Research Guides

Department of Chemistry University of Oxford

Professor P. P. Edwards FRS

Our current research topics cover a broad range of interests and activities, from Metal-Insulator Transitions (MITs) to sustainable and renewable chemistry for energy. A brief summary of areas of interest are presented below: 

 

1. Turning Insulators into Metals

What, Why and When is a Metal?   Download

There are numerous systems and materials for which small changes in temperature, pressure or composition can transform a non-metallic (insulating) material into a highly conducting metallic state. C.N.R. Rao of Bangalore has drawn a graphic analogy, noting this process is akin to "Turning Wood into Copper". A detailed understanding of this remarkable electronic phase transition is one of our major interests.

 

2. Hydrogen Storage in Solids

One of the most extensive research interests in the group is into the storage of hydrogen in solids, in conjunction with Prof. Bill David and the Rutherford-Appleton Laboratory.  Hydrogen is widely regarded as the most promising alternative to carbon-based fuels since it will help alleviate the inevitable environmental and energy supply concerns when fossil fuels become scarce and/or unsustainable, due to ecological and energy/security reasons. Hydrogen is ideal as a synthetic fuel; it is light weight, highly abundant -recall, hydrogen is the most abundant element in the universe- and when used as an energy carrier it generates no emissions other than normally benign water molecules.

This research theme encompasses Carbon Materials, Metal Hydrides, Borohydrides, Amidoboranes, Amide Systems, Alanates and Metal Borohydride/Halide Ammines for Hydrogen Storage. At the heart of the activity is an attempt to understand -and hence control- the micro-, meso-, and nano-structure of low atomic number hydrogen storage materials. To achieve a breakthrough requires a suitable storage material of 6-7 weight percent hydrogen! 

 

3. Turning Carbon Dioxide into Fuel

A major initiative with Dr. Tiancun Xiao has been formed between Oxford and the King Abdulaziz City for Science and Technology (KACST), which aims to promote frontier scientific and technological challenges associated with clean energy from fossil fuels. These include:

  • Development of new-generation catalysts based on meso-porous solids;
  • Fuel economy materials
  • Tri-reforming techniques for CO2 conversion

This project is part of an global initiative to implement the ‘hydrogen economy’ in a pragmatic sense, whereby hydrogen is placed in the fuel rather than used as the fuel. 

 

Turning CO2 to Fuels   ----A new UK -China -Saudi Arabia initiative

CO2 is recognised as one of the most potent Greenhouse Gases and its continuous increase in the atmosphere is cited, quite correctly, as a major cause of advancing climate change for our planet. Flue gas, the result of fossil fuel combustion, in power plants, heavy and petroleum and petrochemical industries represent the main source of anthropogenic CO2 emissions.

Carbon capture and storage (CCS) from such large sources of fossil fuel combustion, is advanced as an essential component of plans to mitigate anthropogenically-induced climate change.

Currently, environmental regulations require exiting flue gas to be purified to remove NOx, SO2 and cooled down before it is emitted to air. These processes all cost energy and require extra operation input. The capture of CO2 from flue gas is a highly energy intensive process and, of course, CCS gives rise to daunting social problems associated with burying huge quantities of CO2.  

The direct utilisation or conversion of CO2 into fuels and chemicals directly at such sources –under their ambient operating conditions and without CCS – is highly desirable, particularly if any energy input came from renewable sources. This, then, is the challenge – and the prize – of this new international initiative linking the UK, China (the world’s largest CO2 emitter) and Saudi Arabia (the world’s largest oil producer).

The most effective way to make use of CO2 is so-called Flue Gas Reforming through the conversion of exiting flue gas mixtures into synthesis gas (“syngas”) and then to synthesise  fuel or chemicals in a single pass. This process is being developed in the King Abdulaziz City for Science and Technology-Oxford Centre of Excellence in Petrochemicals. Flue Gas Tri Reforming of Methane (FRM), based on simultaneous Oxygen-CO2-Steam reforming of methane produces “synthesis gas, or syn gas” from the flue emissions  that is perfectly suited for the production of a wide range of fuels and industrially important chemicals, We have developed new-generation, step-change catalysts, which are specifically designed, to have minimal effect on a power plant's generation capacity, but are sufficiently robust to efficiently convert the N2-rich syngas into super-clean fuel or chemicals.

