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In this paper, hydrogen adsorption in metal-organic framework MIL-101(Cr) is investigated through a combination of sorption experiments, modeling of experimental isotherms, differential scanning calorimetry (DSC), neutron scattering, in situ synchrotron powder X-ray diffraction, and molecular simulations. The molecular simulations at 77 K for H2 adsorption in the material show excellent correspondence with excess uptakes determined from experimental isotherms. The simulations also indicate that H2 adsorption at a low pressure is mainly located in the 0.7 nm supertetrahedron and that, with increasing pressure, H2 starts to accumulate in the small (2.9 nm) and large (3.4 nm) cages. The inelastic neutron scattering results show that, in contrast to reports for hydrogen adsorption under the same conditions for microporous carbons, there is no solid-like H2 or any higher density H2 phases adsorbed in the pores of MIL-101(Cr). This indicates that, with increasing pressures, the adsorbed density of the MIL-101(Cr) remains constant but the volume of adsorbate increases and that higher densities for adsorbed hydrogen require pore sizes smaller than 0.7 nm, which is the size of the smallest pore in MIL-101(Cr). The enthalpies of adsorption are also investigated for this material using simulations, the Clapeyron equation applied to the isosteres and DSC, with the direct calorimetric method showing good agreement at zero coverage with the other two methods. The simulations and the Clapeyron equation are also in good agreement up to 6 wt % coverage.

Methane is touted as a replacement for fossil fuels in transport applications due to its lower costs of production and cleaner combustion. Storage of methane is still a problem and different technologies have been considered, including compression and liquefaction. Adsorption in a porous material is a potential alternative for methane storage, as it can increase densities at moderate pressures and temperatures. For practical applications, in addition to the quantities stored and working capacities, it is important to equally consider aspects such as kinetics of storage and thermal management of the storage system. In this paper, the kinetics and enthalpies of adsorption of methane in activated carbons AX-21 and TE7, and metal-organic framework MIL-101 (Cr) are extracted from readily available gas sorption data. The adsorption kinetics at 300 K and 325 K are analysed and fitted with the linear driving force (LDF) model, and mass transfer coefficients (MTC) and effective diffusivities are estimated. The effective diffusivities have a range of values from 1.79 × 10−13 m2 s−1 for the MIL-101 (Cr) at 300 K to 9.36 × 10−10 m2 s−1 for the TE7 at 325 K. The activation energies for the effective diffusivities based on an Arrhenius-type temperature dependence are calculated as 7.42, 7.09 and 5.38 kJ mol−1 for the AX-21, the MIL-101 (Cr) and the TE7, respectively. The enthalpies of adsorption are calculated with the Clausius-Clapeyron equation and the differences observed when calculating these with excess and absolute amounts are presented and discussed, with the results showing that enthalpies can have up to 10% differences if using excess amounts instead of absolute quantities. The isosteric enthalpies are also compared with enthalpies at zero-coverage obtained from differential calorimetry experiments for the MIL-101 (Cr), and a ∼3.5 kJ mol−1 difference is observed, which underlines the importance of refining calculation methods and bridging the gap between direct and indirect methods for calculating enthalpies of adsorption.

Our investigations into molecular hydrogen (H2) confined in microporous carbons with different pore geometries at 77 K have provided detailed information on effects of pore shape on densification of confined H2 at pressures up to 15 MPa. We selected three materials: a disordered, phenolic resin-based activated carbon, a graphitic carbon with slit-shaped pores (titanium carbide-derived carbon), and single-walled carbon nanotubes, all with comparable pore sizes of < 1 nm. We show via a combination of in situ inelastic neutron scattering studies, high-pressure H2 adsorption measurements, and molecular modelling that both slit-shaped and cylindrical pores with a diameter of ~0.7 nm lead to significant H2 densification compared to bulk hydrogen under the same conditions, with only subtle differences in hydrogen packing (and hence density) due to geometric constraints. While pore geometry may play some part in influencing the diffusion kinetics and packing arrangement of hydrogen molecules in pores, pore size remains the critical factor determining hydrogen storage capacities. This confirmation of the effects of pore geometry and pore size on the confinement of molecules is essential in understanding and guiding the development and scale-up of porous adsorbents that are tailored for maximising H2 storage capacities, in particular for sustainable energy applications.

