The International Symposium on Atomic, Cluster, and Surface Physics, SASP, is a continuing biennial series of winter conferences founded in 1978 by members of the former Institute für Atomphysik der Universität Innsbruck, Austria. SASP symposia aim to foster scientific knowledge and facilitate the exchange of information among scientists in atomic, molecular, cluster, plasma, and surface physics. The symposia highlight fundamental concepts and applications across these interdisciplinary science areas. Since the beginning, the SASP format, besides oral contributions and posters, has provided ample free time for informal discussions. Traditionally, SASP alternates between Austria and other alpine countries. For the 2024 edition, SASP returns to the mountains of Trentino, Italy, where the Trento group previously organized the 1992 and 2000 editions.
Daniela Ascenzi, Luca Matteo Martini and Paolo Tosi are professors at the Department of Physics, University of Trento
Matteo Michielan is a PhD student at the Department of Physics, University of Trento
Low-temperature Plasma for Society's Decarbonization (pag.190-191)
Replacing fossil fuels with renewable energy sources and seeking alternatives or chemical feedstocks is crucial to decreasing greenhouse gas emissions. However, contemporary societies heavily depend on fossil fuels for energy, chemicals, food, and material production. The latter includes the much-used steel, cement, plastic, and ammonia. Thus, the transition to renewable energy sources is very challenging. Due to the fluctuating and distributed nature of renewables, advanced energy storage technologies are necessary. Long-term energy storage in a stable and dense form is also required for those sectors where energy density is pivotal, such as hauling and aviation. One possibility is recycling CO2 and converting electricity from variable sources into chemical energy using abundant molecules such as H2O and N2. In this way, CO2 becomes a raw material rather than a waste product. In addition, using common molecules such as nitrogen and water would solve supply chain issues, ensure economic security, and cut geopolitical tensions.
Traditional chemical processes rely on thermal energy, which, however, is not selective. Taking advantage of non-equilibrium conditions might allow one to exceed the thermodynamics limits. The aim is to direct energy towards molecular dissociation, minimizing heat waste. In recent years, we have been using plasma discharges to activate CO2 and N2. We exploit the significant difference between the temperatures of electrons and gas. The temperature of electrons is much higher than that of gas. This imbalance creates favorable conditions for highly endothermic reactions at relatively low temperatures. We investigated pulsed nanosecond discharges operated at atmospheric pressure, which promise a high degree of non-equilibrium. In particular, we have studied the effect of different pulse sequences on the processes, demonstrating that the pulsing temporal scheme profoundly influences the overall performance. Unveiling dissociation mechanisms requires fast diagnostics with high spatial and time resolution. Using emission spectroscopy and laser induced fluorescence (LIF) we have been able to probe the time evolution of CO2 dissociation. Contrary to naıve expectations that most molecules would split apart during the discharge, dissociation increases after the discharge pulse. This finding suggests that direct electron excitation to a dissociative electronic state is not the leading cause. Instead, the delay of hundreds of nanoseconds between the electron impact and dissociation hints at an indirect mechanism mediated by CO2 excitation. We also investigated the ion chemistry in gaseous discharges [5]. and the role of vibrationally excited CO2 + cations on the reaction with CH4. New experiments are currently underway to study the plasma-catalysis activation of nitrogen gas.
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