Synergistic atom co-sharing and S-scheme heterojunction: constructing Cu/CuO/Cu2O with ultrathin graphene-like carbon derived from basil seeds for enhanced photo-oxidation of benzyl alcohols to aldehydes

Abstract

This study is centered on the oxidative transformation of alcohols into their respective aldehyde compounds, employing an S-scheme heterostructure featuring CuO/Cu₂O on graphene-like carbon (GLC) derived from a basil seed hydrogel. Experimental characterization and theoretical calculations highlight that the implementation of S-scheme heterostructures achieves not only enhanced charge-separation efficiency, facilitated by the interfacial built-in electric field, Cu co-sharing at the CuO/Cu₂O interface, and electron carrier activity of the GLC support, but also maintains a strong driving force for photocatalytic organic conversion. The resulting nanocomposites play a crucial role in transferring and reducing the recombination of photoexcited charge carriers, preserving the oxidizability of CuO holes and the reducibility of Cu₂O electrons. Through meticulous adjustment of precursor amounts, the CuO–Cu₂O/GLC heterojunction exhibited the highest photocurrent at 6.83 mA cm⁻², demonstrating optimal performance in the photocatalytic selective oxidation of benzyl alcohol with an average conversion rate of 95.0%. Furthermore, the stability of CuO–Cu₂O/GLC was thoroughly investigated, revealing sustained high conversion even after five repeated experiments, underscoring its potential for practical applications. The study also proposes a plausible mechanism for the transformation of benzyl alcohol into benzaldehyde through capture experiments of active species. Importantly, this research introduces a straightforward in situ hydrothermal growth protocol for efficiently constructing metal oxide heterostructures wrapped in an rGO support. It provides valuable insights into designing new synthetic strategies for preparing efficient photocatalysts and hints at the development of novel, efficient, and practical photocatalytic systems.