Review A systematic review on 2D materials for volatile organic compound sensing Y. Ravi Kumar a , Kalim Deshmukh b,⇑ , Tomáš Kovár ˇík b , S.K. Khadheer Pasha a,⇑ a Department of Physics, VIT-AP University, Amaravati, Guntur 522501, Andhra Pradesh, India b New Technologies-Research Centre, University of West Bohemia, Plzen ˇ 30100, Czech Republic article info Article history: Received 8 December 2021 Accepted 3 March 2022 Available online 16 March 2022 Keywords: 2D-materials VOC sensors Sensing mechanism Sensitivity Detection limit abstract Volatile organic compounds (VOCs) are organic chemicals that are toxic and detrimental to the human body and the environment. Therefore, a great mandate for the selective as well as sensitive recognition of VOCs, process control, environmental monitoring, and medical diagnosis is necessary. In the last few years, various forms of nanomaterials have been explored for gas and VOCs sensing with the detection on the miniaturized scale using various sensing approaches including optical, chemiresistive, and electro- chemical techniques. Two-dimensional (2D) materials have received tremendous attention owing to their unique structure and extraordinary physical as well as chemical properties which make them an attrac- tive platform for numerous applications including electronics, optoelectronics, energy storage and con- version, catalysis, and chemical sensors. 2D-materials offer unique sensing properties with extremely high sensitivity which is particularly important for the detection of toxic pollutants such as nitrogen dioxide (NO 2 ) and toxic VOCs such as benzene and formaldehyde. This review emphasizes the state- of-the-art recent developments in synthesis, VOCs sensing performance and sensing mechanism of numerous 2D-materials including graphene, graphene oxide (GO), graphene nanoplatelets (Gr-NPls), gra- phene nanosheets (GNs), transition metal dichalcogenides (TMDs), hexagonal boron nitride (h-BN), MXenes, black phosphorus (BP) and graphdiyne etc. A brief descriptions of various synthesis approaches of 2D materials are given along with their fundamental VOCs sensing mechanisms. Finally, the perfor- mances of various 2D-materials derived VOC sensors are summarized. Ó 2022 Elsevier B.V. All rights reserved. Contents 1. Introduction ........................................................................................................... 2 2. Source and types of VOCs ................................................................................................ 3 3. Detection techniques of VOCs ............................................................................................. 3 4. Synthesis approaches of 2D materials ...................................................................................... 7 4.1. Physical approaches ............................................................................................... 7 4.1.1. Micromechanical exfoliation ................................................................................. 7 4.1.2. Ultrasonic exfoliation ....................................................................................... 7 4.2. Chemical approaches............................................................................................... 7 4.2.1. Hydro/Solvothermal synthesis ................................................................................ 9 4.2.2. Microwave-assisted method ................................................................................. 9 4.2.3. Topochemical transformation ................................................................................ 9 4.2.4. Chemical vapour deposition (CVD) ........................................................................... 10 5. Sensing mechanisms of VOCs ............................................................................................ 11 6. Types of VOC sensors and current status ................................................................................... 13 6.1. Chemiresistive sensors ............................................................................................ 13 6.2. Field effect transistor based sensors ................................................................................. 14 https://doi.org/10.1016/j.ccr.2022.214502 0010-8545/Ó 2022 Elsevier B.V. All rights reserved. ⇑ Corresponding authors. E-mail addresses: deshmukh@ntc.zcu.cz (K. Deshmukh), khadheerbasha@gmail.com (S.K. Khadheer Pasha). Coordination Chemistry Reviews 461 (2022) 214502 Contents lists available at ScienceDirect Coordination Chemistry Reviews journal homepage: www.elsevier.com/locate/ccr