Volume 1 Issue 10, October 2018

Catalysis can contribute in many ways to achieving the UN Sustainable Development Goals. Here, the opportunities arising through the interplay of biomass valorization and distributed production approaches are discussed.

Development of an earth-abundant and inexpensive copper-based catalyst is desirable for CO₂ hydrogenation. Now, the combined application of a stable copper hydride and a Lewis pair is shown to effect activation of CO₂ as well as heterolysis of H₂, achieving significant turnover numbers.

The electroreduction of CO represents a promising approach toward artificial hydrocarbon synthesis, but its rate is limited by the sluggish transport of CO in aqueous electrolytes. Recent work shows how the issue can be circumvented by using gas diffusion electrodes.

Due to its ready availability and low cost, copper is an attractive metal for the homogeneous reduction of CO₂ to formate. However, although CO₂ can readily insert into copper hydrides to produce metal-bound formate, subsequent regeneration of the catalytic species with H₂ is more challenging. Here a dual strategy is used, whereby a copper hydride activates CO₂ and a Lewis pair heterolytically splits H₂, leading to dramatically improved performance.

The low solubility of CO in aqueous electrolytes limits the implementation of CO electrolysers, since low current densities are typically achieved despite the fact that they deliver rather high Faradaic efficiencies to multi-carbon products. Now, Jiao and co-workers report a CO flow electrolyser with a well-controlled electrode–electrolyte interface that can achieve multi-carbon Faradaic efficiencies of 91% with a partial current density of 630 mA cm^–2.

Ta₃N₅ is a semiconductor with very promising photocatalytic properties. However, performing overall water splitting with this material has remained elusive. Now, Domen and co-workers report a method for the synthesis of defect-free single-crystal Ta₃N₅ nanorods capable of splitting water into hydrogen and oxygen in the presence of a co-catalyst.

The electrochemical transformation of CO₂ into liquid fuels is a major challenge. Now, Jaramillo, Hahn and co-workers present a Au/Cu catalyst highly active to C₂₊ alcohols at low overpotentials as a result of a tandem mechanism where CO₂ is reduced to CO on Au and further reduced to C₂₊ alcohols on nearby Cu.

Lignin-first approaches, which prioritize lignin upgrade over cellulose, can open the way to full biomass valorization, but are still hampered by the need of harsh reaction conditions and difficulties in catalyst recovery. Now, a photocatalytic strategy based on the use of cadmium sulfide quantum dots is reported that overcomes these limitations.

Single-atom catalysts have proven successful in many catalytic applications. Now, Li, Wu and co-workers show that single-atom catalysts can be prepared directly from bulk metals using an ammonia atmosphere, owing to the formation of volatile metal–ammonia species that are trapped by the nitrogen-rich carbon support.

Post-synthesis refining of Fischer–Tropsch products is a costly but necessary step to adjust the selectivity of the process towards specific fuels. Now, a catalytic system based on a cobalt-loaded Y-type zeolite is reported that can be tuned to selectively produce gasoline, jet fuel or diesel fuel directly from syngas.

Organocatalysed photoredox-mediated atom transfer radical polymerization is a very promising method, although many challenges still lie ahead. Now, Kwon, Gierschner, Kim and co-workers present a computer-aided-design strategy to identify organic photoredox catalysts for this process. The success of the design strategy is demonstrated by polymerizations of methyl methacrylate and styrene.