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Miniaturized micro-machined catalytic gas sensors offer great advantages regarding power consumption and response time. In combination with a porous catalyst layer high sensitivity can be achieved. However, often this approach does not provide sufficient long-term stability. In this article a miniaturized catalytic gas sensor for hydrogen detection is presented based on colloidally prepared and stabilized platinum nanoparticles as a catalytic layer. Due to its miniaturized design and the highly porous catalyst, a very short response time of

Micro-technologically based catalytic gas sensors offer great advantages regarding sensitivity, power consumption and response time, especially in connection with a porous catalyst layer, which however often provides no sufficient long-term stability. This paper presents a miniaturized catalytic gas sensor for hydrogen detection based on colloidally prepared platinum nanoparticles as a catalytic layer. Compared to conventional sensors, the sensitivity of the catalytic layer is increased while the amount of catalytic material is decreased, due to the high surface of nanoparticles and the direct contact to the sensor. Because of the susceptibility of the nanoparticles to thermally induced sintering, an approach is adopted where the nanoparticles are embedded in an organic network, consisting of stabilizing surfactants adsorbed on the nanoparticle's surface. Agglomeration is reduced and the adhesion to the substrate is improved so that a highly improved stability compared to sensors fabricated with nanoparticles without surfactants is observed. Additionally, the sensor design allows a precise control of the temperature of the catalyst, which also contributes to the stability by keeping the temperature constant. Thermal loading effects are avoided. A sensitivity of up to 2.5 mV/100 ppm was observed.

This paper presents a miniaturized catalytic gas sensor for hydrogen detection. Due to its micro technological design and high porous nanoparticle based platinum catalyst, a very short response time

This paper presents a miniaturized catalytic gas sensor for hydrogen detection. As catalyst, functionalized platinum nanoparticles are used whose increased surface allows a high sensitivity while using a minimal amount of material. The particles are stabilized by a ligand shell consisting of a diamine compound. These ligands lead to a cross-linking between the nanoparticles and thereby they prevent agglomeration. Sensors signal has been stable only with a low decrement for several hours. For comparison, a non-stabilized nanoparticle based catalyst is stable for only several minutes. A new sensor design provides a better controlling of the catalytic temperature, which also improves the stability of the sensor.