Publications

The rapid increase in anthropogenic greenhouse gas concentrations in the last several decades means that the effects of climate change are fast becoming the familiar horsemen of a planetary apocalypse. Catalysis one of the pillars of the chemical and petrochemical industries will play a critical role in the effort to reduce the flow of greenhouse gases into the atmosphere. This Special Issue is timely as it provides a collection of high-quality manuscripts in a diverse range of topics which include the production of green hydrogen via water electrolysis the steam reforming of ethanol propane or glycerol the dry reforming of methane and the autothermal reforming of diesel surrogate fuel. The topic of the transformation of biomass waste to chemicals is also well represented as is the tackling of CO₂ emissions via novel utilization technologies. The Editors are grateful to all authors for their valuable contributions and confident that this Special Issue will prove valuable to scholars university professors and students alike.

There is a growing conversation around the role that hydrogen can play in the future of the UK and how to best harness its potential to secure jobs show climate leadership promote industrial competitiveness and drive innovation. The Government’s ‘Ten Point Plan for a Green Industrial Revolution’ included hydrogen as one of its ten actions targeting 5GW of ‘low carbon’ hydrogen production by 2030. Britain is thus joining the EU US Japan Germany and a host of other countries seeking to be part of the hydrogen economy of the future.<br/><br/>A focus on clean green hydrogen within targeted sectors and hubs can support multiple Government goals – including demonstrating climate leadership reducing regional inequalities through the ‘levelling up’ agenda and ensuring a green and cost-effective recovery from the coronavirus pandemic which prioritises jobs and skills. A strategic hydrogen vision must be honest and recognise where green hydrogen does not present the optimal pathway for decarbonisation – for instance where alternative solutions are already readily available for roll-out are more efficient and cost-effective. A clear example is hydrogen use for heating where it is estimated to require around 30 times more offshore wind farm capacity than currently available to produce enough green hydrogen to replace all gas boilers as well as adding costs for consumers.<br/><br/>This paper considers the offer of hydrogen for key Government priorities – including an inclusive and resilient economic recovery from the pandemic demonstrating climate leadership and delivering for all of society across the UK. It assesses existing evidence and considers the risks and opportunities and how they might inform a strategic vision for the UK. Ahead of the forthcoming Hydrogen Strategy it sets expectations for Government and outlines key recommendations.

Arup have conducted interviews with targeted industry and government stakeholders to gather data and perspectives to support the development of this study. Arup have also utilised private and publicly available data sources building on recent work undertaken by Geoscience Australia and Deloitte and the comprehensive stakeholder engagement process to inform our research. This study considers the supply chain and infrastructure requirements to support the development of export and domestic hubs. The study aims to provide a succinct “Hydrogen Hubs” report for presentation to the hydrogen working group.



The hydrogen supply chain infrastructure required to produce hydrogen for export and domestic hubs was identified along with feedback from the stakeholder engagement process. These infrastructure requirements can be used to determine the factors for assessing export and domestic hub opportunities. Hydrogen production pathways transportation mechanisms and uses were also further evaluated to identify how hubs can be used to balance supply and demand of hydrogen.



A preliminary list of current or anticipated locations has been developed through desktop research Arup project knowledge and the stakeholder consultation process. Over 30 potential hydrogen export locations have been identified in Australia through desktop research and the stakeholder survey and consultation process. In addition to establishing export hubs the creation of domestic demand hubs will be essential to the development of an Australian hydrogen economy. It is for this reason that a list of criteria has been developed for stakeholders to consider in the siting and design of hydrogen hubs. The key considerations explored are based on demand supply chain infrastructure and investment and policy areas.



Based on these considerations a list of criteria were developed to assess the viability of export and domestic hydrogen hubs. Criteria relevant to assessing the suitability of export and domestic hubs include:

• Health and safety provisions;
• Environmental considerations;
• Economic and social considerations;
• Land availability with appropriate zoning and buffer distances & ownership (new terminals storage solar PV industries etc.);•
• Availability of gas pipeline infrastructure;
• Availability of electricity grid connectivity backup energy supply or co-location of renewables;
• Road & rail infrastructure (site access);
• Community and environmental concerns and weather. Social licence consideration;
• Berths (berthing depth ship storage loading facilities existing LNG and/or petroleum infrastructure etc.);
• Port potential (current capacity & occupancy expandability & scalability);
• Availability of or potential for skilled workers (construction & operation);
• Availability of or potential for water (recycled & desalinated);
• Opportunity for co-location with industrial ammonia production and future industrial opportunities;
• Interest (projects priority ports state development areas politics etc.);
• Shipping distance to target market (Japan & South Korea);
• Availability of demand-based infrastructure (i.e. refuelling stations).

