Polymeric graphitic carbon nitride materials (for simplicity: g-C(3)N(4)) have attracted much attention in recent years because of their similarity to graphene. They are composed of C, N, and some minor H content only. In contrast to graphenes, g-C(3)N(4) is a medium-bandgap semiconductor and in that role an effective photocatalyst and chemical catalyst for a broad variety of reactions. In this Review, we describe the "polymer chemistry" of this structure, how band positions and bandgap can be varied by doping and copolymerization, and how the organic solid can be textured to make it an effective heterogenous catalyst. g-C(3)N(4) and its modifications have a high thermal and chemical stability and can catalyze a number of "dream reactions", such as photochemical splitting of water, mild and selective oxidation reactions, and--as a coactive catalytic support--superactive hydrogenation reactions. As carbon nitride is metal-free as such, it also tolerates functional groups and is therefore suited for multipurpose applications in biomass conversion and sustainable chemistry.

Polymeric Graphitic Carbon Nitride as a Heterogeneous Organocatalyst: From Photochemistry to Multipurpose Catalysis to Sustainable Chemistry

Catalysis for the valorization of exhaust carbon: from CO2 to chemicals, materials, and fuels. technological use of CO2.

In recent years, Carbon Capture and Storage (Sequestration) (CCS) has been proposed as a potential method to allow the continued use of fossil-fuelled power stations whilst preventing emissions of CO2 from reaching the atmosphere. Gas, coal (and biomass)-fired power stations can respond to changes in demand more readily than many other sources of electricity production, hence the importance of retaining them as an option in the energy mix. Here, we review the leading CO2 capture technologies, available in the short and long term, and their technological maturity, before discussing CO2 transport and storage. Current pilot plants and demonstrations are highlighted, as is the importance of optimising the CCS system as a whole. Other topics briefly discussed include the viability of both the capture of CO2 from the air and CO2 reutilisation as climate change mitigation strategies. Finally, we discuss the economic and legal aspects of CCS.

Carbon capture and storage update

Carbon dioxide exits in the atmosphere and is produced by the combustion of fossil fuels, the fermentation of sugars and the respiration of all living organisms. An active goal in organic synthesis is to take this carbon--trapped in a waste product--and re-use it to build useful chemicals. Recent advances in organometallic chemistry and catalysis provide effective means for the chemical transformation of CO₂ and its incorporation into synthetic organic molecules under mild conditions. Such a use of carbon dioxide as a renewable one-carbon (C1) building block in organic synthesis could contribute to a more sustainable use of resources.

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Using carbon dioxide as a building block in organic synthesis

Conversion of Biomass into Chemicals over Metal Catalysts

Cyclohexanone is an industrially important intermediate in the synthesis of materials such as nylon, but preparing it efficiently through direct hydrogenation of phenol is hindered by over-reduction to cyclohexanol Here we report that a previously unappreciated combination of two common commercial catalysts-nanoparticulate palladium (supported on carbon, alumina, or NaY zeolite) and a Lewis acid such as AlCl3-synergistically promotes this reaction Conversion exceeding 999% was achieved with >999% selectivity within 7 hours at 10-megapascal hydrogen pressure and 50 degrees C The reaction was accelerated at higher temperature or in a compressed CO(2) solvent medium Preliminary kinetic and spectroscopic studies suggest that the Lewis acid sequentially enhances the hydrogenation of phenol to cyclohexanone and then inhibits further hydrogenation of the ketone

Selective phenol hydrogenation to cyclohexanone over a dual supported Pd-Lewis acid catalyst.

https://www.rsc.org/suppdata/CC/C0/C0CC04829A/C0CC04829A.PDF

Highly efficient synthesis of cyclic carbonates from CO2 and epoxides over cellulose/KI

Solvent-free synthesis of substituted ureas from CO2 and amines with a functional ionic liquid as the catalyst

A series of betaine-based salts containing quaternary ammonium ion and carboxylic acid group were synthesized by direct protonation of anhydrous betaine using different Bronsted acids. The catalytic activity of these salts for the synthesis of cyclic carbonates via cycloaddition reaction of CO2 with epoxides was studied. The effects of anions of the salts, reaction temperature, pressure, reaction time, and the amount of catalyst used on the reaction were studied. It was demonstrated that the carboxylic acid group in the catalyst had synergetic effect with halide anion, and high yield of cyclic carbonates and excellent selectivity could be achieved at optimized condition.

Shuguang Liang

Papers

Selective phenol hydrogenation to cyclohexanone over a dual supported Pd-Lewis acid catalyst.

Highly efficient synthesis of cyclic carbonates from CO2 and epoxides over cellulose/KI

Solvent-free synthesis of substituted ureas from CO2 and amines with a functional ionic liquid as the catalyst

Synthesis of cyclic carbonates from carbon dioxide and epoxides over betaine-based catalysts

Hydrogenolysis of glycerol catalyzed by Ru-Cu bimetallic catalysts supported on clay with the aid of ionic liquids