Cu/SAPO-34 synthesized via a one-pot method with relatively low silicon content and copper loading at around 2 wt.% facilitated continuous oxidation of methane to methanol with a methanol space time yield of 504 μmolCH3OH/gcat/h. Remarkably, the methanol yield exceeded 1800 mmolCH3OH/molCu/h at 623 K. Typically, the presence of trace oxygen in the system was the key to maintaining the high selectivity to methanol. Characterization results from a series of techniques, including XRD, SEM, TEM, H2-TPR, NH3-TPD, UV-vis, and FTIR, indicated that Cu2+ existed in the position where it moves from hexagonal rings to elliptical cages as the active center.
