Design of micro-nano spherical β-NiOOH/FeMoO4 composite with enhanced photo-Fenton performance

In this work, micro-spherical β-NiOOH/FeMoO4 with multiple active sites was prepared by one-step solvothermal method and its performance in the photo-Fenton system was investigated. The results indicate that highest degradation efficiency of methylene blue (MB) was obtained when the molar ratio of nickel to iron was 1:2.5. In addition, composites were assessed for its degradation performance for MB by adjusting the concentration of H2O2, pH and catalyst dosage. The pseudo-first-order kinetic rate constant of MB degradation in β-NiOOH/FeMoO4 catalyzed photo-Fenton system was 0.234 min−1 about 5 folds that of pristine FeMoO4 micro-sphere. The degradation mechanism of MB was deduced by active species quenching experiments and technology of coumarin fluorescent probe. And its degradation pathway was proposed by LC-MS identifying reaction intermediates produced during photo-Fenton catalysis. Recycling tests have confirmed excellent stability of β-NiOOH/FeMoO4 composite. In conclusion, this study demonstrates the β-NiOOH/FeMoO4 composite is a promising heterogeneous photo-Fenton catalyst.