Hydrogen-Tolerant CuO/TiO₂ Catalysts Enabled by Oxygen Anchoring for Nitrile Hydrogenation

Designing reducible metal oxide catalysts that remain stable under hydrogenation conditions represents a longstanding challenge in heterogeneous catalysis, as most oxides are readily reduced and structurally degraded in H₂-rich environments. Here, we report an oxygen-anchoring strategy that enables hydrogen-tolerant metal oxide catalysts. Using this approach, a CuO/TiO₂ catalyst stabilized by an oxygen-rich C─O framework (HT-CuO/TiO₂) was constructed for the selective hydrogenation-coupling of nitriles to secondary amines. The oxygen functionalities within the C─O framework act as anchoring sites that stabilize CuO nanoclusters and suppress their reduction under hydrogen. The stabilized CuO nanoclusters function both as hydrogen activation centers and Lewis acid sites for nitrile adsorption. Meanwhile, the introduction of TiO₂ leads to the formation of intimate CuO─TiO₂ interfacial structures, accompanied by the presence of Ti³⁺ species and enhanced hydrogen activation behavior. Notably, this hydrogen-tolerant behavior extends to a range of reducible metal oxides, including CuO, Cu₂O, CoO, and NiO, demonstrating the generality of the oxygen-anchoring stabilization principle. This work establishes a general strategy for stabilizing reducible metal oxides under hydrogen and unlocks their catalytic potential for hydrogenation chemistry.