Scheduling hydrogen release from water: Photosynthesis splits water to provide protons and electrons for plant growth; oxygen is a by-product. When chemists split water, they're also more interested in making fuel, and the simplest product is hydrogen (a combination of protons and electrons). One challenge is keeping the reactive hydrogen and oxygen product streams separate. Rausch et al. present a scheme that captures the protons and electrons in a molecular cluster of silico-tungstic acid. Later, they expose the cluster to platinum, coaxing the acid into releasing hydrogen. Eliminating the mixing risk increases the potential for household use. Science , this issue p. 1326

The electrolysis of water is considered a promising route to the production of hydrogen from renewable energy sources. Electrolysers based on proton exchange membranes (PEMs) have a number of advantages including high current density, high product gas purity and the ability to operate at high pressure. Despite these advantages the high cost of such devices is an impediment to their widespread deployment. A principal factor in this cost are the materials and machining of flow plates for distribution of the liquid reagents and gaseous products in the electrochemical cell. We demonstrate the production and operation of a PEM electrolyser constructed from silver coated 3D printed components fabricated from polypropylene. This approach allows construction of light weight, low cost electrolysers and the rapid prototyping of flow field design. Furthermore we provide data on the operation of this electrolyser wherein we show that performance is excellent for a first generation device in terms of overall efficiency, internal resistances and current–voltage response. This development opens the door to the fabrication of light weight and cheap electrolysers as well as related electrochemical devices such as flow batteries and fuel cells.

Despite huge potential, automation of synthetic chemistry has only made incremental progress over the past few decades. We present an automatically executable chemical reaction database of 100 molecules representative of the range of reactions found in contemporary organic synthesis. These reactions include transition metal–catalyzed coupling reactions, heterocycle formations, functional group interconversions, and multicomponent reactions. The chemical reaction codes or χDLs for the reactions have been stored in a database for version control, validation, collaboration, and data mining. Of these syntheses, more than 50 entries from the database have been downloaded and robotically run in seven modular chemputers with yields and purities comparable to those achieved by an expert chemist. We also demonstrate the automatic purification of a range of compounds using a chromatography module seamlessly coupled to the platform and programmed with the same language.

A hybrid electrolyser utilising anthraquinone disulfonic acid allows H₂ and O₂ production to be decoupled at current densities of up to 3.71 A cm⁻², and provides an inherently safer and more flexible approach to water splitting.