Hydrogen production via direct core-shell conjugation of functionalized fullerenes and ZnO QDs with accelerated optical catalytic properties

Efficient charge separation and operational stability remain central challenges in photoelectrochemical (PEC) hydrogen production. Here, we engineer a series of ZnO–fullerene (C₆₀, C₇₀, and C₈₄) core–shell quantum dot (QD) nanocomposites designed to regulate interfacial charge transfer and suppress recombination. Oxygen-functionalized fullerenes form direct conjugates with ZnO QDs, yielding uniform and robust core–shell architectures. The nanocomposites exhibit highly efficient nonradiative pathways associated with interfacial electron transfer, with photoluminescence quenched by up to 98.4%, consistent with efficient interfacial charge separation. Across the series, photoelectrochemical performance increases with fullerene size, reflecting improved interfacial energetics and charge-transfer kinetics. ZnO–C₈₄ demonstrates the most favorable energetic alignment with the FTO substrate and delivers the best performance, with a 3.5-fold enhancement in hydrogen evolution relative to pristine ZnO. Furthermore, the ZnO–C₈₄ PEC cell exhibits strong operational durability, retaining 85.3% of its photocurrent after 24 h of continuous operation. These findings establish fullerene-shell engineering as an effective strategy to simultaneously enhance charge separation and mitigate photocorrosion in oxide photoelectrodes, providing a rational framework for the interface engineering of oxide quantum-dot photoelectrodes.