Secondary interaction-manipulated metal–organic crystalline nanotube array for gas sensing

Abstract

Although having attracted growing interest, the design and preparation of metal–organic crystalline nanotube arrays (MO-CNAs) remains a challenge. Herein, a Pb⋯S metal–nonmetal secondary interaction strategy was proposed to prepare a Pb(II)-based MO-CNA (Pb-HTT), endowing Pb-HTT with high thermal/chemical stability, a porous structure, and open metal sites. With unique unsaturated metal centers for guest accommodation, Pb-HTT exhibited the best sensing performance with both response time <0.1 min and theoretical limit of detection <0.1 ppb in comparison to all reported room-temperature NO₂ chemiresistive sensing materials. It also showed highly selective sensing toward NO₂ among 10 interfering gases. The experimental XANES data and theoretical calculation verified the exact active sites of Pb centers on Pb-HTT and revealed the sensing mechanism. Notably, this study not only provides a useful metal–nonmetal secondary interaction strategy for the construction of MO-CNAs, but also accelerates the application of semiconducting CNAs in structure-directed functional electronic devices.