Novel application of attapulgite on high performance and low-cost humidity sensors

Abstract

Attapulgite, as a natural mineral with excellent physicochemical properties, abundant reserves, and low price, has been widely used in industry and agriculture. With the advancement of research, novel applications of attapulgite are still emerging. In this work, a low-cost humidity sensor based on attapulgite is firstly fabricated. The results show that the attapulgite humidity sensor exhibits excellent humidity sensing performance at room temperature (25 °C). The impedance variation of the sensor is more than five orders of magnitude within the humidity range from 0 % to 91.5 % relative humidity (RH) at the excitation frequency of 100 Hz and the response time (adsorption process) of the senor is only 3 s. Especially, the sensor not only has a good linear response to high RH (28.8 %–91.5 %), but also to low RH (0 %–28.8 %). Moreover, the sensor exhibits small humidity hysteresis (∼3.4 % RH), good repeatability and long-term stability. This work expands the novel application of attapulgite on humidity sensors, and also brings opportunities for the development of high performance and low-cost humidity sensors.