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.