화학공학소재연구정보센터
Applied Catalysis A: General, Vol.556, 137-154, 2018
Smart designing of metal-support interface for imperishable dry reforming catalyst
A strategy has been made to design a more active and stable metal-support interface by controlled synthesis of Ni nanoparticle on bimodal alumina support for CO2 reforming with methane. A bimodal porous alumina support was prepared via the evaporation-induced self-assembly (EISA) method, and the nickel nanoparticles (5 wt.%) on bimodal alumina was synthesized using four different synthesis methods such as freeze drying, wet impregnation, urea deposition-precipitation, and chemical vapor deposition method. The reactivity of nickel nanoparticles was evaluated for CO2 reforming with methane, concerning the CO2 and CH4 conversion as well as the H-2 to CO ratio of the produced syngas. The catalysts were thoroughly characterized before and after the reaction using different techniques such as X-ray diffraction (XRD), N-2 sorption analysis, H-2-temperature programmed reduction (H-2-TPR), H-2-temperature programmed desorption (H-2-TPD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), inductive coupled plasma-mass spectrometry (ICP-MS) and transmission electron microscopy (TEM). Characterization of various catalysts revealed that variation of synthesis procedure affects the metal-support interface and the type of nickel species present on the gamma-alumina support, as well as the textural properties of the catalysts. The catalytic behavior was entirely different for each of the as developed metal-support interface, derived in by the use of different synthesis procedures. The catalyst prepared by urea deposition-precipitation method was found to be most active and stable at 700 degrees C and latm for a period of a 100h run of time on stream with diluted gas feed and even without the dilution of feed gas for next 25h of the run. Comparing with bimodal catalyst, a unimodal catalyst with same metal loading exhibited the inferior catalytic activity and stability. The results of the comparative study showed that the stable catalytic performance of the bimodal structured catalyst is due to the combined effect of the type of metal-support interface of the catalyst, smaller size of nickel particle and bimodal structure of support material. The bimodal pore character of catalyst support has shown to prevent, Ni particles from sintering during the reaction and hence, better catalytic performance and resistance to coking.