Carbon Dioxide and Alkanes as Electron-sink and Source in a Solar Nanocell: towards Tandem Photosynthesis of Carbon Monoxide and Methanol

Lead Research Organisation: University of Manchester
Department Name: Physics and Astronomy


A major solar energy challenge is the goal of artificial synthesis in which sunlight is used to generate fuels or high energy chemicals. Natural photosynthesis uses solar energy to generate dioxygen and carbohydrates from carbon dioxide and water, but the targets of artificial photosynthesis can be more diverse. Our vision is to create a solar nano-device which will drive the coupled photo-conversion of methane and carbon dioxide into methanol and carbon monoxide respectively. This challenging target differs fundamentally from the familiar one of splitting water into hydrogen and oxygen. Our target offers products both on the oxidation and the reduction sides that are significant fuels or feedstocks. The photocatalytic reduction of CO2 and oxidation of alkanes represent long-standing goals of great complexity, but we base our concepts on well-established principles. We break down the goals into individual components, each of which is highly challenging within its own right and delivery of each would constitute a major breakthrough. The challenges will be met by a team of scientists, integrated across the four centres of Manchester, Nottingham, York and Norwich, who lead teams with expertise in photophysics, nanoscience, photochemistry, electrochemistry and synthesis. Thus these researchers will seek to establish the science required to underpin technologies that will allow the conversion of abundant and environmentally damaging feedstocks into products of high economic value by constructing a new class of solar device capable of driving green chemical reactions.
Description In order to carry out this project, 4 linked grants were awarded by EPSRC to the 4 universities, forming the 'SolarCAP'
consortium. Here we describe the progress made under the grant to the University of Manchester. This work was focussed
on the physics of the light-harvesting elements (in particular the QDs), and on establishing the degree of success of the
grafting chemistry linking the catalyst or porphyrin molecules to the nanoparticle surfaces. We have used ultrafast laser
spectroscopies to measure the current carriers that are created in the QDs when light is absorbed. The material of most
interest to us is InP (which is relatively non-toxic, and absorbs sunlight strongly). We have been able to demonstrate that
InP QDs show a phenomenon called 'carrier multiplication', where one incoming photon of sunlight can create more than
one set of current carriers. This is important because it can improve the efficiency of light harvesting - and this is the first
time this effect has been demonstrated in relatively non-toxic QDs.
Meanwhile, our collaborators at the Universities of York and UEA have synthesised catalyst molecules for the target
reactions (with considerable success, particularly for the carbon dioxide reduction reaction; this work will be described in
their final reports). The next stage of the work (at UEA) was to attempt to graft these molecules onto the surfaces of the
QDs and the gold nanoparticles. It was then crucial to establish that the molecules were grafted to the nanoparticle
surfaces, and to measure the composition of the nanoparticle-molecule system. The University of Manchester team used
soft X-ray synchrotron radiation (at MAXlab, in Sweden) to perform a non-destructive depth-profiling analysis that allows us
to determine the chemical composition of the surface layers of the nanoparticles. For example, we have been able to
demonstrate that porphyrin molecules have been successfully attached to the surfaces of polymer-coated gold
nanoparticles. Thus parts of our overall concept design are now functioning.
During the project we have also used EPSRC Pathways to Impact support (to the University of Manchester) to develop
high quality public engagement activities directly linked to the SolarCAP project. Ours was one of 21 projects (from 97
applications) selected for exhibition at the Royal Society Summer Science Exhibition in July 2011.
Exploitation Route Further development of the 'oxidation' end of the nanocell.
Sectors Chemicals,Energy,Environment

Description Work done under this grant was selected by the Royal Society to exhibit at the Royal Society Summer Science Exhibition 2011 'Putting Sunshine in the Tank - using Nanotechnology to make Solar Fuel', exhibit visited by 13,800 members of the general public, school children and Fellows of the Royal Society (PI Wendy Flavell). This activity generated a significant number of articles in the blogosphere, coverage on the BBC News website and a number of specialist magazines. A number of associated schools' talks, family fun days (e.g. at the Manchester Museum of Science and Industry in August 2010) etc. took place during the grant period and are continuing.
First Year Of Impact 2010
Sector Energy,Culture, Heritage, Museums and Collections
Impact Types Cultural,Societal

Description British Council
Amount £6,000 (GBP)
Funding ID ARC grant; joint DAAD 
Organisation British Council 
Sector Charity/Non Profit
Country United Kingdom
Start 03/2009 
End 03/2011
Description EPSRC
Amount £980,280 (GBP)
Funding ID EP/J002518/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 08/2011 
End 09/2016
Description EPSRC
Amount £45,719 (GBP)
Funding ID EP/I500529/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 09/2010 
End 04/2011
Description University of Manchester, The
Amount £18,000 (GBP)
Funding ID Royal Society Summer Science Exhibition 2011 
Organisation University of Manchester 
Sector Academic/University
Country United Kingdom
Start 12/2010 
End 07/2011