With the increased efforts in finding new energy storage systems for mobile and stationary applications, an intensively studied fuel molecule is dihydrogen owing to its energy content, and the possibility to store it in the form of hydridic and protic hydrogen, for example, in liquid organic hydrogen carriers. Here we show that water in the presence of paraformaldehyde or formaldehyde is suitable for molecular hydrogen storage, as these molecules form stable methanediol, which can be easily and selectively dehydrogenated forming hydrogen and carbon dioxide. In this system, both molecules are hydrogen sources, yielding a theoretical weight efficiency of 8.4% assuming one equivalent of water and one equivalent of formaldehyde. Thus it is potentially higher than formic acid (4.4 wt%), as even when technical aqueous formaldehyde (37 wt%) is used, the diluted methanediol solution has an efficiency of 5.0 wt%. The hydrogen can be efficiently generated in the presence of air using a ruthenium catalyst at low temperature.

Formaldehyde has been a key platform reagent in the chemical industry for many decades in a large number of bulk scale industrial processes. Thus, the annual global demand reached 30 megatons per year, and currently it is solely produced under oxidative, energy intensive conditions, using high-temperature approaches for the methanol oxidation. In recent years, new fields of application beyond the use of formaldehyde and its derivatives as i.e. a synthetic reagent or disinfectant have been suggested. For example dialkoxymethane could be envisioned as a direct fuel for combustion engines or aqueous formaldehyde and paraformaldehyde may act as a liquid organic hydrogen carrier molecule (LOHC) for hydrogen generation to be used for hydrogen fuel cells. To turn these new perspectives in feasible approaches, it requires also new less energy-intensive technologies for the synthesis of formaldehyde. This perspective article spreads light on the recent directions towards the low-temperature reductive synthesis of formaldehyde and its derivatives and low-temperature formaldehyde reforming for hydrogen generation. These aspects are important for the future demands on modern societies’ renewable energy management, in the form of a methanol and hydrogen economy, and the required formaldehyde-feedstock for the manufacture of many formaldehyde-based daily products.

A brief summary of selected pioneering and mechanistic contributions in the field of carbon-carbon cross-coupling reactions with palladium nanoparticles (Pd-NPs) in ionic liquids (ILs) is presented. Five exemplary model systems using the Pd-NPs/ILs approach are presented: Heck, Suzuki, Stille, Sonogashira and Ullmann reactions which all have in common the use of ionic liquids as reaction media and the use of palladium nanoparticles as reservoir for the catalytically active palladium species.