A low temperature H 2 sensor based on intermediate hydroxy tin oxide

Abstract

Nanosize powders of SnO 2 were prepared by two precipitation methods, namely tin chloride hydrolysis and tin ethoxide hydrolysis. The precipitation was followed by a sequential washing procedure using solvents of decreasing polarity. This process helped to enhance the surface area of the resulting powders and to make them suitable for sensor applications by preventing their agglomeration. The sensors fabricated from such powders were found to exhibit a sensitivity of ∼90% for 100 ppm H 2 at 443 K and ∼50% for 500 ppm LPG at an operating temperature of 523 K. Their ability to sense H 2 at such low temperatures is attributed to the large surface area which offers a large number of active sites for reaction with H 2 and the possible participation of hydroxyl groups of the oxy-hydroxy phase in the sensing action.