scholarly journals Alkaline modified A-site deficient perovskite catalyst surface with exsolved nanoparticles and functionality in biomass valorisation

2021 ◽  
Vol 8 (1) ◽  
pp. 1342-1350
Author(s):  
Ahmed Umar ◽  
Dragos Neagu ◽  
John T.S. Irvine
Keyword(s):  
Fossil Fuels ◽  
Carbon Deposition ◽  
Driving Forces ◽  
Catalyst Surface ◽  
Catalyst Support ◽  
Metal Catalyst ◽  
Perovskite Catalyst ◽  
Support Interaction ◽  
Catalytic Behaviour ◽  
A Site

Environmental problems associated with the use of fossil fuels and increase in energy demands due to rise in population and rapid industrialisation, are the driving forces for energy. Catalytic conversion of biomass to renewable energies is among the promising approaches to materialize the above. This requires development of robust catalysts to suppress deactivation due to carbon deposition and agglomeration. In this work, surface properties and chemistry such as exsolution of B-site metal catalyst nanoparticles, particle size and distribution, as well as catalyst-support interactions were tailored through the use of alkaline dopants to enhance catalytic behaviour in valorisation of glycerol. The incorporation of alkaline metals into the lattice of an A-site deficient perovskite modified the surface basic properties and morphology with a consequent robust catalyst-support interaction. This resulted in promising catalytic behaviour of the materials where hydrogen selectivity of over 30% and CO selectivity of over 60% were observed. The catalyst ability to reduce fouling of the catalyst surface as a result of carbon deposition during operation was also profound due to the robust catalyst-support interaction occurring at the exsolved nanoparticles due to their socketing and the synergy between the dopant metals in the alloy in perovskite catalyst systems. In particular, one of the designed systems, La0.4Sr0.2Ca0.3Ni0.1Ti0.9O3±δ, displayed almost 100% resistance to carbon deposition. Therefore, lattice rearrangement using exsolution and choice of suitable dopant could be tailored to improve catalytic performance.

A tes

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
IJE Manager
Keyword(s):  
Energy Supply ◽  
Fossil Fuels ◽  
Geographical Location ◽  
Weather Conditions ◽  
Past Century ◽  
Solar Pv ◽  
Pv Systems ◽  
Trade Offs ◽  
A Site ◽  
Selection Methodology

In the past century, fossil fuels have dominated energy supply in Indonesia. However, concerns over emissions are likely to change the future energy supply. As people become more conscious of environmental issues, alternatives for energy are sought to reduce the environmental impacts. These include renewable energy (RE) sources such as solar photovoltaic (PV) systems. However, most RE sources like solar PV are not available continuously since they depend on weather conditions, in addition to geographical location. Bali has a stable and long sunny day with 12 hours of daylight throughout the year and an average insolation of 5.3 kWh/m2 per day. This study looks at the potential for on-grid solar PV to decarbonize energy in Bali. A site selection methodology using GIS is applied to measure solar PV potential. Firstly, the study investigates the boundaries related to environmental acceptability and economic objectives for land use in Bali. Secondly, the potential of solar energy is estimated by defining the suitable areas, given the technical assumptions of solar PV. Finally, the study extends the analysis to calculate the reduction in emissions when the calculated potential is installed. Some technical factors, such as tilting solar, and intermittency throughout the day, are outside the scope of this study. Based on this model, Bali has an annual electricity potential for 32-53 TWh from solar PV using amorphous thin-film silicon as the cheapest option. This potential amount to three times the electricity supply for the island in 2024 which is estimated at 10 TWh. Bali has an excessive potential to support its own electricity demand with renewables, however, some limitations exist with some trade-offs to realize the idea. These results aim to build a developmental vision of solar PV systems in Bali based on available land and the region’s irradiation.

scholarly journals Applications of Modified Biochar-Based Materials for the Removal of Environment Pollutants: A Mini Review

2020 ◽  
Vol 12 (15) ◽  
pp. 6112 ◽  
Author(s):  
Jung Eun Lee ◽  
Young-Kwon Park
Keyword(s):  
Iron Oxides ◽  
Functional Groups ◽  
Advanced Oxidation Process ◽  
Catalyst Support ◽  
Environmental Pollutants ◽  
Metal Catalyst ◽  
Modified Biochar ◽  
Eutrophic Water ◽  
Iron Iron ◽  
Titanium Dioxides

The biochar treated through several processes can be modified and utilized as catalyst or catalyst support due to specific properties with various available functional groups on the surface. The functional groups attached to the biochar surface can initiate active radical species to play an important role, which lead to the destruction of contaminants as a catalyst and the removal of adsorbent by involving electron transfer or redox processes. Centering on the high potential to be developed in field applications, this paper reviews more feasible and sustainable biochar-based materials resulting in efficient removals of environmental pollutants as catalyst or support rather than describing them according to the technology category. This review addresses biochar-based materials for utilization as catalysts, metal catalyst supports of iron/iron oxides, and titanium dioxide because the advanced oxidation process using iron/iron oxides or titanium dioxides is more effective for the removal of contaminants. Biochar-based materials can be used for the removal of inorganic contaminants such as heavy meals and nitrate or phosphate to cause eutrophication of water. The biochar-based materials available for the remediation of eutrophic water by the release of N- or P-containing compounds is also reviewed.

