Facile oxygen doped heterojunction structured hybrid particles with γ-aluminium oxide dispersed over graphitic carbon nitride for dehydrogenation of sodium borohydride in methanol: Catalytic properties and mechanism

Abstract

It is important to develop new metal-free catalysts that are both low-cost and environmentally friendly with high performance. Recently, heterojunction catalysts have been used more than single-component catalysts in catalytic reactions. The current study reports the facile production of a new environmental and green metal-free nanocatalyst by three stages including the synthesis of graphite carbon nitride (GCN) from urea, synthesis of GCN-γ-Al2O3 hybrid composite from GCN and aluminium oxide (γ-Al2O3), and synthesis of O-doped GCN-γ-Al2O3 from the interaction of hybrid GCN-γ-Al2O3 with nitric acid treatment. The obtained O-doped GCN-γ-Al2O3 hybrid material was used to catalyse the green and environmental H2 production(H2-P) from sodium borohydride (NaBH4) methanolysis for the first time. The chemical compositions and morphology structures of these heterojunction-structured hybrid catalysts were carefully characterized by SEM-EDS, XRD, FTIR, TEM, and XPS analyses, and the catalytic activities and reusability were systematically evaluated. The H2 generation rate (HGR) values of GCN, GCN-γ-Al2O3 and O doped GCN-γ-Al2O3 catalysts were found as 3486, 5310 and 10080 ml min-1 g-1, respectively. The activation energy (Ea) for the O-doped GCN-γ-Al2O3 catalyst was 35.12 kJ mol-1. Besides, the mechanism of the O-doped GCN-γ-Al2O3 catalyst in the NaBH4 methanolysis reaction(NaBH4-RM) was tried to be clarified.