Sorbitol-derived carbon overlayers encapsulated Cu nanoparticles on SiO(2): Stable and efficient for the continuous hydrogenation of ethylene carbonate

An ultrastable and efficient Cu@C/SiO(2) nanocatalyst was fabricated for the hydrogenation of ethylene carbonate, in which Cu nanoparticles are encapsulated by sorbitol-derived graphitized carbon overlayers. During the calcination of Cu-sorbitol/SiO(2) precursors under N(2) atmosphere, sorbitol decomposed to CO and CO(2). The in situ generated CO not only reduced Cu(2+) to Cu(0)/Cu(+), but also formed graphitized carbon overlayers on the Cu surface via the disproportionation of CO. The Cu@C/SiO(2) catalyst exhibited superior catalytic performance (91% MeOH yield and 43.6 h(−1) TOF) at a H(2)/EC molar ratio of 20. Of particular note, the Cu@C/SiO(2) catalyst showed remarkable long-term stability during 736 h time-on-stream test without any deactivation. The graphitized carbon overlayers on the surface of Cu nanoparticles not only functioned synergistically with the surface Cu(0)/Cu(+) sites to promote the EC hydrogenation but also suppressed the sintering of Cu nanoparticles. Furthermore, the interaction of Cu nanoparticles and graphitized carbon overlayers stabilized the surface Cu(+)/(Cu(0)+Cu(+)) ratio.