CO2 conversion covers a wide range of possible application areas from fuels to bulk and commodity chemicals and even to specialty products with biological activity such as pharmaceuticals. In the present review, we discuss selected examples in these areas in a combined analysis of the state-of-the-art of synthetic methodologies and processes with their life cycle assessment. Thereby, we attempted to assess the potential to reduce the environmental footprint in these application fields relative to the current petrochemical value chain. This analysis and discussion differs significantly from a viewpoint on CO2 utilization as a measure for global CO2 mitigation. Whereas the latter focuses on reducing the end-of-pipe problem “CO2 emissions” from todays’ industries, the approach taken here tries to identify opportunities by exploiting a novel feedstock that avoids the utilization of fossil resource in transition toward more sustainable future production. Thus, the motivation to develop CO2-based chemistry does...

Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle Assessment

CO2 methanation is a well-known reaction that is of interest as a capture and storage (CCS) process and as a renewable energy storage system based on a power-to-gas conversion process by substitute or synthetic natural gas (SNG) production. Integrating water electrolysis and CO2 methanation is a highly effective way to store energy produced by renewables sources. The conversion of electricity into methane takes place via two steps: hydrogen is produced by electrolysis and converted to methane by CO2 methanation. The effectiveness and efficiency of power-to-gas plants strongly depend on the CO2 methanation process. For this reason, research on CO2 methanation has intensified over the last 10 years. The rise of active, selective, and stable catalysts is the core of the CO2 methanation process. Novel, heterogeneous catalysts have been tested and tuned such that the CO2 methanation process increases their productivity. The present work aims to give a critical overview of CO2 methanation catalyst production and research carried out in the last 50 years. The fundamentals of reaction mechanism, catalyst deactivation, and catalyst promoters, as well as a discussion of current and future developments in CO2 methanation, are also included.

Supported Catalysts for CO2 Methanation: A Review

Methanation of coal-or biomass-derived carbon oxides for production of synthetic natural gas (SNG) is gaining considerable interest due to energy issues and the opportunity of reducing greenhouse gases by carbon dioxide conversion. The key component of the methanation process is the catalyst design. Ideally, the catalyst should show high activity at low temperatures (200-300 degrees C) and high stability at high temperatures (600-700 degrees C). In the past decades, various methanation catalysts have been investigated, among which transition metals including Ni, Fe, Co, Ru, Mo, etc. dispersed on metal oxide supports such as Al2O3, SiO2, TiO2, ZrO2, CeO2 etc. have received great attention due to their relatively high catalytic activity and selectivity. Furthermore, over the past few years, great efforts have been made both in methanation catalysts development and reaction mechanism investigation. Here we provide a comprehensive review to these most advancements, covering the reaction thermodynamics, mechanism and kinetics, the effects of catalyst active components, supports, promoters and preparation methods, hoping to outline the pathways for the future methanation catalysts design and development for SNG production.

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Recent advances in methanation catalysts for the production of synthetic natural gas

Catalytic deactivation due to agglomeration and metal particle growth has motivated the researchers around the globe to encapsulate the active metal particles into protective shells of mesoporous support. This strategy of encapsulation has emerged as a powerful tool to restrict particle growth thereby improving the catalytic performance, owing to higher accessibility for active sites. In the past decade, various hierarchical mesoporous scaffolds with multiple porosities integrated into single structure have been synthesized by considering prototypical SBA-15 support. In this regard, we review the recent developments for designing the SBA-15 support and strategies for encapsulating the metals on to porous inorganic protective shells. An overview of the conventional synthesis techniques, progress and strategies for improving the metal incorporation into these pore channels and its impact on dispersion as well as catalytic properties of SBA-15 supported catalyst are extensively reviewed. Furthermore, a perspective on the challenges and opportunities for resolving the issue of sintering under harsh reforming conditions is substantiated.

Advanced synthesis strategies of mesoporous SBA-15 supported catalysts for catalytic reforming applications: a state-of-the-art review

Methanation of carbon oxides (CO and CO2) was studied over Ni-based catalysts supported on CeO2, Al2O3, and Y2O3 oxides. Catalysts were synthesized by solution combustion synthesis and characterized by N2-physisorption, XRD, H2-TPR, TEM, CO-chemisorption, UV–vis DRS, XPS, and CO2-TPD. The effect of reaction temperature (250−500 °C) was investigated under atmospheric pressure, space velocity (GHSV) of 10,000 h−1, and stoichiometric reactants ratio of (H2-CO2)/(CO + CO2) = 3. It can be concluded that the nature of Ni-support interactions played a crucial role in enhancing CO and CO2 hydrogenation at low reaction temperature. Ni/CeO2 catalyst deactivated rapidly due to coke deposition, while the formation of NiAl2O4 spinel explained the lower activity of the Al2O3-supported system. Activity data for Ni/Y2O3 catalysts were closely related to the degree of Ni dispersion as well as to the medium-strength basicity. Good anti-coking and anti-sintering ability were observed after 200 h of lifetime test.

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CO and CO2 methanation over Ni catalysts supported on CeO2, Al2O3 and Y2O3 oxides

Effect of impregnation solvent on Ni dispersion and catalytic properties of Ni/SBA-15 for CO methanation reaction

Synthesis, characterization and properties of anti-sintering nickel incorporated MCM-41 methanation catalysts

Effect of MoO3 on the heat resistant performances of nickel based MCM-41 methanation catalysts

Several nickel-incorporated SiO2 catalysts with MoO3 molar content in range of 0.5% to 5.0% were prepared by the hydrothermal synthesis method and investigated for synthetic natural gas (SNG) produ...

Xin Meng

Papers

Effect of impregnation solvent on Ni dispersion and catalytic properties of Ni/SBA-15 for CO methanation reaction

Synthesis, characterization and properties of anti-sintering nickel incorporated MCM-41 methanation catalysts

Effect of MoO3 on the heat resistant performances of nickel based MCM-41 methanation catalysts

Effect of MoO3 on Structures and Properties of Ni-SiO2 Methanation Catalysts Prepared by the Hydrothermal Synthesis Method

Highly dispersed nickel within mesochannels of SBA-15 for CO methanation with enhanced activity and excellent thermostability