ZnO/γ-Fe₂O₃ Charge Transfer Interface toward Highly Selective H₂S Sensing at a Low Operating Temperature of 30 °C

ZnO/γ-Fe₂O₃ heterostructure has been deposited in the form of thin films using a single step facile electrochemical technique. Considering the unique properties of both ZnO and γ-Fe₂O₃ toward the sensing of reducing gases, the concept of forming a heterostructure between them has been conceived. The structural characterization of the deposited material has been performed using X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy, which revealed a flowerlike morphology with the coexistence of both ZnO and γ-Fe₂O₃ leading to the formation of a heterostructure. The material showed excellent sensing properties toward the selective detection of H₂S at room temperature (30 °C) among the three test gases, namely, CH₄, H₂S, and CO. The effect of relative humidity was also studied to have an idea about the performance of the device under a real situation. The results are promising and better than those of many commercially available sensors. The room temperature selective detection will help in facile fabrication of portable gadgets.