008. Characterization and drug release investigation of amorphous drug-hydroxypropyl methylcellulose composites made via supercritical carbon dioxide assisted impregnation. JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS 48 (4):1112-1119, .
  8. Gong, K; Rehman, IU; Darr, JA. 2007. Synthesis of poly(sebacic anhydride)-indomethacin controlled release composites via supercritical carbon dioxide assisted impregnation. INTERNATIONAL JOURNAL OF PHARMACEUTICS 338 (1-2):191-197.
  9. Rehman, S; Movasaghi, Z; Tucker, AT; Joel, SP; Darr, JA; Ruban, AV; Rehman, IU. 2007. Raman spectroscopic analysis of breast cancer tissues: identifying differences between normal, invasive ductal carcinoma and ductal carcinoma in situ of the breast tissue. JOURNAL OF RAMAN SPECTROSCOPY 38 1345-1351.

Recent Fuel cell related research

  1. Highly Conductive Low Nickel Content Nano-composite Dense Cermets from Nanopowders Made via a Continuous Hydrothermal Synthesis Route.Jawwad Darr; Xiaole Weng; Dan Brett; Vladimir Yufit; Paul Shearing; Nigel Brandon; Mike Reece; Haixue Yan, solid state ionics 2010 in press
  2. Weng, XL; Boldrin, P; Abrahams, I; Skinner, SJ; Kellici, S; Darr, JA. 2008. Direct syntheses of Lan+1NinO3n+1 phases (n = 1, 2, 3 and infinity) from nanosized co-crystallites. JOURNAL OF SOLID STATE CHEMISTRY 181 (5):1123-1132.
  3. Gribov, EN; Parkhomchuk, EV; Krivobokov, IM; Darr, JA; Okunev, AG. 2007. Supercritical CO2 assisted synthesis of highly selective nafion-zeolite nanocomposite membranes for direct methanol fuel cells. JOURNAL OF MEMBRANE SCIENCE 297 (1-2):1-4, .
  4. Weng, XL; Boldrin, P; Abrahams, I; Skinner, SJ; Darr, JA. 2007. Direct syntheses of mixed ion and electronic conductors La4Ni3O10 and 3Ni2O7 from nanosized coprecipitates. CHEMISTRY OF MATERIALS 19 (18):4382-4384.