Influence of surface oxygen functionalities' presence on the catalytic properties of CNT-supported Cu catalysts in the reforming of methanol

This article investigates the influence of oxygen-containing groups on the properties of CNTs and CNT-supported catalyst. The carbon nanotubes were treated using H
₂
O
₂
solution and by annealing in Ar atmosphere (800°C) in order to introduce and to eliminate oxygen surface functionalities, respectively. Their properties of CNTs were investigated using TGA, XRD, BET, and TPD-NH
₃
. The reducibility of Cu/CNTs catalysts was investigated using TPR-H
₂
technique and their activity was studied in the oxidative steam reforming of methanol. Both oxidation and annealing treatments were found to increase the specific surface area of CNTs. The formation of oxygen groups was confirmed using TGA and TPD-NH
₃
. Their presence resulted in significant degradation of the thermal stability and increased surface acidity of carbon nanomaterial. The obtained results also showed that even the elimination of the insignificant amounts of oxygen containing groups on CNT surface as well as mild oxidation can significantly alter the catalytic properties of CNT-based catalysts. The highest catalytic activity was observed for copper catalysts supported on oxidized CNTs in terms of methanol conversion and selectivity towards hydrogen formation.