The increasing use of hydrogen as an alternative energy source demands a highly reliable sensor for ensuring the safety issue in different applications. A newly established idea, ligand-linked nanoparticles catalyst, can comply with the growing need for a sensor with high sensitivity and fast response. However, a fundamental challenge is the long-term stability of the sensor with ligand-linked nanopartcles catalyst. In the context of this dissertation, a combustible hydrogen gas sensor is

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... ped using ligand-linked Pt nanoparticles catalyst with improved sensitivity, selectivity and stability. One of the prime grounds for the deactivation of the ligand-linked nanoparticles catalyst is the inhomogeneous heating. The ligands in the over-heating places can be destroyed, as a result, the nanoparticles are sintered. Conversely, water accumulation in the low heating places deactivates the catalyst. Therefore, the sensor is designed through modelling based on physical constraints focusing on the homogeneous temperature distribution in the catalyst area. The design is optimized also to meet the other requirements such as low power consumption, high sensitivity and thermal insulation, transparency in the catalyst area etc. Subsequently, the challenges of the microtechnological processes were confronted and the problems were solved through a series of additional experiments in the chronological fabrication process. Finally, a highly sensitive thermoelectric sensor with a Seebeck coefficient of 273 µV/K, the main hub of the thesis, is developed. An additional thermoresistive sensor is fabricated that gives the privilege of a comparative performance analysis with the thermoelectric sensor. Pt nanoparticles linked by five different bi-functional ligands containing the aromatic ring in the backbone is used as the catalyst in this work, namely Pt-PDA, PtDAN, Pt-DACH, Pt-BEN, Pt-DATER. The catalyst is characterized through morphological analysis (e.g. SEM) as well as gas sensing experiments. The performance of the sensor base [...]