New Insights into SnO2/Al2O3, Ni/Al2O3, and SnO2/Ni/Al2O3 Composite Films for CO Adsorption: Building a Bridge Between Microstructures and Adsorption Properties

Since the environment and human body face with harmful effects of toxic gases such as carbon monoxide (CO), many research efforts have been directed towards elimination of these species through various adsorption processes. Unique properties of γ-Al2O3 in CO capture have led us to prepare SnO2/Al2O3, Ni/Al2O3, and SnO2/Ni/Al2O3 composite nanocrystalline films by the roll-coating method. Crystalline structure and morphology of the coatings were investigated using X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM), respectively. Performed analyzes revealed complex microstructure of the coatings composed of fine-grain, well dispersed nanoparticles aggregated to form larger, well-developed clusters. In the following adsorption characteristics of the samples were measured using KIMO KIGAZ 210 continuous-flow gas analyzer. Finally, the kinetics of the CO adsorption process was studied using various diffusion models: pseudo-first-order, pseudo-second-order and intra-particle.