Probing\nthe Metal/Oxide\nInterface of IrCoCeO<sub><i>x</i></sub> in N<sub>2</sub>H<sub>4</sub>·H<sub>2</sub>O Decomposition: An Experimental\nand Computational Study

Understanding\nthe structure of a functional catalyst\nis crucial\nto disclosing the complexity of heterogeneous processes and improving\ntheir efficiency. Herein, coprecipitated cobalt–ceria (CoCeO<sub><i>x</i></sub>) oxides doped with Ir (IrCoCeO<sub><i>x</i></sub>) were synthesized and used to assess the performances\nof metal/oxide interfaces in the N<sub>2</sub>H<sub>4</sub>·H<sub>2</sub>O decomposition performed in aqueous NaOH. Kinetic experiments\nin batch showed that CoO is the active phase of CoCeO<sub><i>x</i></sub> and that the copresence of Ir and Co (IrCoCeO<sub><i>x</i></sub>) enhanced H<sub>2</sub> productivity. A\ncomprehensive characterization (X-ray diffraction, transmission electron\nmicroscopy, X-ray photoelectron spectroscopy (XPS), X-ray absorption\nspectroscopy, and in situ diffuse reflectance infrared Fourier transform\nspectroscopy) combined with robust computational modeling based on\nthe density functional theory was employed to attribute the IrCoCeO<sub><i>x</i></sub> performance enhancement to the Ir/CoO metal/oxide\ninterface, the active site of the reaction. On these sites, the improved\nH<sub>2</sub> productivity in the presence of aqueous NaOH was studied\noperando through modulated excitation-attenuated total reflectance\ninfrared coupled with phase sensitive detection. The formation of\nsurface Co-hydroxyl and -imido groups at the Ir/CoO interface induced\nthe preferential breakage of the N–H bond of N<sub>2</sub>H<sub>4</sub>·H<sub>2</sub>O, favoring the production of H<sub>2</sub>.