Catalyst decorated multi-dimensional sacrificial templates derived porous one-dimensional $WO_3$ scaffold

Abstract

Porous metal oxide nanostructures synthesized by diverse sacrificial templating routes have been widely applied in the field of chemical sensors. Herein, we report novel synthetic methods of two kinds of WO3 based gas sensing layers, i.e., (i) one-dimensional (1D) multi-walled carbon nanotubes, zero-dimensional (0D) poly-styrene colloids, and Pt encapsulated apoferritin templates derived Pt functionalized hierarchically intercon-nected multi-dimensionally porous $WO_3$ nanofibers, and (ii) sodium doped cellulose nanocrystal and Pt en-capsulated apoferritin templates assisted $Na_2W_4O_{13}-Pt$ of co-catalysts decorated $WO_3$ nanotubes as high per-formance acetone and hydrogen sulfide sensing layers, respectively. On the basis of porous nanostructures, two distinct benefits, i.e., enhanced surface area and abundant gas penetration pathway into the inner sens-ing layers, were obtained which are essential requirements for effective gas adsorption-desorption reactions, fast gas diffusion, and high gas response. As a result, Pt functionalized hierarchically interconnected multi-dimensionally porous $WO_3$ nanofibers exhibited highly selective and sensitive acetone sensing characteristics ($R_{air}/R_{gas}$ = 10.8 @ 1 ppm) and $Na_2W_4O_{13}-Pt$ of co-catalysts functionalized $WO_3$ nanotubes exhibited superior hydrogen sulfide sensing properties ($R_{air}/R_{gas}$ = 203.5 @ 1ppm), especially in highly humid ambient (95% RH). These works pave a new path to overcome critical shortcomings of SMOs based chemical sensors, thus providing potential exhaled breath sensing platforms with high sensing performance.