Abstract
Iron (Fe)-based catalysts are widely used for taming nitrogen oxides (NOx) containing flue gas, but the regeneration and long-term reusability remains a concern. The reusability can be acquired by external additives, and resultantly can not only increase the cost but can also add to process complexity as well as secondary pollutants. Herein, a self-sustainable material is designed to regenerate the catalyst for long-term reusability without adding to process complexity. The catalyst is based on reduced graphene-oxide impregnated by Fe2O3-MnO (rGO@Fe2O3-MnO; G-F-M) for spontaneous intra electron (e-)-transfer from Mn to Fe. The developed catalyst; G-M-F exhibited 93.7% NOx reduction, which suggests its high catalytic activity. The morphological and structure characterizations confirmed the Fe/Mn loading, contributing to e--transfer between Mn and Fe due to its conductivity. The synthesized G-F-M showed higher NOx reduction about 2.5 folds, than rGO@Fe2O3 (G-FeO) and rGO@MnOx (G-MnOx). The performance of G-M-F without and with an electrochemical system was also compared, and the difference was only 5%, which is an evidence of the spontaneous e- transfer between the Mn and Fe-NOx complex. The designed catalyst can be used for a long time without external assistance, and its efficiency was not affected significantly (<3.7%) in the presence of high oxygen contents (8%). The as-prepared G-M-F catalyst has great potential for executing a dual role NOx removal and self-regeneration of catalyst (SRC), promoting a sustainable remediation approach for large-scale applications.
[Display omitted]
•Self-healing rGO@Fe2O3-MnO is prepared to propel applicability of catalytic reduction systems.•rGO@Fe2O3-MnO maintained > 90 % NOx removal for 48 h compared to rGO@FeO and rGO@MnOx.•GC-MS analysis confirmed efficient catalytic conversion of NOx into N2 (∼81 %) and N2O (9.4 %).•Catalyst’s efficacy for NOx reduction was not affected significantly (<3.7 %) in presence of O2 (8 %).•Redox potential of Mn is higher than Fe, facilitating e- transfer from Mn to Fe for self-regeneration.