Volume 2 Issue 5, May 2019

The preeminent Haber–Bosch process has been feeding humankind for more than one hundred years. Are electrochemical pathways for ammonia synthesis able to compete with it in the future? Electrocatalysts, electrolytes and novel cell design may be key.

CO₂ hydrogenation is frequently acclaimed as a strategy for greenhouse gases mitigation, although the carbon footprint of the corresponding electrocatalytic or thermocatalytic process is often neglected. This Perspective analyses the amount of CO₂ generated during methanol production for different catalytic processes and hybrid thereof.

Photocatalytic water splitting with particulate semiconductors represents a promising strategy for the generation of hydrogen as a solar fuel. This review covers recent advances in the development of reaction systems and photocatalysts towards the scale-up of this technology, emphasizing at the same time the challenges to overcome.

A common problem with double C–H activation/cross-coupling is the formation of homocoupled products. Here, the authors show that an ionic group on one reagent during Fe catalysed cross-couplings can lead to a clearly defined order of C–H activation and hence the avoidance of homocoupled side-products.

H₂ is a promising mediator of electrons from electrodes to microbes for chemicals production from CO₂—but its low solubility limits the productivity. This work reports nanoemulsions as H₂ carriers that improve the solubility and transfer kinetics of H₂, increasing the productivity of the system.

For hydrogen to become a direct, portable fuel source, the difficulties with its storage and subsequent release must be addressed. Here ethylene glycol is shown to act as an efficient, reversible liquid-to-liquid hydrogen carrier—particularly attractive due to its theoretical H₂ capacity of 6.5 wt%.

Upgrading CO to high-value multicarbon products is a promising avenue for fuel and chemical feedstock production. Here triangular Cu nanosheets that selectively expose the (111) surface exhibit a high acetate partial current density (131 mA cm^–2) and Faradaic efficiency (48%) in CO electroreduction.

In heterogeneous catalysis, solvents—and their interaction with metal supports—have a complex effect on reactivity. This study shows that, in Pd-catalysed furfural hydrogenation, water influences the rate and selectivity by favouring a proton transfer rather than a purely surface-bound mechanism.

Electromicrobial production can replace fossil carbon with CO₂ and electricity as feedstocks for chemical production. This work analyses and compares different electromicrobial production approaches, providing a data-driven roadmap for the sustainable and efficient implementation of this technology.

The electrochemical reduction of nitrogen to ammonia represents a challenge of major interest that would substantially decrease the burden of the energy-consuming Haber–Bosch process. Now, Yin, Yan, Zhang, Si and colleagues achieve high ammonia yield and Faradaic efficiency over 66% using bismuth nanocatalysts promoted by alkali cations.

Electrochemical water splitting in acidic conditions is limited by the lack of inexpensive and stable anode catalysts. Now, Simonov and colleagues report a non-noble metal-based oxygen evolution catalyst formed in situ that exhibits high stability for acidic water oxidation due to a self-healing mechanism.