Design and development of novel gas sensors: from materials preparation to industrial integration

In modern society, gases play a strategic role across key sectors such as energy, industry, environmental monitoring, and healthcare. Despite their advantages - high reactivity, ease of mixing, purification, and transport - gases present significant safety risks. Many are toxic (e.g., H2S, Cl2, NOx), flammable or explosive (e.g., CH4, LPG, acetylene, H2), or both (e.g., CO). Because most gases are colourless, odourless, and tasteless, accidental leaks are difficult to detect and may cause severe accidents if not promptly identified. Reliable detection systems are therefore essential. Gas sensors provide an effective solution for monitoring hazardous, asphyxiant, or polluting gases in industrial, environmental, and public health contexts. However, emerging global challenges-such as greenhouse gas reduction, energy transition, and stricter environmental regulations-have increased the demand for more selective, stable, durable, and cost-effective devices. This doctoral thesis aims to overcome key limitations of current gas sensors, including poor selectivity, limited stability, and short lifetimes, through the development of innovative materials and alternative fabrication methods, focusing on metal oxide semiconductor chemoresistive and electrochemical sensor technologies.