Metal–Organic Coordination Polymers: A Review of Electrochemical Sensing of Environmental Pollutants

Environmental contamination has been a notorious danger to mankind. Fast development, modern industrialization, change in lifestyle of the masses, and incomplete knowledge about material safety data sheets (MSDS) of every material/chemical discharged cause degradation of the environment. To monitor and control of such pollution, there is an urgent requirement for innovative methods for identification, classification, and quantification of the pollutants with excellent performance (like high selectivity, high sensitivity, fast response time, and reliability). Among several analytical sensing techniques, an electrochemical method of detection, using metal–organic frameworks (MOFs) as the sensing platform for trace quantity recognition of ecological analytes, grabs most of the attention due to its very high sensitivity, nonspecific way of measurement (absorption/fluorescence are very specific), both redox noninnocent and innocent analytes could be determined, quick response time, use of single instrument for different measurements, etc. MOFs are porous coordination polymers (CPs) formed by coordination of metal nodes/clusters and multitopic organic linkers as ligands. Due to their large surface area, permanent porosity, abundant microcrystalline structures and ease of the tailoring, postsynthetic modification properties of MOFs have made them advantageous for storage, catalysis, sensing, separation, and biological applications. On combining with small biomolecules, organic dyes, nanoparticles, nanowires, nanofibers, etc., composite MOFs have better mechanical stability, catalytic performance, conductivity, and sensing application. This review is focused on the recent attention of the electrochemical sensing applications of MOFs and their composites. Electrochemical sensors are an economical and suitable technique for the detection of different analytes and are extensively utilized in agriculture, food, oil, dyes and pigments, pharmaceutical industries, and biomedical applications. Herein, we have highlighted the use of MOFs in the sensing of different environmental contaminants i.e., volatile organic compounds (VOCs), phenolic compounds, heavy metal ions, antibiotics, pesticides, hydrazine, nitrite, nitroaromatic compounds, etc. This Review covers the publications from 2000 to 2024 (January), and we are confident that this review will enable new inspiration to exploit MOFs-based advanced electrochemical sensing properties in the future.