Ultra-small Metal Particles for the Storage and Conversion of CO2, CH4 and H2

Lead Research Organisation: University of Greenwich
Department Name: Pharm., Chem. & Environmental Sci., FES

Abstract

The present project proposes a new approach to replace fossil fuels by man-made ones using ultra-small metal particles.

Our current energy needs are met by fossil fuels. This approach however is unsustainable owing to the different timescales of fuel production and combustion, the latter of which also generates greenhouse gases, changing the climate globally. On the other hand, uneven occurrence and distribution of sustainable energy sources, such as solar or wind power, warrants energy storage. Nature stores the Sun's energy as reduced carbon, e.g. coal, oil and gas. The present proposal will also employ this approach.

Context
Heterogeneous catalyst activity is dependent on the catalyst's surface area. With decreasing catalyst size, the surface-to-volume ratio increases, leading to improved activities. This could lead to the assumption that single atoms have the highest catalytic activity. However, size reduction may also alter the materials' physical and chemical properties related to the delocalisation of free electrons. Chemical reactivity of transition-metals is not only dependent on the atom numbers in a cluster but also on their arrangement, i.e. shape, owing to the spatial properties of d orbitals. In order to design transition-metal catalysts with selective and enhanced catalytic activity, it is thus crucial to establish the relationship between particle geometry and reactivity.

Aims and Objectives
The proposed project, will focus on ultra-small transition-metal particles, in the 1-50 atom range, supported on highly porous metal-organic frameworks. The particles' geometry-catalytic activity relationship will be explored for the conversion of feedstock harvested from air (CH4 and CO2) and water (H2) into synthetic fuels.

The proposed project will first develop methods to synthesise shape- and size-controlled ultra-small metal particles using metal-organic frameworks as templates. The greatest challenge is identified as increased surface energy, a consequence of the increased surface-to-volume ratio. High surface energy in turn compromises the thermodynamic stability of particles and renders their size control difficult. Geometry control of the ultra-small transition-metal particles will be achieved by establishing strong metal-support interactions by i) preliminary computational calculations in collaboration with Prof Thomas Heine and ii) the application of metal-organic frameworks with chemical functionalities capable of selective host-guest interactions, which is herein proposed for the first time.

Subsequently, the activity of the stable ultra-small transition-metal catalysts will be explored for the conversion of methane into longer chain hydrocarbons, the conversion of carbon dioxide through reduction with H2 (or CH4) and the activation and storage of hydrogen under mild conditions. Thanks to the PI's experience in both the functionalisation of metal-organic frameworks and their application as support for metal nanoparticles, together with her unique skillset in coordination and physical chemistry, and gas technologies, she is ideally placed to carry out this interdisciplinary and ambitious research.

Applications and Benefits
The particles will have various properties depending on their size and shape and will be exploited for ambient-temperature hydrogen storage, and the catalytic conversion of carbon dioxide, methane and hydrogen. Synthesis of fuels from pollutants such as CO2 and CH4 will reduce atmospheric pollution and convert them into more valuable chemicals while making use of already existing distribution infrastructures. The development of renewable, low-carbon energy carriers will benefit our society for energy security and the reduction of atmospheric pollutant levels.

The proposed project will also accrue technology for gas sensing, drug delivery, electronics, water purification, gas separation, and in fuel cell and battery research.

Planned Impact

The proposed research aims at developing a new methodology to convert feedstock harvested from air and water (CO2, CH4 and H2) into synthetic fuels, using supported ultra-small transition-metal catalysts.
Apart from the immediate scientific and technological impact of the development of reliable techniques to control the geometry of particles, the proposed research will also have an impact on the societal level. Energy security and decreasing greenhouse-gas levels are both very important for our society to solve. In the long term, the proposed project will enable technologies to convert carbon dioxide and methane into synthetic fuels, thereby both decreasing their atmospheric levels while using sustainable sources (waste). Also, by tackling hydrogen production, stationary hydrogen storage and hydrogen activation, a completely green energy carrier will be promoted.

The analysis of beneficiaries and stakeholders of the proposed project is presented below:

- The commercial private sector will benefit from the proposed research directly in the long term as the synthesis of fuels under mild conditions can be economically viable and thus will create employment. In addition, as the
synthetic method relies on feedstock harvested from air and water, there are no geographic limitations and so both production and profit can be kept in the United Kingdom.
- Policy makers and government agencies will benefit from the proposed research indirectly in the long term as the transition to synthetic fuels from mined fossil fuels will create energy security, as no geographic limitations and
thus no geopolitical issues are involved, and it will also reduce atmospheric greenhouse gas levels, easing strains on extreme-weather measures and also on health care.
- The proposed project features a collaboration with a museum, which will benefit from the project directly in the short term through public engagement events.
- The wider public will benefit from the proposed research indirectly in the long term as the reduction of atmospheric pollutants and greenhouse gas levels will result in better quality of life and better health. The foundation of
new companies will create wealth and employment, which will also be of the benefit of the wider UK and global society.

Through the conversion of atmospheric pollutants into synthetic fuel using hydrogen generated from water via sustainable methods such as direct photolysis, both national health and wealth will improve. Particulars include reducing the impact of climate change and foundation of new businesses.

It should be mentioned that in order for this transition to take place, efficient and viable methods for the separation of atmospheric pollutants from air need to be developed and further scientific advances in direct water photolysis or photovoltaics are needed. If these pre-requisites are met the proposed project will have a high and important impact on both economy and society.

