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Thermal CO Oxidation and Photocatalytic CO₂ Reduction over Bare and M-Al₂O₃ (M = Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au) Cotton-Like Nanosheets.

ABSTRACT: Aluminum oxide (Al₂O₃) has abundantly been used as a catalyst, and its catalytic activity has been tailored by loading transition metals. Herein, γ-Al₂O₃ nanosheets were prepared by the solvothermal method, and transition metals (M = Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au) were loaded onto the nanosheets. Big data sets of thermal CO oxidation and photocatalytic CO₂ reduction activities were fully examined for the transition metal-loaded Al₂O₃ nanosheets. Their physicochemical properties were examined by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction crystallography, and X-ray photoelectron spectroscopy. It was found that Rh, Pd, Ir, and Pt-loading showed a great enhancement in CO oxidation activity while other metals negated the activity of bare Al₂O₃ nanosheets. Rh-Al₂O₃ showed the lowest CO oxidation onset temperature of 172 °C, 201 °C lower than that of bare γ-Al₂O₃. CO₂ reduction experiments were also performed to show that CO, CH₃OH, and CH₄ were common products. Ag-Al₂O₃ nanosheets showed the highest performances with yields of 237.3 ppm for CO, 36.3 ppm for CH₃OH, and 30.9 ppm for CH₄, 2.2×, 1.2×, and 1.6× enhancements, respectively, compared with those for bare Al₂O₃. Hydrogen production was found to be maximized to 20.7 ppm during CO₂ reduction for Rh-loaded Al₂O₃. The present unique pre-screening test results provided very useful information for the selection of transition metals on Al₂O₃-based energy and environmental catalysts.

SUBMITTER: Yoon HJ

PROVIDER: S-EPMC8152517 | biostudies-literature |

REPOSITORIES: biostudies-literature

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