Metal–Metal Oxide Catalytic Interface Formation and Structural Evolution: A Discovery of Strong Metal–Support Bonding, Ordered Intermetallics, and Single Atoms

In-depth investigation of metal–metal oxide interactions and their corresponding evolution is of paramount importance to heterogeneous catalysis as it allows the understanding and maneuvering of the structure of catalytic motifs. Herein, using a series of core/shell metal/iron oxide (M/FeOx, M = Pd, Pt, Au) nanoparticles and through a combination of in situ and ex situ electron and X-ray investigations, we revealed anomalous and dissimilar M–FeOx interactions among different systems under reducing conditions. Pd interacts strongly with FeOx after high-temperature reductive treatment, featured by the formation of Pd single atoms in the FeOx matrix and increased Pd–Fe bonding, while Pt transforms into ordered PtFe intermetallics and Pt single atoms immediately upon the coating of FeOx. In contrast, Au does not manifest strong bonding with FeOx. As a proof of concept of tailoring metal–metal oxide interactions for catalysis, optimized Pd/FeOx demonstrates 100% conversion and 86.5% selectivity at 60 °C for acetylene semihydrogenation

Cascade Dual Sites Modulate Local CO Coverage and Hydrogen-Binding Strength to Boost CO₂ Electroreduction to Ethylene

Rationally modulating the binding strength of reaction intermediates on surface sites of copper-based catalysts could facilitate C–C coupling to generate multicarbon products in an electrochemical CO2 reduction reaction. Herein, theoretical calculations reveal that cascade Ag–Cu dual sites could synergistically increase local CO coverage and lower the kinetic barrier for CO protonation, leading to enhanced asymmetric C–C coupling to generate C2H4. As a proof of concept, the Cu3N-Ag nanocubes (NCs) with Ag located in partial Cu sites and a Cu3N unit center are successfully synthesized. The Faraday efficiency and partial current density of C2H4 over Cu3N-Ag NCs are 7.8 and 9.0 times those of Cu3N NCs, respectively. In situ spectroscopies combined with theoretical calculations confirm that Ag sites produce CO and Cu sites promote asymmetric C–C coupling to *COCHO, significantly enhancing the generation of C2H4. Our work provides new insights into the cascade catalysis strategy at the atomic scale for boosting CO2 to multicarbon products