Figure 7

(a) Isothermal NO_x storage over MgAlO_x at 250, 300, 350, and 400 °C, (b) Outlet NO₂/NO_x over MgAlO_x at 250, 300, 350, and 400 °C, (c) isothermal NO_x storage over MgAlO_x and MgAlO_x–rGO at 350 °C, (d) isothermal NO_x storage over XK/MgAlO_x–rGO (X = 5, 10, 15, and 20 wt%) at 350 °C.