Progress in Layered Double Hydroxide-Based Materials for Gas and Electrochemical Sensing Applications

In the current scenario, it is considered that environmental pollution is one of the significant challenges for the global world. Various toxic and hazardous substances such as hydrazine, phenolic compounds, and pharmaceutical waste significantly contribute to environmental pollution. Exposure to such substances and compounds increases the chances of negative effects on human health as well as the environment. Therefore, it is considered that monitoring toxic gases and hazardous substances/compounds is of great significance. In the past few years, layered double hydroxide (LDH)-based materials have received significant interest for gas sensing and electrochemical sensing studies. The presence of layered structured, larger surface area, decent conductivity, and electrochemical properties makes them a suitable material for sensing applications. This motivates us to summarize the recent progress in the development of LDH material-based gas and electrochemical sensors for the detection of toxic and hazardous gases/compounds. It was observed in previous reports that LDH-based materials are promising candidates for gas sensing as well as electrochemical sensing applications. It was found that LDH and its composites may exhibit larger surface areas and high electrical conductivity when combined with other materials such as metal oxides, MXenes, polymers, and metal sulfides. Thus, researchers prepared hybrid composites of LDH-based materials for gas and electrochemical sensing applications. It is worth mentioning that many solvents which have negative impacts on the environment could not be detected by electrochemical methods, while some toxic compounds/substances could not be determine by gas sensing methods. This may create a gap between the determinations of different kinds of pollutants that exist in the environment. Thus, it is required to find a bi-functional material which can be used for kind of sensing technology. In addition, it may also overcome the limitations or gap between the two sensing techniques. LDH-based materials have demonstrated excellent performance in gas and electrochemical sensing technologies. Thus, it would be of great significance to employ the single LDH-based materials for gas as well as electrochemical sensing applications. In this review article, we have tried our best to compile the progress in the various LDH-based materials for gas sensing and electrochemical sensing applications towards the detection of hazardous compounds.