Volume 2 Issue 8, August 2019

Understanding the nature of active sites in carbon electrocatalysis remains a subject of dispute and a great scientific challenge. Convincing new evidence supports the fact that, for oxygen reduction, defects present in carbon materials are more powerful catalytic sites than nitrogenated sites.

S-adenosylmethionine (SAM)-dependent methyltransferase enzymes have significant synthetic potential, but their utility as biocatalysts has been limited by the availability of SAM. An elegant and simple method addressing this long-standing problem has now been developed using a halide methyltransferase (HMT) enzyme for SAM regeneration in vitro.

A strategy using pressure was devised to structurally identify conformational transitions in protein ensembles, allowing the rational prediction of mutations that induce pressure-driven enzyme activation. These results highlight the power of flexibility–function analyses in protein engineering design and applications.

Electrochemical carbon dioxide reduction is an attractive approach for obtaining fuels and chemical feedstocks using renewable energy. In this Review, the authors describe progress so far, identify mechanistic questions and performance metrics, and discuss design principles for improved activity and selectivity.

First-principles-based multiscale models provide mechanistic insight and allow screening of large materials spaces to find promising new catalysts. In this Review, Reuter and co-workers discuss methodological cornerstones of existing approaches and highlight successes and ongoing developments in the field.

Metal oxide alloys are important industrial catalysts, but their structure–activity relationships are poorly understood. Now, a study encompassing a combination of computational tools and machine learning approaches sheds light on the activity and selectivity of zinc–chromium oxides during syngas conversion.

The synthesis of stereodefined alkenes is challenging, and often relies on the steric bias of the substituents. Here the authors report a photoredox/nickel catalysed difunctionalization of alkynes, giving access to either E- or Z-tri-substituted alkenes, depending on the photocatalyst used.

The active sites of metal-free carbon catalysts for the oxygen reduction reaction remain still elusive. Now, Yao, Dai and co-workers combine work-function analyses with macro/micro-electrochemical measurements on highly oriented pyrolytic graphite and conclude that pentagon defects are the main active sites for acidic oxygen reduction.

Regenerating expensive S-adenosylmethionine (SAM) in enzymatic in vitro reactions is challenging—but important for the commercial scope of SAM-dependent enzymes. This work reports a simple two-enzyme cascade for the in vitro regeneration of SAM for the enzymatic methylation of diverse substrates.

The roughness factor of an electrode has been generally used to increase total rates of production, though rarely as a means to improve selectivity. Now, Jaramillo, Hahn and co-workers direct the selectivity of CO reduction to multicarbon oxygenates at low overpotentials by increasing the roughness factor of nanostructured Cu electrodes.

The synthesis of ethanol via CO₂ hydrogenation is a challenging process, often hampered by low selectivity. This work reports a Zr₁₂ cluster-based metal–organic framework as support for cooperative Cu(i) sites that catalyse CO₂ hydrogenation to ethanol with remarkable selectivity upon promotion with caesium. Credit: Cloud background, CC0 1.0 Universal Public Domain Dedication.

Combining enzymatic and heterogeneous catalysts is challenging due to different reaction requirements. Here, a method is presented constructing single protein–polymer nanoconjugates as nanoreactors for the in situ synthesis of enzyme–metal nanohybrids with high activity at ambient conditions.

The fleeting nature of transition state ensembles of protein motions has precluded their experimental observation. This work provides an atomistic insight into the rate-determining structural transition of adenylate kinase during catalysis by high-pressure NMR and molecular dynamics simulations.