Development of Al/Al2O3-coated wire-mesh honeycombs for catalytic combustion of volatile organic compounds in air

Abstract

A wire-mesh honeycomb (WMH) catalyst was constructed from alternating layers of flat and corrugated wire-mesh sheets packed within a frame. The wire-mesh sheets were first coated with aluminum particles using an electrophoretic deposition method. The coated layer was suitably porous and showed a good adherence to the wire surface because of sintering of aluminum particles after thermal treatment at 800degreesC. An additional calcination at 500degreesC formed a thin layer (similar to50 nm in thickness) of oxide phase on each aluminum particle in the deposited layer. Then, Al/Al2O3-coated WMH modules were coated with a Pt (1.0 wt %)/TiO2 catalyst. Their catalytic activities were compared with the conventional ceramic honeycomb (CH) modules with the same catalyst loading for catalytic combustion of various volatile organic compounds (VOCs) in air. The WMH modules showed a better performance than the CH modules for all of the VOCs tested, especially at high temperatures. Kinetic study has shown that the better performance with WMH was caused by an improved external mass-transfer rate as a result of the existence of additional flow across the channel walls of the wire mesh.