Photocatalytic Reduction of Carbon Dioxide by Water: A Step towards Sustainable Fuels and Chemicals

Photo catalytic reduction of carbon dioxide orartificial photo synthesisto yield hydrogen and hydrocarbons like methane, methanol etc., has emerged as a subject/process of intensive study due to its potential applications towards abatement of atmospheric CO2levels and conversion to fuels and chemicals. This Chapter provides a comprehensive picture of the process that has posed several scientific and technological challenges, like activation of most stable molecules-CO2and water, extremely low conversion rates, complex reaction pathways involving multi electron transfer steps and short catalyst life. All the major aspects/developments on this process like, the salient features and technological aspects, thermodynamic and kinetic characteristics, various types of photo-active catalysts-, like, titania based catalysts and titania with various dopants and modifiers, various metal oxides/sulfides/nitrides/ layered titanates, binary and ternary oxides of Nb, Ta, Ga & In mixed oxide catalysts, metal complexes, and supra molecular catalysts-, sensitization by macro cylic ligands, influence of process parameters, catalyst structure-property-activity correlations, aspects of deactivation of catalysts, reaction mechanistic aspects and sequential surface reaction pathways, recent trends and future directions have been covered. Design and development of efficient catalyst systems and achieving higher yield of desired products (higher selectivity) and extending the catalyst life are the key issues being pursued by the researchers. The process is in nascent stage and further improvements are needed as CO2conversion rates are extremely small, with products formed in terms of 1-10 micro moles/hr. One of the means of improving the process efficiency is to carry out electrochemical reduction of CO2using solar electric power, with an integrated Photo electrochemical cell (PEC). Yet another option is to reduce CO2to methanol with hydrogen produced using solar powered PEC.

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A Numerical Study of the Influence of Process Parameters on the Efficiency of Staged Coal Gasification Using Mixtures of Oxygen and Carbon Dioxide

Energy Systems Research ◽

10.38028/esr.2021.02.0003 ◽

2021 ◽

pp. 27-34

Author(s):

I. G. Donskoy

Keyword(s):

Carbon Dioxide ◽

Reaction Temperature ◽

Numerical Study ◽

Process Efficiency ◽

Conversion Degree ◽

Fuel Conversion ◽

Influence Of Process Parameters ◽

Gasification Process ◽

Coal Fuel ◽

Coal Particles

The paper considers a staged conversion process of pulverized coal fuel in the MHPS-type gasifier, which uses mixtures of oxygen and carbon dioxide as a gasifying agent instead of air. Similar conversion processes can be applied in the process diagrams with the capture and disposal of carbon dioxide. The research tool is a reduced-order mathematical model of coal particles' conversion in a reacting gas flow. Replacement of nitrogen with carbon dioxide leads to significant changes in the gasification process characteristics: the average reaction temperature decreases, but this decrease is partially compensated by an increase in the concentration of gaseous reactants. Thus, the gasification process efficiency and the fuel conversion degree increase. Calculations make it possible to identify a range of parameters with the highest cold gas efficiency values. The influence of oxygen concentration is estimated, the dependence of the fuel conversion degree on the reaction temperature is analyzed.

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Recent Catalytic Advances in Hydrotreatment Processes of Pyrolysis Bio-Oil

Catalysts ◽

10.3390/catal11020157 ◽

2021 ◽

Vol 11 (2) ◽

pp. 157 ◽

Cited By ~ 1

Author(s):

Giuseppe Bagnato ◽

Aimaro Sanna ◽

Emilia Paone ◽

Enrico Catizzone

Keyword(s):

Carbon Dioxide ◽

Carbon Dioxide Emissions ◽

Fossil Fuels ◽

Added Value ◽

Reaction Pathways ◽

Synthetic Fuels ◽

Lignocellulosic Residues ◽

Bio Oil ◽

Fuels And Chemicals ◽

Pyrolytic Oil

Catalytic hydrotreatment (HT) is one of the most important refining steps in the actual petroleum-based refineries for the production of fuels and chemicals, and it will play also a crucial role for the development of biomass-based refineries. In fact, the utilization of HT processes for the upgrading of biomass and/or lignocellulosic residues aimed to the production of synthetic fuels and chemical intermediates represents a reliable strategy to reduce both carbon dioxide emissions and fossil fuels dependence. At this regard, the catalytic hydrotreatment of oils obtained from either thermochemical (e.g., pyrolysis) or physical (e.g., vegetable seeds pressing) processes allows to convert biomass-derived oils into a biofuel with properties very similar to conventional ones (so-called drop-in biofuels). Similarly, catalytic hydro-processing also may have a key role in the valorization of other biorefinery streams, such as lignocellulose, for the production of high-added value chemicals. This review is focused on recent hydrotreatment developments aimed to stabilizing the pyrolytic oil from biomasses. A particular emphasis is devoted on the catalyst formulation, reaction pathways, and technologies.

