The Pt-ceria synergy may be described as the dehydrogenation of formate formed on the surface of the partially reducible oxide (PRO), ceria, by Pt across the interface, with H 2 O participating in the transition state. However, due to the rising costs of rare earth oxides like ceria, replacement by a less expensive partially reducible oxide, like manganese oxide, is desirable. In this contribution, a comparison between Pt/ceria and Pt/manganese oxide catalysts possessing comparable Pt dispersions reveals that there are significant differences and certain similarities in the nature of the two Pt/PRO catalysts. With ceria, partial reduction involves reduction of the oxide surface shell, with Ce 3+ at the surface and Ce 4+ in the bulk. In the case of manganese oxide, partial reduction results in a mixture of Mn 3+ and Mn 2+ , with Mn 2+ located at the surface. With Pt/CeO X , a high density of defect-associated bridging OH groups react with CO to yield a high density of the formate intermediate. With Pt/MnO X , the fraction of reactive OH groups is low and much lower formate band intensities result upon CO adsorption; moreover, there is a greater fraction of OH groups that are essentially unreactive. Thus, much lower CO conversion rates are observed with Pt/MnO X during low temperature water-gas shift. As with ceria, increasing the Pt loading facilitates partial reduction of MnO X to lower temperature, indicating metal-oxide interactions should be taken into account.

Pt-promoted tungsten-hafnia catalysts containing different amounts of tungsten (15 and 20 wt% WO 3) were prepared and tested for hydroisomerization of n-hexadecane in a trickle-bed reactor. All catalysts were calcined under dry air flow at 723 K for 3 h. Pt-promoted sulfated hafnia was also prepared for the purpose of comparison. The catalysts were characterized using BET surface area, X-ray diffraction, and DRIFTS for the adsorption of pyridine. Tungsten-based hafnia catalysts exhibit moderate activity (\80 %) for hydroisomerization of n-hexadecane at a higher operating temperature of 673 K compared to sulfated hafnia ([95 %), which had an operating temperature of 493 K. However, tungsten-based hafnia catalysts were more selective towards iso-C 16 even at higher n-hexadecane conversions. More cracking products were obtained with sulfated hafnia in which the selectivity to iso-C 16 decreases exponentially with n-hexadecane conversion. The less acidic tungsten-hafnia catalysts may be suitable for producing more isomerized products compared to the sulfated analog.

This article describes the results of an investigation on the influence of loading silane treated sugar cane bagasse (SB) on the morphology and properties of recycled polypropylene (rPP). The samples are prepared through melt extrusion followed by injection moulding. The Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) results show that SB-rPP composites have a fairly strong interfacial interaction and a change in crystallization for the highest containing SB composite, however, some fibre pull-outs are observed as the SB content is increased. The interaction influences the thermal and mechanical properties of the samples in a complex way. There are strong indications of a stronger interfacial interaction on the highest containing SB composite, which is supposedly accountable for the increased crystallinity and melting temperature.

Both conventional and microwave pre-treated catalysts were used to examine a better catalyst for Fischer-Tropsch synthesis (FTS). The results obtained from catalyst characterization and Fischer-Tropsch reactions are reported and discussed in this chapter. Also reported are the results obtained from unsupported catalysts: unpromoted, promoted and partially reduced catalysts. The results are based on the effect of microwave pretreatment on catalytic activity and selectivity in Fischer-Tropsch synthesis (FTS). The effect of duration (the time the catalyst spends in the microwave for the pre-treatment), the effect of the power level, and the effect of bed size and shape are shown and discussed. A number of characterization techniques i.e. Powder X-ray diffraction (PXRD), temperature programmed reduction (TPR), thermogravimetric analysis (TGA), Mössbauer spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques were used to examine the microwave effect on iron Fischer-Tropsch catalyst precursors. In addition, surface sensitive techniques were also employed to further examine the microwave effect i.e. temperature programmed surface reaction (TPSR) and secondary ion mass spectrometry (SIMS) studies. CHAPTER 6, RESULTS AND DISCUSSION 73 6.2 CHARACTERIZATION OF UNSUPPORTED CATALYSTS 6.2.1 MICROWAVE EFFECT Unsupported catalysts were prepared following the precipitation method. It is important to notice that the predominant iron-containing phase after catalyst preparation is hematite (-Fe 2 O 3). Characterization techniques were used to examine the microwave effect on these catalysts (hematite containing catalysts). The results obtained are displayed below: 6.2.1.1 TEM ANALYSIS a = Iron catalyst before microwave pre-treatment, b = Iron catalyst after microwave pre-treatment.

Pt-promoted tungsten-hafnia catalysts containing different amounts of tungsten (15 and 20 wt% WO 3) were prepared and tested for hydroisomerization of n-hexadecane in a trickle-bed reactor. All catalysts were calcined under dry air flow at 723 K for 3 h. Pt-promoted sulfated hafnia was also prepared for the purpose of comparison. The catalysts were characterized using BET surface area, X-ray diffraction, and DRIFTS for the adsorption of pyridine. Tungsten-based hafnia catalysts exhibit moderate activity (\80 %) for hydroisomerization of n-hexadecane at a higher operating temperature of 673 K compared to sulfated hafnia ([95 %), which had an operating temperature of 493 K. However, tungsten-based hafnia catalysts were more selective towards iso-C 16 even at higher n-hexadecane conversions. More cracking products were obtained with sulfated hafnia in which the selectivity to iso-C 16 decreases exponentially with n-hexadecane conversion. The less acidic tungsten-hafnia catalysts may be suitable for producing more isomerized products compared to the sulfated analog.

