Carbon nanotubes are promising materials for various applications. In recent years, progress in manufacturing and functionalizing carbon nanotubes has been made to achieve the control of bulk and surface properties including the wettability, acid–base properties, adsorption, electric conductivity and capacitance. In order to gain the optimal benefit of carbon nanotubes, comprehensive understanding on manufacturing and functionalizing carbon nanotubes ought to be systematically developed. This review summarizes methodologies of manufacturing carbon nanotubes via arc discharge, laser ablation and chemical vapor deposition and functionalizing carbon nanotubes through surface oxidation and activation, doping of heteroatoms, halogenation, sulfonation, grafting, polymer coating, noncovalent functionalization and nanoparticle attachment. The characterization techniques detecting the bulk nature and surface properties as well as the effects of various functionalization approaches on modifying the surface properties for specific applications in catalysis including heterogeneous catalysis, photocatalysis, photoelectrocatalysis and electrocatalysis are highlighted.

Carbon nanotube catalysts: recent advances in synthesis, characterization and applications.

In a carbon constrained world, at least four classes of greenhouse gas mitigation options are available: Energy efficiency, fuel switching, introduction of carbon dioxide capture and storage along with renewable generating technologies, and reductions in emissions of non-CO2 greenhouse gases. The role of energy technologies is considered crucial in climate change mitigation. In particular, carbon capture and storage (CCS) promises to allow for low-emissions fossil-fuel based power generation. The technology is under development; a number of technological, economic, environmental and safety issues remain to be solved. With regard to its sustainability impact, CCS raises a number of questions: On the one hand, CCS may prolong the prevailing coal-to-electricity regime and countervail efforts in other mitigation categories. On the other hand, given the indisputable need to continue using fossil fuels for some time, it may serve as a bridging technology towards a sustainable energy future. In this paper, we discuss the relevant issues for the case of Germany. We provide a survey of the current state of the art of CCS and activities, and perform an energy-environment-economic analysis using a general equilibrium model for Germany. The model analyzes the impact of introducing carbon constraints with respect to the deployment of CCS, to the resulting greenhouse gas emissions, to the energy and technology mix and with respect to interaction of different mitigation efforts. The results show the relative importance of the components in mitigating greenhouse gas emissions in Germany. For example, under the assumption of a CO2 policy, both energy efficiency and CCS will contribute to climate gas mitigation. A given climate target can be achieved at lower marginal costs when the option of CCS is included. We conclude that, given an appropriate legal and policy framework, CCS, energy efficiency and some other mitigation efforts are complementary measures and should form part of a broad mix of measures required for a successful CO2 mitigation strategy.

Greenhouse Gas Mitigation in a Carbon Constrained World: The Role of Carbon Capture and Storage

This comprehensive critical review combines, for the first time, recent advances in nanoscale surface chemistry, surface science, DFT, adsorption calorimetry, and in situ XRD and TEM to provide new...

Chemical and Thermal Sintering of Supported Metals with Emphasis on Cobalt Catalysts During Fischer–Tropsch Synthesis

Cleaner alternative liquid fuels derived from the hydrodesulfurization of waste tire pyrolysis oil

Graphene and CNTs-supported cobalt catalyst, is introduced for Fischer–Tropsch synthesis (FTS). The catalysts were prepared using wet impregnation method with cobalt loading of 15.0 wt%. The catalysts were characterized by TGA, BET, XRD, XPS, H 2 chemisorption, TPR, and TEM techniques. The activity, selectivity and stability of the catalysts in FTS were assessed in a fixed-bed micro-reactor, and the results were compared with each other. Comparing TEM images showed dispersion of cobalt clusters in graphene-supported catalyst is higher and the average clusters size decreased from 7.5 to about 6.0 nm. Graphene as the support shifted the reduction temperature of cobalt oxide species to lower temperatures. Degree of CO conversion increased from 61 to 74%, FT synthesis rate increased by about 22%; the product distribution shifted to the higher molecular weight hydrocarbons, compared to CNTs-supported catalyst. On the graphene-supported cobalt catalyst, 480 h continuous FT synthesis decreased 22% of the initial CO conversion. However, at the same time for CNTs-supported catalyst the CO conversion decreased 34%.

