Strong coke-resistivity of spherical hollow Ni/SiO2 catalysts with shell-confined high-content Ni nanoparticles for methane dry reforming with CO2

Hollow nanocatalysts, which are vehemently researched for their delimited cavity and enclosed shell, could manifest tunable focal properties besides well-defined active sites, thus enhancing the catalytic functionality. Herein, nickel-silicate hollow spheres (NHSs) with varied shell thickness and interior cavity size were commensurately designed. Distinction between various NHSs-derived Ni/SiO2 with identically mimicked morphologies was realized by examining their catalytic performance for methane dry reforming (DRM) reaction with sweeping pre- and post-reaction characterizations (TEM, XPS, XANES, in-situ DRIFTS). Besides facilitating the DRM reaction up to its thermodynamic limit, it was revealed that optimal NHS conformation is beneficial as a potential natural barrier against sintering and coking bottlenecks. Furthermore, a fine-tuned shell composition could endow improved Ni-sintering resistivity and enhanced reactivity to the NHS nanocatalysts. Our findings prove that the hollow interior space with a conducive shell thickness positively influences the reactant conversion and coking hindrance during the DRM reaction.