Volume 6 Issue 12, December 2023

The search for novel biocatalysts for plastic degradation has recently become a hot topic. Now, multiple catalytic triads of well-known serine esterases were introduced into non-catalytic protein nanopores to enable the hydrolysis of PET nanoparticles.

Enantioselective synthesis of chiral cyclobutanes via direct cycloaddition of C–C single bonds with C=C double bonds has remained an unmet challenge. Now, a photoelectrocatalytic system enabling asymmetric dehydrogenative [2+2] cycloaddition of alkyl ketones and alkenes has been developed.

Elucidating the origin of light-induced reaction rate enhancement in plasmonic photocatalysis is very challenging. Now, bimetallic supercrystals are reported to boost photocatalytic hydrogen evolution from formic acid with the sole aid of intensified electric fields.

Iron–nitrogen–carbon (FeNC) catalysts are a viable alternative to platinum, but still lack the necessary performance. Now, pyrolysis under forming gas is found as a path to boosting their site density, activity and durability.

With climate change concerns deepening, CO₂ fixation pathways to produce value-added chemicals are currently of interest. Now, synthetic biology and machine learning help developing such a pathway across modules that have been tested in vivo in Escherichia coli for the production of acetyl coenzyme A.

Direct CO₂-to-C₂₊ and tandem CO₂-to-CO and CO-to-C₂₊ electrocatalytic systems have been proposed as strategies for sustainable fuel and chemical synthesis. This Perspective considers the role of acidic CO₂ gas on the cathodic microenvironment and local pH and draws connections between this and product selectivity in the electrochemical CO₂ reduction reaction and the electrochemical CO reduction reaction, focusing on the competition between two major pathways: ethylene/ethanol and acetate.

Electrocatalytic NO_x reduction (NO_xR) to ammonia has recently become an increasingly popular alternative to the more challenging N₂ reduction. This Perspective critically assesses the possible ways NO_xR could contribute to the ammonia economy and clarifies the necessary steps for a rigorous experimental protocol.

Thanks to a unique set of properties, liquid metal catalysts provide advantages compared to traditional solid systems, yet their potential in heterogeneous catalysis has not been fully explored. This Perspective identifies some of the key advances in the field of liquid metal catalysis, discussing areas where progress is expected through further fundamental understanding as well as reactor engineering.

Inexpensive Fe–N–C single-atom catalysts are a promising solution to replace costly Pt-based cathode catalysts in fuel cells, but they typically suffer from low durability. Now, the degradation mechanisms of Fe–N–C catalysts are identified under operando conditions as a function of time, and potential solutions are proposed.

CO₂ electroreduction is a promising process for the production of high-value chemicals, but achieving high selectivities for specific products is challenging. Now, a Faradaic efficiency of 87% for acetate is achieved on a Cu/CuO_x catalyst under 58 atm CO₂(g), where high and low concentrations of dissolved CO₂(aq) and proton donor HCO₃⁻ are shown to promote acetate formation, respectively.

Anion-exchange membrane fuel cells are promising devices to produce electricity from green hydrogen, but the development of suitable cathode catalysts is required for their successful deployment. Now, Co(CN)₃ microcrystals with cyanide linkages and well-defined coordination structures are shown to exhibit high oxygen reduction reaction performance in alkaline conditions.

The development of innovative strategies for the capture and biodegradation of nanoplastics is sought after. Now, artificial hydrolytic active sites are incorporated into non-catalytic membrane nanopores generating pore-based biocatalytic nanoreactors that depolymerize polyethylene terephthalate plastic nanoparticles.

Asymmetric catalytic photoelectrochemical reactions for the construction of complex compounds are underdeveloped. Now, merging photoelectrochemistry with asymmetric catalysis has enabled the dehydrogenative [2 + 2] photocycloaddition between alkyl ketones and alkenes affording enantioenriched cyclobutanes.

Different locations have been proposed for the catalytic centre of particulate methane monooxygenase for methane oxidation to methanol. Now, cryoelectron microscopy structures and electron nuclear double resonance spectroscopic measurements of the enzyme with a product analogue identify Cu_D as the active site and provide insights into substrate binding.

Plasmonic composites have potential for photocatalytic conversions using solar light; however, complex interactions between light and the components are poorly understood. Here, a highly ordered two-dimensional plasmonic bimetallic AuPt supercrystal demonstrates a high rate of H₂ generation from formic acid while providing insight into the interaction between plasmonic antenna and catalyst.

Fe–N–C catalysts are a promising alternative to precious metals in fuel cell cathodes, but they suffer from durability issues. Now, a preparation method is reported that allows increasing the active site density while also improving durability.

Few synthetic CO₂-fixation pathways have been tested in vivo. Now, the new-to-nature THETA cycle is designed, realized in vitro and modular implemented in vivo. This cycle involves 17 enzymes, including the two most active carboxylases known so far, to produce the central building block acetyl-CoA using CO₂.

Plasmonic photocatalysis presents opportunities for efficient utilization of sunlight for chemical transformations, yet its mechanisms, including the relative contribution of thermal and non-thermal effects, remain controversial. Here the authors develop methodology to monitor both effects and propose a metric, overall light effectiveness, to evaluate and maximize the total light-driven enhancement.