Plasmonic Ag@TiO₂ Core–Shell Nanoparticles for Enhanced CO₂ Photoconversion to CH₄

Abstract

Ag@TiO 2 nanoparticles (NPs) with Ag metal cores and TiO 2 semiconductor shells were prepared with a hydrothermal method and their structure was characterized by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The core−shell Ag@TiO 2 NPs were deposited on a glass plate and employed as photocatalysts for CO 2 conversion by irradiation of solar simulator (AM1.5) under CO 2 atmosphere. Selective CH 4 evolution by CO 2 photoconversion was attained with the core−shell Ag@TiO 2 NP photocatalyst. The CH 4 evolution rate normalized by specific surface areas was 10 times higher than those of reference TiO 2 NPs and conventional TiO 2 NPs with accompanying Ag deposits. The role of the Ag core was also demonstrated in photodecomposition of a dye by the core−shell Ag@TiO 2 NPs. These results suggested that the high photocatalytic activity of the core−shell Ag@TiO 2 NPs was archived due to bandgap improvement of the TiO 2 shell and increase of photon flux to the TiO 2 shell by the plasmonic Ag core.

Engineering approach toward catalyst design for solar photocatalytic CO 2 reduction: A critical review

“…Subsequently, Pt nanoparticles played a pivotal role in gathering the electrons from the CB of TiO 2 nanocrystals and transferred them to rGO; as a result, the photogenerated electrons reached a tiny region of the wrapped rGO shell and participated in the CO 2 reduction reaction while the left holes on the VB of TiO 2 reacted with water to generate oxygen. Similar previously published works with high value are also available here, 84,122‐125 which highlight the importance of core‐shell structure engineering and offer a novel idea for catalyst design. However, progress toward encapsulation technology in artificial photosynthesis is still at an early stage, and further in‐depth and rigorous investigations are required, both in synthesis methods and fundamental understanding of the reaction mechanisms behind and the mutual relationship between structures and properties.…”

Inside‐and‐Out Semiconductor Engineering for CO2 Photoreduction: From Recent Advances to New Trends

“…The conversions of CO 2 into valuable products, such as CH 4 , [ 43–50 ] CH 3 OH, [ 51–55 ] or HCOOH, [ 56–61 ] have been reported, but the yield and selectivity of these products still need to be improved. [ 62 ] As the most common product in gas system, CO formation just requires two protons and two electrons, whereas CH 4 formation needs eight protons and electrons and prefers to be produced on noble metal cocatalysts.…”

Plasmonic Metal Nanoparticles for Artificial Photosynthesis: Advancements, Mechanisms, and Perspectives

“…The light scattering effect of PNPs is that PNPs can scatter the incident photons, which are not absorbed by the semiconductor, and then some of them can be utilized. A core−shell Ag@TiO 2 photocatalyst realized selective CH 4 evolution of 14.8 μmol g −1 under irradiation of simulated solar light for 3 h. [ 57 ] The enhanced activity was attributed to the light scattering effect by the Ag core NPs ( Figure a,b). Similarly, Au/P‐doped g‐C 3 N 4 photocatalyst for HER and CO 2 reduction was reported.…”