Improved CO₂ photocatalytic reduction using a novel 3-component heterojunction

A new class of three-component photocatalyst system is designed with plasmonic AuCu nanoprisms embedded between a porous single crystalline TiO₂ nanoplate thin film and polyhedral zeolitic imidazolate frameworks (ZIF-8) nanoparticles for enhanced CO₂ photocatalytic reduction. The ZIF-8 plays a role of CO₂ capture to enhance the reactant concentration on the catalyst, while the AuCu nanoprisms function mainly as a mediator to improve the charge density at the interfaces and facilitate the charge transfer to the CO₂ adsorption sites on ZIF-8 for subsequent CO₂ reduction. The reactant CO₂ could be not only readily collected on the newly designed catalyst, but also more efficiently converted to CO and CH₄. As a result, compared to the reference sample of two-component system of TiO₂ and ZIF-8 with a CO₂ conversion rate of 12.5 μmol h⁻¹ g⁻¹, the new three-component photocatalyst exhibited a nearly 7-fold improvement in CO₂ photocatalytic reduction performance with CO₂ conversion reaching an outstanding value of 86.9 μmol h⁻¹ g⁻¹, highlighting the importance of rational heterojunction design in facilitating reactant adsorption, charge transfer and reaction processes in photocatalysis.