Rhodri E. Owen

High CO2 and CO conversion to hydrocarbons using bridged Fe nanoparticles on carbon nanotubes

An aerosol assisted chemical vapour deposition method has been used to generate a carbon nanotube (CNT) based iron catalyst for the conversion of CO and CO2 to longer chain hydrocarbons. The same formed iron nanoparticles (NPs) used to catalyse the growth of the CNTs were activated in-line to act as catalysts for the CO and CO2 reduction. This methodology negates the multiple steps associated with the purification and subsequent tethering of metal catalyst nanoparticles to CNT supports common in the literature. Results show superior CO and CO2 conversion and selectivity to higher-order hydrocarbons when compared with a traditional system where iron NPs have been deposited onto CNTs from a solution.

Cobalt catalysts for the conversion of CO2 to light hydrocarbons at atmospheric pressure

A series of cobalt heterogeneous catalysts have been developed that are effective for the conversion of CO2 to hydrocarbons. The effect of the promoter and loadings have been investigated.

Towards Carbon-Neutral CO2 Conversion to Hydrocarbons

With fossil fuels still predicted to contribute close to 80 % of the primary energy consumption by 2040, methods to limit further CO2 emissions in the atmosphere are urgently needed to avoid the catastrophic scenarios associated with global warming. In parallel with improvements in energy efficiency and CO2 storage, the conversion of CO2 has emerged as a complementary route with significant potential. In this work we present the direct thermo-catalytic conversion of CO2 to hydrocarbons using a novel iron nanoparticle-carbon nanotube (Fe@CNT) catalyst. We adopted a holistic and systematic approach to CO2 conversion by integrating process optimization-identifying reaction conditions to maximize conversion and selectivity towards long chain hydrocarbons and/or short olefins-with catalyst optimization through the addition of promoters. The result is the production of valuable hydrocarbons in a manner that can approach carbon neutrality under realistic industrial process conditions.

Fe@CNT-monoliths for the conversion of carbon dioxide to hydrocarbons: structural characterisation and Fischer–Tropsch reactivity investigations

The direct conversion of carbon dioxide to hydrocarbons with a high economic value, such as olefins, can contribute to preventing further green house gas emissions in the atmosphere. In this paper, we report a synthesis, characterisation and catalytic study centred on iron nanoparticle–carbon nanotube arrays grown on monoliths (Fe@CNT-m). These have been used for the catalytic conversion of carbon dioxide to hydrocarbons, showing superior properties than the powder form. The monolith-supported structure also overcomes limitations of the powder catalyst, such as high-pressure drops and potential toxicity of airborne CNT powders, that have, so-far, limited its use in industry. The optimal process conditions (temperature pressure, flow rate and reaction time) have been identified along with deactivation mechanisms. The different catalytic performance of the residual iron NPs outside and inside the CNTs has also been investigated.

Kinetics of CO2 Hydrogenation to Hydrocarbons over Iron-Silica Catalysts

The conversion of CO2 to hydrocarbons is increasingly seen as a potential alternative source of fuel and chemicals, while at the same time contributing to addressing global warming effects. An understanding of kinetics and mass transfer limitations is vital to both optimise catalyst performance and to scale up the whole process. In this work we report on a systematic investigation of the influence of the different process parameters, including pore size, catalyst support particle diameter, reaction temperature, pressure and reactant flow rate on conversion and selectivity of iron nanoparticle -silica catalysts. The results provided on activation energy and mass transfer limitations represent the basis to fully design a reactor system for the effective catalytic conversion of CO2 to hydrocarbons.