Transforming Alloys into Au-Loaded Nanoporous Transition Metal Oxide Catalysts for Room Temperature CO Oxidation

Developing a room-temperature complete oxidation reaction for CO holds great promise in solving the growing air pollution problem, and catalysis is considered an effective way to achieve this goal. Herein, Au nanoparticles were supported in situ on three substrates─Co3O4 nanosheets, Mn3O4 octahedrons, and NiO ligaments─through dealloying melt-spun Al–TM–Au (TM = Co, Mn, and Ni) alloy ribbons in NaOH solution, followed by subsequent calcination. The experimental results showed that the Au/Co3O4-300 °C sample with Co3O4 as the support material exhibited the best catalytic performance, enabling complete CO conversion at 30 °C (near room temperature). This sample did not decay in catalytic activity even after 110 h of continuous testing in high concentrations of H2O (30 vol %) and CO2 (20 vol %), showing excellent water resistance, CO2 toxicity resistance, and long-term stability. In addition, systematic characterization indicated a strong interaction between Au and Co3O4 nanosheets with a large specific surface area, exposed {112} crystal planes, and high oxygen mobility. This synergy resulted in enhanced electron transfer at their interface, thereby generating elevated concentrations of Auδ+ and surface-active oxygen. Consequently, the Au/Co3O4-300 °C composite exhibited optimal performance among products prepared from the Al–TM–Au alloy systems. Herein, we provide a pathway for developing green and highly active room-temperature catalysts for CO oxidation reactions.