Preparation And Characterization Of New Environmental-protective Type Of Pd-Pt,Cu/ Anodic Oxidation Stainless Steel Wire Mesh Catalysts For Volatile Organic Compounds Elimination

VOCs are one of the main sources of air pollution. Among current technologies on VOCs control, catalytic combustion technology has been regarded as the most effective one because of its relatively low energy consumption, high efficiency and simple equipments. Moreover, there is no associated pollution such as nitrogen oxides (NOx) production. And a catalyst with high activity is the key to catalytic combustion of VOCs.In order to conquer the disadvantages of conventional cordierite honeycomb support, such as low thermal stability and easy fragmentation, we applied stainless steel wire mesh (SSWM) as the catalyst support. Moreover, the anodic oxidation treatment was applied to design a porous membrane over the stainless steel wire mesh surface to enlarge the surface area.The stainless steel wire mesh has excellent performance as catalyst support and some excellent experimental results have been obtained in the past. To broaden the stainless steel wire mesh application in catalyst support, we applied the Type 304, 0.12mm×80 mesh as the catalyst support. As green chemistry is a novel chemical concept, the research greatly optimized the process of removal of oil, primary oxides and other superficial impurities of the stainless steel wire mesh; systematically investigated the membrane formation of during the anodic oxidation process; changed the anodic oxidation electrolytes to form the membrane of medium thickness and right size hole. A Low levels and environment-friendly catalyst of 0.1% Pd-0.05% Pt/stainless steel wire mesh catalyst was prepared for VOCs elimination. The morphologies and reducibility of the stainless steel wire mesh supports and catalysts were characterized by means of scanning electron microscopy (SEM), temperature-programmed reduction (TPR), X-ray photoelectron spectrometry (XPS) and Energy-dispersive X-ray spectroscopy (EDX). The results indicated that 0.1%Pd-0.05%Pt/SSWM held better catalytic performance for VOCs. The temperatures of complete acetone and toluene conversion are low to 180 and 240℃, respectively. Moreover, the catalyst shows stable activity under the reaction of toluene oxidation at 200℃for 300 h.On the basis of the pretreatment of catalyst support above, Cu/stainless steel wire mesh catalysts were synthesized via electrochemical deposition. The effect of different active component load methods on the catalysts catalytic activity was investigated; also the electrochemical deposition voltage and time. When the electrochemical deposition voltage and time was 3V and 15min, the catalyst Cu/SSWM exhibit best catalytic activity; The temperatures of complete acetone, toluene and ethyl acetate conversion were 240.220 and 260℃, respectively. The surface structure and reducibility of the stainless steel wire mesh supports and Cu catalysts were characterized by means of SEM, TPR, XRD, XPS arid EDX. The results indicated that high dispersed CuO species on the support surface and the interaction between CuO species and the anodic oxidation membrane play an important role in catalytic activity and stability.