Recent progress in Ag3PO4-based all-solid-state Z-scheme photocatalytic systems

Research Progress on Inactivation of Bacteriophages by Visible-Light Photocatalytic Composite Materials: A Mini Review

Infectious diseases caused by waterborne viruses have attracted researchers' great attention. To ensure a safe water environment, it is important to advance water treatment and disinfection technology. Photocatalytic technology offers an efficient and practical approach for achieving this goal. This paper reviews the latest studies on visible-light composite catalysts for bacteriophage inactivation, with a main focus on three distinct categories: modified UV materials, direct visible-light materials and carbon-based materials. This review gives an insight into the progress in photocatalytic material development and offers a promising solution for bacteriophage inactivation.

A dual S-scheme TiO2@In2Se3@Ag3PO4 heterojunction for efficient photocatalytic CO2 reduction

The excellent photoresponse of semiconductors enables them to be promising photocatalysts for CO₂ reduction, but practical application is hampered by fast recombination of photogenerated carriers, low CO₂ capture capacity and poor stability. Herein, mesoporous hollow nanospheres of a dual S-scheme titanium dioxide@indium selenide@silver phosphate (TiO₂@In₂Se₃@Ag₃PO₄) heterojunction with a large specific surface area are designed and synthesized. The products of photocatalytic CO₂ reduction are CH₄, CH₃OH and CO with yields of 3.98, 4.32 and 8.2 μmol g^-1 h^-1, respectively, and the photocatalysts exhibit excellent cycle performance. The excellent photocatalytic performance is attributed to the large specific surface area of the samples and the construction of dual S-scheme heterojunctions. The large specific surface area can provide sufficient active sites for photocatalytic activity. Simultaneously, the built-in electric field (IEF) in the dual S-scheme exposed to light can facilitate the migration of photogenerated electrons from the CB of the oxidation photocatalyst (OP) to the VB of the reduction semiconductor (RP), where they recombine with the photogenerated holes on the VB of the RP, leaving behind photogenerated carriers with high redox ability for photocatalytic activity. This work provides new insights into the mechanism and design of highly efficient heterojunction photocatalysts for CO₂ reduction.

Porous direct Z-scheme heterostructures of S-deficient CoS/CdS hexagonal nanoplates for robust photocatalytic H2 generation

Unique porous S-deficient CoS/CdS hexagonal nanoplates exhibited an outstanding photocatalytic capability for H2 production, due to excellent visible-light response, efficient Z-scheme charge separation, and abundant H2-evolving active sites.

All-solid-state Z-scheme Ag3PO4/CSs/AgBr heterostructures for efficient visible-light photocatalysis and the photocatalytic mechanism

A novel solid-state Z-scheme photocatalyst Ag₃PO₄/CSs/AgBr (carbon spheres, CSs) was rationally designed and successfully synthesized via a facile hydrothermal coprecipitation reaction. AgBr and Ag₃PO₄ were effectively loaded on the surface of the CSs and Ag₃PO₄/CSs/AgBr showed wide visible light absorption and superior photocatalytic performance. On the basis of ultraviolet photoelectron spectroscopy (UPS) analysis and scavenger reactions, a possible photocatalytic reaction mechanism for Ag₃PO₄/CSs/AgBr is proposed. The CSs act as a charge carrier transfer bridge for constructing the all-solid-state Z-scheme photocatalyst. The photogenerated electrons from Ag₃PO₄ and holes from AgBr congregate and recombine in the CSs phase, leaving photogenerated electrons with strong reduction abilities in the conduction band (CB) of AgBr and holes with strong oxidation abilities in the valence band (VB) of Ag₃PO₄. Some Ag⁺ ions accept electrons and turn to Ag nanoparticles (NPs), leading to the surface plasmon resonance of Ag NPs on AgBr. Therefore, the photocatalytic performance and stability were significantly improved.

Ionic Liquid-Assisted Synthesis of Ag3PO4 Spheres for Boosting Photodegradation Activity under Visible Light

