Speaker
Description
Controlling interfacial charge transfer is vital for designing thin-film materials for CO₂ electroreduction (eCO₂RR) and photocatalytic H₂ production. We employ atomic layer deposition (ALD)–physical vapor deposition (PVD) supercycles to engineer ZnO/Cu interfaces with sub-nanometer precision. XPS and EDX analysis confirm sub-at.% Cu incorporation and strong electronic coupling, enabling precise modulation of interface density and defect states while maintaining conformality on porous substrates.
In eCO₂RR, ZnO/Cu-modified GDEs achieve current densities of 100 mA cm⁻² and Faradaic efficiencies for CO up to 72% at 20 mA cm⁻², with CO₂ conversion exceeding 30%. Operando restructuring, evidenced by morphological reconstruction and surface composition shifts, does not lead to immediate failure, with optimized energetics allowing operation below 2.5 V, enabling direct photovoltaic-to-fuel integration.
In photocatalytic H₂ generation, ALD-grown ZnO films significantly outperform commercial powders, reaching up to 1000 µmol g⁻¹. A critical design rule is established: surface-only Cu yields ~832 µmol g⁻¹, whereas embedding Cu within the ZnO matrix increases productivity to 5660 µmol g⁻¹ (>5× vs. pristine ZnO). This demonstrates that subsurface (buried) junctions are decisive for promoting charge separation and suppressing recombination.
Ultimately, functionality in both platforms emerges from the interplay of interface density, band alignment, and defect-mediated transport. These results establish ALD–PVD supercycles as a robust materials-by-design strategy for tailoring interfacial properties, offering clear guidelines for designing high-performance oxide/metal catalysts.