A highly efficient Fe/Beta catalyst for the liquid-phase oxidation of naphthalene: The influence of Fe species and zeolite acidity

•Prepared three Fe/Beta catalysts by impregnation (im), ion-exchange (ex) and hydrothermal (hy) method.•As high as 78 wt.% content of isolated Fe3+ species were incorporated into Beta zeolites and the Fe distributed homogeneously through the Beta zeolites by hydrothermal method.•The total acid density increased after the incorporation of Fe species by hydrothermal method.•Fe/Beta(100)-hy with the highest content of isolated Fe3+ species and enhanced acid density showed the highest catalytic activity in the liquid-phase oxidation of naphthalene.