Embedded-Type Cu Nanoparticle with Largely Enhanced Catalytic Activity and Stability Toward Methanol Steam Reforming.

Hydrogen production through low-temperature methanol steam reforming (MSR) reaction plays a critical role in the development of new energy but remains a great challenge. Herein, we report a Cu/Zn(Ga)O catalyst, which is prepared via an interface reconstruction strategy. Interestingly, this catalyst is featured with a unique mortise-and-tenon structure: Cu nanoparticles are embedded into the Zn(Ga)O substrate, which ensures a stable Zn-O-Cu-O-Ga interface structure. The resulting Cu/Zn(Ga)O catalyst exhibits 99.3% CHOH conversion with an H production rate of 124.6 µmol g  s at 225 °C, which is preponderant to the state-of-the-art catalysts. Furthermore, an ultra-high catalytic stability was demonstrated through a 400 h stream-on-line test without obvious decline. Kinetic isotope analysis, in situ spectroscopy characterizations, and theoretical calculations reveal that the MSR reaction over Cu/Zn(Ga)O catalyst follows the formaldehyde oxidation route. The CHO* and HO molecule adsorb at the adjacent Cu-O interface (intrinsic active site) with an oxygen-terminal adsorption configuration, which promotes electron transfer from the d-band center of Cu to the O (s,p)-band of the substrate molecule. This significantly reduces the energy barrier of C─H bond cleavage in CHO* dehydrogenation (the rate-determining step) and HO dissociation, accounting for the extraordinarily enhanced H production.