Electrocatalysis for fuels

Efficient redox catalysis offers an important avenue in using renewable energy to process fuels. To this end, efforts in homogeneous, heterogeneous and microbial catalysis may each advance our fundamental understanding and technological capabilities.

Homogenous transition metal electrocatalysts are topical owing to their role in processing electrical energy and mediating the synthesis of chemical fuels. Mechanisms can be uncovered using electrochemical techniques and data analyses, along with complementary spectroscopic techniques. This Review presents case studies highlighting the utility of these methods in the context of electrocatalysis for chemical fuel production.

[NiFe] hydrogenases are enzymes containing nickel and iron centres that catalyse hydrogen evolution with performances that rival those of platinum catalysts. Now, a NiFe model complex has been reported that mimics the structure and the Ni-centred hydrogen evolution activity found at the active site of [NiFe] hydrogenases.

Catalytic nitrogen fixation is a very active research area, given the need to develop mild routes for ammonia production. Here the authors report a PCP-pincer molybdenum complex allowing for highly efficient ammonia generation under ambient conditions.

Combine energy generation and storage to ensure that networks remain robust as more renewable technologies are adopted, urge John P. Lemmon.

Advances in electrocatalysis at interfaces are vital for driving technological innovations related to energy. New materials developments for efficient hydrogen and oxygen production in electrolysers and in fuel cells are described.

Splitting water is an attractive means by which energy — either electrical and/or light — is stored and consumed on demand. Active and efficient catalysts for anodic and cathodic reactions often require precious metals. This Review covers base-metal catalysts that can afford high performance in a more sustainable and available manner.

This Perspective discusses an approach to artificial photosynthesis based on arrays of semiconducting microwires and flexible polymeric membranes, and highlights the scientific and engineering challenges involved in delivering an artificial photosynthetic system that is simultaneously safe, robust, efficient and scalable.

Electroreduction of carbon dioxide into useful fuels helps to reduce fossil-fuel consumption and carbon dioxide emissions, but activating carbon dioxide requires impractically high overpotentials; here a metal atomic layer combined with its native oxide that requires low overpotentials to reduce carbon dioxide is developed, adapted from an existing cobalt-based catalyst.

In water-alkali electrolyzers, sluggish water dissociation kinetics on platinum-free electrocatalysts result in poor hydrogen-production activities. Here the authors report a MoNi₄electrocatalyst which reduces the kinetic energy barrier of water dissociation, leading to improved hydrogen-production performance.

Metal-free doped-graphene materials are emerging as electrocatalysts for energy conversions, but their activity remains low. Here, Jiao et al. explore the origins of catalytic activity for hydrogen evolution, suggesting pathways to metal-free catalysts with activity to rival metal-containing benchmarks.

The performance of solid-oxide fuel cells and electrolyser cells is largely governed by the electrochemical interface. The authors review the evolution of the interface under operation, highlighting approaches to control and improve interfacial architectures and cell performance.

Electrochemical reduction of carbon dioxide is a sustainable way of producing carbon-neutral fuels. Here, the authors take a combined nanoscale and molecular approach to develop a highly active and selective cobalt phthalocyanine/carbon nanotube hybrid electrocatalyst for carbon dioxide reduction to carbon monoxide.

Electrocatalysts based on earth-abundant elements have emerged as promising candidates to replace noble metal materials. Here, the authors develop porous hybrid nanostructures combining amorphous Ni-Co complexes with 1T phase MoS₂for enhanced electrocatalytic activity for overall water splitting.

In order to fully utilize sulfur vacancies in MoS₂ catalysts for industrial applications, a facile and general route for making sulfur vacancies in MoS₂ is needed. Here, the authors introduce a scalable route towards generating sulfur vacancies on the MoS₂basal plane using electrochemical desulfurization.

Controlling proton-coupled electron transfer reactions—an important process for fuel cells—can be challenging. Lipid-modified electrodes are now used to modulate proton transport to a Cu-based catalyst that facilitates oxygen reduction reactions.

While crystal phase modification may endow materials with altered functionality, the fabrication of allomorphic noble metal nanomaterials is challenging. Here, the authors synthesize an unusual hexagonal close-packed platinum-nickel alloy and demonstrate its enhanced hydrogen evolution catalytic activity.

Methane is an abundant energy source that is used for power generation in thermal power plants via combustion, but direct conversion to electricity in fuel cells remains challenging. Now, a microbial fuel cell is demonstrated to efficiently convert methane directly to current by careful selection of a consortium of microorganisms.

Electrodes colonized by microbial electrocatalysts can serve as useful components in the electrosynthesis of valuable chemical products. This Review outlines the mechanisms by which electrons are transferred between microorganisms and electrodes, and describes the challenges involved in designing robust and efficient systems.

Microbial fuel cells generate electricity from a variety of sources, however from methane only negligible electrical power has been reported so far. Here the authors convert methane into electricity using a synthetic consortium consisting of an engineered archaeal strain, microorganisms from methane-acclimated sludge, andGeobacter sulfurreducens.