Pt nanocluster-Fe single atom pairs dual-regulate charge extraction and interfacial reaction for enhanced photoelectric response.

Energy level mismatches between semiconductors and cocatalysts often induce carrier recombination, limiting photocatalytic and photoelectrochemical (PEC) efficiency. Here, we integrate Pt nanocluster-Fe single-atom pairs with CuO to regulate both solid-solid and solid-liquid interfaces in PEC systems. Experimental and theoretical analyses reveal that an Ohmic contact at the CuO/Pt interface accelerates electron extraction, while Pt-to-Fe charge transfer enhances oxygen reduction at Fe sites, collectively boosting reaction kinetics. Leveraging this, we construct a PEC biosensor exploiting chelating effect of glyphosate on CuO to impede electron transfer, achieving a detection limit of 0.41 ng/mL. This interface engineering strategy advances cocatalyst design for enhanced energy conversion and sensing applications by simultaneously addressing carrier dynamics and interfacial reaction barriers.