Novel noble-metal-free ceramic filter with controlled pore structure for environmental cleaning

We previously reported the complete decomposition of volatile organic compounds (VOCs) on hydroxyapatite (HAp) powder and initially demonstrated the catalytic reaction mechanism, which makes HAp the most prom-ising alternative to conventional noble-metal nanoparticle catalysts for the control of VOC emission and envi-ronmental cleaning. To further the practical application of the previous study, we fabricated porous HAp via facile gel-casting assisted direct forming with the aim of developing a new type of ceramic filter. The structural features of the pore, such as pore size and porosity, are selectively controlled by altering the amount of surfactant added and the forming time. The resultant porous HAp was successfully applied as a catalyst filter for VOC decomposition and exhibited performance that was comparable to that of HAp powder. In addition, the corre-lation between pore structure tailored gas permeability and catalytic performance of HAp filters was also investigated in depth. Instead of a noble-metal nanoparticle catalyst that must be carried by a porous ceramic filter, the superior catalytic activity achieved using the HAp filter itself presents a novel strategy for future VOC decomposition techniques.

Automated summary

The study achieved complete decomposition of volatile organic compounds on HAp powder, and developed a new type of porous HAp ceramic filter with comparable catalytic performance to HAp powder. By controlling the structural features of the pores such as pore size and porosity, the catalytic performance and gas permeability of porous HAp can be adjusted. The superior catalytic activity of HAp filters without the need for noble-metal nanoparticle catalysts presents a novel strategy for future VOC decomposition techniques.