Regulating Lattice Oxygen on the Surfaces of Porous Single-Crystalline NiO for Stabilized and Enhanced CO Oxidation

Abstract

The long-range ordered lattice structure and interconnected porous microstructure of porous single crystals (PSCs) provide structural regularity and connectivity in remote electron movement to stabilize oxygen vacancies and activate lattice oxygen linked to surface active sites. In this work, we prepare NiO powder, single-crystal (SC) NiO, and PSC NiO. NiO contains a significant amount of oxygen vacancies. We find that the structure of porous NiO can create more oxygen vacancies. We load Pt onto these NiO crystals by atomic layer deposition (ALD) to activate lattice oxygen on definite NiO surfaces. The results show that Pt-loaded NiO effectively exhibits CO oxidation performance, in which Pt-loaded PSC NiO completely oxidizes CO at 65 °C. With 1% CO fully adsorbed, the density of activate lattice oxygen becomes an essential factor affecting performance. PSC NiO with deposited Pt clusters exhibited stable CO oxidation catalysis when run in air at ~65 °C for 300 h.