“…An extensive literature review has been performed on ODHE-CO 2 , and the summary is given in Table . It can be observed from the table that several active metals such as Cr-based, − Ga-based, ,, Ni-based, Au-based, , Fe-based, Co-based, Ce-based, and Mo-based catalysts and also mixed with promotors − supported on various metal oxides such as SiO 2 , ZrO 2 , TiO 2 , MgO, Al 2 O 3 , etc., were tested for ODHE-CO 2 . Nakagawa et al were among the first to perform the ODHE-CO 2 using Ga-based and Cr-based catalysts and achieved the maximum ethylene yields ( Y C2H4 ) of 20 and 10%, respectively, in comparison to the 2–3% yield achieved without the catalyst at a temperature and molar ratio of CO 2 /C 2 H 6 and GHSV of 650 °C and 5 and 9000 L/kg cat ·h, respectively.…”