Utilizing a Bi₂₄O₃₁Br₁₀/MIL-88A(Fe)-derived mixed-phase α,β-Fe₂O₃@C heterojunction photocatalyst for the...

In recent years, pernicious organic pollutants, including pharmaceuticals and personal care products (PPCPs), have been ubiquitous in water bodies. Resorcinol (RCL), as a major constituent of PPCPs, is used extensively in industries and households, contributing to its occurrence in water matrices. Owing to the persistence and endocrine-disrupting potential of RCL, its complete mineralization is imperative. In this regard, Bi₂₄O₃₁Br₁₀/Fe₂O₃@C composites were synthesized via a solvothermal route, wherein mixed-phase α,β-Fe₂O₃@C was obtained through the thermal conversion of MIL-88A(Fe). Among the as-prepared samples, including the individual components, the heterostructure containing 5 wt% α,β-Fe₂O₃@C (Bi₂₄O₃₁Br₁₀/α,β-Fe₂O₃@C-5%, denoted as BOBFC(5%)) exhibited the highest photocatalytic degradation in 10 mg L^-1 RCL (98.8%) after 180 min of visible light irradiation. The enhanced performance of BOBFC(5%) is attributed to its increased specific surface area, narrower band gap, and reduced charge-carrier recombination, as validated by the Brunauer-Emmett-Teller (BET), UV-vis diffuse reflectance spectroscopy (UV-DRS), and photoluminescence (PL) spectroscopy results. Moreover, the efficient charge transfer across the heterointerface resulted in the generation of superoxide (˙O₂ ^-) radicals and holes (h⁺), which combinedly contributed to the photocatalytic activity. Furthermore, the agar well diffusion test against E. coli exhibited no visible inhibition zone, indicating the non-toxic behaviour of BOBFC(5%). Subsequently, BOBFC(5%) retained its degradation efficacy over 5 consecutive cycles, highlighting its remarkable stability. Additionally, the in silico evaluation revealed that the transformation products formed during the photocatalysis of RCL were less toxic. Hence, this work presents an efficient novel photocatalyst that can be used in sustainable wastewater treatment systems.