This major initiative couples together UK scientists, engineers and socio-economists with their counterparts in the Chinese Academy of Sciences, as well as coal producers in Shanxi Province (the largest coal mining province and coal consumer in China) and oil producers in Saudi Arabia.

Due to our unique technology in hot flue-gas CO2 utilization, we are also coupled with the China Huaneng Group (the world’s biggest thermal power generator) and the China Lu'an Group, one of the biggest Coal-to-Fuel and Chemicals Company in China. In addition, other major coal-mining provinces for example, Guizhou Province (the biggest coal producer in South China) and the Inner Mongolia Province will also join us in developing Flue Gas Reforming for their coal-bed gas, e.g. methane.

Even with the huge improvements in efficiencies and exceptional growth in solar, wind and wave power, for the foreseeable future, the world will still rely on hydrocarbon fossil fuels. The effective direct utilisation of CO2 at large-scale sources of fossil fuel combustion – without CCS – opens up new and exciting possibilities.

Our advances in catalysis are leading to new high-efficiency processes, where CO2 can be directly transformed into super-clean fuel and other commodities. The greatest challenge is to now ensure that the resulting energy/CO2 balance of the entire process is either carbon-neutral, or ideally carbon-negative.

In this new international project, we are rapidly advancing the science, the technology and also the socio-economic and socio-political impact of such CO2 utilisation processes. The time is indeed ripe to respond with a modern, international and multidisciplinary initiative to the historic achievements of the 2015 Paris Agreement.

 

Peter P Edwards, Tiancun Xiao, Jinghai Li, Hamid Almegren, Sir John Meurig Thomas and

 Sir John Houghton

Oxford, Beijing, Cambridge, Riyadh; January 2018

 

4. Transparent, but Highly Conducting Metal Oxides

Transparent conductors (TC) are extremely important functional materials, with applications in many industries. The most important TC is indium tin oxide (ITO), as it possesses the ideal

combination of optical transparency and high conductivity. However, indium is extremely costly and thus it would be beneficial if indium free or reduced-indium TCs, with similar or better electrical properties, could be produced. To that end our research encapsulates: 

  • Increased electron mobility, and hence conductivity of ITO materials. Enhanced conductivity would lead to reduced film thickness, and thus reduced indium usage.
  • Increased number of charge carriers (electrons). Similarly, increasing the number of charge carriers in ITO enhances conductivity.
  • Synthesis and processing of new transparent conductor materials. 
 
5. Bandgap Tuning for Photovoltaic and Photocatalytic Devices

The group focuses on two main areas of photo-active semiconductor research: the tuning of bandgaps in doped ZnO systems for photovoltaics, and p-n heterojunction systems for photocatalysis.

Doping of ZnO with sulphur to produce single crystal, orientated thin films is being investigated for application in the photovoltaic splitting of water to release hydrogen. Spray pyrolysis techniques are being developed to produce films of S/ZnO and the optical, crystallographic and defect properties of the films are examined. 

We have also developed composite catalysts based around the n-type ZnFe2O4 and p-type BiOBr semiconductors for the purification of water by photodegradation of organic dyes such as Rhodamine B. 

 

6. Metals in Ammonia: Solvated Electrons to Liquid Metals

Familiar from undergraduate courses (and all the way back to to the work of sir HumphryDavy in 1808!) are the beautiful blue and bronze colours of alkali metal-ammonia solutions. A thorough understanding of these complex systems, and the fascinating nature of their compositional metal-insulator transitions, is pursued in our group, whereby we study the chemistry and physics of alkali metals as solutes in ammonia/primary amines and associated systems. 

  • Detailed investigations of the nature of the solvated electron in alkali metal ammonia solutions using both ESR and NMR spetroscopies.
  • The study of metal mixed solvent systems by ESR and NMR spetroscopies.
  • The close examination of the phase separation boundary region of the sodium ammonia solution using various spectroscopic techniques.
  •  ESR measurements are carried out in conjunction with the Center for Advanced Electron Spin Resonance (CAESR) in Oxford. 

