Despite the high thermodynamic stability of CO2, biological systems are capable of both activating the molecule and converting it into a range of organic molecules, all of which under moderate conditions. It is clear that, if we were able to emulate Nature and successfully convert CO2 into useful chemical intermediates without the need for extreme reaction conditions, the benefits would be enormous: One of the major gases responsible for climate change would become an important feedstock for the chemical and pharmaceutical industries! Iron-nickel sulfide membranes formed in the warm, alkaline springs on the Archaean ocean floor are increasingly considered to be the early catalysts for a series of chemical reactions leading to the emergence of life. The anaerobic production of acetate, formaldehyde, amino acids and the nucleic acid bases - the organic precursor molecules of life - are thought to have been catalyzed by small cubane (Fe,Ni)S clusters (for example Fe5NiS8), which are structurally similar to the surfaces of present day sulfide minerals such as greigite (Fe3S4) and mackinawite (FeS).Contemporary confirmation of the importance of sulfide clusters as catalysts is provided by a number of proteins essential to modern anaerobic life forms, such as ferredoxins, hydrogenases, carbon monoxide dehydrogenase (CODH) or acetyl-coenzyme A synthetase (ACS), all of which retain cubane (Fe,Ni)S clusters with a greigite-like local structure, either as electron transfer sites or as active sites to metabolise volatiles such as H2, CO and CO2. In view of the importance of (Fe,Ni)S minerals as catalysts for pre-biotic CO2 conversion, we propose employing a robust combination of state-of-the-art computation and experiment in a grand challenge to design, synthesise, test, characterise, evaluate and produce for scale-up novel iron-nickel sulfide nano-catalysts for the activation and chemical modification of CO2. The design of the (Ni,Fe)S nano-particles is inspired by the active sites in modern biological systems, which are tailored to the complex redox processes in the conversion of CO2 to biomass.The scientific outcome of the Project will be the design and development of a new class of sulphide catalysts, tailored specifically to the reduction and conversion of CO2 into chemical feedstock molecules, followed by the fabrication of an automated pilot device. Specific deliverables include:i. Atomic-level understanding of the effect of size, surface structure and composition on stabilities, the redox properties and catalytic activities of (Fe,Ni)S nano-catalysts;ii. Development of novel synthesis methods of Fe-M-S nano-clusters and -particles with tailored catalytic properties (M = Ni and other promising transition metal dopants);iii. Rapid production and electro-catalytic screening of lead nano-catalysts for the activation/conversion of CO2;iv. Development and application of a new integrated design-synthesis-screening approach to produce effective nano-catalysts for desired reactions;v. Construction of a prototype device capable of catalysing low-temperature reactions of CO2 into products at typical low-voltages, that can be obtained from solar energy; vi. Identification of optimum process for scale-up in Stage 2, from the Economic, Environmental and Societal Impact evaluationThe target at the end-point of Stage 1 is the fabrication of a photo-electrochemical reactor capable of harvesting solar energy to (i) recover CO2 from carbon capture process streams, (ii) combine it with hydrogen, and (iii) catalyse the reaction into product. In Stage 2 of the project, the prototype will be developed into a scaled-up commercially viable device, using optimum catalyst(s) in terms of (i) reactivity/selectivity towards the desired reaction; (ii) economic impact; and (iii) environmental, ethical and societal considerations.

