Au-Pt Loaded Graphene/MoS₂ Heterostructure for High-Performance NH₃ Sensing at Room Temperature

Rapid detection of NH<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> gas is necessary because of its hazardous impacts on human health and other living beings. Two-dimensional (2D) graphene, MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>, WS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>, etc. showed great promise for room temperature gas sensing applications due to their high surface-to-volume ratio, and excellent electronic, and mechanical properties. However, their applications are still limited by poor sensitivity and selectivity, incomplete recovery, and poor stability. The formation of graphene/MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> heterostructure can overcome the limitations of NH3 gas sensing applications. The sensitivity can be further enhanced by loading Au-Pt on the graphene/MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> heterostructure. The Au-Pt loaded graphene/MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> sensor is studied through COMSOL Multiphysics by considering an interdigitated electrode structure. An enhanced sensitivity of 0.06316 ppm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> was realized for Au-Pt loaded graphene/MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>, indicating its potential for high-performance NH3 sensing. Moreover, the sensors exhibited a detection limit of down to 4 ppm. The enhanced sensing performance can be attributed to the abundant active sites on MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>/Graphene and fast electron transport in graphene/MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> heterostructure. Additionally, the catalytic effect of Au and Pt lowers the activation energy for NH<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> adsorption, eventually improving the sensor performance. This research can be useful for selecting suitable sensing materials and the optimum designs for high-performance gas sensors.