ChemSusChem

Catalysis is a strategic field of science because it involves new ways of meeting energy and sustainability challenges. These challenges are main concerns in the context of a global vision on societal challenges and world economy, rendering green chemistry a “leitmotiv” in any project. The concept of green chemistry, which makes science of catalysis even more creative, has become an integral part of sustainability. Chemists and engineers working in these disciplines are creating scientific and technological breakthroughs that will be crucial to the future success of human society. This is only made possible by innovative discoveries from research groups all over the world. Scientists are working very hard to discover a variety of nanocatalysts to develop green and sustainable protocols, and this Special Issue on “Green Chemistry by Nanocatalysis”, with guest editors Vivek Polshettiwar and Jean-Marie Basset (King Abdullah University of Science and Technology) and Didier Astruc (Univ. Bordeaux) will stimulate more research in this field.

The fifth element: At the start of the fifth volume, ChemSusChem is in good shape and ready to grow further as a leading publication in the fields of sustainable chemistry and energy materials. This Editorial looks at recent developments surrounding ChemSusChem and other journals from the ChemPubSoc Europe portfolio.

Green chemistry by nanocatalysis: Catalysis is a strategic field of science because it involves new ways of meeting energy and sustainability challenges. The concept of green chemistry, which makes the science of catalysis even more creative, has become an integral part of sustainability. This special issue is at the interface of green chemistry and nanocatalysis, and features excellent background articles as well as the latest research results.

An appraisal of copper: This review highlights the general features of nanoparticles as catalyst with particular reference to copper and the recent developments in the copper(0) nanoparticle-catalyzed bond formations and related reactions. The mechanisms of the reactions have been outlined and discussed with respect to the active catalytic species and possible intermediates. The scope, limitations, and green aspects of the reactions are also highlighted.

Fenton menace: The Fenton reaction involves generating hydroxyl radicals from hydrogen peroxide, and is very useful for the degradation of moderate concentrations of organic pollutants in aqueous solutions. We review metal nanoparticles, particularly iron-containing ones, which are widely used to promote the generation of hydroxyl radicals and other reactive oxygen species from hydrogen peroxide to degrade organic pollutants, and are the subject of this Review.

A fusion made in heaven: Collaboration of nanoscience with catalysis leads to the development of a new class of sustainable materials that fills the gap between homogeneous and heterogeneous catalysis. The advantages of nanosize in catalysis and its implications key issues in catalysis, such as activity, selectivity, and separation from the reaction medium, are discussed.

Spotless bioethanol: not required? Green Hydrogen can be produced from crude bioethanol by using a finely tuned catalyst. This Minireview surveys the composition of bioethanol from first and second generation biomass, the reactions involved in the catalytic ethanol steam reforming process and the design of catalysts adapted for hydrogen production from a real bioethanol feed.

Noble amines recycled: Fibrous high-surface-area nano-silica functionalized with aminopropyl groups and loaded with well-dispersed Pd nanoparticles is evaluated for the Suzuki coupling of aromatic halides. It is active for the reaction of a range of aryl bromides and iodides as well as chlorides with aryl boronic acids in good to excellent yields. The catalyst can be recovered and reused for a number of cycles with negligible loss in activity.

Green nanocatalysts: Optically active compounds derived from N-methylephedrine, N-methylprolinol, or cinchona derivatives with bromide or chiral lactate counterions are used as protective agents for rhodium(0) nanoparticles in asymmetric catalysis of the hydrogenation of ethyl pyruvate and m-methylanisole in water as a green solvent.

Nanotubes say goodbye to H₂S: Nitrogen-doped carbon nanotubes (N-CNTs) are synthesized by using a chemical vapor deposition method under a mixture of C₂H₆/NH₃/Ar with Fe/Al₂O₃ as a growth catalyst. N-CNTs can be used as a metal-free catalyst for the selective oxidation of H₂S into elemental sulfur. The desulfurization activity can be further improved by supporting the N-CNT on a macroscopic host structure such as SiC foam.

Stable morsels of metal: Palladium nanoparticles stabilized in tetraalkylphosphonium halide ionic liquids are stable, efficient, and recyclable catalysts for a variety of hydrogenation reactions at ambient pressures with sustained activity (see picture).

