Climate change and environmental pollution are two of the biggest threats faced by humankind in this century. In the past few decades, an increasing concern about the severe impact on health and climate change from the presence of nitrogen oxides (NOx) in fuel exhaust has led legislators to a drastic decrease in the permitted amount of NOx emissions from automotive engines and power stations. In this context, while facing an unprecedented global increase in CO2 and NOx emissions, with emerging catastrophic effects, this grant proposal aims at designing new graphene-based 2D materials for green catalysis. Industrial catalysis is a highly energy intensive process that requires access to diminishing mineral resources, such as precious and rare earth metals. Graphene, the new "Miracle 2D Material" discovered in 2004, could offer a solution, but pure graphene is not chemically active for heterogeneous catalysis. The vision behind this research proposal is to use computational tools and modelling to design catalytically active graphene-based materials in which the properties of the active sites are tuned according to the desired chemical activity toward CO2 and NOx. In particular, we will investigate the role of chemical doping by substitutional insertion of boron, nitrogen and phosphorus (B-, N- and P-doping), defects (single vacancies, SW vacancies and edges), defect densities and strain on industrially and environmentally critical processes: 1) the reduction of NOx (deNOx process); 2) the sequestration and conversion of CO2. The specific aims of this proposal can therefore be summarized as follows: 1) Reduction of NOx: the current technology employed in deNOx treatment of NOx-rich fuel gas exhausts often requires increasingly expensive precious metals such as Pt, Pd and Rh. In order to reduce the concentration of the active metal phase in the deNOx catalysts the metal phase is often prepared as nanoparticles dispersed on an inert support or bound into coordination complexes with inorganic oxides. The catalyst preparation presents several technological challenges because the metal nanoparticles employed as active sites on inorganic supports, zeolites and metalorganic frameworks and are difficult to synthetize and grow in the desired size, shape and concentration. Alternative catalysts, in particular those based on activated 2D carbon materials, offer a viable alternative to costly traditional catalysts because they intrinsically offer much higher surface area, are extremely robust and flexible and can be prepared from common organic chemicals such as hydrocarbons, pyridine or ammonia (for N-doped graphene), phosphine or pyridine (for P-doped graphene). 2) Sequestration and conversion of CO2: To address the current trend in CO2 emission and global warming requires novel technology to both limit the amount of CO2 produced and to capture the CO2 contained in the gas exhausts from energy processes. In the past few years, graphene has generated considerable interest for its capacity to increase the efficiency of solar-fuel generation in photocatalytic materials. Graphene based technology has been shown to promote the reduction of CO2 to hydrocarbons and water. In these novel technologies, graphene has several roles: from suppressing the charge recombination and increasing the migrations of photogenerated electrons and holes, to the direct catalytic dissociation of CO2 and production of CO2-xH2x species (CH4, CH2O) and CH3OH. In this research, we will investigate the mechanism of CO2 sequestration and conversion on doped and defective graphene with the aim of designing the most promising functional modification of graphene that would be catalytically active while simultaneously maintaining a higher carrier mobility.

Thermal management has become a critical issue in electronics because of increasing volumetric power densities and the harsh environments in which they are deployed. Active cooling is often required for high rates of heat dissipation because conventional passive cooling techniques are inadequate. Porous metal has been demonstrated to be highly efficient and cost effective in heat dissipation by forced fluid cooling. A main problem impeding its wider application is the high pumping power required to move the working fluid through the cooling device due to its large resistance to fluid flow. This project sets out to address the scientific and technical issues in thermal applications of porous metals manufactured by the space holder methods, which have distinctive porous structure and unique heat transfer behaviour. The aims of the research are to understand the mechanistic relationships between flow resistance, heat transfer and pore structure and to develop technologies to create tailored porous metal structures for significantly enhanced heat transfer performance with minimised flow resistance. A combination of manufacturing, properties characterisation, modelling and process development will be carried out to identify the fundamental structural properties underpinning the thermal fluid behaviour in porous metals, to quantify their effects on heat transfer coefficient and fluid flow resistance, and to design and create heterogeneous porous structures for a step change in overall active cooling performance. The global market for thermal management products is more than $10 billion with an annual growth rate of 6.8%. UK has a significant share in this market and is one of the leaders in developing new materials and technologies for active cooling devices for electronics. This project will provide scientific understanding and technical development underpinning the design and manufacture of a promising class of porous metals that are currently being developed by industry for thermal management applications. This research will ensure that UK maintains the leading position in this niche field. This research will also benefit the research and development of non-thermal porous products for environmental and energy applications, e.g., sound absorbers, porous electrodes and catalyst supports, where flow resistance has a deterministic effect.