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Light-driven reduction of carbon dioxide: Altering the reaction pathways and designing photocatalysts toward value-added and renewable fuels

Chemical Engineering Science ◽

10.1016/j.ces.2021.116547 ◽

2021 ◽

Vol 237 ◽

pp. 116547

Author(s):

Quyet Van Le ◽

Van-Huy Nguyen ◽

Trinh Duy Nguyen ◽

Ajit Sharma ◽

Gul Rahman ◽

...

Keyword(s):

Carbon Dioxide ◽

Value Added ◽

Reaction Pathways ◽

Renewable Fuels

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Efficient catalyst-free chemical fixation of carbon dioxide into 2-oxazolidinones under supercritical condition

Chinese Chemical Letters ◽

10.1016/j.cclet.2011.04.004 ◽

2011 ◽

Vol 22 (9) ◽

pp. 1063-1066 ◽

Cited By ~ 8

Author(s):

Jing Xiu Xu ◽

Jin Wu Zhao ◽

Zhen Bin Jia

Keyword(s):

Carbon Dioxide ◽

Supercritical Condition ◽

Chemical Fixation ◽

Efficient Catalyst ◽

Catalyst Free ◽

Fixation Of Carbon Dioxide

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N-Heterocyclic carbene functionalized MCM-41 as an efficient catalyst for chemical fixation of carbon dioxide

Green Chemistry ◽

10.1039/c0gc00541j ◽

2011 ◽

Vol 13 (3) ◽

pp. 644 ◽

Cited By ~ 152

Author(s):

Hui Zhou ◽

Yi-Ming Wang ◽

Wen-Zhen Zhang ◽

Jing-Ping Qu ◽

Xiao-Bing Lu

Keyword(s):

Carbon Dioxide ◽

Chemical Fixation ◽

Efficient Catalyst ◽

Fixation Of Carbon Dioxide ◽

Mcm 41

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Non-Stoichiometric Redox Active Perovskite Materials for Solar Thermochemical Fuel Production: A Review

Catalysts ◽

10.3390/catal8120611 ◽

2018 ◽

Vol 8 (12) ◽

pp. 611 ◽

Cited By ~ 15

Author(s):

Anita Haeussler ◽

Stéphane Abanades ◽

Julien Jouannaux ◽

Anne Julbe

Keyword(s):

Carbon Dioxide ◽

Solar Energy ◽

Energy Conversion ◽

Operating Conditions ◽

Solar Fuel ◽

Fuel Production ◽

Concentrated Solar Energy ◽

Redox Active ◽

Conversion Rates ◽

Wide Range

Due to the requirement to develop carbon-free energy, solar energy conversion into chemical energy carriers is a promising solution. Thermochemical fuel production cycles are particularly interesting because they can convert carbon dioxide or water into CO or H2 with concentrated solar energy as a high-temperature process heat source. This process further valorizes and upgrades carbon dioxide into valuable and storable fuels. Development of redox active catalysts is the key challenge for the success of thermochemical cycles for solar-driven H2O and CO2 splitting. Ultimately, the achievement of economically viable solar fuel production relies on increasing the attainable solar-to-fuel energy conversion efficiency. This necessitates the discovery of novel redox-active and thermally-stable materials able to split H2O and CO2 with both high-fuel productivities and chemical conversion rates. Perovskites have recently emerged as promising reactive materials for this application as they feature high non-stoichiometric oxygen exchange capacities and diffusion rates while maintaining their crystallographic structure during cycling over a wide range of operating conditions and reduction extents. This paper provides an overview of the best performing perovskite formulations considered in recent studies, with special focus on their non-stoichiometry extent, their ability to produce solar fuel with high yield and performance stability, and the different methods developed to study the reaction kinetics.

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