Paradigmatic demonstration of sonochemical carbon dioxide reduction proceeded over Cu-based catalysts

Xia, Dong, Qin, Yi, Regmi, Yagya N. ORCID: https://orcid.org/0000-0001-6588-7683, King, Laurie A. and Kwan, James ORCID: https://orcid.org/0000-0002-3795-6108 (2025) Paradigmatic demonstration of sonochemical carbon dioxide reduction proceeded over Cu-based catalysts. Journal of CO2 Utilization, 102. 103220. ISSN 2212-9820

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Abstract

Sonochemical carbon dioxide (CO2) reduction represents a promising decarbonization technology. However, relevant studies regarding the usage of solid catalysts in sonochemical reactor are rare. Herein, we investigate four distinct highly nanostructured cuprous oxides and sulfides for sonochemical CO2 reduction via ultrasound-induced cavitation. Specifically, we investigate Cu2O cubes, Cu7S4/Cu2O cubes, Cu7S4 cages and Cu7S4 sheets morphologies. Each nanostructure is found to produce CO and H2 in various ratios ranging from 1.0 – 2.3. Through a systematic study, we investigate the role of different acoustic conditions on affecting CO2 sonolysis, involving the measurements in CO2-saturated H2O, 5 %CO2/Ar-saturated H2O, N2-saturated H2O, 5 %CO2/N2-saturated H2O and CO2-saturated KHCO3. We show that Cu2O cubes have the highest CO2-to-CO conversion (up to 4286.4 μmol·L−1·g−1·h−1) in 5 %CO2/Ar-saturated H2O. In addition, the as-synthesized Cu2O cubes exhibited promising sonochemical stability, with CO and H2 production rates stabilizing at around 890.3 μmol·L−1·g−1·h−1 and 966.9 μmol·L−1·g−1·h−1, respectively. Post sonochemical analysis indicated that the Cu2O cubes maintain relatively high CO2-to-CO conversion, as well as their morphology. This work provides the first proof-of-concept demonstration of using inexpensive Cu-based catalysts to enable low-carbon sonochemical CO2 reduction.