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Green Chemistry

Chemistry has always had a central role in the provision of food and energy, materials and medicines. Recent years have increasingly seen chemistry research move towards environmentally friendly, sustainable products and processes, and the focus of the 2018 Gordon Research Conference on Green chemistry is the development of sustainable means for the provision of food, energy and water. 

This Collection features selected Green Chemistry content published in the Nature family of journals. These research, review, comment and protocol articles have been sorted into four categories:

Water splitting includes articles related to artificial photosynthesis, or electrochemical reactions of water. More content on this topic can be found in the related collections Electrocatalysis for fuels and Chemistry at the nexus of water and energy.

Carbon dioxide collects articles that involve the trapping and downstream reactions of carbon dioxide.

Biomass utilisation covers the conversion of biomass to fuels and other value-added products.

Greener synthesis articles describe developments aimed at making chemical reactions more environmentally friendly, both in terms of the processes and the safety of the products. A full list of related articles published across nature.com can be found on the Green Chemistry subject page.

The section on Cleaner water contains articles relating to harvesting, desalination and disinfection of water.

Water splitting

A major challenge facing solar-to-fuel technologies is the integration of light-absorbing and catalytic components into efficient water-splitting devices. Here, the authors construct a photochemical diode array to harvest visible light and split pure water at high solar-to-hydrogen efficiencies.

Article | Open Access | | Nature Communications

Electrochemical water oxidation in acidic media is a promising water-splitting technique, but typically requires noble metal catalysts. Now, two polyoxometalate salts based on earth-abundant metals have shown excellent catalytic performance for the oxygen evolution reaction. The barium salt of a cobalt-phosphotungstate polyanion outperformed the state-of-the-art IrO2 catalyst at pHs lower than 1.

Article | | Nature Chemistry

The generation of hydrogen fuel from water and visible light requires photoelectrodes that are inexpensive, stable and highly active. Now, Luo, Grätzel and co-workers report Cu2O photocathodes that reach these goals. Incorporation into an unassisted solar water splitting device gives ~3% solar-to-hydrogen conversion efficiency.

Article | | Nature Catalysis

Electrocatalytic water splitting to produce H2 is impeded by slow reaction kinetics over noble-metal-free catalysts at the electrodes. Here, the authors use high-frequency alternating magnetic fields to locally heat FeC–Ni core–shell catalysts, enhancing the kinetics of the oxygen and hydrogen evolution reactions.

Article | | Nature Energy

Morphological changes in catalyst structure are known to occur during electrocatalysis, and understanding such changes is important to gain insight into the catalytic process. Now, in the case of iridium oxide, these surface changes are probed in atomic-scale detail during the oxygen evolution reaction, and correlated with activity and stability.

Article | | Nature Catalysis

Carbon dioxide

The electroreduction of carbon dioxide to liquid products provides an appealing method to convert atmospheric carbon into valuable fuels. Here, the authors perform a topotactic transformation of bismuth oxyiodide to bismuth nanosheets that act as highly selective CO2-to-formate electrocatalysts.

Article | Open Access | | Nature Communications

CO is a vital building block in organic synthesis but, due to its toxicity, storage and transport can be problematic. This review focuses on the methods — both chemical and electrochemical — for the in situ generation of CO from CO2, and its subsequent incorporation into chemicals through catalytic means.

Review Article | | Nature Catalysis

The conversion of carbon dioxide into multi-carbon alcohols would enable the synthesis of sustainable liquid fuels with high energy densities. Now, vacancy-engineered core–shell copper-based catalysts are able to shift the selectivity of electrochemical CO2 reduction into alcohols instead of alkenes, as obtained with bare-copper catalysts.

Article | | Nature Catalysis

The generation of useful chemicals from CO2 and renewable energy is an attractive—but challenging—endeavour. This work reports on the long-term operation of commercial electrodes for efficient CO2 reduction, with subsequent fermentation of the syngas product completing the technical photosynthesis of alcohols.