The purpose of this study was to investigate the synergy of expanded graphite (EG) and Cloisite 15A (C15A) on the thermal conductivity and thermomechanical properties of ethylene-vinyl acetate copolymer/poly (ɛ-caprolactone) (EVA/PCL) blend. Scanning electron microscopy (SEM) results showed that the blend had a phase separation, in which the PCL phase (appeared as droplets) was dispersed uniformly in the EVA matrix in all samples. The results from SEM and X-ray diffraction (XRD) showed that as the EG content increases, graphite sheets increase, leading to a high probability of re-stacking and poor dispersion as well, however the synergy rendered an increase in the storage modulus for the composite containing low content of EG (5phr) in both the EG and clay containing samples. The addition of EG showed a slight increase in thermal stability,but the presence of C15A decreased the onset of degradation of EVA/PCL blend. However, at high temperatures the synergistic effect of EG and C15A showed better thermal stability for EVA/PCL blend than EG alone. The addition and increase in EG content improved thermal conductivity of the EVA/PCL blend in both the clay containing and EG containing samples, however the clay-containing samples showed lower values compared to EG only.

This article investigated the cellulose obtained from sugarcane bagasse by five different extraction mercerization methods. The comparison of the methods gives a clearer picture of that is more effective and feasible for production of SCB cellulose. All the celluloses were characterised by X-Ray Diffraction (XRD), Fourier Transform Infrared (FT-IR), Thermal Gravimetric Analysis (TGA), Scanning Electron Microscope (SEM) and Optical Microscope (OM). All the methods led to white material resembling pure cellulose due to removal of non-cellulosic constituents as can be seen by disappearance of aromatic bands. The removal indicated a decrease in diameter and improved thermal stability in most methods. The materials in general stand a better chance of competing as fillers for polymeric composites.

Cancer and bacterial diseases have been the most incidental diseases to date. According to the World Health Report 2018, at least every family is affected by cancer around the world. In 2012, 14.1 million people were affected by cancer, and that figure is bound to increase to 21.6 million in 2030. Medicine therefore sorts out ways of treatment using conventional methods which have been proven to have many side effects. Researchers developed photothermal and photodynamic methods to treat both cancer and bacterial diseases. These methods pose fewer effects on the biological systems but still no perfect method has been synthesized. The review serves to explore porphyrin and gold nanorods to be used in the treatment of cancer and bacterial diseases: porphyrins as photosensitizers and gold nanorods as delivery agents. In addition, the review delves into ways of incorporating photothermal and photodynamic therapy aimed at producing a less toxic, more efficacious, and specific compound for...

Waste recycling has been the main topic of various scientific researches due to environmental management. Renewable agricultural sources such as pineapple leaf, sisal, jute, piassava, coir, and sugarcane bagasse are among agro waste, normally known as biomass, which is recently used for reinforcing polymeric materials. Sugarcane bagasse fiber residues has been extensively investigated and employed as a source of reinforcement of polymers. The major residue is normally burnt for energy supply in the sugar and alcohol industries and as a result, tons of ash is created. The ash contained inorganic components which are valuable for reinforcement in polymeric materials. This chapter reports on the use of sugarcane bagasse, sugarcane bagasse ash (SBA) and its cellulose as reinforcing fillers for polymers.

A simple, efficient and low cost microwave irradiation-assisted hydrothermal method for indium oxide (In 2 O 3) synthesis has been developed. Different reaction periods were employed in order to study the crystal phase stability of the material. Crystal phase, morphology and optical properties were determined using X-ray diffraction (XRD), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy (UV-Vis) respectively. The pure cubic bixbyite type In 2 O 3 obtained consisted of particles that were less than 10 nm, which tend to agglomerate and form bigger clusters. Textual properties of the obtained nanoparticles were further studied through nitrogen adsorption isotherms. The Brunauer-Emmett-Teller (BET) surface area of the prepared samples ranged between 83 and 96 m 2 /g. Surface properties of the materials revealed a much higher percentage (about 50%) of vacancy oxygen content, which has been related to improved material reactivity in metal oxides.

We review the conversion of waste biomass into recyclable materials using different methods of materials treatment such as thermal, mechanical and chemical processes. Renewable and sustainable biomaterials are increasingly becoming alternatives for synthetic strong materials, e.g. composites. The type of treatment of biomaterial will determine the form to which the biomass is converted and its subsequent applications. It is anticipated that the transformation will produce materials that have superior qualities, properties and characteristics. These include biopolymer materials such as cellulose and hemicellulose, which have all been obtained as products of treatment and extraction from plant materials such as lignocellulose. The main reason for inefficient biomass conversion has been found to be poor manipulation of composite properties during biomass treatment process. The treatment processes are expected to facilitate dehydration, dehydrogenation, deoxygenation and decarboxylation...

The viability of large-scale biodiesel production ultimately boils down to its cost of commercialisation despite other very important factors such as the negative environmental and health effects caused by the direct combustion of fossil diesel. How much each country’s economy will be influenced by the production of biodiesel will be determined by the commitment of various stakeholders to the much-needed transition from petroleum-based resources to renewable resources. Biodiesel production is largely determined by the cost of the feedstock (>70%) and this review focuses on the use of waste oil resources as biodiesel feedstock with a special focus on waste cooking oil (WCO). Generating value from waste oil provides an alternative waste management route as well as a positive environmental and economic contribution. The transesterification process for biodiesel production, its catalysis and some important technical and economic aspects are covered in this communication with a specia...