Sonocatalytic carbon dioxide reduction for syngas production over surface‐roughened Cu _x O

Abstract

The transition to a carbon‐circular economy requires efficient technologies for converting CO ₂ into value‐added chemical feedstocks. Sonocatalytic CO ₂ conversion has recently emerged as a compelling approach to drive this conversion. Here, we report a surface‐roughened Cu _x O catalyst for sonocatalytic CO ₂ reduction in aqueous media, achieving a marked CO ₂ ‐to‐CO conversion alongside H ₂ production, yielding tunable syngas (CO/H ₂ ) ratios relevant to Fischer–Tropsch and methanol synthesis processes. We demonstrate that the CO/H ₂ ratio is systematically controlled by varying the solution composition (KHCO ₃ , CH ₃ COOK, and KCl), revealing solution‐mediated selectivity as an unexplored lever in CO ₂ sonocatalytic systems. Prolonged testing in CO ₂ ‐saturated KHCO ₃ solutions induced morphological deformations of the Cu _x O catalyst which were shown to benefit sonolysis, as evidenced by higher CO production rates during long‐term operation. Our findings highlight surface‐roughened Cu _x O catalyst for sonocatalytic conversion of CO ₂ ‐saturated solutions to syngas and introduce solution engineering as a new approach to tune product selectivity.