Probing the efficiency of platinum nanotubes for the H2 production by water gas shift reaction: A DFT study

Abstract The water gas shift (WGS) reaction is an important step in many industrial processes and has thus stimulated various investigations focusing on optimising its catalysts. Previous studies comparing the reactivity of pure and doped-metallic nanotubes towards the catalysis of water dissociation, the key rate-limiting step for the WGS reaction on copper surfaces, suggest that platinum nanotubes stand up as being probably the most active catalysts for the water gas shift reaction. Therefore, we present here a detailed analysis of the performance of platinum nanotubes in the catalysis of the WGS reaction, by employing the Pt(5,3) nanotube as catalyst model and periodic density functional theory calculations. To do so, several reaction pathways were considered on the faces of the Pt(5,3) nanotube and then, energetic balances for the elementary steps on each pathway were determined. This allowed us to conclude that the most feasible reaction route for the WGS reaction on this nanotube follows an associative mechanism through the carboxyl intermediary. The results of this study revealed also that the Pt(5,3) nanotube is an adequate system for the catalysis of the WGS reaction, apart from avoiding the sintering problem intrinsic to catalysts based on nanoparticles dispersed on a support.