Synthesis of Pt/K(2)CO(3)/MgAlO(x)–reduced graphene oxide hybrids as promising NO(x) storage–reduction catalysts with superior catalytic performance

Pt/K(2)CO(3)/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 K(2)CO(3) (denoted as Pt/K/MgAlO(x)–rGO) were obtained by sequential impregnation. The influence of 5% H(2)O on the NO(x) storage capacity of MgAlO(x)–rGO loaded with 2 wt% Pt and 10% K(2)CO(3) (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 H(2)O 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.