NiFe₂O₄-Triggered Hydrogen Spillover Pathway over NiFe-Layered Double Hydroxide (LDH) for Robust Room-Temperature...

Active hydrogen (*H)-mediated catalytic decomposition over layered double hydroxides (LDHs) offers an attractive approach to ozone (O₃) elimination in humid environments. However, their catalytic performance still seriously suffers from the insufficient ability for direct H₂O activation, which restricts the replenishment of consumed surface *H and causes a potential competitive effect. Herein, a NiFe₂O₄-engineered NiFe-LDH catalyst with separated reactive sites was developed for room-temperature O₃ removal, where NiFe₂O₄ acts as a hydrogen pump for H generation, and NiFe-LDH for O₃ conversion. Results reveal that the NiFe₂O₄/NiFe-LDH composite catalyst exhibits significantly enhanced catalytic activity and durability, achieving 99% of O₃ decomposition under 70% relative humidity at 25 °C with a reaction rate of 1319 μmol·g^-1·h^-1, which is 4.6 times that of pure NiFe-LDH. Experimental and density functional theory calculations demonstrate that H is efficiently generated from adsorbed H₂O on Fe sites of NiFe₂O₄ and subsequently transfer to the surface of NiFe-LDH for replenishing the consumed *H sites. This configuration weakens competitive adsorption and preferentially triggers a cross-interface hydrogen spillover pathway, which enables highly efficient and robust O₃ decomposition under harsh conditions. This work provides a novel and promising hydrogen spillover strategy through spatially separated active sites for boosting the level of O₃ purification.