Search

This paper utilized the hydrothermal method and freeze-drying technology to prepare the macroscopic aerogel structure and powder structure of MOF-808/RGO. Through comparative analysis of aspects such as photocatalytic CO 2 reduction performance, electron transfer efficiency, macroscopic structure, and microstructure, it has been discovered that aerogel structure can provide favorable conditions for mass transfer of CO 2 and water molecules, and light propagation. The introduction of RGO successfully captures electrons and the reduction reaction occurs on the surface of the material. [Display omitted] • Macroscopic aerogel and powder structures of the MOF-808/RGO composite photocatalysts were fabricated separately and used for comparison. • The photocatalytic performance of the MOF-808/RGO macroscopic aerogels in reducing CO 2 to CO was approximately 16 times that of MOF-808 and 12 times that of RGO. • The aerogel structure provides an abundance of pore structures within the material. • The presence of the aerogel structure successfully enhanced the photothermal and photoelectric conversion efficiencies of the composite photocatalysts. Three-dimensional (3D) macroscopic aerogels have emerged as a critical component in the realm of photocatalysis. Maximizing the integration of materials can result in enhanced efficiency and selectivity in photocatalytic processes. In this investigation, we fabricated MOF-808/reduced graphene oxide (RGO) 3D macroscopic aerogel composite materials employing the techniques of hydrothermal synthesis and freeze-drying. The results revealed that the macroscopic aerogel material exhibited the highest performance in CO 2 reduction to CO, particularly when the concentration of RGO was maintained at 5 mg mL−1. In addition, we synthesized powder materials of MR-5 composite photocatalysts and conducted a comparative analysis in terms of photocatalytic CO 2 reduction performance and electron transfer efficiency. The results show that the macroscopic aerogel material boasts a high specific surface area, an abundant internal pore structure, and increased active sites. These attributes collectively enhance light energy utilization, and electron transfer rates, thereby, improving photothermal and photoelectric conversion efficiencies. Furthermore, we conducted in-situ FT-IR measurements and found that the M/R-5 aerogel exhibited the best CO 2 adsorption capacity under a CO 2 flow rate of 10 mL min−1. The density functional theory results demonstrate the correlation between the formation pathway of the product and the charge transfer pathway. This study provides useful ideas for realizing photocatalytic CO 2 reduction of macroscopic aerogel materials in gas–solid reaction mode. [ABSTRACT FROM AUTHOR]

High selectivity and fast charge separation are two important factors for photocatalytic wastewater treatment. Herein, we prepared a molecular imprinted Ag/Ag 3 VO 4 /g-C 3 N 4 photocatalyst (MIP) that exhibited great specific recognition ability along with excellent photocatalytic activity. The ultrathin g-C 3 N 4 nanosheets with high surface are used to prepare. The Z-scheme Ag 3 VO 4 /g-C 3 N 4 heterostructure and the surface plasmon resonance of the photoreduced Ag0 together contributed to the improvement of the separation efficiency of photogenerated electrons and holes. In addition, MIP provides the specific recognition ability to preferentially adsorb the target pollutant. The selectivity of photocatalysis was evaluated by the degradation of oxytetracycline and tetracycline solutions. Photoluminescence and transient photocurrent measurements further prove the improved charge separation efficiency of MIP. A plausible photocatalytic reaction mechanism is proposed based on electron spin resonance measurement and the active species trapping experiments, where indicates that the main active species of this photocatalytic process are O 2 − and h+. This research provides an effective strategy for the simultaneous enhancement of selectivity and activity via molecular imprinting. [ABSTRACT FROM AUTHOR]

Graphical abstract Schematic illustration of the formation of CQDs/ZnO@HNTs in the whole synthetic process. Highlights • We have experimentally demonstrated the carbon incorporated ZnO via coupling CQDs. A notable transformation of burger-like CQD s /ZnO morphology was observed and the HNTs have been introduced to improve the dispersity of hybrid photocatalysts. • From efficiently modulation of band structure of CQD s -based materials, the as-prepared CQD s /ZnO@HNTs display a remarkable optical excitation in photogenerated reactive oxygen species (ROS). • This work provides an efficient and novel strategy for element incorporated with introduced inorganic quantum dots owing to the quantum size effect. • It also developed a new sight of CQD s participated phase tuning for semiconductors, offering a beneficial route for expanding the application of VLD photodegradation based on band-tuning semiconductors and other low-dimension materials. Abstract Environmentally friendly photodegradation of refractory pollutants utilizing semiconductor photocatalysis evolution exhibits satisfactory efficiency and low energy consumption, but some of its unbefitting band position largely limits practical applications. The controllable band structure tuning via coupling low-dimensional materials with enormous potential in semiconductor photocatalysis, notably attractive carbon quantum dots (CQDs) induced for a better utilization of low-energy photoexcitation of promising inherent optical properties and photocatalytic performance on organic pollutant degradation. Here, a CQDs modified ZnO hybrid materials was synthesized and the CQDs preluded carbon-incorporated burger-like ZnO nanoparticles clusters were presented thus demonstrated a specific doping-effect. The dispersity improved by loading halloysite nanotube (HNTs) for efficiently photocatalytic activity enhancement. Furthermore, the band structure, excitation and photocatalytic reactive oxygen species (ROS) generation were detected to reveal the photochemical properties and plausible mechanism of CQDs hybrid nanomaterials system. It is observed that the superoxide radical (O 2 −), and singlet oxygen(1O 2) are the principal ROS agents under UV–vis excitations. This work not only displays a CQDs modified system of expanding photo-response range to visible light but also throws a way for quantum elemental incorporated on the influence of band-tuning for semiconductor- dominated photocatalysts. [ABSTRACT FROM AUTHOR]

Achieving the intelligent controllability of the photocatalyst to the surrounding environment is a very meaningful work. Here, the polyacrylic acid (PAA) modified Ag/AgCl-40/CN composite was constructed to achieve an intelligent response of pH value. PAA exhibits hydrophilic properties at high pH value, increasing the adsorption capacity to tetracycline (TC) molecules. The morphology of PAA from contracted state to diastolic state, releasing the Ag/AgCl-40/CN catalyst. In addition, PAA modified Ag/AgCl-40/CN can prevent the loss of AgCl. The g-C 3 N 4 nanosheets (CN) as a carrier enhance the dispersibility of the AgCl particles. The LSPR effects of Ag nanoparticles produce more electrons acting on photocatalytic degradation. On the results of experiment, the degradation of TC by PAA@Ag/AgCl-40/CN shows an excellent degradation activity when the high pH value. Photoluminescence spectroscopy and photocurrent demonstrate that carrier separation efficiency of PAA@Ag/AgCl-40/CN is higher than CN and Ag/AgCl-40/CN. The detection of the main active substances •O 2 − and h+, revealing a reasonable mechanism for the PAA@Ag/AgCl-40/CN hybrid system. This work provides a procedure to obtain smart materials that can switch photocatalytic processes. [ABSTRACT FROM AUTHOR]