An important impact of the proposed project and in particular the public engagement activities included will be the shifting of public perception of atmospheric pollutants such as carbon dioxide from waste to potential feedstock. This will also enable to revise our society's general perception of waste materials. This is one of the greatest challenges of the 21st century and while some things can be regulated by policies the best solution to tackle waste management is to encourage approaches to re-using and not discarding wastes.

The time scales involved in the impact of the proposed research are typically longer than the project itself. It is expected that perceptible economic and societal impact of the project would take 10-15 years.

The MSc student will acquire technical skills, which he or she will be able to apply in the industry, while the management, leadership and communication skills acquired by the PI through the project could be applied in all employment sectors.

Publications

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Butson JD (2019) Interrogation of the Effect of Polymorphism of a Metal-Organic Framework Host on the Structure of Embedded Pd Guest Nanoparticles. in Chemphyschem : a European journal of chemical physics and physical chemistry

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Coupry DE (2016) Controlling embedment and surface chemistry of nanoclusters in metal-organic frameworks. in Chemical communications (Cambridge, England)

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Malouche A (2019) Interactions of Hydrogen with Pd@MOF Composites. in Chemphyschem : a European journal of chemical physics and physical chemistry

 
Description This research is still on-going but I have already made some key findings.
The main interest in this work is how a porous framework may control the properties of ultrasmall particles embedded in their pores. I have found that besides of the size and shape of the pores the chemical nature of the pores also influences the embedded particles and that this may be modelled theoretically. Furthermore, by controlling these properties it is possible to tailor the guest particles for specific applications such as catalysis, or the facilitation of certain reactions.
My preliminary results have already demonstrated that there is a strong interplay between the chemical nature of the supporting framework and the chemical properties of the embedded particles.
My future work will shed further light on the mechanism of this interplay and how it could be used to design better performing materials.

Since the last update I was able to shed light on some of the very important properties of catalyst supporting MOFs in catalytic reactions. In particular, this relates to the chemistry of not only the organic linkers but also the cationic units. I have been able to also test the impact of some linkers on Cu catalysts supported on MOFs and it was revealed that the long-range effects of the functionalities on the acidity of the cationic units is of great importance.
Some metals embedded in functionalised MOFs were stabilised as exotic clusters of 3-5 atoms, as revealed by pair distribution function analysis.
Exploitation Route I believe that the findings (once published) will be put to use for catalyst design and so may reach industrial applications.
Sectors Chemicals,Education,Energy

 
Description So far the main non-academic impact is related to my outreach activities. I am collaborating with @Bristol (Bristol) and CsoPa (House of Marvels, Budapest Hungary) to set up workshops to reach out to students in their secondary education. So far I have given a talk at the Eotvos Lorand University, which was attended by the scientific manager of CsoPa (a talk is scheduled for May 2017) and I have visited @Bristol to discuss ideas of public outreach activities based on my research project. Since the last update I have held the planned sessions at CsoPa and in addition I also had a public lecture on my specific scientific activities for a local Kent audience.
Sector Chemicals,Energy
Impact Types Cultural

 
Description Royal Society
Geographic Reach National 
Policy Influence Type Participation in a national consultation
 
Description Erasmus+
Amount £1,300 (GBP)
Organisation erasmus + 
Sector Public
Country United Kingdom
Start 02/2017 
End 02/2017
 
Description Higher Education and Infrastructure Funding
Amount £50,000 (GBP)
Organisation University of Greenwich 
Sector Academic/University
Country United Kingdom
Start 04/2016 
End 07/2016
 
Description International Exchanges
Amount £12,000 (GBP)
Organisation The Royal Society 
Sector Academic/University
Country United Kingdom
Start 03/2017 
End 03/2019
 
Description Density Functional Theory Analysis of Supported Nanoclusters 
Organisation National Institute of Advanced Industrial Science and Technology
Country Japan 
Sector Public 
PI Contribution I have synthesised the metal-organic frameworks and embedded the nanoclusters.
Collaborator Contribution Dr Hyunjeong Kim at AIST has been collecting total scattering data on the empty and loaded metal-organic frameworks, the difference pattern of which she has been using to model the crystalline phase of the embedded nanoclusters.
Impact This is a multidisciplinary collaboration. This collaboration has already provided data included in a publication (http://pubs.rsc.org/en/Content/ArticleLanding/2016/CC/C6CC00659K#!divAbstract) and more publication is underway.
Start Year 2016
 
Description Supported nanocluster catalysts for the direct conversion of CO2 with H2 
Organisation Utrecht University
Department Group of Inorganic Chemistry and Catalysis
Country Netherlands 
Sector Academic/University 
PI Contribution I have synthesised novel catalyst samples
Collaborator Contribution Catalyst testing of two of my samples have been performed for methanol synthesis
Impact Not yet applicable.
Start Year 2017
 
Description Public Lecture 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Lecture title: From Nano-Frameworks to Synthetic Fuels. Around 30 members of the general audience, mostly pensioners in attendance. The presentation was followed by a discussion.
Year(s) Of Engagement Activity 2017,2018
 
Description Workshop on new catalysts for fuel synthesis 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Undergraduate students
Results and Impact I have been invited to give a talk to undergraduate students at the University Eortvos Lorand in Budapest (Hungary), One of the main outcomes of this talk was is that I set up a collaboration with CsoPa (House of Marvels) a scientific outreach centre in Budapest to design and present workshop activities for school children based on my scientific research, scheduled for My 2017 and to be rolled out in the UK too.
Year(s) Of Engagement Activity 2017