Highly dispersed Ag2O-CuO nanospheres supported on γ-χ-Al2O3 for methanol dehydration to dimethyl ether

In this manuscript, the wet impregnation method was used to support Ag2O, CuO, and Ag2O-CuO nanoparticles on gamma-chi-Al2O3 to assess their catalytic capabilities in the methanol dehydration (MD) reaction to produce dimethyl ether (DME); the operation conditions were 1 atm and temperature ranging between 200 and 240 degrees C. It was found that Ag2O-CuO/gamma-chi-Al2O3 catalyst result in MD conversions up to 88 % and selectivities of 100 %, under 240 degrees C conditions. The catalytic activity of the Ag2O-CuO/gamma-chi-Al2O3 catalyst is related to the high dispersion, homogeneity and larger size of the Ag2O-CuO nanoparticles (-12.6 nm) compared to Ag2O and CuO nano particles, which have sizes of 9.52 and 10 nm, respectively. Additionally, the catalytic activity of the Ag2O-CuO/gamma-chi-Al2O3 material is related to its total acidity (weak and moderate), 0.056 mmol/g, showing a difference of 25 %, 28.57 and 5.35 % with respect to the gamma-chi-Al2O3, CuO/gamma-chi-Al2O3 and Ag2O/gamma-chi-Al2O3 materials, respectively. Finally, the catalytic stability measurements of the Ag2O-CuO/gamma-chi-Al2O3 catalyst remained relatively constant over time, presenting a conversion value of 79 % after 2.6 h of reaction due to the low apparent activation energy, 112.6 kJ/mol. The results of the exergy analysis indicate that the chemical exergy of the system ranges between 1/6 and 1/3 of the physical exergy, and most of the energy available to produce work is in the form of heat.

Automated summary

The wet impregnation method was used to support Ag2O, CuO, and Ag2O-CuO nanoparticles on gamma-chi-Al2O3 to evaluate their catalytic capabilities in the methanol dehydration (MD) reaction for dimethyl ether (DME) production. The Ag2O-CuO/gamma-chi-Al2O3 catalyst showed high catalytic activity and stability.