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.