ChemSusChem

The front cover of this special issue on “Advanced Materials for Sustainable Energy and a Greener Environment” highlights the three featured hot research topics: (1) the use of natural systems to design functional materials (see Fan et al., Xu et al.); (2) the use of solar energy for environmental remediation, electricity production, and as an energy source for chemical transformation (see Palmisano et al., Aprile et al., Wu et al., Cheng et al. and Wu et al.); and (3) new materials for energy storage and conversion (see Lobato et al., Schwenzer et al. and Liu et al.,) and for more efficient and sustainable chemical processes to reduce the consumption energy and raw materials (see Chen et al., Siffert et al., Yuan et al., Prato et al., and Bonifazi et al.).

Nature is a great school for materials science. Materials found in nature have many inspiring structures, such as hierarchical organizations, periodic architectures, or nanostructures, which endow them with amazing functions, such as energy harvesting and conversion, antireflection, or others. Biotemplated materials with structural specialty, complexity, and related unique functions could be applied for areas of energy and environment technologies with enhanced performances. Furthermore, many useful prototypes of nature could be used for the biomimetic design of novel materials or systems for a sustainable world.

Materials for sustainability: The consumption rate of fossil fuels compared to the available resources and the calamity of global warming are two problems currently facing humanity. This issue describes research to address these problems, focusing on the use of natural systems to design functional materials, solar energy for environmental remediation, electricity production, and as energy source, and new materials for energy storage and conversion.

Respect the hierarchy! Natural materials have inspiring structures and amazing functions. We highlight the synthesis and applications of biotemplated materials for six key areas of energy and environmental technologies, namely, photocatalytic H₂ evolution, CO₂ reduction, solar cells, lithium-ion batteries, photocatalytic degradation, and gas/vapor sensing (see picture).

Vanadium redox flow batteries (VRFBs) offer the potential to overcome problems of large-scale energy storage in the megawatt range. The underlying basic science issues associated with membrane use in VRFBs and an overview of membrane-related research approaches are presented.

Friendly multis: Organic–inorganic hybrid mesoporous metal phosphonate materials can be prepared from a series of polyphosphonic acids, and their structure can be tuned to wormhole-like, cellular foam, hexagonal, and cubic morphologies. These materials are environmentally friendly and can be used in adsorption, separation, solar light utilization, and catalysis. In this Minireview, recent progress in the preparation of mesoporous metal phosphonate materials is summarized.

Fluffy supports do better: This Minireview discusses the use of porous multimodal oxide materials and non-porous materials or zeolites as supports for the preparation of noble metal-based catalysts. The oxides offer not only a high activity in the oxidation of VOCs, but also reaction conditions that reduce the formation of by-products and coke deposition. The hierarchical nature of the porous network provides a larger surface area for a good dispersion of the deposited active phase.

Counting on substrate and oxidation: The Minireview illustrates the use of heterogeneous photocatalysis for performing selective oxidation reactions of alcohols dissolved in water. For instance, the hydroxylation of benzene bearing both, an electron donor group (EDG) or an electron withdrawing group (EWG), and the formation of various aldehydes from the corresponding alcohols are presented.

Cell of Duty: The integration of living cells into hybrid materials enables the use of these cells in various new applications, under conditions that would normally be too harsh. Material scientists seek to develop materials-based chemical strategies to allow the cells to survive such environments and be used in, for example, biosensors, bioreactors, and self-powered devices. This Minireview provides an overview of artificial coatings for cell protection.

Oxygenic carbon nanotubes: Covalent and non-covalent strategies are utilized for the functionalization of carbon nanotubes with positively charged groups and subsequently negatively charged, inorganic catalysts, leading nanomaterials for electrocatalytic water splitting. Both multi- and single-walled carbon nanotubes react with under microwave irradiation and solvent-free conditions, whereas the formation of non-covalent nanoconjugates is accomplished by reaction of carbon nanotubes with trimethylammonium acetyl pyrene.

Hole diggers: The hierarchically structured porous solid-acid catalyst described in this report possess a remarkable pore system, encompassing well-defined macrochannels, interconnected mesopores, intracrystalline mesopores, and tunable zeolite micropores. Importantly, the catalyst exhibits very strong acidity and superior catalytic activity for esterification reactions.

Titania/silica composites with different Ti/Si ratios are synthesized via a non-aqueous synthesis route, involving the reaction of metal alkoxides and formic acid in supercritical carbon dioxide The high-surface-area composites photocatalytically degrade phenol in aqueous medium, and can eliminate acetaldehyde from air.

Sink into the black: A new supramolecular depolluting material based on carbon nanotubes (CNTs) able to reversibly and selectively trap transition-metal ions is reported (see picture). This is the first example of an easy and fully sustainable material with a great potential for applications in depolluting liquid waste from metal contamination.

Relaxing between the sheets: Lead-free perovskite ceramics have potential applications for energy storage, and their microstructure strongly affects their suitability. In (1−x)Ba(Zr_0.15Ti_0.85)O₃–x(K_0.5Na_0.5)NbO₃ (BZT–KNN) the response of a sheet structure (X), an additional feature of this particular material compared to the typical grain (G) and grain boundary (GB) properties, plays an important role in its relaxation dielectric properties.

Do the splits: A TiO₂/fluorine-doped tin oxide (FTO) electrode is prepared by a dip-coating method and used as a photoanode to split an aqueous solution of formic acid to produce hydrogen (see picture). The splitting voltage is substantially lower and the energy-conversion efficiency can be 1.79 %.

Titania illuminated: Dimensionally ordered macroporous (DOM) titania, prepared by using a 480 nm colloidal template and calcined at 700 °C, demonstrates the best photocatalytic activity, which can be attributed to the effects of both structural and photonic properties.

Performance pays for stability: Scanning electron microscopy (SEM) and elemental mapping are used to record (a) an SEM image of the surface, and the distributions of (b) sulphur and (c) titanium in a TiOSO₄–polymer composite membrane. Fuel cells employing such a membrane reveal an improved stability under harsh cycling conditions.

Big beads better: The effect of the diameter of mesoporous TiO₂ beads in dye-sensitized solar cells is studied. Cells with larger beads achieve the highest conversion efficiency, mainly because of their higher electron diffusion coefficient.