A framework that includes the assessment criteria has been developed to aid decision making rather than recommending specific locations that would be most appropriate for a hub. This is because there are so many dynamic factors that go into selecting a location of a hydrogen hub that it is not appropriate to be overly prescriptive or prevent stakeholders from selecting the best location themselves or from the market making decisions based on its own research and knowledge. The developed framework rather provides information and support to enable these decision-making processes.

Because of differences in irradiation levels it could be more efficient to produce solar electricity and hydrogen in North Africa and import these energy carriers to Europe rather than generating them at higher costs domestically in Europe. From a global climate change mitigation point of view exploiting such efficiencies can be profitable since they reduce overall renewable electricity capacity requirements. Yet the construction of this capacity in North Africa would imply costs associated with the infrastructure needed to transport electricity and hydrogen. The ensuing geopolitical dependencies may also raise energy security concerns. With the integrated assessment model TIAM-ECN we quantify the trade-off between costs and benefits emanating from establishing import-export links between Europe and North Africa for electricity and hydrogen. We show that for Europe a net price may have to be paid for exploiting such interlinkages even while they reduce the domestic investments for renewable electricity capacity needed to implement the EU’s Green Deal. For North African countries the potential net benefits thanks to trade revenues may build up to 50 billion €/yr in 2050. Despite fears over costs and security Europe should seriously consider an energy partnership with North Africa because trade revenues are likely to lead to positive employment income and stability effects in North Africa. Europe can indirectly benefit from such impacts.

A systematic study of different ratios of CO CO₂ N₂ gas components on the hydrogen storage properties of the Na₃AlH₆ complex hydride with 4 mol% TiCl3 8 mol% aluminum and 8 mol% activated carbon is presented in this paper. The different concentrations of CO and CO₂in H₂ and CO CO₂ N₂ in H₂ mixture were investigated. Both CO and CO₂gas react with the complex hydride forming Al oxy-compounds NaOH and Na₂CO₃ that consequently cause serious decline in hydrogen storage capacity. These reactions lead to irreversible damage of complex hydride under the current experimental condition. Thus after 10 cycles with 0.1 vol % CO + 99.9 vol %H₂ and 1 vol % CO + 99 vol %H₂ the dehydrogenation storage capacity of the composite material decreased by 17.2% and 57.3% respectively. In the case of investigation of 10 cycles with 1 vol % CO₂ + 99 vol % H₂ gas mixture the capacity degradation was 53.5%. After 2 cycles with 10 vol % CO +90 vol % H₂  full degradation was observed whereas after 6 cycles with 10 vol % CO₂+ 90 vol % H₂ degradation of 86.8% was measured. While testing with the gas mixture of 1.5 vol % CO + 10 vol % CO₂+ 27 vol % H₂ + 61.5 vol % N2 the degradation of 94% after 6 cycles was shown. According to these results it must be concluded that complex aluminum hydrides cannot be used for the absorption of hydrogen from syngas mixtures without thorough purification.

To become sustainable the production of electricity has been oriented towards the adoption of local and renewable sources. Distributed electric and thermal energy generation is more suitable to avoid any possible waste and the Micro Gas Turbine (MGT) can play a key role in this scenario. Due to the intrinsic properties and the high flexibility of operation of this energy conversion system the exploitation of alternative fuels and the integration of the MGT itself with other energy conversion systems (solar field ORC fuel cells) represent one of the most effective strategies to achieve higher conversion efficiencies and to reduce emissions from power systems. The present work aims to review the results obtained by the researchers in the last years. The different technologies are analyzed in detail both separately and under a more complete view considering two or more solutions embedded in micro-grid configurations.

