The electrochemical hydrogenation of organic substrates using water as the hydrogen source is a desirable strategy but encompasses a series of challenges, such as low solubility, side reactions or product separation. Here, Alexis Bordet, Nicolas Kaeffer and colleagues put forward a Pickering emulsion system in which the organic substrates and aqueous electrolytes are in different phases and the reaction occurs at the interface, achieving high Faradaic efficiency and avoiding solubility or separation issues.

See Han et al.

In their work, Wenbin Lin and colleagues introduce a family of tunable artificial enzymes equipping metal–organic framework monolayers with an amino acid-coordinated metal centre and photoactive cofactors. Different analogues of such photoactive catalysts can thus be integrated into an efficient artificial photosynthesis system.

See Lan et al.

Unveiling the critical role of the interfacial electric double layer in electrocatalytic kinetics is of high interest, yet it remains challenging. Herein, by combining ab initio molecular dynamics simulations, in situ surface-enhanced infrared absorption spectroscopy and computational spectroscopy, Shengli Chen and colleagues demonstrate that significant differences in connectivity within the hydrogen-bond networks in the electric double layer are the cause of the pH effect on the kinetics of hydrogen electrocatalysis.

See Li et al.

Ni–Fe carbon monoxide dehydrogenases (CODHs) can oxidize CO at a high rate, but their O2 sensitivity is a major drawback for potential industrial application. Here, Hyung Ho Lee, Yong Hwan Kim and colleagues engineer the selectivity of a gas channel in a CODH for efficient removal of CO from industrial flue gas in the presence of O2.

See Kim et al.

Chiral copper sulfide nanoparticles functionalized with D-penicillamine can cleave the capsid of tobacco mosaic virus in a site-selective fashion under sunlight irradiation. This composite catalyst functions like a protease and can inhibit viral infections in protoplasts and plants with negligible adverse effects.

See Gao et al.

Gaining complete understanding of complex reaction networks is pivotal for process optimization, yet it is a very challenging endeavour. Here, Javier Pérez-Ramírez, Patrick Hemberger, Guido Zichittella and colleagues employ operando photoelectron photoion coincidence spectroscopy to monitor the mechanistic intricacies of the methanol and methyl chloride conversions to hydrocarbons on zeolite catalysts.

See Cesarini et al.

Exploring structure sensitivity for sub-nanometre metal catalysts poses remarkable challenges. Here, Yang-Gang Wang, Hongyang Liu, Wu Zhou, Ding Ma and colleagues tackle this challenge for supported palladium clusters as catalyst for the dehydrogenation of dodecahydro-N-ethylcarbazole, a representative liquid organic hydrogen carrier.

See Dong et al.

Integrating electrochemical and biocatalytic components is difficult owing to incompatible rates and conditions. Now, Jie Zeng, Tao Yu, Chuan Xia and colleagues describe a spatially decoupled system combining CO2 electrolysis with yeast fermentation, which efficiently produces glucose or fatty acids from CO2 and H2O.

See Zheng et al.

It had been suggested for a long time that enzymes use charge repulsion to promote catalysis. The enzyme orotidine-5’-monophosphate decarboxylase served as a reference system for this proposal. Now, Diederichsen, Mata, Tittmann and colleagues present the structural analysis of this enzyme in complex with the genuine substrate, which unexpectedly reveals that the charged groups of substrate and enzyme do not repel each other but share a proton in a productive interaction.

See Rindfleisch et al.

Catalytically active single-layer two-dimensional materials maximize the amount of available active sites. Now, Zheng Liu, Zhuhua Zhang, Qi Jie Wang and colleagues put forward a method to prepare amorphous single-layer noble-metal chalcogenide catalysts for the hydrogen evolution reaction.

See He et al.

Biocatalytic conversion of aromatic compounds is an exciting topic of importance for the funnelling of lignin-derived aromatic compounds to target products. In their Review, Gregg Beckham, Lindsay Eltis and colleagues discuss the critical reactions of aromatic O-demethylation, hydroxylation and decarboxylation.

See Erickson et al.

Photoelectrocatalytic H2O2 production is coupled with heterogeneous propylene epoxidation in an integrated proof-of-concept device. This approach allows for direct production of propylene oxide using O2 and light without external bias or sacrificial reagents.

See Ko et al.