A low temperature catalytic combustible gas sensor based on Ru supported zeolite catalyst films

Abstract

• The zeolite supported noble metal catalysts prepared by wet impregnation method can effectively improve the catalytic activity of combustible gases CO and H 2 . • The catalytic sensor prepared by using noble metal catalyst supported by zeolite as sensitive material has high gas-sensitive response to combustible gases H 2 and CO. • The sensor has good response and linearity to combustible gases, good repeatability, high stability. Catalyst based on Ru loaded HZSM5 zeolite is prepared by a wet impregnation method, which is screen printed onto alumina substrates and serves as sensitive materials for the catalytic combustion sensor. The results show that Ru-HZSM5 catalyst has a high catalytic activity to combustible gases such as hydrogen (H 2 ) and carbon monoxide (CO) at low temperature. However, a poor dispersion of Ru reduces the catalytic activity of the catalyst when the Ru loading is too high. It is due to the pore structure of the sensitive material which facilitates the acquisition of high dispersion characteristics and gas selective regulation. The catalytic sensor based on Ru-HZSM5 also has high selectivity for combustible gases. Due to the low operating temperature, the sensor has a high selectivity for combustible gases and no cross-response to interfering gases such as ammonia (NH 3 ) and volatile organic compound (VOCs). Therefore, the catalytic type gas sensor with low power consumption and good selectivity can be used for monitoring CO, H 2 and other combustible gases. The Ru supported zeolite catalyst was prepared by wet impregnation method, and a catalytic combustion sensor was fabricated by screen printing. The results show that the catalytic activity of the catalyst was closely related to the Ru loading and operating temperature. The response of the catalytic sensor increases linearly with the concentration of the combustible gas. The preparation of Ru supported HZSM5 catalyst by wet impregnation is a very effective technology. The catalytic activity of the sensitive material is significantly promoted by the noble metal Ru highly loading in the catalyst. The response to different concentrations of combustible gas H 2 also proves the loading relationship of Ru on zeolite surface.