Rational design of hierarchically-structured CuBi₂O₄ composites by deliberate manipulation of the nucleation and growth kinetics of CuBi₂O₄ for environmental applications

A versatile, eco-friendly synthesis scheme was developed to fabricate a series of hierarchically-structured CuBi₂O₄ composites for environmental applications. By simple tuning of the synthesis protocol (i.e. controlling the ethylene glycol to water ratio in the reaction matrix and employing different auxiliary metal precursors consisting of Cu²⁺, Co²⁺ or Fe³⁺ species), deposition of various metal oxides on CuBi₂O₄ was achieved. The proposed one-pot synthesis protocol utilizes the fast nucleation and controlled growth kinetics of CuBi₂O₄ to deliberately immobilize the desired metal oxides on the surface of the CuBi₂O₄. The manipulation of the diffusion rate, mass transfer kinetics and atomic mobility of the metal precursors by controlling the viscosity and dielectric properties of the reaction matrix lead to the formation of different CuBi₂O₄ composites with the desired properties. The synergistic coupling effect between the CuBi₂O₄ and deposited metal oxide contributed to the superior performance of the novel CuBi₂O₄ composites. The CuBi₂O₄ composites demonstrate excellent potential for various environmental applications such as being a catalyst for generating sulfate radicals from peroxymonosulfate for organic pollutant removal in water and being a disinfectant. The proposed green synthesis protocol is simple and offers flexibility for fabricating hierarchically-structured CuBi₂O₄ composites with enhanced properties for targeted applications.