Size‐tunable Ni‐Cu Core‐Shell nanoparticles – structure, composition, and catalytic activity for the reverse water‐gas shift reaction

We describe a facile and efficient methodology for the solvothermal synthesis of size-tunable, stable, and uniform NiCu core-shell nanoparticles (NPs) for application in catalysis. We are able to tune the diameter of the nanoparticles in a range from 6 to 30 nm and to adjust the Ni:Cu ratio from 30:1 to 1:1. Furthermore, the influence of different reaction parameters on the final nanoparticles is studied. The nanoparticles are structurally characterized by a method combination of TEM, ASAXS, XAFS, and XPS. Using these analytical methods, it is possible to elucidate a core-shell-shell structure of all particles and their chemical composition. In all cases, we observe a depletion from the core to the shell, with the core consisting of NiCu alloy, surrounded by an inner Ni-rich shell and an outer NiO shell. The SiO2-supported NiCu core-shell nanoparticles show pronounced selectivity of >99% for CO in the catalytic reduction of CO2 to CO using hydrogen as reactant (reverse water-gas shift reaction) independent of size and Ni:Cu ratio. This article is protected by copyright. All rights reserved.