NaBr-Assisted Aqueous Synthesis of Perovskite-Embedded PbBr(OH) Hierarchical Nanostructures for Dye Photodegradation

Abstract

Halide perovskite nanomaterials have demonstrated promising potential in various fields, including photocatalysis for environmental remediation. However, perovskites' poor stability toward water makes it difficult to use them for the photocatalytic degradation of organic pollutants in wastewater. Herein, we develop a facile and scalable NaBr-assisted room-temperature aqueous phase procedure for the synthesis of all-inorganic CsPbBr 3 -embedded PbBr(OH) with controlled hierarchical structures, excellent ambient stability, and strong activity for photocatalytic degradation of dyes (e.g., methyl orange and methylene blue) in simulated organic wastewater. It is exceptional that the added NaBr can complex PbBr 2 to form a transparent aqueous solution, enabling the subsequent reaction with the aqueous Cs 2 CO 3 precursor to produce CsPbBr 3 -embedded PbBr(OH) microflowers and microspheres. The photocatalysis shows that the CsPbBr 3 -embedded PbBr(OH) photocatalysts exhibit excellent photocatalytic activity for dye degradation under visible-light irradiation, which is significantly stronger than that of commercial TiO 2 and some other perovskite-based materials produced using a previously reported method. The excellent stability of the CsPbBr 3 -embedded PbBr(OH) as a photocatalyst is verified by nine consecutive photocatalytic cycles without a noticeable drop in photodegradation efficiency. This work will shed light on the green synthesis of ultra-stable perovskite-based nanomaterials for photocatalytic degradation of organic pollutants as well as other promising water treatment technology prospects.

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“…Seldomly reported, the photocatalysts are susceptible to mechanical stress and eventual fracture caused by the stirring in the batch reactor, generating smaller particles and a higher surface area, which overestimates the photocatalytic performance and jeopardizes the claimed easy removal of the photocatalysts after a test. Also, porosity data, like specific surface area and pore diameter, are not properly discussed or even totally or partially missing in some papers in the literature [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ], neglecting possible synergies and effects granted by the catalytic supports in what regards, e.g., mass transfer. Concerning the particle size, most of the reported microspherical supports are usually very small, ranging from 0.5 to 3 µm [ 18 , 19 , 20 , 21 , 23 , 24 , 25 ], which may impose problems and extra complexity and costs in a real-life application, in what regards the setup and recovery aspects.…”