The distinct role of boron doping in Sn₃O₄ microspheres for synergistic removal of phenols and Cr(VI) in simulated wastewater

A powerful photocatalyst is the key for photocatalytic environmental purification via sunlight harvesting and utilization. In this work, novel boron doped Sn₃O₄ microspheres constructed from nanoplates were designed and fabricated. Density functional theory (DFT) studies were carried out to investigate the boron doping mechanism, in which DFT predicted that boron doping would enhance the light harvesting capability and the photo-response of Sn₃O₄, which was proved by diffuse reflectance spectra (DRS) and transient photocurrent responses. Attributed to its unique porous structure, and enhanced light harvesting and high carrier utilization capabilities, the boron doped Sn₃O₄ microsphere exhibited high efficiency for Cr(IV) removal and azo dyestuff degradation. Moreover, an unexpected synergistic effect upon simultaneous removal of phenols (phenol, bisphenol A and p-chlorophenol) and Cr(VI) was observed.