Synthesis of amorphous CoSn(OH)₆ nanocubes for photocatalytic reduction of 4-nitrophenol

Catalytic reduction of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) is an important method for treating toxic nitroaromatic pollutant. In this work, amorphous CoSn(OH)₆ nanocubes were synthesized by coprecipitation and calcination methods for 4-NP photocatalytic reduction. The crystal structure, morphology and optical property of the samples were characterized by XRD, SEM, TEM, XPS, and UV–vis DRS. The amorphous CoSn(OH)₆ nanocubes showed excellent photocatalytic performance in 4-NP reduction. The effects of catalyst dosage, 4-NP concentration, and sodium borohydride concentration on the conversion rate of 4-NP were investigated. The results showed that the conversion rate of 4-NP could reach 98.38% in 15 min at room temperature under visible light irradiation. After five cycles of experiments, the conversion rate of 4-NP remained above 90%, indicating the good catalytic stability of the amorphous CoSn(OH)₆ nanocubes. Finally, the mechanisms of photocatalytic reduction on amorphous CoSn(OH)₆ nanocubes are also discussed. The successful preparation of amorphous CoSn(OH)₆ nanocubes may enable the widespread use of amorphous polymetallic oxides for the removal of nitrophenols from wastewater in the future.