Inorganic catalytic systems for the reduction/degradation of 2,4-dinitrophenol: Theoretical, practical and mechanistic aspects

2,4-Dinitrophenol (2,4-DNP) is a pollutant that must be converted into less toxic 2,4-Diaminophenol (2,4-DAP). It is done by using various reducing agents like sodium borohydride and hydrazine hydrate. However, the reduction of 2,4-DNP is not kinetically favorable, therefore, a range of catalytic systems have been reported that can be used to speed up the conversion of 2,4-DNP into 2,4-DAP. Metal-based nanoparticles supported by suitable stabilizers are widely used as catalysts for reducing 2,4-DNP. Theoretical, practical and mechanistic aspects of inorganic nanoparticles catalyzed reduction of 2,4-DNP into 2,4-DAP have been discussed in this review. Langmuir-Hinshelwood (L-H) mechanism has been widely reported to explain the process of catalytic reduction of 2,4-DNP. This review presents the possible catalysts supported by various systems that have been reported to catalyze the reduction of 2,4-DNP in aqueous medium.