Area Of Photocatalysis Research Articles

Bioorthogonal Synthetic Chemistry Enabled by Visible-Light Photocatalysis.

The field of bioorthogonal chemistry has revolutionized our ability to interrogate and manipulate biological systems at the molecular level. However, the range of chemical reactions that can operate efficiently in biological environments without interfering with the native cellular machinery, remains limited. In this context, the rapidly growing area of photocatalysis offers a promising avenue for developing new type of bioorthogonal tools. The inherent mildness, tunability, chemoselectivity, and external controllability of photocatalytic transformations make them particularly suitable for applications in biological and living systems. This minireview summarizes recent advances in bioorthogonal photocatalytic technologies, with a particular focus on their potential to enable the selective generation of designed products within biologically relevant or living settings.

Bioorthogonal Synthetic Chemistry Enabled by Visible‐Light Photocatalysis

AbstractThe field of bioorthogonal chemistry has revolutionized our ability to interrogate and manipulate biological systems at the molecular level. However, the range of chemical reactions that can operate efficiently in biological environments without interfering with the native cellular machinery, remains limited. In this context, the rapidly growing area of photocatalysis offers a promising avenue for developing new type of bioorthogonal tools. The inherent mildness, tunability, chemoselectivity, and external controllability of photocatalytic transformations make them particularly well‐suited for applications in biological and living systems. This minireview summarizes recent advances in bioorthogonal photocatalytic technologies, with a particular focus on their potential to enable the selective generation of designed products within biologically relevant or living settings.

Utilizing samarium doped BiVO4 microspheres for solar-Powered photocatalysis and Microbial Defense

Due to their unique features and numerous uses, samarium-doped bismuth vanadate (BiVO4) photocatalysts have recently attracted a lot of interest from researchers in the area of photocatalysis. In this work, the synthesis of BiVO4 nanoparticles, both unmodified and doped with Sm3+, using a co-precipitation technique, is thoroughly examined. It is worth mentioning that the photocatalytic efficacy of Sm3+-doped BiVO4 nanoparticles was higher than that of pure BiVO4 nanoparticles. This is because the band gap was reduced and the synergistic effects of Sm3+ ions worked together to effectively suppress the recombination of photo-generated charge carriers. Improving charge carrier migration and separation, and thus photocatalytic performance is dependent on the introduction of samarium dopants. Additionally, samarium-doped bismuth vanadate was investigated for its antibacterial properties, and it was shown that it could eliminate bacteria and other germs in both watery and airborne settings using photocatalytic activity. When Sm3+ ions were added to the BiVO4 matrix, the antibacterial activity was significantly increased when tested against a variety of gram-positive and gram-negative bacteria, including, but not limited to, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Proteus vulgaris. Most importantly, the photocatalyst showed remarkable stability and recyclability; at a doping level of 7 wt% Sm3+-doped BiVO4 performed optimally. This work presents a simple method for synthesizing BiVO4 nanoparticles by co-precipitation, which shows great potential for the effective removal of organic pollutants and microbes from polluted water sources. The generated nanoparticles may be either pure or doped with Sm3+.

Effect of poling on photocatalytic activity with SrBi4Ti4O15 catalyst

AbstractThis research article is related to a bismuth oxide‐layered pseudo‐perovskite ferroelectric material and its capabilities in the area of photocatalysis. SrBi4Ti4O15 (SBT) catalyst was prepared via a solid‐state reaction followed by calcination at 950°C sustained over 4 h. X‐ray diffraction, X‐ray photoelectron spectroscopy, bandgap analysis, Raman spectroscopy, and scanning electron microscopy confirmed the successful synthesis of the SBT catalyst. The photocatalysis capability was checked on a methylene blue (MB) model dye. The poling of the SBT catalyst was performed under 2 kV/mm of electric field. The poling of the catalyst material played a crucial role in enhancing the photocatalytic activity. Moreover, the effect of volume (k(v)), initial concentration (k(ic)) of the MB dye, amount of catalyst (k(c)), and intensity (k(i)) of the light were examined and analyzed by the mathematical model. This study suggested that higher intensity and amount of catalyst enhance photocatalytic activity, whereas higher concentration and volume of dye suppress the photocatalytic activity. The amount of catalyst showed the highest effect on the photocatalytic activity. The rate constant is influenced by these factors and the order of influence is k(c) > k(i) > k(v) ≃ k(ic).