Halo III: A new synthetic route to indium(0) nanoparticles via an electrochemical reduction of haloindate(III) ionic liquids to indium(I), and its subsequent disproportionation to indium(0) and indium(III) in the bulk electrolyte, is reported. In this sustainable method, the ionic liquid acts simultaneously as metal source, templating agent, and stabilizing agent, with the electron as the only reducing agent.

Tailored foam bed: Cerium oxide with a foam morphology is used as a support for gold nanoparticles. The foams are synthesized using L-asparagine to produce a cerium coordination polymer foam, which is calcined to give the oxide foam. The activity of the Au/foamCeO₂ for solvent-free benzyl alcohol oxidation is superior to standard Au/CeO₂ catalysts.

Coating glassy caves: A highly efficient and recyclable nanocatalyst, consisting of SiO₂ nanosphere-supported Pd nanoparticle multicores, coated with a hollow and nanoporous ZrO₂ shell, is synthesized. The catalyst shows excellent catalytic activity in the hydrogenation of olefins and nitro groups, even at room temperature and moderate hydrogen pressure, owing to the small and stable Pd nanoparticles and their bare surface. The nanocatalyst also proves to be stable and can be recycled several times.

Down to the core with oxides: A versatile method for preparing functional core–shell catalysts is demonstrated for Pd and Pt cores with CeO₂, TiO₂, and ZrO₂ shells. Unique catalytic properties are observed for the different combinations of core–shell structures due to the enhanced interactions between the metals and shells.

Will it blend? Yes, it does! Furfural can be converted to a variety of biofuel components. Some upgrade pathways promise to deliver blending components with excellent fuel properties at moderate upgrade cost and CO₂ emission. However, the overall manufacturing chain still presents major challenges in the production and recovery of furfural with good efficiency and competitive cost.

Unwritten tales of isosorbide: Isosorbide is a versatile platform chemical that can be derived from cellulosic biomass as a sustainable resource. Numerous derivatives can be obtained by using various chemical, chemocatalytic, and biotechnological processes to enable the replacement of products in numerous applications that are currently based on fossil resources.

Elements with potential: A silicon–air battery using an alkaline solution as electrolyte is comprised of only environmentally friendly and widely available elements, including silicon, potassium, oxygen, and hydrogen. The assembled battery exhibits an average working potential between 0.9 to 1.2 V at variable discharge current densities, and high specific capacities are achieved.

Occupy TiO₂: Co-grafting dyes with amphiphilic molecules containing phosphinic or phosphonic acid end groups can form a more compact monolayer than the adsorption of dye alone. This insulating molecular layer can effectively shield the back electron transfer from the conduction band of TiO₂ to redox electrolytes. Herein coadsorbents are found to not only influence the dye loading, but also the geometry and electronic properties of the system.

Squeezing products through holes: We have successfully developed an organic solvent nanofiltration process for the separation of [Pd(PPh₃)OAc]⁻ from the products found in a Heck coupling postreaction mixture. A quantitative recovery of the products is achieved in a purity that meets the health and safety specifications for pharmaceutical products by using a commercially available membrane.

Immobilized for crimes of pyrolysis: Quaternary ammonium- and amino-functionalized silica catalysts promote the cycloaddition of sulfur dioxide to epoxides to produce cyclic sulfites in high yields (79–96 %) that are comparable to those with the homogeneous catalysts. Separation of the functionalized silica catalyst from the product solution by filtration avoids pyrolysis of the cyclic sulfites during purification by distillation.

Supercritical tuning: The outstanding characteristic of water as a reaction medium is the possibility of tuning its properties by changing the temperature and pressure. In combination with small amounts of sulfuric acid, even the most resistant compounds show significant conversion within seconds. The kinetics of the hydrolysis of valeronitrile are investigated under supercritical conditions, which results in remarkable yields of valeric acid.

Plastics, naturally: Creosol (2-methoxy-4-methylphenol), which can be readily derived from lignin, is selectively condensed with a series of aldehydes under stoichiometric conditions. The resulting compounds are isolated in good yields and purities. This method can be used to produce molecules that may have applications as renewable replacements for bisphenol A.