Hollow Mesoporous SnO₂/Zn₂SnO₄ Heterojunction and RGO Decoration for High-Performance Detection of Acetone

In this article, the synthesis procedure and sensing properties toward acetone of rGO-HM-SnO2/Zn2SnO4 composites with a hollow mesoporous structure are presented comprehensively. The rGO-HM-SnO2/Zn2SnO4 heterojunction structure is prepared through a self-sacrificial template strategy with a concise acid-assisted etching method. The as-prepared hollow mesoporous architectures are investigated by SEM, TEM, and HRTEM. The phase structure and valence state are also characterized by XRD and XPS, respectively. It is obvious that the hollow mesoporous architecture affords a large specific surface area, which can provide more reaction active sites of sensing materials significantly. Compared to the initial SnO2/Zn2SnO4 composites, the gas sensor fabricated by rGO-HM-SnO2/Zn2SnO4 shows the best gas-sensing properties, and the response value toward 100 ppm acetone is as high as 107 at 200 °C. Moreover, the rGO-HM-SnO2/Zn2SnO4 sensing material reveals excellent properties of shorter response-recovery times and higher long-term stability. This excellent performance can be ascribed to the synergistic effect of the hollow mesoporous n-n heterojunction and abundant-defect rGO. The relevant sensing mechanism of rGO-HM-SnO2/Zn2SnO4 sensing materials is investigated in detail.