Sensitive detection of fish odor in drinking water using benzaldehyde gas sensors with mesoporous indium-doped zinc oxide nanospheres

Sensitive detection of volatile odor compounds is of paramount importance for the effective control and mitigation of odor issues in drinking water, yet it remains a formidable challenge. While semiconductor gas sensors have been extensively utilized for detecting a wide range of volatile organic compounds, their application in detecting volatile odor compounds specifically in drinking water has been limited. Herein, mesoporous indium-doped zinc oxide nanospheres have been developed to sensitively detect benzaldehyde, a representative fishy odorant, in drinking water. This work presents the first reported semiconductor gas sensor specifically designed for the detection of benzaldehyde in drinking water, thereby addressing a critical gap in odor monitoring. The sensing material exhibits mesoporous framework with large pore size (12.8 nm), a high specific surface area (56.59 m²/g), and uniform diameter (∼72 nm). When employed for benzaldehyde detection, the gas sensor demonstrates superior sensing performance, characterized by a high response (10.1 at 11.1 ppm), rapid response/recovery time (35/39 s), a low detection limit (0.38 ppm), excellent selectivity, and long-term stability. The excellent sensing performance is ascribed to the large specific surface area with open accessible framework, increased chemisorbed oxygen ratios, and improved electron transfer efficiency attributed to the indium dopants. Moreover, the sensor can successfully identify benzaldehyde vapor in real source water, indicating its potential for on-site detection of odorants in drinking water. This research offers new insights into the monitoring of volatile odor compounds in water using semiconductor gas sensors.