Facile precipitation microfluidic synthesis of Monodisperse and inorganic hollow microspheres for Photocatalysis

BACKGROUND Hollow microspheres have potential applications for wide-range fields, especially photocatalysis, attracting tremendous attention in material science. However, conventional synthesis of hollow microspheres involves complicated procedures, high cost and poor yields, greatly impeding their development. Due to the limitations of raw material for the polymerization or hydrolysis routes so far the hollow materials prepared in a microfluidics chip were limited to some specific substances. RESULTS Herein, a controllable precipitating reaction strategy in droplets was presented to form the hollow structure from easily accessible industrial chemical materials (such as nitrates of Zinc, Copper and Cobalt, and Ferrous sulfate). After generating monodisperse droplets and followed introducing precipitant into the droplets in a microfluidics chip, the spherical shell was constructed through the accumulation of precipitated particles at the oil/water interface of droplets and further particle growth on the inner shell. As a result, hollow microspheres with a Janus shell of different inner and outer morphology were formed. The photocatalytic activities of these hollow microspheres were evaluated for RhB photodegradation oxidation based on heterogeneous photo-Fenton. The photocatalytic activities of the fresh hollow samples showed better than their solid samples or their oxidized hollow samples. CONCLUSION With microfluidic technology, the transition-metallic inorganic hollow microspheres can be rapid, low-costly manufactured through direct precipitation reaction in droplets. The prepared alpha-Co(OH)(2) hollow microspheres showed promising photocatalytic activity. (c) 2021 Society of Chemical Industry (SCI).