Chabazite (CHA), one of the most common zeolite framework types, has a remarkable capacity to accommodate a wide range of different cations within the unique CHA framework. This has led to CHA being applied extensively in ion exchange, and studied for highly selective gas sorption, most notably through a trapdoor mechanism. Here, we report the systematic study of a series of six chabazite zeolites (i.e.K-CHA, Cs-CHA, Ca-CHA, Ba-CHA, Sr-CHA and Zn-CHA) obtained by subjecting the parent chabazite (KNa-CHA) to exchange operations with cations of different valences and atomic radii. These samples were examined using numerous techniques and it was found that the differences in valence and size between extra-framework cations exert a significant effect on the abundance of these cations positioned in the framework, resulting in differing nitrogen sorption ability measured in the synthesised chabazite zeolites. These findings will help to understand how the zeolite counter-cation affects the ability of the CHA material to selectively sequester and separate gases through the use of the trapdoor mechanism.

Controlling the assembly and disassembly of nanoscale protein cages for the capture and internalisation of protein or non-proteinaceous components is fundamentally important to a diverse range of bionanotechnological applications. Here, we study the reversible, pressure-induced dissociation of a natural protein nanocage,E. colibacterioferritin (Bfr), using synchrotron radiation small angle X-ray scattering (SAXS) and circular dichroism (CD). We demonstrate that hydrostatic pressures of 450 MPa are sufficient to completely dissociate the Bfr icositetramer into protein dimers, and the reversibility and kinetics of the reassembly process can be controlled by selecting appropriate buffer conditions. We also demonstrate that the heme B prosthetic group present at the subunit dimer interface influences the stability and pressure lability of the cage, despite its location being discrete from the inter-dimer interface that is key to cage assembly. This indicates a major cage-stabilising role for heme within this family of ferritins.

Lignin, a natural biopolymer and abundant by-product, is a particularly promising feedstock for carbon-based materials and a potentially sustainable alternative to phenolic resins, which are typically derived from crude oil. The source and method used to isolate lignin have a large impact on the thermal properties of the polymer, and can affect resultant materials prepared from lignin. Previous investigations into lignin characterisation often utilise a variety of feedstocks and isolation methods, which can make robust comparisons challenging. We present a systematic investigation into the chemical composition of lignins extracted using an identical Organosolv isolation method but from different biomass feedstocks: hemp hurds, eucalyptus chips, flax straw, rice husk and pine. We show how the aromatic structure of lignin can affect the thermal behaviour of the polymer, which correlates to the structure of resulting carbons. Carbons from lignins with a high syringyl unit content display a pronounced foaming behaviour which, on activation, results in a high-surface area material with hierarchical porosity.

Porous superhydrophobic nanofibrous networks based on cellulose acetate butyrate (CAB) were prepared using electrospinning. The morphology and wettability of the prepared fibrous networks was studied using scanning electron microscopy and static contact angle measurements. The porous nanofiber networks exhibited superhydrophobicity and superoleophilicity with a water contact angle of ∼165° and an oil contact angle of ∼0°. The porous nature of the nanofibres themselves is thought to lead to an increased surface area making them suitable for sorption applications. Due to their hydrophobic and oleophilic nature, they were tested for their oil sorption capacity. They demonstrated an oil sorption capacity of ∼60 g/g for motor oil, which is four times that of commercially used polypropylene. The nanofibrous mats also demonstrated excellent reusability, retaining ∼80% of their sorption capacity for up to 5 cycles of use.

