| Nano-titanium dioxide has such chemical and energy band properties , as weak N-type, wide band gap, and low activity of outer shell electrons of Ti, etc. which seriously affect the decrease of it's resistance. we make pre-treatment ,long-time heating, getting the rutile structure. Modification of nano-TiO2 in doping precious metals Ru in accordance with the different weight ratio, reducing the material resistance, improve it's sensitive to TMA.Freshness is a very important indication of the fish edibleness. By the recent research, it is found that TMA vapor is produced when the fish is being stored. So, TMA vapor is very suitable to measure fish freshness and field applications. In this paper, on the basis of a large number of literature, which is about fishfreshness, puting forward the nano-TiO2 was used for matrix. Modification of nano-TiO2 in doping precious metals Ru in accordance with the different weight ratio; in the experiment we overcame that the sensitive materials can not be sintered in the long time. The temperature of fixed-sintering is 600℃, to conduct to sinter the materal breakthroughly for a long time that is 48h, reducing the material resistance, and maintaining its high sensitivity to TMA. The TMA- sensing mechanism of TiO2 (nano)-based sensitive materials and the catalytic mechanism of modification of nano-TiO2 in doping precious metals Ru.The paper researches the difference that the sensitivity for the Ru/TiO2 (nano) sensor response to TMA because of the doping of different weight ratio, the aging time, different work voltage . At the same time, we make testing in interfere gas NH3 and H2, continuum determine mutative freshness of crucian after it died. Analysises the reasons for different sensitivity in different conditions. The result show that, weight ratio of 2.0 percent of Ru , the aging time for 48h, best working voltage in 6V, it has characteristics of element to TMA as quick response time, good selectivity, good practicability, response to lower minimum. |
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