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

This project proposes to make highly selective nano-particulate catalysts using a novel method ('biocasting') for a set of defined catalytic reactions and to develop understanding of how to control the catalyst manufacturing process to achieve the desired selectivity which is not readily achieved using chemical manufacturing alone.. Controlled growth of metal nanoparticles in various naturally occurring and modified bacteria will be used to produce the required catalysts supported on cell surfaces.Previous work, has demonstrated that bacteria can be used as a catalyst support for nanoparticulate metals, including platinum and palladium. The process involves reducing the metal enzymatically from a salt solution over a bacterial culture, with templating and stabilisation achieved using biochemical components at the living/nonliving interface, followed by post-processing, which kills the bacterial cells but retains the special catalytic properties of nanoparticles. Such materials have been shown to provide selectivity towards desirable products in catalytic reactions including double bond isomerisation and selective hydrogenation, but at present there is a lack of understanding of why this superior selectivity occurs. One factor may be the crystal structure, including the ratios of edge to terrace and corner atoms which influence the adsorption of reactants upon the catalyst surface. Another effect is the rate of diffusion of reactants to the metal surface. This proposal will develop understanding of why the nanoparticles give rise to superior catalytic selectivity, and thus will enable the rational design and production of nanoparticles for given applications. The present proposal will seek to clean the biotemplated metal particles using chemical and electrochemical methods in order to control the metal cluster morphology, and to block selectively certain active sites on the catalyst using Bi, Pb, sulphur or bacterially derived agents incorporated at the synthesis stage. By switching on or off active sites in this way and associated characterization and testing of the catalysts, it will be possible to identify which types of sites are associated with favourable selectivity in chemical transformations.The produced catalysts will be characterized using a range of techniques which will elucidate information about the nanoparticle size, shape, cluster structure, redox behaviour, electrochemical and spectroscopic behaviour (SERS, XPS, XRD, TPD, DRIFTS and CV). Catalytic selectivity will be studied in a range of selective hydrogenation and double bond isomerisation reactions. The ultimate goal is to replace Lindlar catalysts based on lead modified palladium and other transition metals with more environmentally benign alternatives; previous studies in ours and collaborators' laboratories have shown that the precious metal can be supplemented with cheap metals such as Fe and can even be sourced as such mixtures from waste and scrap for economic manufacture.Current methods for nanoparticle manufacture are not 'clean' and/or not scalable. The major advantage of biomanufacturing is its scalability; we have routinely grown several kilos of the bacteria at the 600 litre scale in our pilot plant. As part of this project we will make Bio-Pd preparations at the 30-100 litre scale (batch cultures), checking the small-scale and large-scale NP products for conserved properties, and also stock aliquots for shelf-life evaluation.

It is not possible to understand the way that a fuel cell operates without understanding how reactants, products, heat and electrochemical potential varies within that fuel cell. A consequence of this is that in order to obtain the best performance out of a fuel cell we cannot treat it like a simple electrical device with a positive and negative terminal: we need to be able to understand what is happening at different points within that fuel cell. Put simply, the purpose of this project is to develop a new way to image what is happening within an operating fuel cell. That is, to develop a way in which we can see how well the different parts of the fuel cell is operating - whether they are operating well, or starved of reactants, or undergoing damaging processes which will limit the longevity of the system.In this programme we intend to build on previous work at NPL, Imperial and UCL to develop a world-class instrument to allow us to study what is happening within an operating fuel cell. We will utilise a specially instrumented fuel cell which will allow us to monitor several very important parameters in real time. In this way we can monitor how the fuel cell operates under the different extreme conditions imposed on it during both normal and abnormal operating conditions. Examples of such extreme conditions occur when the fuel cell is started up, or shut down or when the fuel cell is pushed to perform at the limits of its performance (as might be expected during an overtaking manoeuvre if the fuel cell were powering a vehicle). Results of this research will be utilised to improve the design of the fuel cell.The hardware will be designed and built at Imperial College, and tested at both Imperial and NPL. A bipolar plate rapid prototyping facility will be built at UCL which will allow us to experiment with different flow-field geometries in order to achieve as even as possible distribution of the parameters being measured with the fuel cell mapping hardware. Modelling will be performed at UCL in order to test improvements to the performance of the cells brought about by using different flow-field architecturesWe have engaged with two major UK fuel cell companies, Johnson Matthey and Intelligent Energy, who are interested in utilising the instrumentation and results of this work.

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.