Abstract
This paper presents a novel atomic layer deposition (ALD) based ZnO functionalization of surface pretreated multiwalled carbon nanotubes (MWCNTs) for highly sensitive methane chemoresistive sensors. The temperature optimization of the ALD process leads to enhanced ZnO nanoparticle functionalization and improvement in their crystalline quality as shown by energy dispersive x-ray and Raman spectroscopy. The behavior of ZnO–MWCNT sensors in presence of methane concentrations down to 2 ppm level has been compared with that of pristine MWCNTs demonstrating that ZnO functionalization is an essential factor behind the highly sensitive chemoresistive nature of the ZnO–MWCNT heterostructures. The sensor is currently being tested under a range of conditions that include potentially interfering gases and changes to relative humidity.
Highlights
Methane (CH4) is a potent greenhouse gas with the 100year global warming potential 28–36 times higher than that of CO2.1 Since 2012, U.S has been the world-leading producer of natural gas.2 The rapidly expanding natural gas infrastructure in the U.S dictates the need for ubiquitous distributed low-cost methane sensors, as current CH4 sensors suffer from low accuracy, high cost, and high power consumption
This paper focuses on the design and fabrication of a methane sensor based on multiwalled carbon nanotubes (MWCNTs) functionalized with ZnO deposited by atomic layer deposition (ALD)
In order for the MWCNT network to function as a chemoresistor, it is necessary that the ALD-deposited ZnO does not create a direct conductive path between the electrodes outside of the MWCNT mesh, i.e., the sensor electrodes are only connected via the MWCNT network
Summary
Methane (CH4) is a potent greenhouse gas with the 100year global warming potential 28–36 times higher than that of CO2.1 Since 2012, U.S has been the world-leading producer of natural gas. The rapidly expanding natural gas infrastructure in the U.S dictates the need for ubiquitous distributed low-cost methane sensors, as current CH4 sensors suffer from low accuracy, high cost, and high power consumption. Methane (CH4) is a potent greenhouse gas with the 100year global warming potential 28–36 times higher than that of CO2.1 Since 2012, U.S has been the world-leading producer of natural gas.. The rapidly expanding natural gas infrastructure in the U.S dictates the need for ubiquitous distributed low-cost methane sensors, as current CH4 sensors suffer from low accuracy, high cost, and high power consumption. Existing metal-oxide CH4 sensors are highly power consuming, have high detection limit (low sensitivity), and low selectivity.. Infrared absorption-based CH4 sensors have low sensitivity and selectivity.. Cavity ringdown spectroscopy sensors are expensive and large, and not suitable for in situ leak detection.. The development of low power, sensitive (1 ppm), selective, and low cost CH4 sensor is critical for enabling ubiquitous deployment throughout the natural gas infrastructure to measure and mitigate methane emissions Existing metal-oxide CH4 sensors are highly power consuming, have high detection limit (low sensitivity), and low selectivity. Infrared absorption-based CH4 sensors have low sensitivity and selectivity. Cavity ringdown spectroscopy sensors are expensive and large, and not suitable for in situ leak detection. The development of low power, sensitive (1 ppm), selective, and low cost CH4 sensor is critical for enabling ubiquitous deployment throughout the natural gas infrastructure to measure and mitigate methane emissions
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