Activated carbons are promising sorbents that have been heavily investigated for the physisorptive storage of hydrogen. The industrial process for production of activated carbons is finely tuned and requires a reliable and uniform feedstock. While the natural biopolymer lignin, a by-product of several industries, has received increasing interest as a potentially sustainable and inexpensive activated carbon feedstock, the ratio of the three aromatic monomers (S, G, and H) in lignin can be heavily affected by the lignin source and growing conditions. The aromatic ratio is known to influence the thermal behavior of the polymer, which could be problematic for production of consistent activated carbons at scale. With the goal of improving the consistency of activated carbons produced from lignins derived from different feedstocks, here we present a route to limiting the influence of lignin feedstock on activated carbon porosity and performance, resulting in a carbonization process that is resilient to changes in lignin source. Two different types of organosolv lignin (representing high S-unit content and high G-unit content feedstocks) were investigated. Resulting activated carbons exhibited a high surface area (> 1000 m2·g-1) with consistent adsorptive properties and reasonable hydrogen uptake of up to 1.8 wt.% at 1 bar and -196 °C. These findings indicate that low temperature carbonization conditions can be used to produce a consistent carbon material using organosolv lignins from any source, paving the way for more widespread use of lignin in large-scale carbon production.

Lignin is a significant by-product of the paper pulping and biofuel industries. Upgrading lignin to a high-value product is essential for the economic viability of biorefineries for bioethanol production and environmentally benign pulping processes. In this work, the feasibility of lignin-derived activated carbons for hydrogen storage was studied using a Design of Experiments methodology, for a time and cost-efficient exploration of the synthesis process. Four factors (carbonisation temperature, activation temperature, carbonisation time, and activation time) were investigated simultaneously. Development of a mathematical model allowed the factors with the greatest impact to be identified using regression analysis for three responses: surface area, average pore size, and hydrogen uptake at 77 K and 1 bar. Maximising the surface area required activation conditions using the highest settings, however, a low carbonisation temperature was also revealed to be integral to prevent detrimental and excessive pore widening. A small pore size, vital for efficient hydrogen uptake, could be achieved by using low carbonisation temperature but also low activation temperatures. An optimum was achieved using the lowest carbonisation conditions (350 °C for 30 min) to retain a smaller pore size, followed by activation under the severest conditions (1000 °C for 60 min) to maximise surface area and hydrogen uptake. These conditions yielded a material with a high surface area of 1400 m2 g−1 and hydrogen uptake of 1.9 wt.% at 77 K and 1 bar.

Purpose: Microalgae have a high potential as a feedstock for the production of biofuels, either indirectly, through the extraction of lipids, which can be transformed into biodiesel, or directly via whole cell conversion using hydrothermal liquefaction (HTL). Both approaches have disadvantages, due to the high cost of cultivating microalgae with sufficient lipid content (>40%), while the whole cell conversion produces low quality oils, which require significant further upgrading. This work investigated the possibility of realising the benefits of both processes, by studying the liquefaction reaction of a lipid-extracted algae hydrolysate. Methods: In order to enhance oil yields, the reaction was conducted in the presence of varying loadings of iso-propyl alcohol (IPA) and applied two waste steel furnace residues as potential liquefaction catalysts. Results: Primarily, The lipid extraction process needs to be optimized to reduce the amount of acid contaminant within the liquefaction medium. For the HTL process, the addition of 50 vol% IPA resulted in remarkably high oil yields of up to 60.2 wt% on an organic basis, whereas the two furnace residues had no positive effect on the product distribution, and instead favoured the formation of solid reaction products. Nevertheless, the results suggested that the presence of iron potentially reduced the nitrogen and oxygen content of the bio-oil. Conclusions: As such, HTL is a suitable method for valorising lipid-extracted algal biomass, where the bio-oil yields can be enhanced substantially by using IPA in conjunction with the water.

