High dispersion strategy of Ni species on the TEA-grafting surfaces of the lamellar clinoptilolite for enhancing CH4-CO2 reforming

This study explores the preparation of the Ni-based catalysts supported on clinoptilolite (CP) for dry reforming of methane (DRM) using three methods: impregnation, complex route, and one-pot synthesis. The impact of these strategies on Ni dispersion and catalytic performance was investigated. Triethylamine was utilized as a complexing agent to improve Ni dispersion, prevent catalyst sintering, and reduce carbon deposition. The physicochemical properties were characterized using X-ray diffraction patterns, Fourier transform infrared spectroscopy, Raman spectra, and X-ray photoelectron spectroscopy spectra, N 2 adsorption–desorption isotherms, scanning electron microscopy and transmission electron microscopy images, hydrogen temperature-programmed reduction and thermogravimetric analysis. The results indicate that the CP-TEA/4Ni catalyst prepared via the complex route exhibited a higher Ni content (2.84 wt%) and demonstrated the highest initial activity at 600 °C (44.5% CH 4 conversion, 43.4% CO 2 conversion). Conversely, the (3NiTEA)CP catalyst synthesized via the one-pot method confined Ni particles within the microporous structures of CP, significantly suppressing carbon deposition and Ni particle growth, and thereby ensuring exceptional stability (105 h at 600 °C). The amorphous and graphitic carbon deposition coexisted in the deactivated catalysts, whereas the I D /I G value of the deactivated CP/TEA-3Ni was higher. Furthermore, Grand Canonical Monte Carlo-Molecular Dynamics coupled simulations revealed that surface Ni clusters were conducive to enhancing CH 4 adsorption heat and facilitating CO 2 diffusion, which effectively inhibited carbon deposition. These findings underscore the role of synthetic strategies in designing high-performance Ni-based catalysts for DRM reaction, offering pathways to more cost-effective, stable, and efficient catalysts for industrial methane reforming and carbon emission reduction.