Owing to the increasing emissions of carbon dioxide (CO2), human life and the ecological environment have been affected by global warming and climate changes. To mitigate the concentration of CO2 in the atmosphere various strategies have been implemented such as separation, storage, and utilization of CO2. Although it has been explored for many years, hydrogenation reaction, an important representative among chemical conversions of CO2, offers challenging opportunities for sustainable development in energy and the environment. Indeed, the hydrogenation of CO2 not only reduces the increasing CO2 buildup but also produces fuels and chemicals. In this critical review we discuss recent developments in this area, with emphases on catalytic reactivity, reactor innovation, and reaction mechanism. We also provide an overview regarding the challenges and opportunities for future research in the field (319 references).

Recent advances in catalytic hydrogenation of carbon dioxide

Advances in the development of novel cobalt Fischer-Tropsch catalysts for synthesis of long-chain hydrocarbons and clean fuels.

The applications of copper (Cu) and Cu-based nanoparticles, which are based on the earth-abundant and inexpensive copper metal, have generated a great deal of interest in recent years, especially in the field of catalysis. The possible modification of the chemical and physical properties of these nanoparticles using different synthetic strategies and conditions and/or via postsynthetic chemical treatments has been largely responsible for the rapid growth of interest in these nanomaterials and their applications in catalysis. In addition, the design and development of novel support and/or multimetallic systems (e.g., alloys, etc.) has also made significant contributions to the field. In this comprehensive review, we report different synthetic approaches to Cu and Cu-based nanoparticles (metallic copper, copper oxides, and hybrid copper nanostructures) and copper nanoparticles immobilized into or supported on various support materials (SiO2, magnetic support materials, etc.), along with their applications i...

http://pubs.acs.org/doi/pdfplus/10.1021/acs.chemrev.5b00482

Cu and Cu-Based Nanoparticles: Synthesis and Applications in Catalysis.

Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40th anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful theoretical methods are dee...

Fundamentals and Catalytic Applications of CeO2-Based Materials

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

Efficient Production of Hydrogen over Supported Cobalt Catalysts from Ethanol Steam Reforming

This tutorial review deals with the catalytic reformation of ethanol and glycerol to produce hydrogen that can be used as an energy carrier in a fuel cell. Both the worldwide production of ethanol in large amounts to be used as a biofuel and that of glycerol as a by-product in biodiesel manufacture are presented. The catalytic reformation processes of both ethanol and glycerol are contemplated, including thermodynamic and kinetic aspects. Catalysts are analyzed as a function of operation conditions, selectivity and stability.

Use of biofuels to produce hydrogen (reformation processes)

The ethanol steam-reforming reaction was studied over ZnO-supported cobalt catalysts (10 wt.% Co). Catalysts were prepared by impregnation of nitrate and carbonyl cobalt precursors. Characterization was accomplished by transmission electron microscopy (TEM), Raman spectroscopy, UV-Vis diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), and in situ techniques: magnetic measurements, and diffuse reflectance infrared spectroscopy (DRIFT) coupled to mass spectrometry. The use of Co 2 (CO) 8 as precursor produced a catalyst that was highly stable and selective for the production of CO-free hydrogen at reaction temperature as low as 623 K. The only by-product was methane and selectivity of 73% to H 2 and 25% to CO 2 was obtained. Under reaction conditions, the catalyst showed 92% of reduced cobalt, mainly as small particles.

CO-free hydrogen from steam-reforming of bioethanol over ZnO-supported cobalt catalysts

In this study, gallium-promoted copper-based catalysts prepared by impregnation methods on silica and ZnO supports, were examined for the hydrogenation of CO 2 to methanol. The surface characteristics of catalysts depended on the support and were related to their catalytic performance. Silica-supported catalysts tested at reaction temperatures between 523 and 543 K were highly selective and stable. The selectivity to methanol was around 99%, the conversion to CO was very low and negligible amounts of hydrocarbons were formed. The use of hydrophobic silica enhanced the performance of the catalyst in terms of activity, selectivity and stability. The modification of properties of copper particles is related to the presence of very small particles of Ga 2 O 3 on the surface.

Pilar Ramírez de la Piscina

Papers

Efficient Production of Hydrogen over Supported Cobalt Catalysts from Ethanol Steam Reforming

Use of biofuels to produce hydrogen (reformation processes)

CO-free hydrogen from steam-reforming of bioethanol over ZnO-supported cobalt catalysts

Highly effective conversion of CO2 to methanol over supported and promoted copper-based catalysts: influence of support and promoter

Effect of sodium addition on the performance of Co-ZnO-based catalysts for hydrogen production from bioethanol