Facet engineered interface design of NaYF₄:Yb,Tm upconversion nanocrystals on BiOCl nanoplates for enhanced near-infrared photocatalysis

Abstract

The combination of upconversion nanocrystals with a wide-bandgap semiconductor is an efficient strategy to develop near-infrared (NIR)-responsive photocatalysts. The photocatalytic activity of the hybrid structures is greatly determined by the efficiency of the energy transfer on the interface between upconversion nanocrystals and the semiconductor. In this work, we demonstrate the interface design of a NaYF:Yb,Tm-BiOCl hybrid structure based on the choice of suitable BiOCl facets in depositing NaYF:Yb,Tm upconversion nanocrystals. It was found that the selective deposition of NaYF:Yb,Tm nanocrystals on the BiOCl(110) facet can greatly enhance the photocatalytic performance in dye degradation compared with the sample with NaYF:Yb,Tm nanocrystals loaded on the BiOCl(001) facet. Two effects were believed to contribute to this enhancement: (1) a stronger UV emission absorption ability of the BiOCl(110) facet from NaYF:Yb,Tm in generating more photo-induced charge carriers resulted from the narrower bandgap; (2) a shorter diffusion distance of photogenerated charge carriers to the BiOCl(110) reactive facet for surface catalytic reactions owing to the spatial charge separation between different facets. This work highlights the rational interfacial design of an upconversion nanocrystal-semiconductor hybrid structure for enhanced energy transfer in photocatalysis.

Visible‐to‐NIR Photon Harvesting: Progressive Engineering of Catalysts for Solar‐Powered Environmental Purification and Fuel Production

“…On the contrary, the emission intensities at the blue region of the NaYF 4 :Yb,Tm@TiO 2 are slightly suppressed likely due to the shielding effect of TiO 2 since the energy is insufficient to excite TiO 2 . Ln element–induced upconversion visible–NIR capture has been validated by many reports through the construction of diverse upconversion/semiconductor composites, including a great number of binary NaYF 4 :Yb,Tm@TiO 2 composites with different structures, NaYF 4 :Yb,Tm–BiOCl nanosheets, ZnWO 4 :Er,Tm,Yb–BiOI, NaGdF 4 :Yb,Tm@TiO 2 , NaYF 4 :Yb,Tm@ZnO, BiVO 4 /CaF 2 :Er,Tm,Yb, NaYF 4 :Yb,Er/Au/CdS, NaYF 4 :Yb,Er,Tm@TiO 2 –Au, and so on.…”

Localized Surface Plasmon Resonance Enhanced Photocatalytic Activity via MoO2/BiOBr Nanohybrids under Visible and NIR light

“…Therefore, in order to improve the utilization efficiency of solar energy, many researchers have focused on efforts to broaden the light response range of the photocatalysts in the past twenty years. A variety of visible‐ and NIR‐light driven photocatalysts, for example Ag/AgCl@ZIF8 heterostructures, up‐conversion nanoparticles, WS 2 , Ag 2 O/TiO 2 and RGO/Ag 2 S/TiO 2 nanohybrids have been designed and prepared . However, most of them either are difficult to synthesize or show low harvesting efficiency of photoenergy and rapid recombination of the photogenerated electrons and holes (e − –h + ).…”

“…A variety of visible-and NIRlight driven photocatalysts, for example Ag/AgCl@ZIF8 heterostructures, up-conversion nanoparticles, WS 2 , Ag 2 O/TiO 2 and RGO/Ag 2 S/TiO 2 nanohybrids have been designed and prepared. [9][10][11][12][13] However, most of them either are difficult to synthesize or show low harvesting efficiency of photoenergy and rapid recombination of the photogenerated electrons and holes (e À -h + ). Consequently, it still remains a challenge to design photocatalytic materials with absorbability of wide spectrum and higher charge separation efficiency.…”

Facet Engineered Interface Design of Plasmonic Metal and Cocatalyst on BiOCl Nanoplates for Enhanced Visible Photocatalytic Oxygen Evolution

“…When the Ag and PdO x are loaded on the different facets (e.g., Ag‐(001)BiOCl(110)‐PdO x and Ag‐(110)BiOCl(001)‐PdO x ), the holes injected by Ag in one plane must transfer to PdO x on other planes through traveling within the bulk of BiOCl in participating in the catalytic oxidation reaction. Thus a long migration distance inevitable results in serious loss of holes (Figure c) . As for the samples with Ag and PdO x loaded on the same facet (e.g., Ag‐(001)BiOCl(001)‐PdO x and Ag‐(110)BiOCl(110)‐PdO x ), the diffuse distance is decreased since the hole transfer occurs only along the loaded surface.…”

“…For one thing, interfacial facet greatly determines the electronic coupling between the components, thus largely affecting the efficiency of charge transfer across the interface . For another, resulted from the varied electronic band structures of different facets, the facet‐dependent charge accumulation also maneuvers the interfacial charge transfer . In this work, for the first time, we report the facet engineered interface design of plasmonic metal–semiconductor–cocatalyst ternary hybrid nanostructures for enhanced photocatalysis in O 2 evolution with Ag nanocubes, BiOCl nanoplates, and PdO x nanocubes as plasmonic metal, semiconductor, and cocatalyst, respectively.…”