What is MASI? We believe that there is a strong link between the looming environmental crisis and the way we use chemical elements. In MASI, a multidisciplinary team of scientists from four UK universities (Nottingham, Cardiff, Cambridge, Birmingham), with 12 industrial and academic partners, is set to revolutionise the ways we use metals in a broad range of technologies, and to break our dependence on critically endangered elements. Simultaneously, MASI will make advances in: the reduction of carbon dioxide (CO2) emissions and its valorisation into useful chemicals; the production of 'green' ammonia (NH3) as an alternative zero-emission fuel and a new vector for hydrogen storage; and the provision of more sustainable fuel cells and electrolyser technologies. At the core of MASI is the fundamental science of metal nanoclusters (MNC), which goes beyond the traditional realm of nanoparticles towards the nanometre and sub-nanometre domain including single metal atoms (SMA). The overall goal of the MASI project is two-fold: (i) to provide a solution for a sustainable use of scarce metals of technological importance (e.g. Pt, Au, Pd), by maximising utilisation of every atom; and (ii) to unlock new properties that emerge in metals only at the atomic scale, allowing for the substitution of critical metals with abundant ones (e.g. Pt with Ni), and provide a platform for the next generation of materials for energy, catalysis and electronics applications. How does it work? We have recently developed the theoretical framework and instrumentation necessary to break bulk metals directly to metal atoms or nanoclusters, with their size, shape and composition precisely controlled. The atomic-scale control of nanocluster fabrication will open the door for programming their chemistry. For example, the electronic, catalytic or electrochemical properties of abundant metals, such as Ni and Co, may imitate endangered metals (Pt or Ru) at the nm and sub-nm scale, or by carefully controlled dispersion of the endangered elements with abundant ones in an alloy nanocluster. Our method allows direct deposition of metal atoms or nanoclusters onto solids (e.g. glass, polymer film, paper etc.), powders (e.g. silica, alumina, carbon etc.) and non-volatile liquids (e.g. oils, ionic liquids) in vacuum with no chemicals, solvents or surfactants and an accurately controlled metal loading. The directness of the MASI approach avoids generating chemical waste and enables a high 'atom economy', surpassing any wet chemistry methods. Moreover, surfaces of our metal nanoclusters are clean and highly active; additionally, being stabilised by interactions with the support material, they can be readily applied wherever electronic, optical or catalytic properties of metals are required. What is unique about these materials and our technology? MASI will offer greener, more sustainable methods of fabrication of metal nanoclusters, without solvents or chemicals, with the maximised active surface area ensuring efficient use of each metal atom. 'Naked', highly active metal surfaces are ready for reactions with molecules, activated by heat, light or electric potential, while tuneable interactions with support materials provide durability and reusability of metals in reactions. In particular, MASI materials will be suitable for the activation of hard-to-crack molecules (e.g. N2, H2 and CO2) in reactions that constitute the backbone of the chemical industry, such as the Haber-Bosch process. Similarly, highly dispersed metals and their intimate contact with the support material, will lead to high capacity for energy storage/conversion required in energy materials and fuel cells technologies. Importantly, MASI nanocluster fabrication technology is fully scalable to kilograms and tons of material, making it ideal for uptake in industrial schemes, potentially leading to a green industrial revolution.

Graphene is ideal for opto-electronics due to its high carrier mobility at room temperature, electrically tuneable optical conductivity, and wavelength independent absorption. Graphene has opened a floodgate for many layered materials (LMs). For a given LM, the range of properties and applications can be tuned by varying the number of layers and their relative orientation. LM heterostructures (LMHs) with tailored properties can be created by stacking different layers. The number of bulk materials that can be exfoliated runs in the thousands, but few have been studied to date. The layered materials research foundry (LMRF) will develop a fully integrated LM-Silicon Photonics platform, serving 5G, 6G and quantum communications, facilitating new design concepts that unlock new performance levels. Graphene and the other non-graphene LMs are at two different stages of development. Graphene is more mature, and can now target functionalities beyond the state of the art in technologically relevant devices. In (opto-)electronics, photonics and sensors, graphene-based systems have already demonstrated extraordinary performance, with reduced power consumption, or photodetectors (PDs) with hyperspectral range for applications such as autonomous driving, where fast data exchange is a critical requisite for safe operation. Applications in light detection and ranging, security, ultrasensitive physical and chemical sensors for industrial, environmental and medical technologies are beginning to emerge and offer great promise. These technologies must be developed to achieve full industrial impact. The other non-graphene LMs are also at the centre of an ever increasing research effort as a new platform for quantum technology. They have already shown their potential, ranging from scalable components, such as quantum light sources, photon detectors and nanoscale sensors, to enabling new materials discovery within the broader field of quantum simulations. The challenge is understanding and tailoring the excitonic properties and the nature of the single photon emission process, as well as to make working integrated devices. Quantum emitters in LMs hold potential in terms of scalability, miniaturisation, integration with other systems and an extra quantum degree of freedom: the valley pseudospin. A major challenge is to go beyond lab demonstrators and show that LMs can achieve technological potential. The LMRF will accelerate this by enabling users to fabricate their devices in a scalable manner, with comparable technology to large-scale manufacturing foundries. This scalability is essential for LMs to become a disruptive technology. The vision is to combine the best of Silicon Photonics with LM-based optoelectronics, addressing key drawbacks of current platforms. ICT systems are the fastest growing consumers of electricity worldwide. Due to limitations set by current CMOS technology, energy efficiency reaches fundamental limits. LM-based optoelectronics builds on the optical/electronic integration ability of Silicon Photonics, which benefits product costs, but with modulator designs simpler than conventional Silicon Photonics at high data rates, giving lower power consumption.