Boosting Electrocatalytic Oxygen Evolution Performance of Ultrathin Co/Ni-MOF Nanosheets via Plasmon-Induced Hot Carriers

Ultrathin metal–organic framework (MOF) nanosheets with large active sites and superior catalytic properties have attracted extensive interests and are promising for oxygen evolution reaction (OER) for water splitting. Herein, we report a novel and highly efficient hetero-nanostructured OER system based on plasmonic Au nanoparticles (NPs) and ultrathin semiconductor-like Co/Ni-MOF nanosheets. The OER performance of the hybrid system can be tuned (by varying the AuNP sizes) and the oxidation current significantly enhanced to ∼10-fold with incorporated AuNPs of ∼20 nm. An onset overpotential (η) of only 0.33 V was achieved under light illumination, which was much lower than the pure Ni/Co-MOF (0.48 V). Further analysis revealed the key role of the plasmonically induced hot holes (via electric- and combined photoexcitation) in boosting the OER performance of the resulting system. The finding and the proposed concept provide a new insight for understanding the plasmon enhancements in catalysis and may open a new avenue to design MOF hetero-nanostructures with high performance for photoelectrocatalysis.