Volume 5 Issue 3, March 2022

Studying the kinetics of high-energy and high-power batteries is a formidable challenge. Now, it has been shown that redox-mediated (RM) catalysis in Li–O₂ and Li–S batteries can be controlled by tuning parameters such as Li-ion concentration or electrolyte solvent, revealing threshold potentials in which rate constants increase several-fold.

Most applications of machine learning in catalysis use black-box models to predict physical properties, but extracting meaningful physical insights from them is challenging. This Perspective discusses machine learning approaches for heterogeneous catalysis and classifies them in terms of their interpretability.

The electrochemical production of ethylene oxide from CO₂ is an attractive yet challenging process. Now, a BaO_x/IrO₂ catalyst for ethylene oxidation is reported and applied in an O₂-redox-mediated paired system for complete CO₂ to ethylene oxide production.

Redox mediators catalyse the otherwise slow and energy-inefficient cycling of Li–S and Li–O₂ batteries. An investigation of the kinetics of mediated Li₂S and Li₂O₂ oxidations when the redox potentials of various mediators are tuned reveals threshold potentials for high reaction rates, which can be optimized in multiple ways.

Poor management of gas flow limits efficiency in tandem (two-catalyst) electrocatalytic CO₂ reduction. Here, the authors develop a segmented gas-diffusion electrode architecture that prolongs the residence time of CO (produced by the first catalyst) at the second catalyst, resulting in high production of further reduced yields.

The scarcity and high price of noble metal catalysts pose critical challenges for the chemical industry, and finding strategies that ensure complete atom efficiency has become a pivotal endeavour. This work introduces the fabrication of amorphous single-layer PtSe_x catalysts for the hydrogen evolution reaction with high atom-utilization efficiency.

Ammonia is industrially synthesized through an established process based on iron or ruthenium transition metal catalysts, although the quest for alternative and more sustainable processes is still ongoing. Here, the authors show that potassium hydride confined between graphene layers can reduce dinitrogen and catalyse ammonia synthesis under mild conditions.

PtRu nanoparticles are the state-of-the-art catalysts for methanol electrooxidation—the anodic reaction in direct methanol fuel cells. Now, a method of dispersing single Pt atoms over Ru nanoparticles is presented and monitored in situ, thereby boosting the catalytic performance in the methanol oxidation reaction.