• Energy Research

Abstract Advanced carbon nanorod promoted binary CaO-La2O3 system with improved physical properties, tailored surface morphology and chemistry were developed in vacuum-impregnating methods. The nanostructured catalyst (CaO–La2O3/AC nanocatalyst) was prepared to convert high FFA waste cooking oil into biodiesel via one step esterification-transesterification reaction. The novel catalyst was characterized by FTIR, SEM, XRD, TGA, BET, TPD-CO2 and TPD-NH3. The high catalytic activity of the nanocatalyst was mainly depends on the high acid and basic density of active sites that contributed from the synergic effect between mesoporous carbon and binary metallic system, which allowed more occurrence of simultaneous esterification-transesterification process of high FFA waste oil without additional pretreatment step. Result showed maximum 98.6 ± 0.5% with acid value 0.4 ± 0.5 mg KOH/g of triglyceride conversion under optimal condition at 3% of catalyst, methanol:oil ratio of 16:1, 100 °C within 4 h of reaction. Furthermore, bi-metallic catalyst with stable carbon nanorod support capable to maintained high reusability with high FAME yield (>98%) with low acid value (

Abstract Jatropha curcas is a highly toxic plant that produces seed containing viscous oil with productivity (2 ton/ha), it grows in tropical and sub-tropical regions and offer greater adaptability to a wide range of climatic and soil conditions. Its oils have been noted as an important alternative to produce green diesel via deoxygenation reaction. This study, deoxygenation of jatropha curcas oil (JCO) was carried out over NiO–Fe2O3 and NiO–ZnO catalysts that supported onto multi-walled carbon nanotube (MWCNT). It had found that high Fe and Zn dosages were ineffective in deoxygenation and greatest activity was observed on NiO(20) Fe2O3(5)/MWCNT catalyst. Structure-activity correlations revealed that low metal loading, large density of weak + medium acidic sites and strong basic sites play key role in enhancing the catalytic activities and n-(C15+C17) selectivity. Comparing carbon nanostructures and carbon micron size supported NiO-Fe2O3 revealed that green diesel obtained from NiO–Fe2O3/MWCNT catalysed deoxygenation had the highest heating value and the lowest amounts of oxygen content. Thereby, it confirmed the importance of carbon nanostructure as the catalyst support in improving the diesel quality. Considering the high reusability of NiO-Fe2O3/MWCNT (6 consecutive runs) and superior green diesel properties (flash point, cloud properties and cetane index) demonstrated the NiO–Fe2O3/MWCNT catalyst offers great option in producing excellent properties of green diesel for energy sector.

Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate’s application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein.

Renewable fuel is a promising alternative as a petroleum replacement in view of the current worldwide demand for petroleum fuel, which is catching up with the world's petroleum supply.

Catalytic reduction of oxygen-containing compounds in palm kernel oil has been studied under H2-free atmosphere condition using microwave system approach over Raney nickel and magnetite activated carbon-based catalysts. The role of porous structure and active O-containing groups of magnetite activated carbon (FeMo/ ACB) catalyst during deoxygenation (DO) at 250 degrees C was investigated. Activated carbon catalysts, obtained from bamboo-derived biochar activation at 800 degrees C with KOH exhibited large surface area and O-containing group. With the introduction of the FeMo/ACB catalyst, the relative content of bio-jet fuel increased remarkably (-80%) with the bio-jet fuel selectivity of -80%. Noted, the high DO activity also showed strong correlation with the presence of high acidic sites, high porosity and surface on the bamboo-derived carbon support, which in turn allows the active metals Fe-Mo to coat the ACB support thoroughly thus promoting a more efficient DO reaction. In addition, the FeMo/ACB catalyst showed excellent reusability over five consecutive cycles, with hydrocarbon fractions ranging from 62% to 80% and bio-jet fuel selectivity from 65% to 80% and minimum coke formation (< 2 wt%).