In this work, a simple chemical precipitation method was employed to prepare spherical-like Ag3PO4 material (IL-Ag3PO4) with exposed {111} facet in the presence of reactive ionic liquid 1-butyl-3-methylimidazole dihydrogen phosphate ([Omim]H2PO4). The crystal structure, microstructure, optical properties, and visible-light photocatalytic performance of as-prepared materials were studied in detail. The addition of ionic liquids played a crucial role in forming spherical-like morphology of IL-Ag3PO4 sample. Compared with traditional Ag3PO4 material, the intensity ratio of {222}/{200} facets in XRD pattern of IL-Ag3PO4 was significantly enhanced, indicating the main {111} facets exposed on the surface of IL-Ag3PO4 sample. The presence of exposed {111} facet was advantageous for facilitating the charge carrier transfer and separation. The light-harvesting capacity of IL-Ag3PO4 was larger than that of Ag3PO4. The photocatalytic activity of samples was evaluated by degrading rhodamine B (RhB) and p-chlorophenol (4-CP) under visible light. The photodegradation efficiencies of IL-Ag3PO4 were 1.94 and 2.45 times higher than that of Ag3PO4 for RhB and 4-CP removal, respectively, attributing to a synergy from the exposed {111} facet and enhanced photoabsorption. Based on active species capturing experiments, holes (h+), and superoxide radical (•O2−) were the main active species for visible-light-driven RhB photodegradation. This study will provide a promising prospect for designing and synthesizing ionic liquid-assisted photocatalysts with a high efficiency.

Highly Efficient Ag3PO4/g-C3N4 Z-Scheme Photocatalyst for Its Enhanced Photocatalytic Performance in Degradation of Rhodamine B and Phenol

Ag3PO4/g-C3N4 heterojunctions, with different g-C3N4 dosages, were synthesized using an in situ deposition method, and the photocatalytic performance of g-C3N4/Ag3PO4 heterojunctions was studied under simulated sunlight conditions. The results revealed that Ag3PO4/g-C3N4 exhibited excellent photocatalytic degradation activity for rhodamine B (Rh B) and phenol under the same light conditions. When the dosage of g-C3N4 was 30%, the degradation rate of Rh B at 9 min and phenol at 30 min was found to be 99.4% and 97.3%, respectively. After five cycles of the degradation experiment for Rh B, g-C3N4/Ag3PO4 still demonstrated stable photodegradation characteristics. The significant improvement in the photocatalytic activity and stability of g-C3N4/Ag3PO4 was attributed to the rapid charge separation between g-C3N4 and Ag3PO4 during the Z-scheme charge transfer and recombination process.

Microwave-Assisted Synthesis of Chalcopyrite/Silver Phosphate Composites with Enhanced Degradation of Rhodamine B under Photo-Fenton Process

A new composite by coupling chalcopyrite (CuFeS₂) with silver phosphate (Ag₃PO₄) (CuFeS₂/Ag₃PO₄) was proposed by using a cyclic microwave heating method. The prepared composites were characterized by scanning and transmission electron microscopy and X-ray diffraction, Fourier-transform infrared, UV–Vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. Under optimum conditions and 2.5 W irradiation (wavelength length > 420 nm, power density = 0.38 Wcm⁻²), 96% of rhodamine B (RhB) was degraded by CuFeS₂/Ag₃PO₄ within a 1 min photo-Fenton reaction, better than the performance of Ag₃PO₄ (25% degradation within 10 min), CuFeS₂ (87.7% degradation within 1 min), and mechanically mixed CuFeS₂/Ag₃PO₄ catalyst. RhB degradation mainly depended on the amount of hydroxyl radicals generated from the Fenton reaction. The degradation mechanism of CuFeS₂/Ag₃PO₄ from the photo-Fenton reaction was deduced using a free radical trapping experiment, the chemical reaction of coumarin, and photocurrent and luminescence response. The incorporation of CuFeS₂ in Ag₃PO₄ enhanced the charge separation of Ag₃PO₄ and reduced Ag₃PO₄ photocorrosion as the photogenerated electrons on Ag₃PO₄ were transferred to regenerate Cu²⁺/Fe³⁺ ions produced from the Fenton reaction to Cu⁺/Fe²⁺ ions, thus simultaneously maintaining the CuFeS₂ intact. This demonstrates the synergistic effect on material stability. However, hydroxyl radicals were produced by both the photogenerated holes of Ag₃PO₄ and the Fenton reaction of CuFeS₂ as another synergistic effect in catalysis. Notably, the degradation performance and the reusability of CuFeS₂/Ag₃PO₄ were promoted. The practical applications of this new material were demonstrated from the effective performance of CuFeS₂/Ag₃PO₄ composites in degrading various dyestuffs (90–98.9% degradation within 10 min) and dyes in environmental water samples (tap water, river water, pond water, seawater, treated wastewater) through enhanced the Fenton reaction under sunlight irradiation.

Investigation of the kinetics and mechanism of Z-scheme Ag3PO4/WO3 p–n junction photocatalysts with enhanced removal efficiency for RhB

The activity of an Ag₃PO₄/polyhedron-like WO₃ photocatalyst could be enhanced 27 times compared to P25 in the visible light-driven region towards RhB.