Abstract
Silica supported nickel nanoparticles of 2.2 +/- 0.4 nm diameter were selectively doped with tin by surface organometallic chemistry while keeping the particle size nearly constant. The catalysts with various tin contents were doped and characterized by TEM, XRD and H-2 chemisorption. In contrast to what is found at high temperature (>= 973 K), dry reforming tests performed at 773 K and successive TPO and TEM analysis showed that tin neither influences the catalyst deactivation rate nor prevents coke formation, present in the form of encapsulating carbon. The nickel dopant does not influence either the selectivity, ruled by reverse water gas shift Thermodynamics, but was shown to have a 3-4-fold decrease of intrinsic activity of the available surface nickel, thus indicating that Sn has a negative effect on adjacent Ni atoms. (C) 2014 Elsevier B.V. All rights reserved.