Tungsten- and molybdenum carbide catalysts of large particle size improve activity, stability and selectivity of the catalyst in (hydro)deoxygenation reactions.

In this contribution, we review the electrochemical upgrading of saccharides (e.g., glucose) and sugar alcohols (e.g., glycerol) on metal and metal-oxide electrodes by drawing conclusions on common trends and differences between these two important classes of biobased compounds. For this purpose, we critically review the literature on the electrocatalytic oxidation of saccharides and sugar alcohols, seeking trends in the effect of reaction conditions and electrocatalyst design on the selectivity for the oxidation of specific functional groups toward value-added compounds. Importantly, we highlight and discuss the competition between electrochemical and non-electrochemical pathways. This is a crucial and yet often neglected aspect that should be taken into account and optimized for achieving the efficient electrocatalytic conversion of monosaccharides and related sugar alcohols into valuable products, which is a target of growing interest in the context of the electrification of the chemical industry combined with the utilization of renewable feedstock.

Hydrogen has gained renewed and growing interest around the world in the recent decades as a high-quality and renewable energy carrier, owing primarily to advances in fuel cells as well as growing environmental concerns. Steam reforming of fossil-based resources is currently the main route to H₂ production. The downside of this process, however, is generation of massive amounts of greenhouse gases including CO₂ as the byproduct which in turn must be captured to fully exploit the potential of H₂. Membrane separation technology has seen significant growth, breakthroughs, and advancements over the last few decades and could be the key component in achieving inexpensive and highly pure H₂. However, only a few numbers of membrane materials can withstand the harsh conditions of H₂ production through steam reforming. Polybenzimidazole (PBI)-based membranes show excellent chemical, thermal, and mechanical stabilities as well as high intrinsic H₂/CO₂ selectivity. The objective of this review is to overview the recent development of structurally modified, cross-linked, mixed matrix, and hollow fiber membranes based on PBI for the development of industrially applicable H₂-selective membranes.

In this paper we show that carbon nanofiber supported copper and nickel nanoparticles can selectively transform ethylene glycol and glycerol into value added oxygenates (organic acids) under anaerobic aqueous conditions. During aqueous phase oxidation Cu based catalysts showed a nearly quantitative yield (96% selectivity at 82% conversion) of glycolic acid from ethylene glycol. The reaction was carried out under alkaline conditions at relatively mild temperatures (150–180 °C) and produced H₂ as co-product. The high selectivity towards glycolic acid was independent of the temperature. For glycerol oxidation a high selectivity (67% at full conversion) towards lactic acid was observed using Cu with competitive formation of glyceric acid, 1,2-propanediol tartronic acid and formation of H₂ as co-product. The activity of Ni was comparable to that of Cu but it was less selective for the formation of desired oxygenates, glycolic acid (31%) and lactic acid (24%), due to the formation of formic acid.

Electrocatalytic glucose oxidation can produce high value chemicals, but selectivity needs to be improved. Here we elucidate the role of the Pt oxidation state on the activity and selectivity of electrocatalytic oxidation of glucose with a new analytical approach, using high‐pressure liquid chromatography and high‐pressure anion exchange chromatography. It was found that the type of oxidation, i.e. dehydrogenation of primary and secondary alcohol groups or oxygen transfer to aldehyde groups, strongly depends on the Pt oxidation state. Pt⁰ has a 7‐fold higher activity for dehydrogenation reactions than for oxidation reactions, while PtO_x is equally active for both reactions. Thus, Pt⁰ promotes glucose dialdehyde formation, while PtO_x favors gluconate formation. The successive dehydrogenation of gluconate is achieved selectively at the primary alcohol group by Pt⁰, while PtO_x also promotes the dehydrogenation of secondary alcohol groups, resulting in more complex reaction mixtures.