Highlights Effect of precursors on the catalytic performance of alumina. AN samples is higher activity than AC, while AN550 is the optimum one. The AN550 showed methanol conversion and DME selectivity of 72% and 100% at 250 °C, respectively. Acid site density affected catalytic performance among the catalysts with alumina phase. Synthesis of alumina catalyst with high activity compared to commercial γ-Al 2 O 3 .Page 3 of 33 A c c e p t e d M a n u s c r i p t Abstract Dimethyl ether (DME) is amongst one of the most promising alternative, renewable and clean fuels being considered as a future energy carrier. In this study, the comparative catalytic performance of γ-Al 2 O 3 prepared from two common precursors (aluminium nitrate (AN) and aluminium chloride (AC)) is presented. The impact of calcination temperature was evaluated in order to optimise both the precursor and pre-treatment conditions for the production of DME from methanol in a fixed bed reactor. The catalysts were characterized by TGA, XRD, BET and TPD-pyridine. Under reaction conditions where the temperature ranged from 180-300˚C with a WHSV= 12.1 h -1 it was found that all the catalysts prepared from AN(η-Al 2 O 3 ) showed higher activity, at all calcination temperatures, than those prepared from AC(γ-Al 2 O 3 ). In this study the optimum catalyst was produced from AN and calcined at 550 ˚C.This catalyst showed a high degree of stability and had double the activity of the commercial γ-Al 2 O 3 or 87% of the activity of commercial ZSM-5 (80) at 250 ˚C.

Herein, we studied the combustion and pyrolysis for miscanthus × giganteus (Elephant Grass) using TG/DSC techniques. Currently, miscanthus is used to an extent in energy generation applications however; issues with regards to its physicochemical combustion characteristics currently hinder this uptake. In this work, the thermal and kinetic analysis of dry miscanthus and its char were investigated for a better understanding of its physicochemical combustion characteristics and consequently, achieving the highest benefit from the combustion process. Different kinetic modeling has been used to calculate the activation energy and the kinetic parameters during combustion/pyrolysis such as the ASTM-E698, Flynn-Wall and Ozawa (FWO) and differential iso-conversional methods. It was observed that the activation energy values were 22.3, 40-150 and 40-165 kJ mol-1 for miscanthus, respectively. Furthermore, miscanthus species were tested in wastewater treatment and showed a potential for the rapid removal of cadmium heavy metal. In addition, a study of miscanthus ash was performed and indicated that it can be used as a source of potassium in the fertiliser industry.

There is a growing interest in the utilisation of biomass for a range of applications. Coupled with 22 this is the appeal of improving the circular economy and as such, there is a focus on reusing, 23 recycling and upcycling of many materials, including biomass. This has been driven by society 24 in terms of demand for more sustainable energy and products, but also by a paradigm shift in 25 attitudes of the population to reduce their personal carbon footprint. Herein we have selected a 26 number of types of biomass (woody, herbaceous, etc.) and surveyed the ways in which they are 27 utilised. We have done this in combination with assessing some kinetic modelling approaches 28 which been reported for the evaluation of different processes for the recycling, reuse and 29 upcycling of biomass. 30

Herein, an in-situ DRIFT technique was used to study the reaction mechanism of methanol dehydration to dimethyl ether (DME). Moreover, the effect of silver loading on the catalytic performance of η-Al2O3 was examined in a fixed bed reactor under the reaction conditions where the temperature ranged from 180-300 °C with a WHSV= 48.4 h-1. It was observed that the optimum Ag loading was found to be 10% Ag/η-Al2O3 with this novel catalyst also showing a high degree of stability under steady-state conditions and this is attributed to the enhancement in both the surface Lewis acidity and hydrophobicity.

EthanolHydrogen Cobalteiron catalyst DRIFTS-MS a b s t r a c t Co 3 O 4 , Fe 2 O 3 and a mixture of the two oxides CoeFe (molar ratio of Co 3 O 4 /Fe 2 O 3 ¼ 0.67 and atomic ratio of Co/Fe ¼ 1) were prepared by the calcination of cobalt oxalate and/or iron oxalate salts at 500 C for 2 h in static air using water as a solvent/dispersing agent. The catalysts were studied in the steam reforming of ethanol to investigate the effect of the partial substitution of Co 3 O 4 with Fe 2 O 3 on the catalytic behaviour. The reforming activity over Fe 2 O 3 , while initially high, underwent fast deactivation. In comparison, over the Co eFe catalyst both the H 2 yield and stability were higher than that found over the pure Co 3 O 4 or Fe 2 O 3 catalysts. DRIFTS-MS studies under the reaction feed highlighted that the CoeFe catalyst had increased amounts of adsorbed OH/water; similar to Fe 2 O 3 . Increasing the amount of reactive species (water/OH species) adsorbed on the CoeFe catalyst surface is proposed to facilitate the steam reforming reaction rather than decomposition reactions reducing by-product formation and providing a higher H 2 yield.

Herein, the synthesis of pure and modified mesoporous nanocrystalline NiO is reported. The catalyst was modified with different wt % F-ions or K 2 O and used to produce Methyl ethyl ketone (MEK) as a potential fuel/solvent. XRD analysis of the promoted catalysts confirmed the formation of Ni-metal covered by the host oxide, compared with pure NiO, especially for the promoted catalysts with x wt % F-ions. CO 2 -TPD results demonstrated the existence of different basic sites over these catalysts with varying strength. The catalytic conversion of sec-butanol (SB) into MEK over the parent NiO catalyst showed 52 % and 76.8 % conversion of SB at 250 and 275°C, respectively, with higher selectivity to MEK > 96 %. Among the promoted catalysts, NiO-10 wt % F À and NiO-1 wt % K 2 O catalysts showed 99 and 95 % conversion, respectively, with retaining the MEK selectivity of � 96 %. The catalytic activity, of the most active catalysts, was correlated with the presence of Ni/NiO interfaces, different types of basic sites, especially strong basic sites, and the surface area and porosity measurements.

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Measuring the Lewis‐acidic surface sites in catalysis is problematic when the material‘s surface area is very low (SBET ≤1 m2 ⋅ g−1). For the first time, a quantitative assessment of total acidic surface sites of very small surface area catalysts (MoO3 as pure and mixed with 5–30 % CdO (wt/wt), as well as CdO for comparison) was performed using a smart new probe molecule, tetrahydrofuran (THF). The results were nearly identical compared to using another commonly used probe molecule, pyridine. This audition is based on the limited values of the surface area of these samples that likely require a relatively moderate basic molecule as THF with pKb=16.08, rather than strong basic molecules such as NH3 (pKb=4.75) or pyridine (pKb=8.77). We propose mechanisms for the interaction of vapour phase molecules of THF with the Lewis‐cationic Mo and Cd atoms of these catalysts. Besides, dehydration of isopropyl alcohol was used as a probe reaction to investigate the catalytic activity of these catalysts to further support our findings in the case of THF in a temperature range of 175–300 °C. A good agreement between the obtained data of sample MoO3‐10 % CdO, which is characterised by the highest surface area value, the population of Lewis‐acidic sites and % selectivity of propylene at all the applied reaction temperatures was found.