| 초록 |
As a template for settlement of catalysts onto the electrospun nanofibers (NFs), we used protein cage, i.e., apoferritin (AF) which can encapsulate metal nanoparticles (NPs) within a small inner cavity, limiting the size of NPs to less than 3 nm. Furthermore, positive charge of the outer shell of AF can prevent bulk aggregation of NPs. Thus, AF is suitable for the activation of uniformly distributed nanoscale catalysts. In this work, we proposed nanoscale PtO2 catalyst-loaded SnO2 multichannel nanofibers (PtO2-SnO2 MCNFs) synthesized by single-spinneret electrospinning combined with AF and two immiscible polymers, i.e., polyvinylpyrrolidone (PVP) and polyacrylonitrile (PAN). During the electrospinning, PVP-tin precursor and PAN are divided into the continuous phase and discontinuous phase by phase separation of two immiscible polymers. After calcination of as-spun NFs, PtO2-SnO2 MCNFs were synthesized through the decomposition of organic components (PVP, PAN, and AF) and crystallization of tin precursors. Taking advantage of AF and the multichannel structure with a high porosity, effective activation of catalysts on both interior and exterior site of MCNFs was realized. As a result, under high humidity condition (95% RH), PtO2-SnO2 MCNFs exhibited a remarkably high acetone response (Rair/Rgas = 194.15) toward 5 ppm acetone gases, superior selectivity to acetone molecules among various interfering gas species, and excellent stability during 30 cycles of response and recovery toward 1 ppm acetone gases. In this study, we first demonstrate the high suitability of multichannel semiconducting metal oxides structure functionalized by apoferritin-encapsulated catalytic nanoparticles as highly sensitive and selective gas-sensing layer. |
