CexZr1-xO2 solid solutions for catalytic synthesis of dimethyl carbonate from CO2: Reaction mechanism and the effect of catalyst morphology on catalytic activity

In the development of green and sustainable processes, one-pot conversion of carbon dioxide into value-added organic chemicals such as dimethyl carbonate (DMC) attracted much attention. In the present study, a series of CexZr1-xO2 solid solutions (x = 0.25, 0.5, 0.75) having acid/base and high surface area was synthesized for efficient production of DMC from CO2 and methanol. The as-prepared catalyst was characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) techniques to determine the size, shape, crystal structure and phases, oxidation states, and surface properties. The characterization results reveals that CexZr1-xO2 solid solutions synthesized by using modified precipitation method possess tetragonal-phase with surface Ce4+, many oxygen defects, high BET surface area (i.e. 116 m(2)/g), distinct morphology and excellent catalytic activity. The CexZr1-xO2 solid solutions showed excellent catalytic activity and stability under mild reaction conditions. The experimental results revealed that the CexZr1-xO2 could be an active and reusable catalyst for the direct synthesis of DMC by modifying their morphology and surface properties.