ABSTRACT
Herein, Au core Pd shell Pt cluster nanorods (Au@Pd@Pt NRs) with enhanced catalytic activity were rationally designed for carbon dioxide (CO2) reduction. The surface composition and Pd-Pt ratios significantly influenced the catalytic activity, and the optimized structure had only a half-monolayer equivalent of Pt (θ Pt = 0.5) with 2 monolayers of Pd, which could enhance the catalytic activity for CO2 reduction by 6 fold as compared to the Pt surface at -1.5 V vs. SCE. A further increase in the loading of Pt actually reduced the catalytic activity; this inferred that a synergistic effect existed among the three different nanostructure components. Furthermore, these Au NRs could be employed to improve the photoelectrocatalytic activity by 30% at -1.5 V due to the surface plasmon resonance. An in situ SERS investigation inferred that the Au@Pd@Pt NRs (θ Pt = 0.5) were less likely to be poisoned by CO because of the Pd-Pt bimetal edge sites; due to this reason, the proposed structure exhibited highest catalytic activity. These results play an important role in the mechanistic studies of CO2 reduction and offer a new way to design new materials for the conversion of CO2 to liquid fuels.
ABSTRACT
Photocatalysis is a promising technology for renewable energy production. Many photocatalysis have realized the visible-light-driven catalytic activity. However, it is still difficult to achieve the enhanced photocatalytic activity with tunable wavelength. We have designed tunable wavelength enhanced photoelectrochemical cells by tuning the surface plasmon resonance (SPR) peaks, which can be controlled by the aspect ratios of the Au nanorods, for both the cathode with the hydrogen evolution reaction and the anode with the electrooxidation of methanol reaction. The optimal photocatalytic activity of the hydrogen evolution and electrooxidation of the methanol can be realized only when the illuminating wavelength matches with the SPR peaks, which is quite selective to the illuminating wavelength. The blue shift of the SPR peak increases the photoelectrocatalytic effect whereas the red shift enhances the photothermal effect. Such studies provide a useful way for improving the photocatalytic activity and the selectivity of the photocatalytic reactions by adjusting the illuminating wavelength.
ABSTRACT
The surface plasmon resonance (SPR) induced photothermal and photoelectrocatalysis effects are crucial for catalytic reactions in many areas. However, it is still difficult to distinguish these two effects quantitatively. Here we used surface-enhanced Raman scattering (SERS) to detect the photothermal and photoelectrocatalytic effects induced by SPR from Au core Pt shell Nanoparticles (Au@Pt NPs), and calculated the quantitative contribution of the ratio of the photothermal and photoelectrocatalysis effects towards the catalytic activity. The photothermal effect on the nanoparticle surface after illumination is detected by SERS. The photoelectrocatalytic effect generated from SPR is proved by SERS with a probe molecule of p-aminothiophenol (PATP).
