Alternative energy technologies are greatly hindered by significant limitations in materials science. From low activity to poor stability, and from mineral scarcity to high cost, the current materials are not able to cope with the significant challenges of clean energy technologies. However, recent advances in the preparation of nanomaterials, porous solids, and nanostructured solids are providing hope in the race for a better, cleaner energy production. The present contribution critically reviews the development and role of mesoporosity in a wide range of technologies, as this provides for critical improvements in accessibility, the dispersion of the active phase and a higher surface area. Relevant examples of the development of mesoporosity by a wide range of techniques are provided, including the preparation of hierarchical structures with pore systems in different scale ranges. Mesoporosity plays a significant role in catalysis, especially in the most challenging processes where bulky molecules, like those obtained from biomass or highly unreactive species, such as CO2 should be transformed into most valuable products. Furthermore, mesoporous materials also play a significant role as electrodes in fuel and solar cells and in thermoelectric devices, technologies which are benefiting from improved accessibility and a better dispersion of materials with controlled porosity.

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Mesoporous materials for clean energy technologies

Oxidative dehydrogenation of propane in the presence of carbon dioxide (ODPC) is a sustainable approach and an attractive catalytic route for propylene production with less environmental footprint than the conventional oxidative dehydrogenation path with oxygen. Researchers have considered CO2 as a mild oxidant that can overcome the problems of over-oxidation and low propylene selectivity, that are typically associated with the current synthesis routes. This article provides a critical review on the current mechanistic understanding of three different catalyst types used in the ODPC reaction based on experimental studies; (i) zeolites with different frameworks, (ii) porous materials-supported metal oxides, and (iii) transition metal oxides and other metal catalysts. A detailed review of the literature compares the framework, pore structure, nature of active sites, reducibility, and the role of promoters and supports for each type of catalytic materials in the absence and presence of CO2, and is followed by a thorough discussion on the promotional effects of CO2 as a soft oxidant on C H bond scission. Future directions with respect to materials design, synthesis and reaction conditions are also discussed.

Oxidative dehydrogenation of propane to propylene with carbon dioxide

Propane dehydrogenation catalyzed by gallosilicate MFI zeolites with perturbed acidity

A greenhouse gas and mild oxidant, CO2 can effect the oxidative dehydrogenation (CO2-ODH) of light alkanes over heterogeneous catalysts. These catalysts are bifunctional in that they mediate CO2 reduction while oxidizing the alkanes, most notably the C2–C4 components in shale gas. In this way, one obtains CO and alkenes as value-added products. Although desirable, this transformation has proven challenging in terms of catalyst design, with most catalysts for the CO2-ODH being metal oxides that typically undergo rapid deactivation. More recently, bimetallic catalysts have been identified as promising systems to activate alkanes by either selectively cleaving C–H bonds to produce alkenes or breaking all the C–C and C–H bonds to produce the dry reforming products CO and H2. This Review describes general trends in the CO2-ODH of light alkanes. We will also outline how to use a combined approach involving flow reactor experiments, in operando characterization and density functional theory to determine whether a catalyst is intrinsically active for CO2-ODH or dry reforming. CO2 reacts with alkanes over heterogeneous catalysts to give CO, H2O and the corresponding alkene. This Review describes catalytic bimetallics and their oxides, as well as experimental and theoretical studies of their mechanisms.

Carbon dioxide reduction in tandem with light-alkane dehydrogenation

Preparation and characterization of SBA-1–supported chromium oxide catalysts for CO2 assisted dehydrogenation of propane

Chromium oxide supported on ZSM-5 as a novel efficient catalyst for dehydrogenation of propane with CO2

Hydrothermally prepared Cr2O3–ZrO2 as a novel efficient catalyst for dehydrogenation of propane with CO2

Well entrapped platinum-iron nanoparticles on three-dimensional nitrogen-doped ordered mesoporous carbon as highly efficient and durable catalyst for oxygen reduction and zinc-air battery.

Runxia Wu

Papers

Chromium oxide supported on ZSM-5 as a novel efficient catalyst for dehydrogenation of propane with CO2

Hydrothermally prepared Cr2O3–ZrO2 as a novel efficient catalyst for dehydrogenation of propane with CO2

Well entrapped platinum-iron nanoparticles on three-dimensional nitrogen-doped ordered mesoporous carbon as highly efficient and durable catalyst for oxygen reduction and zinc-air battery.

Rare earth oxide modified Cr2O3-ZrO2 catalyst, preparation method and application

Catalyst for normal heptane isomerization reaction and preparation method thereof