Synthesis of Pt doped Mg–Al layered double oxide/graphene oxide hybrid as novel NOx storage–reduction catalyst

Abstract

We report the synthesis of Pt doped Mg–Al layered double oxide/graphene oxide (Pt–LDO/GO) hybrid as novel NO_x storage and reduction (NSR) catalyst. For the preparation of layered double hydroxide/GO hybrids, LDHs and graphite oxide were first exfoliated into single-layers, followed by self-assembly. LDO/GO hybrids were obtained by thermal treatment of LDH/GO. The obtained LDH/GO and LDO/GO hybrids were thoroughly characterized using XRD, SEM, TEM, FT-IR, and BET analyses. Then the NO_x storage capacity of neat LDO and LDO₍₁₀₎/GO hybrids were compared by isothermal NO_x adsorption tests. The influence of adsorption temperature, gas flow, calcination temperature, and LDH dispersion concentration were systematically studied. The results demonstrated that the NO_x storage capacity of neat LDO was significantly improved from 0.175 to 0.314 mmol g⁻¹ by introducing only 7 wt% of GO, which could be attributed to the enhanced particle dispersion and stabilization. Moreover, the NO_x storage capacity of the hybrid could be further increased close to 0.335 mmol g⁻¹ catalyst by doping with 2 wt% Pt. The Pt–LDO₍₁₎/GO also exhibited excellent lean-rich cycling performance, with an overall 71.7% of NO_x removal. This work provided a new scheme for the preparation of highly dispersed LDH/GO hybrid type NSR catalyst.