Construction of Flower-like ZnO Nanoclusters on Functionalized Graphene Nanosheets for Room Temperature Formaldehyde Sensing

Background: Formaldehyde (HCHO) is one of the sources of indoor air pollution and a recognized carcinogenic gas, which sets a huge threat to human health. Therefore, it is urgent to develop a formaldehyde gas sensor with high efficiency, low consumption, and low limit of detection. Methods: With solvothermal and supramolecular assembly methods, we fabricate a nanocomposite of ZnO/5-aminonaphthalene-1-sulfonic acid (ANS)-reduced graphene oxide (rGO) through in situ assembling flower-like ZnO nanoclusters on ANS-modified graphene nanosheets for room temperature formaldehyde detection. Results: The flower-like ZnO/ANS-rGO based gas sensor exhibits high response (32%, 5 ppm), ultra-fast response/recovery times (18/23 s), high selectivity, long-term stability and a low practical limit of detection (pLOD) of 1 ppm toward HCHO at room temperature, offering significant advantages and competitiveness in chemiresistive room temperature HCHO sensors. Conclusion: The unique flower-like nanostructure of ZnO and the functionalization with ANS molecules jointly improved the HCHO sensing performance of the composite at room temperature. This work provides a new approach to designing and preparing high-performance room temperature gas sensing materials.