Abstract Lignin-derived bio-oil required upgrades to reduce its oxygen functionalities to produce high quality liquid fuel that is comparable to those of petroleum source. Hydrodeoxygenation is a process with potential which utilised high hydrogen pressure to remove oxygen groups by modifying the C–O–C, C–O–H and C–C linkages from oxygenates of bio-oil to produce aromatic-based fuels with high energy density and stability. Researchers were focusing on creating new Ni-based catalysts recently for hydrodeoxygenation reaction which emphasises on the affordability, availability, and good catalytic activity. This led to the accumulation of huge literature pertaining Ni-based catalysts. Hence, this review was being called to provide good understanding of hydrogeoxygenation process. The present review includes topics of short summary on lignocellulose biomass and lignin compound in relation to its potential structure such as (i) fuel precursors, (ii) lignin conversion processes, (iii) lignin-derived bio-oil chemistry with emphasis on different type of oxygenates and (iv) catalytic hydrodeoxygenation reaction. In addition, an overview of hydrodeoxygenation catalysts requirements for hydrodeoxygenation of lignin-derived bio-oil was discussed. A detailed discussion of Ni-based catalysts in hydrodeoxygenation of lignin-derived bio-oil such as (i) synthesis conditions influencing good dispersion of nickel-based catalysts; (ii) reaction networks of model compounds with consideration of various catalyst functions; (iii) evaluation of catalytic activities and hydrocarbon selectivity of mono-metallic nickel-based catalysts; and (iv) critical discussion of the role of catalyst's bimetallic synergy towards activity and hydrocarbon selectivity. In addition, deactivation profiles of Ni-based catalysts which included the factors affecting the catalyst stability were critically discussed. Finally, recommendations of future research toward the usage of renewable hydrogen for sustainable upgrading, suggestions on enhancement of reactivity, product selectivity and stability of Ni-based catalysts were discussed herein.

Nanocellulose was successfully isolated from Gelidium elegans red algae marine biomass. The red algae fiber was treated in three stages namely alkalization, bleaching treatment and acid hydrolysis treatment. Morphological analysis was performed by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). TEM results revealed that the isolated nanocellulose had the average diameter and length of 21.8±11.1nm and of 547.3±23.7nm, respectively. Fourier transform infrared (FTIR) spectroscopy proved that the non-cellulosic polysaccharides components were progressively removed during the chemically treatment, and the final derived materials composed of cellulose parent molecular structure. X-ray diffraction (XRD) study showed that the crystallinity of yielded product had been improved after each successive treatments subjected to the treated fiber. The prepared nano-dimensional cellulose demonstrated a network-like structure with higher crystallinity (73%) than that of untreated fiber (33%), and possessed of good thermal stability which is suitable for nanocomposite material.

Abstract Catalytic deoxygenation is a biofuel upgrading process to eliminate the high oxygen content which will lead to corrosion, instability and lower heating value problems. Biofuel have a high oxygen content, which deteriorates the biofuel quality. Therefore, the upgrading of biofuels via catalytic deoxygenation is necessary. Metal oxide such as TiO2, Al2O3, SiO2, ZrO2 and CeO2 is known as a promising support for the production of hydrocarbon-graded biofuel via deoxygenation process. The choice of support is significant to provide the maximum acid strength for the hydrogenolysis of C-O bonds. Al2O3 supported catalyst has drawn attention due to the high acidity. However, the high acidity leads to coke deposition, unstable and deactivation of the catalyst. Thus, it is important to develop methods to reduce catalyst coking and enhance the lifetime of the catalyst. Recently, Al2O3-TiO2 supported catalyst has drawn increasing attention in deoxygenation process owing to its unique properties which can solve the issues from Al2O3. Controlled synthesis method is significant to improve the effectiveness of Al2O3-TiO2 in catalytic reaction since the physicochemical properties of the catalyst are co-related to the processing methodology. Hence, this review describes the use of selected metal oxide supported catalyst for biofuel conversion in deoxygenation process. Moreover, the synthesis method of Al2O3-TiO2 is comprehensively discussed. The physicochemical properties of Al2O3-TiO2, metals and metal oxides supported on Al2O3-TiO2 are further discussed. Finally, future prospective and challenges of deoxygenation process for biofuel synthesis are discussed in order to produce quality hydrocarbon like biofuel using metal oxide supported catalyst.