Rapid and highly sensitive detection of formaldehyde gas via a polyoxometalate–CuBi ₂O ₄ composite gas sensor

Abstract

Quick response and high sensitivity are equally important for the practical application of gas sensors. In this study, we introduced polyoxometalates (POMs) into a classical ternary metal oxide CuBi 2 O 4 for the first time by convenient electrospinning and prepared a group of heater-type gas sensors by using CuBi 2 O 4 /PW 12 composite nanofibers. The sensor performances to formaldehyde gas were explored. The results proved that the gas-sensing response of the CuBi 2 O 4 /PW 12 (PW 12 = H 3 PW 12 O 40 •xH 2 O) composite sensor to 100 ppm formaldehyde gas was increased to 6.68, which was 3.92 times greater than the sensing capacity of the pure CuBi 2 O 4 sensor. Simultaneously, the sensor exhibited a highly rapid response/recovery time of only 1/2 s, which is significantly faster than performances of CuBi 2 O 4 gas sensors reported in the past literature. The cause of the improvement of the sensing performance was assessed via mechanism study, and it was found that the introduction of PW 12 into the sensor contributed to its enhanced performance. It was found that PW 12 , as an electron acceptor, increased carrier mobility and reduced electron-hole recombination, thus contributing to enhanced gas-sensing properties. Moreover, other gas-sensing parameters such as selectivity, humidity resistance, repeatability, long-term stability were investigated. Hence, this study contributed to the literature on the development of polyoxometalates-based gas sensors.

A visible-light-active ellagic acid-based titanium-oxo cluster for room temperature chemiresistive sensing

“…Therefore, intense research efforts have been devoted to the development and exploitation of the photocatalytic activity of TiO 2 and the expansion of its application to the visible-light region. In recent years, crystalline titanium-oxo clusters (TOCs) have attracted much attention as molecular model compounds of nanoscale TiO 2 materials due to their structural controllability and precise atomic structure [5][6][7][8][9]. At present, the reported applications of TOCs mainly focus on photocatalytic CO 2 reduction, photocatalytic hydrogen production, photocatalytic organic reactions, and I 2 adsorption [10].…”