Article | | Nature Catalysis

Biomass utilisation

Photoreforming can produce H2 through the simultaneous reduction of water and the oxidation of organic molecules, such as those derived from biomass, but cheaper and more active photocatalysts are required. This study shows that CdS/CdOx produces H2 from unprocessed lignocellulose suspensions at high rates under solar illumination.

Article | | Nature Energy

A bioeconomy — that is, an economy in which fuels, chemicals and other products are sourced from biomass — can contribute to a sustainable and prosperous future. Realizing a bioeconomy will necessitate new methods for processing the complex structure of biomass to produce commodity chemicals. Many exciting opportunities are availing themselves to chemists brave enough to tackle this challenging problem.

Comment | | Nature Reviews Chemistry

With petrol prices on the rise, biofuels are big news these days. For applications in the transportation sector, perhaps the best known liquid biofuel is biomass-derived ethanol. But ethanol has its limitations: it is highly volatile, absorbs water and has a low energy density. A team from the University of Wisconsin-Madison has developed a two-step catalytic process that can convert fructose into a potentially better liquid biofuel, 2,5-dimethylfuran (DMF). This has 40%-higher energy density and a higher boiling point than ethanol, and is not water soluble. Fructose can be made directly from biomass or from glucose and although there's some work needed before DMF production can be made commercially viable, this new catalytic process looks promising.

Letter | | Nature

Access to renewable hydrogen represents an important target for the success of the hydrogen economy. Now, a one-pot method is presented for the conversion of cellulosic biomass into hydrogen via formic acid as the intermediate, followed by its application to a fuel cell.

Article | | Nature Catalysis

The choice of solvent system has important implications regarding the catalytic upgrading of carbohydrate-containing biomass. Here, Dumesic and co-workers study solvation effects in organic solvent/water mixtures and employ the obtained information to control the rate and selectivity of the acid-catalysed dehydration of fructose.

Article | | Nature Catalysis

As a consequence of high chemical resistance and low solubility in conventional solvents, deconstructing biomass into fuels and other useful chemical building blocks remains a challenge. Now, through enzyme modification and ionic liquid solvents, it is possible to homogeneously biocatalytically convert cellulose to sugars at a rate 30 times greater than is achievable in water.

Article | | Nature Chemistry

Greener synthesis

As a consequence of high chemical resistance and low solubility in conventional solvents, deconstructing biomass into fuels and other useful chemical building blocks remains a challenge. Now, through enzyme modification and ionic liquid solvents, it is possible to homogeneously biocatalytically convert cellulose to sugars at a rate 30 times greater than is achievable in water.

Article | | Nature Chemistry

Many methods exist for the recycling of plastic solid waste. Chemical recycling, which can take many forms from high-temperature pyrolysis to mild, solution-based catalytic depolymerization, can afford enormous economic and environmental benefits. This Review covers the state of the art in chemical recycling and the design of high-performance polymers amenable to such processes.

Review Article | | Nature Reviews Chemistry

This protocol describes a simple, metal- and additive-free method to convert haloarenes directly to boronic acids and esters. These can be used to synthesize organic compounds for applications including drug discovery and materials science.

Protocol | | Nature Protocols

Oxidation chemistry is critical to introducing molecular complexity during chemical synthesis. Development of sustainable oxidation chemistry demands strategies to harness O2 as a terminal oxidant. Access to hypervalent iodine compounds — a class of broadly useful chemical oxidants — from O2 increases the scope of aerobic oxidation chemistry that can be achieved.

Article | | Nature Chemistry

Despite the biological importance of sulfones, available synthetic methods usually involve toxic metals and reagents or harsh conditions. Here, the authors report an environmentally benign procedure for the metal-free carbon-sulfur bond formation of allylic sulfones in neutral aqueous medium at room temperature.

Article | Open Access | | Nature Communications