Synthesis of Ni-doped ceria nanoparticles and their unusual surface reduction in hydrogen

This work presents an original approach to preparing pure and Ni-doped CeO2 nanoparticles (NPs) that can be directly drop-casted on a substrate or calcined to form powders. The reduction of the NPs in H-2 is very different than the one usually anticipated for supported Ni-CeO2 catalysts. In situ soft X-ray absorption and infrared spectroscopies revealed that the reduction of Ce4+ into Ce3+ in H-2 proceeds via simultaneous oxidation of Ni2+ ions into Ni delta+(2