Layered cobalt catalyst reimagines pigment as a pathway for CO₂ recycling

Researchers at the Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, have introduced a new approach for electrochemical carbon dioxide (CO₂) reduction. By designing multilayer cobalt phthalocyanine (CoPc)/carbon core-shell structures, the team has demonstrated a catalyst architecture that makes CO₂ conversion into carbon monoxide (CO) both stable and efficient.

The research is published in the journal Applied Catalysis B: Environment and Energy.

The study combined large-scale data analysis and artificial intelligence (AI) to screen 220 molecular candidates. Cobalt phthalocyanine—widely known as a blue pigment—emerged as the most effective option for selective CO production. This discovery became the basis for constructing electrodes optimized for CO₂ utilization.

“We wanted to move beyond conventional thinking that isolated molecules perform best,” said Hiroshi Yabu, a professor at the (WPI-AIMR) who led the research. “Instead, our results show that stacking these molecules in ordered layers produces a much stronger catalytic effect.”

The team created a hybrid design in which CoPc forms crystalline layers around conductive carbon particles. This multilayer core-shell catalyst showed high current density and maintained CO selectivity above 90% for extended operation, even under demanding electrochemical conditions.

A central insight from the study is that the enhanced performance originates from the multilayered arrangement rather than individual molecules. Experiments revealed that ordered stacking promotes charge transfer at the catalyst surface, while theoretical calculations confirmed that this electronic effect significantly increases catalytic activity.

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“This project shows how combining data-driven material selection with nanoscale design can reveal new directions for CO₂ recycling,” added Yabu. “The ability to predict and test structures systematically will help us move faster toward practical applications.”

The findings suggest that multilayer molecular architectures may offer a pathway to more effective catalysts, not only for CO₂-to-CO conversion but also for other reactions central to clean energy production.

The researchers now plan to test the system under industrial conditions and explore whether similar designs can enhance hydrogen or ammonia production.

By demonstrating how a familiar material—once mainly used as a pigment—can be reimagined for sustainable technologies, the work underscores the role of creative catalyst design in advancing carbon recycling.

The study marks a step toward practical systems that can help reduce CO₂ emissions while producing fuels and useful chemicals.