Green Synthesis of Nano‐Sized Metal Oxides (Ag₂O, CuO, ZnO, MgO, CaO, and TiO₂) Using Plant Extract for a Sustainable Environment

ABSTRACT The demand for green synthesis of metal oxide nanomaterials is increasing tremendously to achieve sustainable development goals and for a clean environment. Simultaneously, metal oxides hold significant importance across various fields, such as catalysis, semiconductors, ceramics, photocatalysis, sensors, medicine, and energy storage, and so forth. The green synthesis process eliminates the use of toxic chemicals in the synthesis process. Different natural solvents (plant extracts) are widely utilized to synthesize metal oxides while maintaining a green environment. The extensively used plant extracts are Lawsonia inermis, Centella asiatica, Azadirachta indica, Moringa olifera, Papaya leaves, Paeonia emodi, Pavetta indica, Cyathea nilgiriensis, Callistemon lanceoletus, Rhaamnus virgata, Daphena alpina, Zephyranthes rosea, Common hops, Gloriosa superba, Thymus vulgaris, Ixoro coccinea, Cassia auriculata, Lanata camara , and so forth, for green synthesis of Ag 2 O, CuO, ZnO, MgO, CaO, and TiO 2 nanoparticles (NPs). The synthesis process and the reaction parameters are very crucial for tuning the properties of nanomaterials. In this review, the synthesis process using plant extract is explored along with the reaction parameter's effects on the morphology of the final product. And Fourier Transform Infrared (FTIR) spectroscopy was evaluated for the metal oxides to show the importance of FTIR in inorganic compound analysis.