Synthetic K+ chabazite (KCHA), Cs+ chabazite (CsCHA) and Zn2+ chabazite (ZnCHA) have been synthesized and investigated in order to relate the differences in their crystalline structures to their thermal stability, moisture content and frequency dependent alternating current (AC) conductivity, permittivity and phase angle at a range of temperatures. The materials are shown to exhibit the universal dielectric response, which is typical of materials consisting of both conductive and insulating regions. Due to the presence of porosity, the three chabazites were hydrated significantly at room temperature and so the dehydrated state was achieved by heating the chabazites to high temperatures to ensure that all different energetic types of water were removed. Cation migration activation energies for KCHA (0.66 ± 0.10) eV, CsCHA (0.88 ± 0.01) eV and ZnCHA (0.90 ± 0.01) eV were determined during the cooling cycle from the fully dehydrated state to provide an accurate measurement of the activation energies. Good thermal stability of the materials was observed up to 710 °C and below 200 °C the electrical properties can be strongly influenced by hydration level. Overall, it was determined that when either hydrated or dehydrated, KCHA had the highest conductivity and lowest cation migration activation energy of the three studied chabazites and thus has the most promising electrical properties for potential use as a gas sensing material in next-generation electrical-based gas sensors.

This work demonstrates the potential of zeolite Y supported nickel phosphide materials as highly active catalysts for the upgrading of bio-oil as an improved alternative to noble metal and transition metal sulphide systems. Our systematic work studied the effect of using different counterions (NH4 +, H+, K+ and Na+) and Si/Al ratios (2.56 and 15) of the zeolite Y. It demonstrates that whilst the zeolite counterion itself has little impact on the catalytic activity of the bare Y-zeolite, it has a strong influence on the activity of the resulting nickel phosphide catalysts. This effect is related to the nature of the nickel phases formed during the synthesis process Zeolites containing K+ and Na+ favour the formation of a mixed Ni12P5/Ni2P phase, H+ Y produces both Ni2P and metallic Ni, whereas NH4 + Y produces pure Ni2P, which can be attributed to the strength of the phosphorus-aluminium interaction and the metal reduction temperature. Using quinoline as a model for the nitrogen-containing compounds in bio-oils, it is shown that the hydrodenitrogenation activity increases in the order Ni2P > Ni0 > Ni12P5. While significant research has been dedicated to the development of bio-oils produced by thermal liquefaction of biomass, surprisingly little work has been conducted on the subsequent catalytic upgrading of these oils to reduce their heteroatom content and enable processing in conventional petrochemical refineries. This work provides important insights for the design and deployment of novel active transition metal catalysts to enable the incorporation of bio-oils into refineries.

A highly porous carbon was synthesised using a coordination complex as an unusual precursor. During controlled pyrolysis a trinuclear copper complex, [CuII3Cl4(H2L)2]•CH3OH, undergoes phase changes with melt and expulsion of different gases to produce a unique morphology of copper-doped carbon which, upon acid treatment, produces highly porous graphitic carbon with a surface area of 857 m2g-1 and a gravimetric hydrogen uptake of 1.1 wt% at 0.5 bar pressure at 77 K.

Recently, much research has been published on the hydrothermal liquefaction (HTL) of microalgae to form bio-crude, which can be further upgraded into sustainable 3rd generation biofuels. However, most of these studies have been conducted in batch reactors, which are not fully applicable to large-scale industrial production. In this investigation an inexpensive laboratory scale continuous flow system was designed and tested for the liquefaction of microalgae produced during wastewater treatment. The system was operated at a range of temperatures (300 °C–340 °C) and flow rates (3–7 mL min− 1), with the feed being delivered using high pressure N2 rather than a mechanical pump. The design incorporated the in-situ collection of solids through a double tube design. The algae was processed at 5 wt% and the results were compared to those from a batch reactor operated at equivalent conditions. By combining high heating rates with extended reaction times, the continuous system was able to yield significantly enhanced bio-crude yields compared to the batch system. This demonstrates the need for inexpensive continuous processing in the lab, to aid in scale up decision making.

