Metal powder–pure water system for rational synthesis of metal oxide functional nanomaterials: a general, facile and green synthetic approach

Abstract

Metal oxide (MO) nanomaterials have played a pivotal role in many fields. The general, facile and green approach for rational synthesis of MO nanomaterials is highly desirable. In this work, a simple approach via an ultrasonic-assisted preoxidation and a subsequent hydrothermal oxidation (UAPO–HO) of metal powders directly in pure water without using any other chemicals has been developed as a general synthetic route to prepare MO nanomaterials. Three representative MO nanomaterials (Mn₃O₄ nanorods, ZnO nanopellets, and Fe₃O₄ nanocubes) have been successfully synthesized by this UAPO–HO approach for the first time. The properties of the newly synthesized MO nanomaterials, such like Mn₃O₄ as an electrode material for supercapacitors, ZnO as an photocatalyst for degrading organic pollutants, and Fe₃O₄ as a magnetic catalyst for disposing antibiotics, are investigated, which demonstrate attractive performance in energy storage and environmental protection. The synthetic approach developed here has the significant advantages of being chemical-utility least, product-purity high, facile, green and mild, which offers a unique clue for synthesis of MO nanomaterials.