J.B. Baruah
Urea is indispensable as a fertilizer, a source of hydrogen, a component of explosives, and in biological activities. The urea-based metal complexes also serve as precursors for nanomaterials. Urea is continuously generated by excretion from animals, and due to its utility in various day-to-day requirements, the demand for it is very high. This article focuses on the recent trends in the synthesis of urea and metal complexes of urea. The review also deals with the use of urea in thermal decompositions of complexes to provide nanomaterials. The utility of metal complexes in the hydrolysis of urea stems from the urease enzyme; the review brings out key examples of different metal complexes in the hydrolysis of urea. The Fertilizer composites of urea with controlled bioavailability and controlled release to maintain an environmentally benign process are described. The electrochemical and photoelectrochemical urea oxidation reaction (UOR) involving different types of electrocatalysts is elucidated. The functional behaviors of the electro and photoelectro catalysts in urea activation for UOR are systematically presented. Use of different nanocomposites and related electro and photo-electrocatalysts in the synthesis of urea from nitrate and carbon dioxide in water is presented. • Photo/electrochemical synthesis of urea. • Metal complexes of urea and hydrolysis. • Use of different composites in urea detections. • Electro- and photo-electrocatalysis for urea oxidation. • Urea composites for a benign ecosystem.