The rapid pace of development in biotechnology has placed great importance on controlling cell-material interactions. In practice, this involves attempting to decouple the contributions from adhesion molecules, cell membrane receptors, and scaffold surface chemistry and morphology, which is extremely challenging. Accordingly, a strategy is presented in which different chemical, biochemical, and morphological properties of 3D biomaterials are systematically varied to produce novel scaffolds with tuneable cell affinities. Specifically, cationized and surfactant-conjugated proteins, recently shown to have non-native membrane affinity, are covalently attached to 3D scaffolds of collagen or carboxymethyl-dextran, yielding surface-functionalized 3D architectures with predictable cell immobilization profiles. The artificial membrane-binding proteins enhance cellular adhesion of human mesenchymal stem cells (hMSCs) via electrostatic and hydrophobic binding mechanisms. Furthermore, functionalizing the 3D scaffolds with cationized or surfactant-conjugated myoglobin prevents a slowdown in proliferation of seeded hMSCs cultured for seven days under hypoxic conditions.

The suitability of biodiesel produced from spent Vietnamese coffee was examined. Previous work shows that the geographical origin of coffee beans has little effect on the composition and physical properties of the biodiesel produced Jenkins et al. [1]. Vietnamese coffee, however, is roasted in a range of fats and oils for flavour enhancement and therefore has a unique fatty acid profile. The oil yield and biodiesel properties of three Vietnamese coffees were assessed and compared to a coffee of more typical composition—Colombian—and traditional biodiesel feedstocks (rapeseed, sunflower and palm). The oil yield from fresh Vietnamese coffee was higher (12.0–14.0 %) than Colombian coffee (9.3 %), while the oil yield from spent Vietnamese coffee (9.3–10.4 %) was comparable to the Colombian coffee (9.5 %). The unsaponifiable matter was only present in low levels in the Vietnamese coffee (1.9–4.9 %) compared to Colombian coffee (30.4 % fresh, 21.4 % spent). Vietnamese coffee biodiesel was more saturated than Columbian coffee biodiesel. It was therefore more viscous and had a higher pour point than the Colombian coffee, and possessed properties more akin to palm biodiesel. Vietnamese coffee biodiesel would therefore be a suitable feedstock for use locally due to the more suitable climate and compatibility with the palm feedstock that is currently used. Spent coffee grounds from Vietnam is demonstrated to be a suitable source of biodiesel

This study of the effect of support of Co-Na-Mo based catalysts on the direct hydrogenation of CO$_2$ into hydrocarbons (HC) provides guidelines for the design of catalysts for CO$_2$ conversion. We demonstrate that the surface area of the support and the metal-support interaction have a key role determining the cobalt crystallite size and consequently the activity of the system. Cobalt particles with sizes

Visible light promoted photocatalytic water oxidations were conducted using a homogenous cobalt complex as a catalyst that was absorbed onto a silica gel substrate. The porous SiO2 contained Ru(bpy)3 2+ as a light harvester and the redox quinone analogue DCPIP as a reversible electron mediator as a step towards utilization of protons and electrons liberated in water oxidations for solar fuels.

Three highly porous Zr(IV)-based metal–organic frameworks, UBMOF-8, UBMOF-9, and UBMOF-31, were synthesized by using 2,2′-diamino-4,4′-stilbenedicarboxylic acid, 4,4′-stilbenedicarboxylic acid, and combination of both linkers, respectively. The mixed-linker UBMOF-31 showed excellent hydrogen uptake of 4.9 wt% and high selectivity for adsorption of CO2 over N2 with high thermal stability and moderate water stability with permanent porosity and surface area of 2552 m2 g−1.

The continually growing profile of energy issues in the 21st century is closely linked to the challenges of national and global development, international economy, and the emphasis on goods transport and human travel all around us. These challenges make headlines and are reflected in the social trends towards environmentally friendly practices and responsible use of energy. However, major advances and large-scale improvements in the infrastructure can only be achieved by engaging all aspects of engineering research and development, with particular emphasis on the design and incorporation of new materials. The Special Issue was commissioned at Materials & Design since the strategic themes in energy materials research are closely aligned with the scope and priorities of the journal [1]. In the transport sector, energy efficiency has been recognized as a major issue, and continues to gain importance. A number of materials-related developments have already taken place, bringing significant reductions in fossil fuel consumption and CO2 emissions. However, to meet the ever more stringent targets ahead there is a need to develop new materials and to optimise the use of existing ones. Advances in this area require considerable concerted research effort and sustaining synergy across the interconnected disciplines of composites, metallurgy, mechanics, and energy storage and generation. This Virtual Special Issue contains a collection of contributed papers on the following topics: (i) materials for lightweight structures including alloys and composites, (ii) materials for energy storage and the use of alternative energy sources, (iii) materials for energy harvesting technologies, (iv) materials for novel sensors.

