Nanosecond repetitively pulsed discharges at atmospheric pressure have shown comparatively high performances for CO2 reduction to CO and O-2. However, mechanisms of CO2 dissociation in these transient discharges are still a matter of discussion. In the present work, we have used time-resolved optical emission spectroscopy to investigate the CO2 discharge progression from the initial breakdown event to the final post-discharge. We discover a complex temporal structure of the spectrally resolved light, which gives some insights into the underlying electron and chemical kinetics. We could estimate the electron density using the Stark broadening of O and C lines and the electron temperature with C+ and C++ lines. By adding a small amount of nitrogen, we could also monitor the time evolution of the gas temperature using the second positive system bands of N-2. We conclude that the discharge evolves from a breakdown to a spark phase, the latter being characterised by a peak electron density around 10(18) cm(-3) and a mean electron temperature around 2 eV. The spark phase offers beneficial conditions for vibrationally enhanced dissociation, which might explain the high CO2 conversion observed in these plasma discharges.<\/p>\n","protected":false},"excerpt":{"rendered":"
Ceppelli M.; Salden T.P.W.; Martini L.M.; Dilecce G.; Tos P.<\/p>\n","protected":false},"featured_media":1294,"comment_status":"closed","ping_status":"open","template":"","meta":[],"product_cat":[574],"product_tag":[1307,1962,1963,1964,1965],"class_list":["post-7125","product","type-product","status-publish","has-post-thumbnail","hentry","product_cat-journal-articles","product_tag-optical-emission-spectroscopy","product_tag-plasma-diagnostics","product_tag-nanosecond-repetitively-pulsed-plasma","product_tag-spectral-line-broadening","product_tag-co2-discharge","prodpage-style2"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product\/7125","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/comments?post=7125"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/media\/1294"}],"wp:attachment":[{"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/media?parent=7125"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product_cat?post=7125"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product_tag?post=7125"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}