Anisotropic Plasmon Resonance Enables Spatially Controlled Photothermal and Photochemical Effects in Hot Carrier-Driven Catalysis

Localized surface plasmon resonance has been demonstrated to provide effective photophysical enhancement mechanisms in plasmonic photocatalysis.However,it remains highly challenging for distinct mechanisms to function in synergy for a collective gain in catalysis due to the lack of spatiotemporal control of their effect.Herein,the anisotropic plasmon resonance nature of Au nanorods was exploited to achieve distinct functionality towards synergistic photocatalysis.Photothermal and photochemical effects were enabled by the longitudinal and transverse plasmon resonance modes,respectively,and were enhanced by partial coating of silica nanoshells and epitaxial growth of a reactor component.Resonant excitation leads to a synergistic gain in photothermal-mediated hot carrier-driven hydrogen evolution catalysis.Our approach provides important design principles for plasmonic photocatalysts in achieving spatiotemporal modulation of distinct photophysical enhancement mechanisms.It also effectively broadens the sunlight response range and increases the efficacy of distinct plasmonic enhancement pathways towards solar energy harvesting and conversion.

Identification of photochemical effects in Ni-based photothermal catalysts

Photochemical catalytic processes can reduce the activation energy so that reactions can occur under milder conditions.However,it is still unknown whether photochemical effects are present in photothermal catalysis over conventional transition metal materials.Herein,the representative photothermal CO_(2)hydrogenation catalyst,Ni@p-SiO_(2),is employed as a model system to quantitatively probe the contribution of photochemical effect.Through a series of catalytic and photophysical characterizations,it is found that negligible photochemical effect in the ultraviolet-visible region can be observed for the traditional Ni-based catalyst.The results of photo-electrochemistry(PEC)test further confirm that no apparent photochemical effect is present for the Ni@p-SiO_(2)catalyst in the aqueous-phase environment.It has been further evidenced that the photochemical contributions can be significantly amplified by introducing plasmonic metals,such as Au,into the system.This work provides a guideline for the design and construction of efficient synergetic photothermal-photochemical catalytic systems.