Experimental hydrogen isotherms on several metal-organic frameworks (IRMOF-1, IRMOF-3, IRMOF-9, ZIF-7, ZIF-8, ZIF-9, ZIF-11, ZIF-12, ZIF-CoNIm, MIL-101 (Cr), NH2-MIL-101 (Cr), NH2-MIL-101 (Al), UiO-66, UiO-67 and HKUST-1) synthesized in-house and measured at 77 K and pressures up to 18 MPa are presented, along with N2 adsorption characterization. The experimental isotherms together with literature high pressure hydrogen data were analysed in order to search for relationships between structural properties of the materials and their hydrogen uptakes. The total hydrogen capacity of the materials was calculated from the excess adsorption assuming a constant density for the adsorbed hydrogen. The surface area, pore volumes and pore sizes of the materials were related to their maximum hydrogen excess and total hydrogen capacities. Results also show that ZIF-7 and ZIF-9 (SOD topology) have unusual hydrogen isotherm shapes at relatively low pressures, which is indicative of “breathing”, a phase transition in which the pore space increases due to adsorption. This work presents novel and more useful correlations using the modelled total hydrogen capacities of several MOFs. These total hydrogen capacities are more practically relevant for energy storage applications than the measured excess hydrogen capacities. Thus, these structural correlations will be advantageous for the prediction of the properties a MOF will need in order to meet the US Department of Energy targets for the mass and volume of on-board storage systems. Such design tools will allow hydrogen to be used as an energy vector for sustainable mobile applications such as transport, or for providing supplementary power to the grid in times of high demand.

A range of low-cost nanoparticulate mixed transition metal oxides were prepared using a simple methodology and used as catalysts in visible light promoted water oxidations. The effect of catalyst and daylight equivalent light intensities on reaction efficiency in terms of O2 yields, TOF and proton production was determined.

Improvements in the efficiency of combustion within a vehicle can lead to reductions in the emission of harmful pollutants and increased fuel efficiency. Gas sensors have a role to play in this process, since they can provide real time feedback to vehicular fuel and emissions management systems as well as reducing the discrepancy between emissions observed in factory tests and ‘real world’ scenarios. In this review we survey the current state-of-the-art in using porous materials for sensing the gases relevant to automotive emissions. Two broad classes of porous material – zeolites and metal–organic frameworks (MOFs) – are introduced, and their potential for gas sensing is discussed. The adsorptive, spectroscopic and electronic techniques for sensing gases using porous materials are summarised. Examples of the use of zeolites and MOFs in the sensing of water vapour, oxygen, NOx, carbon monoxide and carbon dioxide, hydrocarbons and volatile organic compounds, ammonia, hydrogen sulfide, sulfur dioxide and hydrogen are then detailed. Both types of porous material (zeolites and MOFs) reveal great promise for the fabrication of sensors for exhaust gases and vapours due to high selectivity and sensitivity. The size and shape selectivity of the zeolite and MOF materials are controlled by variation of pore dimensions, chemical composition (hydrophilicity/hydrophobicity), crystal size and orientation, thus enabling detection and differentiation between different gases and vapours.

The potential of neutron powder diffraction in the location of hydrogen atoms in molecular materials and inorganic-molecular complexes is reviewed. Advances in instrumentation and data collection techniques that have made this field accessible are reviewed, along with a wide range of applications carried out by our collaboration investigating functional materials, hydrogen-containing minerals and molecular compounds. Some of the limitations in this area, particularly for molecular systems, are also addressed.

