Donor–Acceptor Conjugated Polymer Nanoparticle@CuO Core–Shell Nanohybrids for Solar-Driven CO₂ Conversion

The increasing concentration of atmospheric CO₂ is one of the primary drivers of global climate change, creating an urgent need to remove or convert it into value-added products. Solar-driven photocatalysis offers a particularly attractive route, as it enables CO₂ conversion using only sunlight as the energy input, without reliance on external electrical power.

Here, we design a core–shell nanohybrid composed of an organic conjugated polymer nanoparticle (CPN) core and an inorganic copper oxide (CuO) shell. Light absorption and catalytic CO₂ reduction are assigned to each component within a single nanoparticle. The CPN core is built from a donor–acceptor heterojunction, whose energy levels are aligned to facilitate directional electron transfer. The CuO shell, deposited via a seed-mediated growth process, serves as the catalytic site for CO₂ adsorption and C–C coupling.

Upon solar irradiation, photoexcited electrons flow sequentially from the donor to the acceptor, and onward to the CuO shell through cascaded energy level alignment. As CuO is reduced to Cu⁰ in situ, oxygen is released from the shell, generating defect sites on the Cu surface. These defect sites promote *CO intermediate adsorption and facilitate C–C coupling, steering the reaction toward C2+ multicarbon products.

CPN@CuO thus acts as a self-activating photocatalyst in which sunlight simultaneously drives catalyst activation and CO₂ reduction without any external power. This work demonstrates that deliberate energy level engineering across the organic–inorganic interface within a single nanoparticle provides an effective strategy for solar-driven CO₂ conversion, offering a new design principle for hybrid photocatalytic systems targeting multicarbon products.