Thermochemical production of ammonia a two-step metal nitride cycle - materials screening and the strontium-based system.

Ammonia synthesis the catalytic Haber-Bosch process is characterized by its high pressures and low single-pass conversions, as well as by the energy-intensive production of the precursors H and N and their concomitant greenhouse gas emissions. Alternatively, thermochemical cycles based on metal nitrides stand as a promising pathway to green ammonia production because they can be conducted at moderate pressures without added catalysts and be further driven by concentrated solar energy as the source of high-temperature process heat. The ideal two-step cycle consists of the nitridation of a metal to form a metal nitride, followed by the hydrogenation of the metal nitride to synthetize NH and reform the metal.

Technical, economic and environmental analysis of solar thermochemical production of drop-in fuels.

This study analyzes the technical performance, costs and life-cycle greenhouse gas (GHG) emissions of the production of various fuels using air-captured water and CO, and concentrated solar energy as the source of high-temperature process heat. The solar thermochemical fuel production pathway utilizes a ceria-based redox cycle for splitting water and CO to syngas - a tailored mixture of H and CO - which in turn is further converted to liquid hydrocarbon fuels. The cycle is driven by concentrated solar heat and supplemented by a high-temperature thermal energy storage for round-the-clock continuous operation.

A solar tower fuel plant for the thermochemical production of kerosene from HO and CO.

Developing solar technologies for producing carbon-neutral aviation fuels has become a global energy challenge, but their readiness level has largely been limited to laboratory-scale studies. Here, we report on the experimental demonstration of a fully integrated thermochemical production chain from HO and CO to kerosene using concentrated solar energy in a solar tower configuration. The co-splitting of HO and CO was performed via a ceria-based thermochemical redox cycle to produce a tailored mixture of H and CO (syngas) with full selectivity, which was further processed to kerosene.

Drop-in fuels from sunlight and air.

Aviation and shipping currently contribute approximately 8% of total anthropogenic CO emissions, with growth in tourism and global trade projected to increase this contribution further. Carbon-neutral transportation is feasible with electric motors powered by rechargeable batteries, but is challenging, if not impossible, for long-haul commercial travel, particularly air travel. A promising solution are drop-in fuels (synthetic alternatives for petroleum-derived liquid hydrocarbon fuels such as kerosene, gasoline or diesel) made from HO and CO by solar-driven processes.

Isothermal relaxation kinetics for the reduction and oxidation of SrFeO based perovskites.

The perovskite oxide SrFeO has favourable redox properties for oxygen exchange applications, including oxygen separation and oxygen production chemical looping cycles. For such applications, lower temperature operation can improve the energy demand and feasibility of the process, but can also lead to kinetic limitations. Here we investigate the oxidation and reduction reaction kinetics of SrFeO in the temperature range 450-750 K.