Photocatalytic synthesis of vanillin using N-doped carbon nanotubes/ZnO catalysts under UV-LED irradiation

Maria J. Sampaio (1) , Anas Benyounes (2, 3) , Philippe Serp (2, 3) , Joaquim L. Faria (1) , Claudia G. Silva (1)

1 LSRE-LCM - Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia
2 LCC - Laboratoire de chimie de coordination
3 Toulouse INP - Institut National Polytechnique (Toulouse)

ZnO synthesized by solid-state thermal process was combined with different contents of nitrogen-doped carbon nanotubes (N-CNT). The materials were characterized by several techniques including thermogravimetric analysis, N2 adsorption-desorption isotherms, scanning and transmission electron microscopies, and diffuse reflectance UV–vis and photoluminescence spectroscopies. The performance of neat ZnO and N-CNT/ZnO composite materials was evaluated in the selective photocatalytic oxidation of vanillyl alcohol into vanillin under UV-LED irradiation. The presence of the carbon phase in the composite materials (from 5.0 to 10 wt.%) revealed to be crucial for increasing the performance of the photocatalysts. The best performance for vanillyl alcohol oxidation was obtained using the composite containing 5% of carbon phase (5.0%N-CNT/ZnO), with an increase of 22% in vanillin concentration comparing to neat ZnO after 2 h of reaction. This enhancement in the efficiency of ZnO by the introduction of the carbon phase is attributed to the action of N-CNT as effective electron scavengers for ZnO, as revealed by the photoluminescence quenching, inhibiting the recombination of electrons and holes.

Domaines: Chimie de coordination

Maria J. Sampaio, Anas Benyounes, Philippe Serp, Joaquim L. Faria, Claudia G. Silva. Photocatalytic synthesis of vanillin using N-doped carbon nanotubes/ZnO catalysts under UV-LED irradiation. Applied Catalysis A : General, 2018, 551, pp.71-78. ⟨10.1016/j.apcata.2017.12.002⟩. ⟨hal-01949859⟩