Ni–Cu Alloy Nanoparticles Confined by Physical Encapsulation with SiO<sub>2</sub> and Chemical Metal–Support Interaction with CeO<sub>2</sub> for Methane Dry Reforming
Yu Shi, Kaihang Han, Fagen Wang
Abstract
Fabrication of sintering- and carbon-free Ni catalysts for methane dry reforming (MDR), which is attractive to upgrade greenhouse gases CH4 and CO2, is challenging. In this work, we innovatively synthesized Ni–Cu alloy nanoparticles confined by physical encapsulation and chemical metal–support interaction (MSI); the synergism of alloy effect, size effect, MSI, and confinement effect in the catalysts gave high rates of CH4 and CO2 of 6.98 and 7.16 mmol/(gNis), respectively, at 1023 K for 50 h. The rates were 2–3 times enhanced compared to those in the literature. XRD, TEM, H2-TPR, and so forth revealed that the alloy effect, size effect, and MSI of Ni–Cu and CeO2 enhanced the MDR activity; MSI promoted the ceria surface lattice oxygen mobility and generated more oxygen vacancies, almost completely gasifying carbon deposits; chemical confinement from MSI and physical confinement from SiO2 nanospheres realized sintering-free alloys and CeO2 nanoparticles. The synergistic approach provides a universal strategy for sintering- and carbon-free Ni catalyst design for MDR reaction.