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─Co 3 O 4 nanosheets, Mn 3 O 4 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/Co 3 O 4 -300 °C sample with Co 3 O 4 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 H 2 O (30 vol %) and CO 2 (20 vol %), showing excellent water resistance, CO 2 toxicity resistance, and long-term stability. In addition, systematic characterization indicated a strong interaction between Au and Co 3 O 4 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 Au δ+ and surface-active oxygen. Consequently, the Au/Co 3 O 4 -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.