(506d) Plasma Aided Nitrogen Fixation: Electrocatalysis Vs Catalysis
AIChE Annual Meeting
2019
2019 AIChE Annual Meeting
Catalysis and Reaction Engineering Division
Catalysis for Nitrogen Chemistry II: Plasma-Enhanced and Other Non-Thermal Approaches for N2 Activation
Wednesday, November 13, 2019 - 1:24pm to 1:42pm
Exploiting environmentally-friendly and sustainable energy sources is a major societal and technological challenge in the 21st century1. Most sustainable technologies such as solar and wind energy are in principle able to meet the global energy demand. However, they are intermittent and require efficient and economic storage solutions. An economically feasible option for long term (seasonal) storage will be chemical feedstock, i.e. storing energy in form of the binding energy of molecules. The main research question that has to be addressed urgently is the most effective way of converting electrical energy into molecules of high energy.
In this context, nitrogen ï¬xation is unquestionably one of the most important chemical and elementary steps of nitrogen cycle. It does not only convert atmospheric nitrogen (low energy molecule) into molecules of high energy (e.g. NH3, NO) but also recycles it into many other daily usage products2,3. However, contemporary chemical industry for nitrogen fixation impose great concerns about the environmental sustainability in terms of immense energy consumption and burdened emissions profile. Nevertheless, plasma-technology that can be directly powered by renewable electricity, has been receiving renewed attention as an alternative “green†approach for N2 activation4 which is one of the fundamental requirement for NO (or NH3) synthesis.
Up to now solutions were mainly sought on material axis, however recent theoretical studies have revealed that there are intrinsic limitations of catalysis (i.e. scaling relationships) which keep the processes far from the optimum performance5. In this work, we will present a unique solution to the aforementioned limitations by employing a hybrid type reactor consisting of a plasma reactor and electrochemical cells with ionic6 or proton conducting membranes. In this approach, electrochemical cells provide reacting species on catalysts with a controllable manner while a radiofrequency plasma is used to increase the reactivity of nitrogen at low energy cost7. Such spatial separation of nitrogen dissociation and catalytic formation of the target molecules provides truely independent parameters to optimise the electrocatalytic reactions. The effect of gas composition, operating temperature and nature of catalysts on the efficiency of nitrogen fixation will be discussed. In addition, the advantages of our approach compared to conventional electro- catalysis, plasma catalysis or pure plasma processes will be also presented.
In this context, nitrogen ï¬xation is unquestionably one of the most important chemical and elementary steps of nitrogen cycle. It does not only convert atmospheric nitrogen (low energy molecule) into molecules of high energy (e.g. NH3, NO) but also recycles it into many other daily usage products2,3. However, contemporary chemical industry for nitrogen fixation impose great concerns about the environmental sustainability in terms of immense energy consumption and burdened emissions profile. Nevertheless, plasma-technology that can be directly powered by renewable electricity, has been receiving renewed attention as an alternative “green†approach for N2 activation4 which is one of the fundamental requirement for NO (or NH3) synthesis.
Up to now solutions were mainly sought on material axis, however recent theoretical studies have revealed that there are intrinsic limitations of catalysis (i.e. scaling relationships) which keep the processes far from the optimum performance5. In this work, we will present a unique solution to the aforementioned limitations by employing a hybrid type reactor consisting of a plasma reactor and electrochemical cells with ionic6 or proton conducting membranes. In this approach, electrochemical cells provide reacting species on catalysts with a controllable manner while a radiofrequency plasma is used to increase the reactivity of nitrogen at low energy cost7. Such spatial separation of nitrogen dissociation and catalytic formation of the target molecules provides truely independent parameters to optimise the electrocatalytic reactions. The effect of gas composition, operating temperature and nature of catalysts on the efficiency of nitrogen fixation will be discussed. In addition, the advantages of our approach compared to conventional electro- catalysis, plasma catalysis or pure plasma processes will be also presented.
References
[1] B. Obama, Science, 355 (2017), 126
[2] B. S. Patil, Q. Wang, V. Hessel and J. Lang, Catal. Today, 256 (2015), 49
[3] R. Hawtof, S. Ghosh, E. Guarr, C. Xu, R. M. Sankaran and J. N. Renner, Sci. Adv., 5 (2019), 5778
[4] S. Cavadias and J. Amouroux, Bull. Soc. Chim. Fr., 2 (1986) 147
[5] A. Vojvodic and J.k. Norskov, Natl. Sci. Rev., 2 (2015) 140
[6] M.N. Tsampas et al, Catal. Sci. Technol., 5 (2015) 4884
[7] V. Guerra et al, Plasma Sources Sci. Technol., 12 (2003) S8