Low-temperature synthesis of α-Fe₂O₃ hexagonal nanoparticles for environmental remediation and smart sensor applications

This work demonstrates the successful synthesis and characterizations of α-Fe₂O₃ hexagonal nanoparticles and their effective utilization for the degradation of hazardous Rhodamine B (RhB) dye and smart chemical sensor applications. The as-synthesized materials were characterized by various analytical techniques which revealed that the prepared nanoparticles are well-crystalline, possessing hexagonal shape, grown in high-density and well matched with the rhombohedral α-Fe₂O₃ structures. The as-synthesized α-Fe₂O₃ nanoparticles were used as efficient photocatalyst for the photocatalytic degradation of RhB-dye under light illumination which showed substantial degradation (~79%) of RhB-dye in 140 min. The considerable photo-degradation of RhB-dye attributed to the unique morphology of the synthesized α-Fe₂O₃ nanoparticles which might import the effective electron/hole separation and generate the large number of oxy-radicals. Moreover, the synthesized α-Fe₂O ₃ nanoparticles were utilized as efficient electron mediators for the fabrication of 4-nitrophenol chemical sensor in aqueous media. The fabricated chemical sensor exhibited a high-sensitivity of ~367.6 μA (mol L ^-1)^-1 cm^-2 and an experimental detection limit of ~1.56×10^-3 mol L^-1 in a short response time of ~10.0 s with linearity in the range of 1.56×10^-3-12. 5×10^-3 mol L^-1 and correlation coefficient (R) of ~0.99963. These investigations demonstrated that the simply synthesized α-Fe₂O₃ nanoparticles can effectively be used as efficient photocatalyst for the photocatalytic degradation of organic dyes and effective electron mediators for the fabrication of highly sensitive chemical sensors in aqueous medium.