Pyroelectric Driven Energy Force in Cobalt Phthalocyanine/Graphene Catalyst Pair for Simultaneous Dual CO₂ Reduction and H₂ Evolution Reactions

As the urgency of climate change grows, the need for efficient, eco-friendly energy sources like hydrogen (H₂) intensifies. Meanwhile, global carbon emissions exacerbate the greenhouse effect and global warming. Despite growing interest in CO₂ reduction reactions (CO₂RR) and H₂ production, challenges persist, including selectivity and high costs associated with electrochemical approaches, as well as low efficiency in photocatalytic methods. In this regard, the utilization of a huge available heat-waste energy source would be highly beneficial and could potentially be achieved using pyroelectric materials, certain structures that, surprisingly, can convert even a modest periodic temperature fluctuation into electrical energy. Here, we confronted this challenge by synergistically exploiting the pyroelectric and electrocatalytic properties of planar molecules (e.g. cobalt phthalocyanine (CoPc)). By demonstrating such a pyroelectric property of CoPc, we present an unprecedented opportunity for CO₂RR and water splitting (as a dual reaction) without the need for external electrical power, relying solely on thermal cycling. Our pyrocatalyst exhibits high CO productivity in the CO₂RR, with yield as high as 15 and H₂ evolution 25 within 12 few-second thermal cycles between 5–50 °C. This fantastic feature comes from an electric field induced due to the separation of charges within the pyrocatalyst with thermal cycling, resulting in a combination of asymmetry in CoPc cell volume expansion coupled with the reorientation and rotation of the CoPc molecule.