Effect of calcination temperature and atmosphere on the properties and performance of CuAl catalysts for glycerol dehydration to acetol

Abstract

A series of CuAl catalysts were prepared by the coprecipitation method. The objective of this study was to investigate the influence of different calcination temperatures (500, 600, and 675 °C) and calcination atmospheres (N₂ or air) on the catalysts physicochemical properties and performance in the gas-phase glycerol dehydration to acetol. The catalytic tests were carried out in a fixed bed reactor at 250 °C, atmospheric pressure, and a catalyst weight to glycerol flow rate ratio (W/m) of 30 g_Catalyst min g_Glycerol⁻¹. The catalysts were characterized by ICP-OES, N₂ adsorption-desorption, X-ray diffraction (XRD), H₂ temperature programmed reduction (H₂-TPR), temperature gravimetric analysis (TGA), and elemental analysis. The characterization results revealed that both calcination temperature and calcination atmosphere influenced the textural and metallic properties. Increasing the calcination temperature lowered the reduction temperature, and decreased the surface area. The calcination atmosphere influenced the surface area and pore diameter, and the N₂ atmosphere generated a larger pore diameter. The best catalytic activity was achieved by the CuAl-675-N catalyst calcined at 675 °C in a N₂ atmosphere, which produced a glycerol conversion of 99.0 % and an acetol yield of 67.3 %. The superior performance could be attributed to textural properties, the Cu phase, and minimized carbon deposition, establishing it as one efficient catalyst derived from inexpensive and widely available metals. This work proposes an economical and simple technique based on calcination to improve the catalytic activity of Cu-based catalysts.