Cobalt supported on Graphene – A promising novel Fischer–Tropsch synthesis catalyst

Enhancement of bimetallic Fe-Mn/CNTs nano catalyst activity and product selectivity using microemulsion technique

Comparing the deactivation behaviour of Co/CNT and Co/γ-Al2O3 nano catalysts in Fischer-Tropsch synthesis

Nowadays, we are experiencing daily growth in the consumption of non-renewable energy resources such as oil and gas. Utilizing these energy sources leads to the production of large amounts of carbon dioxide. The emission of this greenhouse gas into the atmosphere accelerates the global warming and its irreparable consequences. Therefore, it is vital to overcome this phenomenon through elimination of the generated carbon dioxide. This could be achieved by focusing on the existing research experiences in this field and considering proposed methods for eliminating this emission. In addition, the removed carbon dioxide gas could be used in the over-harvesting process of hydrocarbon reservoirs. This study will use VOSviewer software for Bibliometric analysis of carbon dioxide capture technologies and identify gaps that could help researchers gain insight and determine future research trends. We will also review the registered patents for carbon capture technologies and identify the inventors and companies involved in patents. The results suggest that the supply of energy from renewable energy sources and the application of energy policy, decision-making methods, and commercialization methods can significantly contribute to the development and evolution of carbon capture technologies. Also, the high number of patents filed by companies reveals that carbon capture technologies are on the way to commercialization.

Analysis of Carbon Dioxide Capturing Technologies and their technology developments

Direct air capture from demonstration to commercialization stage: A bibliometric analysis

An extensive study of Higher Alcohol Synthesis (HAS) from synthesis gas using cobalt (Co) promoted alkalized MoS2 catalysts supported on Carbon NanoTubes (CNTs) is reported. Up to  5wt.% of Co is added to the 15wt.% Mo-wt.%K/ CNTs by incipient wetness impregnation method. Most of the metal particles were homogeneously distributed inside the tubes and the rest on the outer surface of the CNTs. The catalysts are extensively characterized by different methods and    the activity and selectivity of the catalysts were assessed in a fixed bed micro-reactor. Temperature Programmed Reduction (TPR) tests showed that addition of cobalt decreased the second TPR peak temperature from 801 to 660oC. The diffraction peaks that represent the characteristic K-Mo-O phase (i.e. K2Mo2O7, K2MoO4, K2Mo7O20, KMo4O6, and K0.33MoO3; these species can enhances formation of higher alcohols) were observed in the X- Ray Diffraction (XRD) patterns of unpromoted Mo-K/CNTs and to a greater extent in the XRD patterns of Co-promoted Mo-K/CNTs catalysts.    Co addition to Mo-K/CNTs not only increased the number of surface sites, but also decreased      the average active metal particle sizes from 7.53 to 5.33 nm and increased the percentage dispersion from 51.1 to 68.2%. Among the catalysts with different Co loadings, catalyst with 5 wt.% Co showed the highest %CO conversion of  38.8%. The total alcohol selectivity reached a maximum of 59.7 wt.% on the catalyst promoted with 3 wt.% cobalt. The catalyst with 3 wt.% Co exhibited selectivity of 41.65 wt.% towards higher alcohols.

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Zahra Zolfaghari

Papers

Enhancement of bimetallic Fe-Mn/CNTs nano catalyst activity and product selectivity using microemulsion technique

Comparing the deactivation behaviour of Co/CNT and Co/γ-Al2O3 nano catalysts in Fischer-Tropsch synthesis

Analysis of Carbon Dioxide Capturing Technologies and their technology developments

Direct air capture from demonstration to commercialization stage: A bibliometric analysis

Cobalt Loading Effects on the Physico-Chemical Properties and Performance of Co Promoted Alkalized MoS2/CNTs Catalysts for Higher Alcohols Synthesis