Research On Inkjet Printing Technology For Micro Catalytic Patterns

Recently, catalytic combustion at micro-scale is of considerable interest becauseof its potentiality of small size, quick start-up, and fully utilizing the high energydensities of fuels at much lower operating temperatures. Compared to conventionalmacro-scale combustion, it is convenience to precisely control the combustioncondition, for example, keeping reaction temperatures at given range. It may findapplications as novel thermoelectric sensors and micro portable power units.Furthermore, it doesn’t contribute to the production of nitrogen oxide which resultingin a significant pollution reduction. However, site-selective, preciselyshape-controlled catalyst layer is important in the micro-space defined catalyticcombustion, which need a rapid and flexible method to selective deposit catalyst layeron various substrates. Noble metal such as platinum, rhodium have been extensivelyused in low temperature catalytic combustion of fuel. But the problem of scarceresources and high cost has lead to the development of noble metal. Therefore, it isnecessary to find an alternative method not only to minimize the consumption ofnoble metal materials, but also to directly deposit micro-patterned catalyst on varioussurface.Inkjet printing is viewed as a versatile manufacturing tool because it allows todirect-write micron-order features by precisely placed individual droplets onto thevarious substrates. Inkjet printing has benefits of high materials efficiency, low costand capability to large area manufacturing. In the last decade, inkjet printingtechnology has been successfully used to fabricate various devices such as organicfield-effect transistors (OFETs), conductive features, polymer light-emitting diode(PLED), radio frequency identification (RFID) tags, and fuel cell. For catalyticcombustion, this technology is feasible to deposit different catalyst patterns such as catalyst dots arrays and films for catalytic combustion.In this work, we presented the use of inkjet printing as a deposition tool forpatterning catalyst layer for use in low temperature catalytic combustion. The maincontent are summarized as follows:The mechanism of inkjet printing droplet was discussed and the mathematicalmodel of droplet formation was established. the dynamics of drop-on-demand (DOD)drop formation was simulated using volume of fluid (VOF) model by Fluent. Weinvestigated the influence of control parameters and the behavior of drolet duringduring the drop formation process.Then, the impacts of parameters, ink properties, such as voltage, pulse width,frequency and temperature, on the droplet formation were investigated extensively.Furthermore, the behaviors of droplet after deposition as well as the effects of dropletspacing and printing methods on the droplet diameter and materials distribution werealso studied.Micro catalyst dots and patterns for low temperature micro catalytic combustionare fabricated by inkjet printing method. The performances of the low temperaturecatalytic combustion were carried out using infrared thermography camera. Weinvestigate the effects of reduction methods, substrates, flow rate and reactiontemperatrue on the performaces of catalytic combustion. We demonstrated thefeasibility of utilizing inkjet printing as deposition tool to pattern catalystfor microcatalytic combustion.