Development of Efficient Metal Catalyst Support

2007 ◽  
Vol 561-565 ◽  
pp. 547-550 ◽  
Author(s):  
Shouichi Muraoka ◽  
Kazuhiro Kitamura ◽  
Satoshi Kishi ◽  
Tatuo Nakazawa ◽  
Yasuo Shimizu
Keyword(s):  
Aluminum Oxide ◽  
Oxide Layer ◽  
Catalyst Support ◽  
Wire Mesh ◽  
Metal Catalyst ◽  
Oxide Surface ◽  
Low Oxygen ◽  
Metallic Catalyst ◽  
Aluminum Oxide Layer ◽  
Aluminum Oxide Surface

A new wire mesh metallic catalyst support has been studied by using a stainless heat resistant steel of including aluminum. This catalyst support was improved for the metal honeycomb catalyst support that had been put to practical use. The wire mesh catalyst support was made in the following procedures. First, it was made from flat plate made by the stainless steel from the machining. Second, the low oxygen atmosphere in the heat treatment furnace did the aluminum extraction processing. Third, the aluminum oxide layer was made on the surface of catalyst support by furnace in air. Metal honeycomb catalyst has been made for several years by this method. The aim of this study was to evaluate the aluminum oxide layer on the surface of wire mesh catalyst support. The aluminum oxide surface was measured using scanning electron microscopy (SEM) and X-ray reflection diffraction (XRD). This catalyst support has the performance similar to the conventional metal honeycomb catalyst support.

Carbon Nanotubes' and Silicon Carbide Whiskers' Growth on Metal Catalysts: Common Features of Formation Mechanisms

2004 ◽  
Vol 858 ◽  
Author(s):  
Vladimir Kuznetsov ◽  
Anna Usoltseva ◽  
Ilya Mazov
Keyword(s):  
Silicon Carbide ◽  
Metal Surface ◽  
Critical Radius ◽  
Catalyst Surface ◽  
Work Of Adhesion ◽  
Metal Catalyst ◽  
Formation Mechanisms ◽  
Reaction Parameters ◽  
Silicon Carbide Whiskers ◽  
Diagram Approach

ABSTRACTThe formation mechanisms of carbon deposits and silicon carbide whiskers on metal surface catalysts have some common steps. The most important are: (1) the formation of metal particle alloys oversaturated with carbon or silicon and carbon atoms and (2) the nucleation of corresponding deposits on the metal catalyst surface. A thermodynamic analysis of the carbon and/or silicon carbide nucleation on the metal surface was performed. The master equations for the dependence of critical radius of carbon or SiC nucleus on reaction parameters, such as reaction temperature, supersaturation degree of catalyst particles with C (or Si and C), work of adhesion of metal to carbon (or metal to SiC), were obtained. These equations combined with the phase diagram approach can be used for the description of different scenarios of carbon and/or SiC deposits formation and for the development of the main principles of catalyst and promoters design.

scholarly journals Propane Fuel Cells: Selectivity for Partial or Complete Reaction

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Shadi Vafaeyan ◽  
Alain St-Amant ◽  
Marten Ternan
Keyword(s):  
Fuel Cells ◽  
Density Functional ◽  
Catalyst Surface ◽  
Polymer Electrolyte Membrane ◽  
Platinum Group Metal ◽  
Pem Fuel Cells ◽  
Metal Catalyst ◽  
Boltzmann Factor ◽  
Functional Theory ◽  
Electrolyte Membrane

The use of propane fuel in high temperature (120°C) polymer electrolyte membrane (PEM) fuel cells that do not require a platinum group metal catalyst is being investigated in our laboratory. Density functional theory (DFT) was used to determine propane adsorption energies, desorption energies, and transition state energies for both dehydrogenation and hydroxylation reactions on a Ni(100) anode catalyst surface. The Boltzmann factor for the hydroxylation of a propyl species to form propanol and its subsequent desorption was compared to that for the dehydrogenation of a propyl species. The large ratio of the respective Boltzmann factors indicated that the formation of a completely reacted product (carbon dioxide) is much more likely than the formation of partially reacted products (alcohols, aldehydes, carboxylic acids, and carbon monoxide). That finding is evidence for the major proportion of the chemical energy of the propane fuel being converted to either electrical or thermal energy in the fuel cell rather than remaining unused when partially reacted species are formed.

