cStudy on NH3-SCR performance of CoMnFeAl-LDO derived from layered double hydroxides supported on CNTs/TiO2NWs and its mechanism

In this study, a series of CoMnFeAl-layered double oxide (LDO) catalysts supported on multi-walled carbon nanotubes (MWCNTs)/titanium dioxide nanowires (TiO 2 NWs) were synthesized via the hydrothermal method. The catalytic performance of the synthesized catalysts was evaluated by the activity tests, and the characterizations and morphologies were measured by using X‐ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption of ammonia (NH 3 -TPD), temperature-programmed desorption of sulfur dioxide (SO 2 -TPD), temperature-programmed reduction of hydrogen (H 2 -TPR), and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). The results demonstrated that both CoMnFeAl-LDO/CNT and CoMnFeAl-LDO/TiO 2 NW catalysts achieved 100 % NO x conversion within their optimal temperature ranges and exhibited excellent sulfur resistance. Morphological studies revealed that the introduction of CNTs or TiO 2 NWs effectively mitigated the aggregation and stacking of LDHs during calcination, resulting in enhanced dispersion of active components. Moreover, these modifications increased surface acidity, redox capability, and SO 2 tolerance of the CoMnFeAl-LDO catalyst. The in situ DRIFTS results indicated that the SCR reactions over CoMnFeAl-LDO/CNT and CoMnFeAl-LDO/TiO 2 NW followed both the Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms. This study highlighted the potential of CNTs/TiO 2 NWs to modify CoMnFeAl-LDO catalysts, offering insights for the design of efficient and sulfur-resistant catalysts to address stringent environmental regulations.