fig3

Figure 3. TEM pattern of the used Au/ZnO catalysts (A) before leaching and (B) after leaching; (C) Negative ion HRMS of the toluene solution after leaching; (D) Proposed mechanism for the gold leaching assisting by oxidative carbonylation of amines. TEM: Transmission electron microscopy; HRMS: high-resolution electrospray-ionization mass spectra.