2D RGO nanosheets supported anti-spinel NiFe2O4 nanocubes for efficient hydroxylation of phenol

A novel type of nanocomposite containing anti-spinel NiFe2O4 nanocrystals and reduced graphene oxide (RGO) is successfully reported for boosting the hydroxylation of phenol. According to a series of characterizations and experimental tests, it is uncovered that the optimal NiFe2O4-RGO(20) is the best catalyst, the phenol conversion is 28.2%, the selectivity is 93.3%, and the molar ratio of catechol to hydroquinone is 2.6. The cyclic test shows that the catalyst still maintained good catalytic activity after 6 cycles of reaction. Deep mechanism study reveals that the outstanding catalytic performance is primarily attributed to the uniform dispersion of NiFe2O4 nanocrystals loaded on the surface of RGO, which not only prevents the stacking of RGO nanosheets, but also significantly enlarge the exposure of active sites. Moreover, it is also uncovered that the NiFe2O4-RGO(20) composite can accelerate the decomposition of H2O2 into & BULL;OH, thus improving the reaction conversion efficiency towards the hydroxylation of phenol.