Research articles

Manganese carbonyl complexes are promising electrocatalysts for CO₂ reduction, but the intricate mechanisms are difficult to probe. Here, vibrational sum-frequency generation spectroscopy is used to detect the transient catalytic intermediates, providing experimental evidence for the mechanism and demonstrating the utility of the analytical approach for molecular electrocatalytic processes in general.

Platinum group metal- and iron-free catalysts are highly desirable for the oxygen reduction reaction in proton-exchange membrane fuel cells. Now, Wu and co-workers show a carbon catalyst with atomically dispersed single Mn sites as an efficient catalyst with enhanced stability in acidic media.

Organoboron compounds are versatile intermediates in organic chemistry, and as such the selective introduction of multiple boron-containing groups is of high interest. Here Shi and co-workers report a copper-catalysed method that can selectively introduce two, three or four boronate groups into common starting materials by simply making minor modifications to the reaction conditions.

Improving the stability of proteins for biotechnological applications is challenging. Now, Gillam and co-workers show that the thermal stability and longevity of enzymes can be remarkably enhanced in a single step from sequences of recent ancestors of primitive vertebrates that existed in mild conditions.

Nature’s oxygen-evolving complex of photosystem II is a multinuclear manganese cluster. Whether mononuclear manganese can also efficiently catalyse water oxidation has been a long-standing question. Now, Li and co-workers show that single atoms of manganese can be anchored on nitrogen-doped graphene to catalyse the oxygen evolution reaction. Credit: Water image Frankie Angel / Alamy Stock Photo.

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.

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.

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.

Although mechanistic understanding can drive new reactivity development, the key bond-forming and -breaking steps in catalytic cycles are often sufficiently fast to elude observation. Here, the authors photochemically produce a key intermediate in Mn-catalysed C–H functionalization, and follow the subsequent steps—spanning processes occurring over seven orders of magnitude in time—using time-resolved infrared spectroscopy.

The precise understanding of the active phase under reaction conditions at the molecular level is crucial for the design of improved catalysts. Now, Strasser, Jones and colleagues correlate the high activity of IrNi@IrO_x core–shell nanoparticles with the amount of lattice vacancies produced by the nickel leaching process that takes place before and during water oxidation, and elucidate the underlying structural-electronic effects.

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.

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.

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.

The design of new catalysts for electrochemical energy storage is of utmost importance. Here, an automated computational screening method is used to identify over 100 intermetallic surfaces as efficient electrocatalysts for CO₂ reduction and H₂ evolution.

Knowledge of the active sites in catalysts—including the sites that form under working conditions—is vital for future design and development. Here, the authors track the atomic-scale changes in a series of well-defined cobalt-based oxide electrocatalysts, showing that the structurally distinct catalysts develop a similar structural motif as they transform into the catalytically active state.

Despite its potential, the visible light-triggered photocatalytic oxidation of toluene remains difficult due to the lack of efficient and scalable catalytic strategies. Now, a photochromic Bi₂WO_6–x/amorphous BiOCl composite is reported with the ability to oxidize toluene into benzaldehyde and benzoic acid with outstanding rates and quantum efficiencies.

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.

Microbial production of haem for applications in healthcare and food supplement industry requires high-performing strains. Here, Lee and co-workers report secretory production of free haem by metabolically engineered Escherichia coli strains to produce up to 239 mg l⁻¹ total haem.

Small-pore zeolites that engender high selectivity for light olefins in the conversion of methanol to olefins deactivate rapidly due to the accumulation of unreactive carbonaceous deposits. Now, experiments show that high-pressure hydrogen added to the methanol feed can substantially enhance catalyst lifetime without compromising selectivity.

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.