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University of Nottingham activities

University of Nottingham activities

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University of Nottingham activities

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  1. University of Nottingham activities • Focus on capacity building. • ASGARD facility for investigating CO2 release. • Is CHn -> C + n/2H2 a feasible route for carbon sequestration and hydrogen production (catalytic cracking of hydrocarbons gases)? • Long-term CO2 utilisation - efficient catalysts for photocatalytic CO2 reduction.

  2. ASGARD Artificial Soil Gassing And Response DetectionMike Steven, Jeremy Colls & Karon SmithUniversity of NottinghamSchools of Geography (MS) and Biosciences (JC&KS) Co-funding from SRIF3 allowed the development of a “permanent” field experimental facility - ASGARD The TSEC programme (UKCCSC) funded13 months effort to establish and test ASGARD and to run one field season.

  3. The ASGARD facility Gas control Gas store Gas monitoring Gas response Gas injection

  4. ASGARD Site layout 2006 N rc LINSEED • Plots 2.5 m square • 8 plots of grass, linseed & barley • 4 Gassed and 4 control plots • Gas injected at 0.6 m depth • Plus 4 “remote” controls for grass (rc) BARLEY rc TEST GRASS

  5. From TSEC study We can control CO2 release rates and soil concentrations. We can relate soil CO2 concentrations to fluxes into the atmosphere. We can detect CO2 induced stress effects in plants at soil concentrations of a few percent by remote sensing techniques. We can discriminate fossil and biogenic carbon by isotopic analysis. Ongoing and future work Responses of plant root systems and effects on competition Stress sensitivities of different plant species determined by spectral responses Soil and soil water chemistry Effects of SO2 contamination in leaked CO2 CO2 pathways in soil Ecosystem recovery after gassing ASGARD: achievements and plans

  6. Is CHn -> C + n/2H2 a feasible route for carbon sequestration and hydrogen production?Colin Snape, Miguel Castro Diaz and Jamie Blackman • Catalytic cracking of hydrocarbon gases gives carbon nanofibres (CNFs). • Driven by the value and utility of the carbon. • CNFs – poor for hydrogen storage but OK as adsorbents • Building sector – cement and bricks combined account for ca. 5% global CO2 emissions. • Replacing existing building materials begins to look attractive as am means of avoiding CO2 emissions. • Still attractive if the yield of hydrogen is not that high (e.g. for coal cf. CH4).

  7. Configuration Hydrogen production via catalytic cracking of hydrocarbons Catalytic decomposition of methane over supported metal catalysts has been widely studied in recent years to produce hydrogen free of CO and CO2. The highest amount of hydrogen per metal has been obtained with a Pd-Ni/CNF catalyst (ca. 16,000 molC/molPd+Ni) after 30 hours [1]. The challenge is to achieve these high conversions with lower cost catalysts (i.e. base metals). An unsupported Ni-Cu (4:1 wt/wt) metal alloy catalyst has been studied for the catalytic decomposition of ethene at 650-700°C. Pure C2H4 (60 ml min-1) was decomposed over 25-100 mg of catalyst precursor in a quartz tube reactor for 3-9 hours. [1] Takenaka et al., Journal of Catalysis 220 (2003) 468-477.

  8. Hydrogen production via catalytic cracking • High H2 selectivities (>75%) and C2H4 conversions (>90%) were achieved before catalyst deactivation. • High yields of ca. 4,500 molC/mol(Cu+Ni) were achieved after 9 hours of reaction at 650oC. • CNFs produced at 650oC cf. amorphous carbon at 700oC.

  9. Hydrogen production via catalytic cracking • Although the conversion of CH4 is thermodynamically less favourable, unsupported Ni-Cu alloy catalysts could provide high conversions because of their high activity at higher temperatures (i.e. 700°C). • Applied Catalysis paper in press. • Further avenues for support are being explored to take the concept forward, especially for carbons in buildings (Halloran paper).

  10. Long Term CO2 Utilisation • (M. W. George - Nottingham) • 1-Year PDRA Aims: • To develop efficient catalysts for photocatalytic CO2 reduction • To develop viable catalysts via understanding catalytic mechanism • Explore the use of supercritical CO2 (scCO2) • – a solvent with several advantages including • (i) highest possible concentration of CO2 • (ii) improved mass transport and high diffusivity • (iii) opportunities for efficient recovery of products

  11. TEA TEA+ charge separation hu • CO2 Reduction If Nature Can Do It, Why Can't We? • Strategy forCO2 Reduction • Reduction of CO2 requires energy •  Photon as energy source (Photochem) •  Electricity as energy source (Electrochem) • Artificial photosynthesis for CO2 reduction • typically requires: • photosensitizer, • catalyst • electron donor • Products are CO, formate, and H2 • Co macrocycles • Ni macrocycles • Cobalt and Iron porphyrins, • Phthalocyanines and corroles • Ru(bpy)2(CO)X • Re(bpy)(CO)3X • Ni(bpy)32+

  12. Key Achievements: • Strategic Alliance and Collaboration with leaders at Brookhaven National Laboratory (Fujita) in Photocatalytic CO2 reduction to develop catalysts for CO reduction in scCO2 • The promise of this new approach to CO2 reduction was picked up by the popular press and made front cover of CE&E news – key publication the American Chemical Society • Development of catalyst which was soluble in scCO2 • Kinetic studies of mechanisms from picosecond (10-12 s) to seconds Mechanistic Studies to understand factors which affect solvent control of the catalytic cycle • Monitoring, for the first time, rate of Cl- from key catalytic intermediate providing the understanding how to design and develop viable new catalytic systems A few seconds A few nanoseconds

  13. Long Term CO2 Utilisation – future work • 1-Year funding developed science which resulted in being invited to join a consortium with UEA (Pickett/Nann); York (Perutz); Manchester (Flavell) to develop a new approach to artificial photosynthesis which was recently funded (ca. £1.5 M - £300 k to Nottingham) under EPSRC Solar Energy Initiative • Carbon Dioxide and Alkanes as Electron-sink and Source in a Solar Nanocell: towards Tandem Photosynthesis of Carbon Monoxide and Methanol • This proposal exploits the knowledge gained out of this one year funding.