 

7. Neutron Spectroscopy for Inorganic Systems

Neutron spectroscopy can be utilised in the study of the dynamics of proton-containing systems. We incorporate a variety of neutron techniques into the research of inorganic systems, as diverse as Li(NH3)4, NH3 coordinated within silicates, and metal hydrides. These techniques include quasielastic neutron scattering (QENS), inelastic neutron scattering (INS) and neutron Compton scattering (NCS), probing dynamics from nanosecond through to attosecond timescales. 

 

 

8. The Continuing Challenge of High-Temperature Superconductivity

 

The observation, in 1987, of high-temperature superconductivity by J.G. Bednorz and K.A. Muller represents one of the greatest experimental discoveries of the last century. The phenomenon is simply not yet understood. Our project has the ultimate goal of a deep understanding of this fascinating natural phenomenon. We try to synthesize materials which we believe might be new superconductors. One recent example is a collaboration with Wojciech Grochala (Warsaw) and centres on fluoroargenates

"On the performance optimisation of Fe catalysts in the microwave-assisted H 2 production by the dehydrogenation of hexadecane."X. Jie, T. Xiao, B. Yao, S. Gonzalez-Cortes, J. Wang, Y. Fang, N. Miller, H. AlMegren, J. R. Dilworth, and P. P. Edwards. Catalysis Today (2018).

 

"H2–rich gas production from leaves."Benzhen  Yao, Tiancun Xiao, Xiangyu Jie, Sergio Gonzalez-Cortes, and Peter P. Edwards. Catalysis Today (2018).

 

"Enhancing the production of light olefins from heavy crude oils: Turning challenges into opportunities."Alotaibi, Faisal M., Sergio González-Cortés, Mohammed F. Alotibi, Tiancun Xiao, Hamid Al-Megren, Guidong Yang, and Peter P. Edwards. Catalysis Today (2018).

‘‘Thermodynamic study of hydrocarbon synthesis from carbon dioxide and hydrogen’’; B. Yao, W. Ma, S. Gonzalez‐Cortes, T. Xiao, P. P. Edwards; Greenhouse Gases: Science and Technology 7, 942-957 (2017).

‘‘Microwaves effectively examine the extent and type of coking over acid zeolite catalysts’’; B. Liu, D. Slocombe, J. Wang, A. Aldawsari, S. Gonzalez-Cortes, J. Arden, V. Kuznetsov, H. AlMegren, M. AlKinany, T. Xiao, P. P. Edwards; Nature communications 8, 514 (2017).

‘‘Rapid Production of High‐Purity Hydrogen Fuel through Microwave‐Promoted Deep Catalytic Dehydrogenation of Liquid Alkanes with Abundant Metals’’; X. Jie, S. Gonzalez‐Cortes, T. Xiao, J. Wang, B. Yao, D.R. Slocombe, H.A. Al‐Megren, J.R. Dilworth, J.M. Thomas, P.P. Edwards; Angew.Chem. Int. Edit. 56, 10170-10173 (2017).

‘‘Hydrogen bonds between methanol and the light liquid olefins 1-pentene and 1-hexene: from application to fundamental science’’; Z. Zhang, T. Xiao, H. Al-Megren, S.A. Aldrees, M. Al-Kinany, V.L. Kuznetsov, M.L. Kuznetsov, P.P. Edwards; Chem. Comm. 53, 4026-4029 (2017).

‘‘Wax: A benign hydrogen-storage material that rapidly releases H2-rich gases through microwave-assisted catalytic decomposition’’; S. Gonzalez-Cortes, D. Slocombe, T. Xiao, A. Aldawsari, B. Yao, V. Kuznetsov, E. Liberti, A. Kirkland, M. Alkinani, H. Al-Megren, P.P. Edwards; Scientific Reports 6, 35315 (2016).

