Improved Gas-Sensitive Properties by a Heterojunction of Hollow Porous Carbon Microtubes Derived from Sycamore Fibers

Abstract

Sycamore villus fibers were used to prepare hollow and porous carbon microtubes (CMTs) and the ZnO/CMT composite with heterojunctions by simple carbonization for the first time. Because the hollow and porous structure provided more channels to facilitate the adsorption and desorption of gas molecules, both CMTs and ZnO/CMT exhibited higher sensitivity and quicker response (<16 s) to and recovery (<2 s) from multiple target analytes. Furthermore, ZnO nanoparticles were uniformly dispersed on the CMTs by zinc acetate-assisted carbonization, which avoided the agglomeration of ZnO and formed a large number of heterojunctions, greatly improving the sensitivity of ZnO/CMT. In comparison to the pure CMTs and ZnO, the response of ZnO/CMT to the four target gases increased by 1.4∼4.3 and 9.9∼18.1 times, respectively. Their limit of detection for NH 3 was calculated as 62.5 and 8.8 ppb, respectively. After 30 days, the responses of CMTs and ZnO/CMTs to 500 ppm NH 3 decreased by 9.4 and 6.5%, respectively. This indicated that CMTs and ZnO/CMT had high sensitivity and good long-term stability. This study provides a feasible way for the gas-sensing application of biomass carbon materials with heterojunction structures.

Wool-Based Carbon Fiber/MoS2 Composite Prepared by Low-Temperature Catalytic Hydrothermal Method and Its Application in the Field of Gas Sensors

“…In order to comprehensively evaluate the gas-sensing performance of WCF-MoS 2 , the performances of recent NH 3 sensors are compared in Table 1 . As shown in Table 1 , the response time and recovery time of WCF–MoS 2 for NH 3 were 16 and 5 s, respectively, which were close to the shortest response time (14 s) and recovery time (4 s) shown by ZnO/CMTs [ 37 ]. Moreover, the LoD (19.1 ppb) of WCF–MoS 2 could not catch up with the LoD (9 ppb) of ZnO/CMTs.…”

“…Figure 4 f,g show the peaks of O 1s in WCF and the WCF–MoS 2 composite, respectively. O V and O C were oxygen vacancies and chemisorbed oxygen species, respectively [ 37 ]. The percentages of O C in the total oxygen element area in WCF and WCF–MoS 2 were 45.6% and 55.7%, respectively.…”

“…Therefore, a depletion layer was formed at the interface between WCF and MoS 2 [ 52 , 53 ]. When the WCF–MoS 2 composite was exposed to the air, the O 2 molecules of the air were adsorbed on the surface of WCF–MoS 2 and captured electrons from the WCF–MoS 2 composite to form negative oxygen ions, as follows [ 37 ]: …”

“…When the WCF–MoS 2 composite was in NH 3 gas, some NH 3 molecules were absorbed on the surface and reacted with . The reaction of NH 3 molecules with can be described as follows [ 37 ]: …”

A dog nose-inspired high-performance NH3 gas sensor of biomass carbon materials with a pleated structure derived from rose tea

“…10 The classical Hummer's method for graphene preparation uses strong acids and oxidizers, which not only pollute the environment but are also unsustainable. 10,11 Therefore, it is imperative to develop a biomimetic material that is both environmentally friendly and sustainable for gas sensors. Biomass carbon materials (BCMs) are emerging potential materials due to their abundant resources, recyclability and environmental friendliness.…”