This latest report describes the potential for CCUS as an important technology during the UK’s energy transition and focuses on the role that metrology (the science of measurement) could play in supporting its deployment. High priority measurement needs and challenges identified within this report include:

• Measuring and comparing the efficiency of different capture techniques and configurations to provide confidence in investments into technologies;
• Improving equations of state to support the development of accurate models used for controlling operational conditions;
• Improving CO₂ flow measurement to support fiscal and financial metering as well as process control and;
• Improving the understanding and validation of dispersion models for emitted CO₂ including plume migration to support safety assessment.

The report can be downloaded from their website

Driven by a small number of niche markets and several decades of application research fuel cell systems (FCS) are gradually reaching maturity to the point where many players are questioning the interest and intensity of its deployment in the transport sector in general. This article aims to shed light on this debate from the road transport perspective. It focuses on the description of the fuel cell vehicle (FCV) in order to understand its assets limitations and current paths of progress. These vehicles are basically hybrid systems combining a fuel cell and a lithium-ion battery and different architectures are emerging among manufacturers who adopt very different levels of hybridization. The main opportunity of Fuel Cell Vehicles is clearly their design versatility based on the decoupling of the choice of the number of Fuel Cell modules and hydrogen tanks. This enables manufacturers to meet various specifications using standard products. Upcoming developments will be in line with the crucial advantage of Fuel Cell Vehicles: intensive use in terms of driving range and load capacity. Over the next few decades long-distance heavy-duty vehicles and fleets of taxis or delivery vehicles will develop based on range extender or mild hybrid architectures and enable the hydrogen sector to mature the technology from niche markets to a large-scale market.

Climate change and global warming as well as growing global demand for hydrocarbons in industrial sectors make great incentives to investigate the utilization of CO₂ for hydrocarbons production. Therefore finding an in-depth understanding of the CO₂ hydrogenation reactors along with simulating reactor responses to different operating conditions are of paramount importance. However the reaction mechanisms for CO₂ hydrogenation and their corresponding kinetic parameters have been disputable yet. In this regard considering the previously proposed Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism which considered CO₂ hydrogenation as a combination of reverse water gas shift (RWGS) and Fischer-Tropsch (FT) reactions and using a one-dimensional pseudo-homogeneous non-isothermal model kinetic parameters of the rate expressions are estimated via fitting experimental and modelling data through a novel swarm intelligence optimization technique called dragonfly algorithm (DA). The predicted reactants conversion using DA algorithm are closer to the experimental data (with about 4% error) comparing to those obtained by the artificial bee colony (ABC) algorithm and are in significant agreement with available literature data. The proposed model is used to assess the effect of reactor configuration on the performance and temperature fluctuations. Results show that axial flow spherical reactor (AFSR) and radial flow spherical reactor (RFSR) exhibiting the same surface area with that of the cylindrical reactor (CR) i.e. AFSR-2 and RFSR-2-i are the most efficient exhibiting hydrocarbons selectivity of 40.330% and 40.286% at CO₂ conversion of 53.763% and 53.891%. In addition it is revealed that the location of the jacket has an essential role in controlling the reactor temperature.

Interactions between incident electromagnetic energy and matter are of critical importance for numerous civil and military applications such as photocatalysis solar cells optics radar detection communications information processing and transport et al. Traditional mechanisms for such interactions in the microwave frequency mainly rely on dipole rotations and magnetic domain resonance. In this study we present the first report of the microwave absorption of Al/H₂ treated TiO₂ nanoparticles where the Al/H₂ treatment not only induces structural and optical property changes but also largely improves the microwave absorption performance of TiO₂ nanoparticles. Moreover the frequency of the microwave absorption can be finely controlled with the treatment temperature and the absorption efficiency can reach optimal values with a careful temperature tuning. A large reflection loss of −58.02 dB has been demonstrated with 3.1 mm TiO₂ coating when the treating temperature is 700 °C. The high efficiency of microwave absorption is most likely linked to the disordering-induced property changes in the materials. Along with the increased microwave absorption properties are largely increased visible-light and IR absorptions and enhanced electrical conductivity and reduced skin-depth which is likely related to the interfacial defects within the TiO₂ nanoparticles caused by the Al/H₂ treatment.