Abstract
A two-dimensional (2D) Dy2O3-Pd-PDA/rGO heterojunction nanocomposite has been synthesised and tested for hydrogen (H2) gas sensing under various functioning conditions, including different H2 concentrations (50 ppm up to 6000 ppm), relative humidity (up to 25 %RH) and working temperature (up to 200 °C). The material characterisation of Dy2O3-Pd-PDA/rGO nanocomposite performed using various techniques confirms uniform distribution of Pd NPs and 2D Dy2O3 nanostructures on multi-layered porous structure of PDA/rGO nanosheets (NSs) while forming a nanocomposite. Moreover, fundamental hydrogen sensing mechanisms, including the effect of UV illumination and relative humidity (%RH), are investigated. It is observed that the sensing performance is improved as the operating temperature increases from room temperature (RT = 30 °C) to the optimum temperature of 150 °C. The humidity effect investigation revealed a drastic enhancement in sensing parameters as the %RH increased up to 20%. The highest response was found to be 145.2% towards 5000 ppm H2 at 150 °C and 20 %RH under UV illumination (365 nm). This work offers a highly sensitive and selective hydrogen sensor based on a novel 2D nanocomposite using an environmentally friendly and energy-saving synthesis approach, enabling us to detect hydrogen molecules experimentally down to 50 ppm.
Highlights
Hydrogen (H2 ) is a non-toxic, odourless, and colourless gas that can be used as a renewable energy source [1]
The surface characteristics of the sensor revealed a uniform distribution of 2D Dy2O3 and Pd NPs onto the PDA/reduced graphene oxide (rGO) nanosheets
Raman analysis showed no significant defects in Pd-PDA/rGO NSs while
Summary
Hydrogen (H2 ) is a non-toxic, odourless, and colourless gas that can be used as a renewable energy source [1]. H2 is abundant on earth in different molecular forms, including water and organic chemical compounds that contain hydrogen-carbon bonds such as hydrocarbons [2]. Different 2D semiconducting materials, including metal oxides, transition metal dichalcogenides (TMDs), and graphene-based materials, have been used as hydrogen sensors due to their electrochemical and physical characteristics [3,4,5,6]. Graphene-based materials are considered as promising hydrogen sensing candidates with low operating temperatures due to their excellent charge carrier mobility, high conductivity, and electrochemical stability [10]. Their recovery is slow and mostly show poor selectivity due to the absence of a direct
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