scholarly journals Spatial Differences in Carbon Intensity in Polish Households

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3108 ◽  
Author(s):  
Edyta Sidorczuk-Pietraszko
Keyword(s):  
Regional Differences ◽  
Fossil Fuels ◽  
Driving Forces ◽  
Ghg Emissions ◽  
Decomposition Analysis ◽  
Policy Instruments ◽  
Carbon Intensity ◽  
Greenhouse Gasses ◽  
Key Factor ◽  
Per Capita

Knowledge about the driving forces behind greenhouse gasses (GHG) emissions is crucial for informed and evidence-based policy towards mitigation of GHG emission and changing production and consumption patterns. Both national and regional-level authorities are capable of addressing their actions more effectively if they have information about the spatial distribution of phenomena related to the policies they conduct. In this context, the main aim of this paper is to explain the regional differences in carbon intensity in Poland. The differences in carbon intensity between regions and the national average were analysed using index decomposition analysis (IDA). Aggregate carbon intensity for regional economies as well as the carbon intensity of households was investigated. For both levels of analysis: total emissions and emission from households economic development is the key factor responsible for the inter-regional differences in carbon emission per capita. In the case of total emissions, the second important factor influencing these differences is the structure of the national power system, i.e., its concentration and the production of energy from fossil fuels. For households, disposable income per capita is a key factor of differences in CO2 emission per capita between regions. Higher households’ incomes contribute to higher emission per capita, mostly due to the shift in consumption towards more energy- and material-intensive goods. The contribution of energy emissivity is quite low and not as varied as in the case of income. This suggests that policy instruments targeted at the consumption of fuels can be rather uniform across regions, while more developed regions should also be subject to measures supporting less energy-intensive consumption. On the other hand, policy in less developed regions should prevent them from following the path of per capita emissions growth.

scholarly journals Parameter Optimisation of Carbon Nanotubes Synthesis via Hexane Decomposition over Minerals Generated fromAnadara granosaShells as the Catalyst Support

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
M. Z. Hussein ◽  
S. A. Zakarya ◽  
S. H. Sarijo ◽  
Z. Zainal
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Catalyst Support ◽  
Chemical Vapour ◽  
Total Iron ◽  
Metal Catalyst ◽  
Iron Loading ◽  
Transmission Electron ◽  
Synthesis Of Carbon Nanotubes ◽  
Anadara Granosa

The synthesis of carbon nanotubes (CNTs) by the chemical vapour deposition (CVD) method using natural calcite fromAnadara granosashells as the metal catalyst support was studied. Hexane and iron (Fe) were used as the carbon precursor and the active component of the catalyst, respectively. Response surface methodology (RSM) based on central composite design (CCD) was used to optimise the effect of total iron loading, the duration of reaction, and reaction temperature. The optimal conditions were total iron loading of 7.5%, a reaction time of 45 min, and a temperature of 850°C with a resulting carbon yield of 131.62%. Raman spectra, field-emission-scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses showed that the CNTs were of the multiwalled type (MWNTs).

Purification of Multi-Walled Carbon Nanotubes Grown by Thermal CVD on Fe-Based Catalyst

2006 ◽  
Vol 48 ◽  
pp. 50-54 ◽  
Author(s):  
Th. Dikonimos Makris ◽  
L. Giorgi ◽  
R. Giorgi ◽  
Nicola Lisi ◽  
Elena Salernitano ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Catalyst Support ◽  
Secondary Phase ◽  
Metal Catalyst ◽  
Purification Method ◽  
Thermal Cvd ◽  
Aluminum Ions ◽  
Before And After ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Aiming at the purpose of using carbon nanotubes as secondary phase in composite materials, removal of metal catalyst, catalyst support and amorphous carbon is crucial to make the most of the required properties. A purification method was developed to remove the metal catalyst from multi-walled nanotubes grown by thermal CVD. A nanosized Fe-based catalyst, prepared by coprecipitation of iron and aluminum ions, followed by solid state reaction, was used to catalyze the growth. Carbon nanotubes were subjected to acid purification and a comparison between nitric acid and a mixture of nitric and hydrochloric acid for the removal of Fe and Fe oxides is provided. Morphological and spectroscopic analyses of the materials were performed, both before and after the purification processes.

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