Researchers at The University of Osaka have developed a catalyst that uses vibrational energy to convert carbon dioxide (CO₂) into carbon monoxide (CO), an important industrial feedstock. The work demonstrates a new piezocatalytic route for CO₂ conversion under mild conditions—at low temperature and ambient pressure, offering a potential path toward future low-energy carbon recycling technologies.

CO₂ emissions are a major driver of global warming, and technologies that convert CO₂ from a waste product into a useful carbon resource are becoming increasingly important for achieving carbon neutrality. CO is a useful product of CO₂ reduction, but conventional production methods require high temperatures and substantial energy input. A promising alternative is to use catalysts that harness mechanical energy, such as vibration, to drive chemical reactions under mild conditions, although their efficiency and product selectivity for CO₂ conversion have remained limited.

The research team designed a catalyst based on barium titanate (BaTiO₃), a piezoelectric material that generates electric charges under mechanical stimulation. By depositing nitrogen-doped carbon containing atomically dispersed nickel on BaTiO₃ nanocubes, the researchers created a material that efficiently reduced CO₂ to CO under ultrasonic vibration at room temperature and ambient pressure.

In five hours of sonication, the new catalyst produced 377 mmol g−1 of CO, compared with 123 mmol g−1 for pristine BaTiO₃, corresponding to a 3.1-fold improvement. No H₂, CH₄, or HCOOH were detected as carbon-reduction products under the tested conditions, indicating almost 100% selectivity for CO among the detected carbon products.

The study also clarified why the catalyst performed so well. The nitrogen-doped carbon helped promote charge separation and transfer, while the isolated nickel single-atom sites acted as highly active centers for CO₂ reduction. Structural analysis showed that the nickel atoms were atomically dispersed in a Ni-N₄ configuration within the carbon layer. The catalyst also remained stable over repeated cycles, suggesting that the nickel sites were firmly anchored during operation.

The work provides a new design strategy for combining piezoelectric materials with single-atom catalytic sites, opening a possible path toward sustainable CO₂ conversion using underutilized mechanical energy. Dr. Yoshifumi Kondo, senior author of the study, commented, “Establishing technologies to recycle industrially emitted CO₂ is essential for achieving carbon neutrality. In this work, we clarified part of the design guideline for reaction-active sites in piezocatalytic CO₂ reduction. Going forward, we hope to develop new low-energy CO₂ conversion methods that make use of underutilized energy, such as mechanical vibration and waste heat.”

Fig. 1

Caption: Schematic images of piezocatalytic CO₂ reduction over Ni single-atom anchored on N-doped carbon deposited on BaTiO₃.

Credit: Yoshifumi Kondo and Tohru Sekino from J. Mater. Chem. A, 2026, 14, 6858.