A sound understanding of any sorption system requires an accurate determination of the enthalpy of adsorption. This is a fundamental thermodynamic quantity that can be determined from experimental sorption data and its correct calculation is extremely important for heat management in adsorptive gas storage applications. It is especially relevant for hydrogen storage, where porous adsorptive storage is regarded as a competing alternative to more mature storage methods such as liquid hydrogen and compressed gas. Among the most common methods to calculate isosteric enthalpies in the literature are the virial equation and the Clausius–Clapeyron equation. Both methods have drawbacks, for example, the arbitrary number of terms in the virial equation and the assumption of ideal gas behaviour in the Clausius–Clapeyron equation. Although some researchers have calculated isosteric enthalpies of adsorption using excess amounts adsorbed, it is arguably more relevant to applications and may also be more thermodynamically consistent to use absolute amounts adsorbed, since the Gibbs excess is a partition, not a thermodynamic phase. In this paper the isosteric enthalpies of adsorption are calculated using the virial, Clausius–Clapeyron and Clapeyron equations from hydrogen sorption data for two materials—activated carbon AX-21 and metal-organic framework MIL-101.It is shown for these two example materials that the Clausius–Clapeyron equation can only be used at low coverage, since hydrogen’s behaviour deviates from ideal at high pressures. The use of the virial equation for isosteric enthalpies is shown to require care, since it is highly dependent on selecting an appropriate number of parameters. A systematic study on the use of different parameters for the virial was performed and it was shown that, for the AX-21 case, the Clausius–Clapeyron seems to give better approximations to the exact isosteric enthalpies calculated using the Clapeyron equation than the virial equation with 10 variable parameters.

The potential of neutron powder diffraction (NPD) to provide vital information on the determination of accurate hydrogen positions in organic molecular crystals is demonstrated through the study of a series of hydrogen bonded molecular complexes with relevance in crystal engineering. By studying complexes designed to contain short, strong hydrogen bonds, the findings are shown to be of particular importance in the study of proton transfer, and the often critical distinction between neutral complexes and salts in these molecular materials. The use of combined NPD and single crystal X-ray diffraction is shown to be particularly potent in this area.

Experimental excess isotherms for the adsorption of gases in porous solids may be represented by mathematical models that incorporate the total amount of gas within a pore, a quantity which cannot easily be found experimentally but which is important for calculations for many applications, including adsorptive storage. A model that is currently used for hydrogen adsorption in porous solids has been improved to include a more realistic density profile of the gas within the pore, and allows calculation of the total amount of adsorbent. A comparison has been made between different Type I isotherm equations embedded in the model, by examining the quality of the fits to hydrogen isotherms for six different nanoporous materials. A new Type I isotherm equation which has not previously been reported in the literature, the Unilanb equation, has been derived and has also been included in this comparison study. These results indicate that whilesome Type I isotherm equations fit certain types of materials better than others, the Toth equation produces the best overall quality of fit and also provides realistic parameter values when used to analyse hydrogen sorption data for a model carbon adsorbent.

Aligned carbon nanotube (CNT) arrays over 150 μm long have been grown by catalytic chemical vapour deposition on the walls of bare cordierite monoliths in a single step. The method described avoids the need for the multiple pre-treatment steps currently applied, and is coupled with an increase in the thickness of the carbon layer obtained by an order of magnitude compared to literature. Uniform CNT growth has been obtained over different lengths of monolith. The resulting CNT/cordierite monoliths have a high surface area and low pressure drop, making them a viable support for use in industrial catalysis.

The reported wide-range nonstoichiometric Ni1+xTe2, 0≤x≤0.83, and Ni1+xSe2, 0.57≤x≤0.92, CdI2/NiAs structure type solid solution fields have been carefully reinvestigated via electron and X-ray powder diffraction to search for evidence of Ni/vacancy ordering and superstructure phases. In the case of telluride, evidence is thereby found for a Ni3Te4 superstructure phase attempting to condense out at x∼0.5 while, in the case of selenide, three quite distinct phases have been identified within the Ni1+xSe2 solid solution field. An intriguing characteristic honeycomb diffuse-intensity distribution has also been observed across the solid solution field in the case of the Ni1+xTe2 system. Its presence has been attributed to low frequency phonon modes along certain very specific directions of reciprocal space.