Chemical Looping Technologies for Sustainable Energy Conversion

Chemical looping technologies harness redox reactions of solid oxygen carriers to enable efficient fuel conversion with intrinsic carbon dioxide separation. In these processes, an oxygen carrier undergoes cyclic reduction by a fuel stream, releasing lattice oxygen to oxidise the fuel into syngas or power while producing a concentrated CO2 stream. Subsequent oxidation of the carrier by air, steam or CO2 regenerates the active material and completes the cycle. Variants such as chemical looping combustion, gasification and water splitting exploit this principle for heat and power generation, hydrogen production and carbon dioxide utilisation. Materials ranging from iron and nickel oxides to perovskite structures are selected for their redox stability, oxygen transport capacity and resistance to sintering. Advances in reactor design—from circulating fluidised beds to membrane‐integrated packed beds—have enhanced mass and heat transfer, facilitating scale-up. The global significance of these approaches lies in their ability to capture carbon with a low energy penalty, integrate with bioenergy feedstocks and produce green hydrogen and syngas, establishing chemical looping as a cornerstone of sustainable energy conversion.

Research from Nature Portfolio

A seminal study has demonstrated near-100 % carbon monoxide selectivity in methane partial oxidation by embedding iron oxide nanoparticles within a mesoporous silica matrix. By engineering low-coordinated lattice oxygen sites, the system suppresses CO2 formation during cyclic redox operation at moderate temperatures, yielding high-purity syngas. Combined experimental and theoretical analysis shows that the mesostructure promotes Fe–O bond cleavage, directing product selectivity and offering a pathway to nanostructured oxygen carriers designed for optimal redox performance in chemical looping conversions of natural gas.

Chemical Looping Technologies for Sustainable Energy Conversion publication trend

The graph below shows the total number of articles in chemical looping technologies for sustainable energy conversion across all publications each year (not limited to Nature Index journals).

Technical terms

Oxygen carrier: A solid metal oxide that transfers lattice oxygen between fuel and oxidant streams in chemical looping.

Redox cycle: The cyclic sequence of reduction (oxygen release) and oxidation (oxygen uptake) reactions of an oxygen carrier.

Chemical looping combustion: A process in which fuel is oxidised by lattice oxygen to produce heat and pure CO2, with water as a by-product.

Syngas: A synthesis gas mixture primarily composed of carbon monoxide and hydrogen, used as feedstock for fuels and chemicals.

Perovskite: A class of oxide materials with an ABO3 crystal structure, valued for tunable redox properties and high oxygen mobility.

References

1. Decarbonising bioenergy through biomass utilisation in chemical looping combustion and gasification: a review. Environmental Chemistry Letters (2023).
2. Unraveling the atomic interdiffusion mechanism of NiFe2O4 oxygen carriers during chemical looping CO2 conversion. Carbon Energy (2024).
3. Core-shell iron-based oxygen carrier material for highly efficient green hydrogen production by chemical looping. Materials Today (2024).
4. Chemical-looping technologies using circulating fluidized bed systems: Status of development. Fuel Processing Technology (2018).
5. Near 100% CO selectivity in nanoscaled iron-based oxygen carriers for chemical looping methane partial oxidation. Nature Communications (2019).
6. Energy and exergy analysis of chemical looping combustion technology and comparison with pre-combustion and oxy-fuel combustion technologies for CO2 capture. Journal of Environmental Chemical Engineering (2015).