Structural and surface evolution of nanostructured Cu-Zn-Al catalyst designed by hybrid plasma-enhanced microwave-irradiated urea-nitrate-combustion for selective H2-production

Abstract

BackgroundRecently, limited sources of fossil fuels and environmental issues have caused to expanded worldwide search for an alternative clean energy. Among these, steam methanol reforming is the most common industrial kind of mature technology to produce hydrogen. MethodsIn this regards, a series of Cu-Zn-Al catalysts were synthesized via conventional urea-nitrate combustion and hybrid plasma-enhanced microwave-irradiated urea-nitrate combustion methods. The samples were characterized using XRD, FESEM, TEM, EDX, BET, FTIR and TPR-H2 techniques. Significant findingsThe crystalline size of CuZnAl-MC-P which was treated with plasma, reduced in comparison to untreated samples. This sample had high dispersion of CuO (111), ZnO (100) and ZnO (002) crystalline facets leading to enhancement of CH3OH conversion and H2-selectivity. As determined by FESEM and EDX, the plasma significantly caused to high dispersion of active sites which led to absence of any agglomeration. These features have led to prominent catalytic performance of plasma treated catalyst. Therefore, complete conversion of methanol and CO selectivity of 0.55% have been obtained at 260 °C using CuZnAl-MC-P sample. Stable performance of CuZnAl-MC-P for 24 h revealed that application of plasma post-treatment has caused strong bonding between components of catalyst and the absence of any agglomeration or sintering of particles.