Color conversion of the magnetically separable Al/Fe oxide RNGO in the selective oxidation of benzyl alcohol induced the observation of its morphology change

Abstract

Herein, via integrating the merits of Fe-based nanoparticles and graphene oxide, magnetic Al/Fe oxide nanoparticles implanted on reduced N-doped graphene oxide (Al/Fe oxide RNGO) were synthesized by solvothermal reaction followed by thermal annealing with a particular temperature and hold time. The synthesized catalyst exhibited excellent performance with more than 80% yield of the desired product benzaldehyde achieved within a 2-hour reaction time. Due to its distinctive magnetism, the material can easily be separated and recycled for subsequent runs. It also demonstrated exceptional stability and recyclability with regard to its performance in a lifetime test without significant capacity or activity loss. The most remarkable finding was the observation of a color shift during the lifetime test due to the change in the morphology, which was further connected with the catalytic performance; initially, a chaotic structure and a comparable inferior catalytic activity were obtained, whereas a waffle or pastry state and a relatively superior activity were observed later. An additional reference without reactants did not display this morphology change; this result supported the employment of the catalyst in the reaction and provided a new alternative methodology to deduce and verify the mechanism.