Charge Transfer In Photocatalysts Research Articles

Efficient Charge Separation in Ag/PCN/UPDI Ternary Heterojunction for Optimized Photothermal-Photocatalytic Performance via Tandem Electric Fields.

Charge separation driven by the internal electric field is a research hotspot in photocatalysis. However, it remains challenging to accurately control the electric field to continuously accelerate the charge transfer. Herein, a strategy of constructing a tandem electric field to continuously accelerate charge transfer in photocatalysts is proposed. The plasma electric field, interface electric field, and intramolecular electric field are integrated into the Ag/g-C3N4/urea perylene imide (Ag/PCN/UPDI) ternary heterojunction to achieve faster charge separation and longer carrier lifetime. The triple electric fields function as three accelerators on the charge transport path, promoting the separation of electron-hole pairs, accelerating charge transfer, enhancing light absorption, and increasing the concentration of energetic electrons on the catalyst. The H2 evolution rate of Ag/PCN/UPDI is 16.8 times higher than that of pristine PDI, while the degradation rate of oxytetracycline is increased by 4.5 times. This new strategy will provide a groundbreaking idea for the development of high-efficiency photocatalysts.

Rational fabrication of cadmium-sulfide/graphitic-carbon-nitride/hematite photocatalyst with type II and Z-scheme tandem heterojunctions to promote photocatalytic carbon dioxide reduction

Artificial photosynthesis has become one of the most attractive strategies for lowering atmospheric carbon dioxide (CO2) level and achieving the carbon balance; whereas, the fast electron–hole recombination and sluggish charge transfer in photocatalysts are themain stumbling blocks to the applications. Constructing semiconductor nano-heterostructures provides a promising strategy to accelerate the separation and transfer of photoinduced charge carriers for promoting the multielectron CO2 reduction reaction. Herein, a CdS/g-C3N4/α-Fe2O3 three-component photocatalyst consisting of type II and Z-scheme tandem heterojunctions is skillfully fabricated via the solvothermal synthesis followed with photoinduced deposition. The CdS/g-C3N4/α-Fe2O3 tandem-heterojunction photocatalyst exhibits superior performance toward the conversion of CO2 to fuels (CO and CH4), compared with the single- and binary-component systems, owing to the favorable energy-level alignment, accelerated charge separation, facilitated water dissociation and sufficient reactive-hydrogen provision. The total consumed electron number of CdS/g-C3N4/α-Fe2O3 catalyst for CO2 reduction is about 10.5 times that of pure g-C3N4. The photocatalytic mechanism is elucidated according to detailed characterizations and in-situ spectroscopy analyses. This work sheds light on the rational construction of heterojunction photocatalysts to promote the conversion of CO2 to solar fuels, without using any sacrifice reagent or noble-metal cocatalysts.

Plasmonic Photocatalysis of Urea Oxidation and Visible-Light Fuel Cells

Summary The intense electric (E-) field associated with the localized surface plasmon resonance (LSPR) of noble-metal nanoantennas provides a rational strategy for enhancing photoinduced charge transfer in photocatalysts. Here, we demonstrate E-field-enhanced direct photocatalytic urea oxidation and a visible-light-driven direct urea fuel cell (LDUFC) with tris(bipyridine)ruthenium(II) ([Ru(bpy) 3 ] 2+ )-enabled plasmonic nanopigments that contain a phospholipid membrane self-assembled around a Ag nanoparticle (NP) whose LSPR overlaps the [Ru(bpy) 3 ] 2+ metal-to-ligand charge transfer (MLCT). In the hierarchical plasmonic nanopigment design, the membrane serves as scaffold and spacer to localize [Ru(bpy) 3 ] 2+ in an electromagnetic “sweet spot” where substantial plasmonic enhancement of photoexcitation is achieved while strong metal-associated quenching of the reactive excited state is avoided. The demonstration of plasmon-enhanced photocatalytic urea oxidation and the implementation of the LDUFC represent important advancements toward improved light-driven waste-water treatment and efficient solar energy conversion.

The Synthesis, Characterization and Visible-Light Photodegradation Performance of Graphitic Carbon Nitride Coupling with CoAPO-5

In order to enhance hole/electron separation and charge transfer in photocatalysts, the heterostructured g-C3N4/CoAPO-5 hybrids materials were synthesized via a simple grinding method and were investigated using X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The optical properties of g-C3N4/CoAPO-5 hybrids materials were measured by ultraviolet-visible diffuse-reflectance spectroscopy (DRS), photoluminescence (PL) spectra and ultraviolet-visible absorption (UV-Vis) spectra. Under visible-light illumination, this work shows the heterogeneous g-C3N4/CoAPO-5 hybrids present a superior photocatalytic activity.