Concurrent CO₂ and plastic waste photocarbovalorizing into fuels using an orbital-engineered high-entropy oxide...

While achieving carbon neutrality remains challenging because of continued usage of fossil fuels and plastics, the conversion of CO₂ to fuels and the upcycling of plastic waste into valuable products present a major opportunity to valorize carbon. This research enhances the value of carbon concurrently in two pollutants, CO₂ and plastic waste, using light, a process we name photocarbovalorizing. A high-entropy oxide photocatalyst is designed for this process, incorporating f⁰ cations (lanthanum and cerium), known for high CO₂ adsorption capacity, alongside d⁰ (tantalum and niobium) and d¹⁰ (zinc) cations for their photocatalytic proficiency. The coexistence of these cations positively generates a heterogeneous electronic structure, facilitates charge separation and transfer, induces oxygen vacancies, and generates lattice strain (confirmed by synchrotron X-ray absorption spectroscopy). The oxide demonstrates CO₂ photoreduction to CO and CH₄; however, concurrent introduction of polyethylene terephthalate (PET) plastic waste not only enhances CO and CH₄ production by 2.5-3.3 times but also produces value-added organic chemicals, such as ethylene glycol and acetic acid, from PET degradation. Beyond introducing high-entropy oxides with mixed f⁰-d⁰-d¹⁰ orbitals as new photocatalysts, these findings establish a process of photocarbovalorizing for the cooperative CO₂ and plastic waste conversion.