Photoreduction of CO 2 into CH 4 Using Novel Composite of Triangular Silver Nanoplates on Graphene-BiVO 4.

Plasmonic photocatalysis, combing noble metal nanoparticles (NMNPs) with semiconductors, has been widely studied and proven to perform better than pure semiconductors. The plasmonic effects are mainly based on the localized surface plasmon resonance (LSPR) of NMNPs. The LSPR wavelength depends on several parameters, such as size, shape, the surrounding media, and the interdistance of the NMNPs. In this study, graphene-modified plate-like BiVO₄ composites, combined with silver nanoplates (AgNPts), were successfully prepared and used as a photocatalyst for CO₂ photoconversion. Triangular silver nanoplates (TAgNPts), icosahedral silver nanoparticles (I-AgNPs), and decahedra silver nanoparticles (D-AgNPs) were synthesized using photochemical methods and introduced to the nanocomposites to compare the shape-dependent plasmonic effect. Among them, T-AgNPts/graphene/BiVO₄ exhibited the highest photoreduction efficiency of CO₂ to CH₄, at 18.1 μmolg⁻¹h⁻¹, which is 5.03 times higher than that of pure BiVO₄ under the irradiation of a Hg lamp. A possible CO₂ photoreduction mechanism was proposed to explain the synergetic effect of each component in TAgNPts/graphene/BiVO₄. This high efficiency reveals the importance of considering the compositions of photocatalysts for converting CO₂ to solar fuels. [ABSTRACT FROM AUTHOR]