AbstractPt/K₂CO₃/MgAlO_x–reduced graphene oxide (Pt/K/MgAlO_x–rGO) hybrids were synthesized, characterized and tested as a promising NO_x storage and reduction (NSR) catalyst. Mg–Al layered double hydroxides (LDHs) were grown on rGO via in situ hydrothermal crystallization. The structure and morphology of samples were thoroughly characterized using various techniques. Isothermal NO_x adsorption tests indicated that MgAlO_x–rGO hybrid exhibited better NO_x trapping performance than MgAlO_x, from 0.44 to 0.61 mmol · g⁻¹, which can be attributed to the enhanced particle dispersion and stabilization. In addition, a series of MgAlO_x–rGO loaded with 2 wt% Pt and different loadings (5, 10, 15, and 20 wt%) of K₂CO₃ (denoted as Pt/K/MgAlO_x–rGO) were obtained by sequential impregnation. The influence of 5% H₂O on the NO_x storage capacity of MgAlO_x–rGO loaded with 2 wt% Pt and 10% K₂CO₃ (2Pt/10 K/MgAlO_x–rGO) catalyst was also evaluated. In all, the 2Pt/10 K/MgAlO_x–rGO catalyst not only exhibited high thermal stability and NO_x storage capacity of 1.12 mmol · g⁻¹, but also possessed excellent H₂O resistance and lean–rich cycling performance, with an overall 78.4% of NO_x removal. This work provided a new scheme for the preparation of highly dispersed MgAlO_x–rGO hybrid based NSR catalysts.