Enhancing photocatalytic CO₂ reduction to butanol by facet-dependent interfacial engineering of CeO₂/Cu₂O

Facet engineering of photocatalysts is a promising approach to enhance performance by leveraging the unique facet-dependent properties arising from surface atomic arrangements. However, the lack of precise control over the facets in multi-component systems has hindered a deeper understanding of facet and interfacial effects on photocatalytic performance. Here, prototype Cu₂O crystals with distinct (100), (111), and mixed (100 +111) exposed facets are synthesized. After combining with CeO₂ (111), the effect of facet-dependent interfacial interaction on photocatalytic CO₂ reduction is investigated. The photocatalytic activities of the composites vary significantly depending on the exposed Cu₂O facets. The Z-scheme CeO₂/Cu₂O (100) heterostructure possesses superior interfacial compatibility with a notable 4.091 e- transfer, much higher than 0.822 e- in CeO₂/Cu₂O (111). ESR and photoelectrochemical analysis demonstrate that the CeO₂/Cu₂O (100) composite exhibits efficient separation and transfer of the photo-induced charge carriers, leading to enhanced photocatalytic performance. CeO₂/Cu₂O (100) composite, without a sacrificial agent, achieves the butanol yield selectivity of over 59 % and a yield rate of 34 µmol/g/h, which is 2.9 times and 87 times higher than that of CeO₂/Cu₂O (100 +111) and CeO₂/Cu₂O (111), respectively. These findings provide a clear view of understanding facet-dependent interfacial effects for improving catalytic performance, offering valuable insights for sustainable chemical production.