‘‘The Catalyst Selectivity Index (CSI): A Framework and Metric to Assess the Impact of Catalyst Efficiency Enhancements upon Energy and CO2 Footprints’’; T. Xiao, T. Shirvani, O. Inderwildi, S. Gonzalez-Cortes, H. Al Megren, D. King, P.P. Edwards; Top. Catal. 58, 682-695 (2015).

"Catalytic dehydrogenation of propane by carbon dioxide: a medium-temperature thermochemical process for carbon dioxide utilisation."X. Du, B. Yao, S. Gonzalez-Cortes, V. L. Kuznetsov, Hamid AlMegren, T. Xiao, and P. P. Edwards. Faraday discussions 183, 161-176(2015).

‘‘Methanol-to-hydrocarbons conversion over MoO 3/H-ZSM-5 catalysts prepared via lower temperature calcination: a route to tailor the distribution and evolution of promoter Mo species, and their corresponding catalytic properties’’; B. Liu, L. France, C. Wu, Z. Jiang, V.L. Kuznetsov, H.A. Al-Megren, M. Al-Kinany, S.A. Aldrees, T. Xiao, P.P. Edwards; Chem. Sci. 6, 5152-5163 (2015).

"Electronic structure of ternary CdxZn1-xO (0≤x≤0.075) alloys"; HHC Lai, VL Kuznetsov, RG Egdell, PP Edwards; Appl. Phys. Lett.; 100; 072106; (2012) 

"A combined experimental inelastic neutron scattering, Raman and ab initio lattice dynamic study of  α-lithium amidoborane"; KR Ryan, AJ Ramirez-Cuesta, K Refson, MO Jones, PP Edwards and WIF David; Phys. Chem. Chem. Phys.; 13; 12249-12253; (2011) 

"High-pressure crystal structure prediction of calcium borohydride using density functional theory"; PC Aeberhard, K Refson, PP Edwards, WIF David; Phys. Rev. B; 83(17); 174102/1-174102/7; (2011)

"Exceptional visible-light-driven photocatalytic activity over BiOBr-ZnFe2O4 heterojunctions"; L Kong , Z Jiang, T Xiao, L Lu, MO Jones, PP Edwards; Chem. Comm.; 47(19); 5512-5514; (2011) 

"Neutron Compton Scattering investigation of sodium hydride: From bulk material to encapsulated nanoparticulates in amorphous silica gel"; AG Seel, A Sartbaeva, J Mayers, AJ Ramirez-Cuesta, PP Edwards; J Chem. Phys.; 134; 114511; (2011)

"... A Metal Conducts and a Non-Metal Doesn't"; PP Edwards, MTJ Lodge, F Hensel, R Redmer; Phil. Trans. R. Soc. A; 368; 941-965; (2010)

"Turning Carbon Dioxide into Fuel"; Z Jiang, T Xiao; VL Kuznetzov; PP Edwards; Phil. Trans. R. Soc. A; 368; 3343-3364; (2010)

"Experimental and density-fuctional study of the electronic structure of In4Sn3O12"; DH O'Neil, A Walsh, RM Jacobs,VL Kuznetsov, RG Egdell and PP Edwards; Phys. Rev. B; 81; 085110; (2010)

"A molecular perspective on lithium-ammonia solutions"; E Zurek, PP Edwards, R Hoffmann; Angew. Chem. Int. Edit.; 48; 8198-8232; (2009)

"Water/oil microemulsion for the preparation of robust La-hexaaluminates for methane catalytic combustion"; Z Jiang, ZP Hao, JX Su, TC Xiao and PP Edwards; Chem. Comm.; 22; 3225-3227; (2009) 

"Tuning the decomposition temperature in complex hydrides: Synthesis of a mixed alkali metal borohydride"; EA Nickels, MO Jones, WIF David, SR Johnson, RL Lowton, M Sommariva and PP Edwards; Angew. Chem. Int. Edit.; 47; 6758-6765; (2008)

"Sir Humphry Davy: Boundless Chemist, Physicist, Poet and Man of Action"; JM Thomas; PP Edwards; VL KuznetsovChem. Phys. Chem.; 9; 59-66; (2008)