Volume 5 Issue 10, October 2022

Understanding the molecular details of photoelectrochemical water oxidation is challenging. Now, theoretical and experimental evidence suggests that the accumulation of three adjacent holes is key to enabling the efficient oxidation of water to molecular oxygen on semiconducting oxides.

The composition of an electrolyte has a significant effect on electrocatalytic reaction rates and product selectivities. One mechanism by which spectator alkali cations can dictate reaction kinetics is now better understood.

Nuclear magnetic resonance (NMR) is a phenomenon at the heart of very important tools in analytical chemistry and medical diagnostics. Thirty-five years ago, Clifford Russell Bowers and Daniel Weitekamp developed the PASADENA experiment — an ingenious chemical scheme that boosts sensitivity of proton NMR by three orders of magnitude, widening the applicability of NMR altogether.

Sensitive and isomer-specific analytical tools detect elusive intermediates and reveal reaction mechanisms. Photoelectron photoion coincidence spectroscopy, introduced in 1966, now serves as a reaction microscope, identifies intermediates, and delineates gaseous and surface-confined processes in heterogeneous catalysis.

In the context of probing electrocatalytic systems, quartz crystal microbalance measurements, initially developed in 1959, provided the base for measuring mass changes at the electrode–electrolyte interface under reaction conditions.

Stability is a key property for any catalyst. The description of stability, however, varies in the literature depending on the subfield. In this Review the authors present a systematic literature analysis aimed at identifying generalized deactivation modes and their prevalence in different areas of catalysis to offer a comprehensive descriptive framework of catalyst deactivation.

Substrate preorganization is a ubiquitous concept in the active sites of natural enzymes and is linked to their intrinsic activity. In this study, a designed cleft in a synthetic supramolecular catalyst is shown to preorganize water, resulting in high water oxidation activity and distinct mechanistic changes.

An asymmetric C–C coupling (Wood–Ljungdahl) pathway has long been known in biological carbon fixation, whereas its occurrence in inorganic systems has remained unclear. In this study, the coupling of *CO and *CH_x intermediates to form multicarbon oxygenates has been experimentally observed on Cu electrodes.

The multihole mechanism of the oxygen evolution reaction on semiconductor electrodes has been hard to elucidate due to a lack of atomic-scale structural characterization of the material interface. Using pulse voltammetry and simulations of α-Fe₂O₃ photoanodes, this study predicts the chemical origin of the third-order rate dependence on holes.

The hydrogen evolution and oxidation reactions on Pt electrocatalysts exhibit much more favourable kinetics in acidic than in alkaline electrolytes. Now, by combining theoretical simulations and spectroscopic measurements, it is demonstrated that the different connectivity of hydrogen-bond networks in the electric double layer is responsible for such an effect.

A detailed understanding of the catalytic target DNA cleavage mechanism by CRISPR–Cas9 has been lacking. Now the key modulating role of Mg²⁺ in the conformational activation of Cas9 and the influence of active site residues on the protonation state of catalytic H840 are demonstrated, ultimately unravelling the catalytic mechanism.

Platinum is the most active catalyst for the hydrogen evolution reaction, but the specific mechanism and the influence of the alkali metal cations remain elusive in alkaline media. Now, electrical transport spectroscopy, electrochemical impedance spectroscopy and ab initio molecular dynamics simulations are combined to elucidate the role of alkali metal cations for this reaction in alkaline electrolyte.

Installation of enantioenriched tri- and tetrasubstituted stereogenic centres is important in the synthesis of bioactive compounds. Now, a sterically encumbered chiral N-heterocyclic carbene-Ni(0) catalyst is introduced for the enantioselective carbofunctionalization of substituted alkenes via multicomponent reactions.

Asymmetric synthetic photoelectrochemical transformations are underdeveloped. Now, the combination of a photocatalyst, a chiral copper catalyst and an electrode allows the enantioselective cyanation of benzylic C–H bonds without a chemical oxidant.

Immunogenicity concerns preclude the use of bacterial kynureninases for cancer immunotherapy, while the human variant lacks the desired therapeutic effect. A human kynureninase enzyme has now been evolved to reach the activity and substrate specificity of its bacterial counterpart.