A novel structured gold nano-particles loaded TiO2 photocatalysts with Al2O3 interlayer were prepared. Photocatalytic activities of CO2 reduction with water were tested to characterize the photocatalysis mechanism of these gold nanoparticles. Atomic layer deposition showed a certain thickness of Al2O3 passivation layer coating could improve overall efficiency via suppressing surface recombination. The combined effect of plasmonic NPs and passivation layer dramatically enhanced photoactivity. UV-vis spectrum, XRD, and SEM were used to characterize the catalysts further. FDTD calculation is also included to validate with experimental results. The contribution of different mechanisms of plasmonic metal NPs was evaluated. LSPR-assisted charge separation effect was determined to be the most critical function of gold NPs. Correlation among different functions of gold NPs with contact type and spatial size is also included.
