Dynamic probing of plasma‐catalytic surface processes: Oxidation of toluene on CeO2. Issue 6 (17th February 2017)

• Record Type: Journal Article
• Authors: Jia, Zixian; Wang, Xianjie; Thevenet, Frederic; Rousseau, Antoine
• Other Names: Nozaki Tomohiro guestEditor.; Bogaerts Annemie guestEditor.; Tu Xin guestEditor.; van de Sanden Richard guestEditor.
• Is Part Of: Plasma processes and polymers. Volume 14:Issue 6(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-02-17
• Subjects: adsorption -- air treatment -- ceria -- DRIFTS -- non‐thermal plasma -- plasma‐catalysis -- toluene -- VOC; Plasma polymerization -- Periodicals; Plasma-enhanced chemical vapor deposition -- Periodicals; Plasma chemistry -- Periodicals
• DOI: 10.1002/ppap.201600114
• Languages: English
• ISSNs: 1612-8850

Abstract

Abstract : This article reports the use of innovative diagnostics to monitor toluene adsorption and oxidation on CeO2 surface under non‐thermal plasma (NTP) exposure. Two plasma‐catalytic configurations are explored, namely: post‐plasma catalysis (PPC) and in‐plasma catalysis (IPC). Since heterogeneous processes are pointed out as key steps of the plasma‐catalyst coupling, the catalyst surface has been monitored by two complementary in situ diagnostics: (i) diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) and (ii) transmission fourier transform infrared spectroscopy using Sorbent track (ST) device. Dielectric barrier discharges (DBD) are used in both PPC and IPC configurations to induce adsorbed toluene oxidation. Toluene in dry air is first adsorbed on the selected catalytic surface: ceria (CeO2 ). Subsequently, the plasma is switched on. During the experiment, the ceria surface is monitored by infrared to study toluene adsorption and oxidation mechanisms. The adsorption capacity of toluene on ceria is, respectively, measured in the configurations of PPC and IPC by DRIFTS and ST. The oxidation of toluene by plasma follows a first‐order reaction regardless of plasma configuration and injected power and IPC is more effective for the toluene removal than PPC. Intermediates of toluene (benzyl alcohol, benzaldehyde and benzoic acid) are also identified on the surface and their respective temporal evolutions as a function of the plasma exposure are studied. Abstract : Toluene adsorption and oxidation on CeO2 surface by non‐thermal plasma (NTP) is in situ monitored using infrared (IR) diagnostics (diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) and transmission mode). The oxidation of toluene by plasma follows a first‐order reaction regardless of plasma configuration and injected power. It was found that IPC was more effective for the toluene removal than PPC. Interestingly, toluene abatement and reaction intermediate formations are characterized in situ throughout the heterogeneous oxidation reaction advancement.