Protective stainless steel micropillars for enhanced photocatalytic activity of TiO2 nanoparticles during wear

Enhanced photocatalytic activity of liquid flame spray (LFS) deposited TiO2 nanoparticles under tribological wear was investigated on metal injection molded (MIM) stainless steel substrates having micropillars as the load carrying support. A combination of LFS with MIM microtextures on the surface is a simple and cost-efficient way for manufacturing efficient photocatalytic substrates. Computer controlled microworking technique in combination with MIM was used to produce stainless steel micropillar surfaces that were functionalized by the LFS deposition of photocatalytically active TiO2 nanoparticles. The photocatalytic activity was measured in gas-phase with an in-house built photoreactor. Our results show that micropillars with controlled spacing we can control the surface area and increased photocatalytic activity of the micropillar substrate was observed compared to flat reference. The wear test confirmed that micropillars not only increase the surface area but they also provide protective support against wear whereas flat reference substrate lost the photocatalytic activity completely during wear.