Polyoxometalate‐Based Frameworks: Construction Strategies and Photocatalytic Applications

AbstractPolyoxometalate‐based frameworks, as a kind of material constructed by polyoxometalates (POMs), metal ions or clusters, organic ligands, are combined both the advantages of oxygen‐rich POMs and porous metal‐organic frameworks (MOFs) within one single system. This integration greatly expands their potential applications compared to the individual POMs or MOFs. Particularly for photocatalysis, the narrow light absorption range of the typical POMs units in the ultraviolet region hinders their extensive uses as visible‐light‐driven photocatalysts. However, the incorporation of photoactive units into POMs‐based frameworks can be considered as an effective approach to overcome this limitation. In this paper, we review selected examples of recent progress based on the POM‐based frameworks along with their construction strategies and applications in various areas of photocatalysis, mainly including water splitting, CO2 reduction, organic synthesis and also the selective coupling reactions.

Confined synthesis of conjugated microporous polymers for selective photocatalytic oxidation of amines

Photocatalytic oxidative coupling of amines is considered a mild, efficient, and sustainable strategy for the synthesis of imines. As a versatile organic semiconductor, conjugated microporous polymers (CMPs) are attractive in photocatalysis areas due to the diversity of their polymeric monomers. Herein, we report that in addition to the design of monomers, size-confined polymerization is also a feasible strategy to modulate the structure and photocatalysis properties of CMPs. We adopted dibromopyrazine as polymeric units to prepare pyrazine-involved hollow spherical CMPs (H-PyB) using a template method and successfully performed size-confined polymerization of hollow samples by resizing the templates. Interestingly, the small confinement space induced the formation of CMPs with better conjugate extensibility, resulting in enhanced conductivity, narrowed bandgaps, improved photoelectric performance, etc. As a result, small-sized H-PyB CMPs had superior activity for the photocatalytic oxidation of amines. Particularly, the smallest H-PyB CMPs that we designed in the present work exhibited excellent performance for the photocatalytic coupling oxidation of amines. When using benzylamine as a model substrate, the yield of the corresponding imine reached ∼ 113 mmol·g−1·h−1, accompanied by almost 100 % selectivity. Furthermore, the as-designed confined samples exhibited stable photocatalytic activity as well as good applicability for oxidative coupling of different amines. This work not merely reports a kind of CMP photocatalysts with excellent performance for the imine coupling oxidation but also proposes an alternative strategy for constructing high-performance organic photocatalysts by size-confined synthesis.

Enhanced photocatalytic properties of s-triazine-based-g-C3N4/BlueP and g-C3N4/G/BlueP vdW heterostructures: A DFT study

Constructing a Z-scheme heterostructure from selected semiconductors has been proved to be an effective route for attaining the strong redox capability and broad light absorption range simultaneously. In this work, we investigated the electronic, optical and photocatalytic properties of g-C3N4/BlueP and g-C3N4/G/BlueP van der waals heterostructures (vdWHs) by density functional theory (DFT) calculations. The staggered band alignment and the interfacial built-in electric field originated from the charge transfer from g-C3N4 to BlueP depict the Z-scheme photocatalytic mechanism of the g-C3N4/BlueP vdWH. Meanwhile, the vdWH shows an enhanced absorbance at the ultraviolet and visible light range compared to the individual g-C3N4 and BlueP monolayers. Furthermore, the intercalation of Graphene monolayer between g-C3N4 and BlueP is proved to modulate the interfacial built-in electric field, while retaining the staggered band alignment simultaneously. The significant enhancement of the visible light region absorption efficiency promoted by the gap-state of intercalated Graphene manifests the co-catalytic effect of Graphene and the applicable prospect of the constructed ternary heterostructure in photocatalysis area.

Ternary composite WS2/GO/Au synthesized from laser ablation and hydrothermal method for photo- and electro-chemical degradation of methylene blue dye

Photocatalysts based on two-dimensional (2D) material with full optical absorption in the visible region have gained a lot of interest as a potential method for the degradation of pollutants, but there are very few single materials that can fulfill this requirement. In this research, we are suggesting the formation of WS2/GO/Au ternary composite prepared by WS2 and GO using nanosecond laser ablation followed by adding Au using the hydrothermal method. Ultraviolet-visible (UV–Vis), Raman, x-ray diffraction (XRD) spectroscopies, and field emission scanning electron microscopy (FE-SEM) were used to investigate the microstructure, morphology, and spectroscopic properties of the samples that had been produced. The UV–Vis spectra suggest the formation of a ternary composite, and FE-SEM shows morphology as Au nanoparticles with a size ranging from 20 to 30 nm are perfectly mixed with WS2 nanosheets, which can be seen on GO sheets. SEM-Energy dispersive x-ray spectroscopic (EDS) images indicate the availability of all elements in prepared samples and the formation of a ternary composite of WS2/GO/Au. XRD and Raman spectroscopy confirm the crystalline nature of AuNPs and WS2 and suggest the transformation of GO into rGO. The prepared pristine (WS2), binary (WS2/GO), and ternary composite show the capability for methylene blue degradation under UV-light irradiation as 41.85 %, 48.26 %, and 83.17 %, while electrocatalytic degradation gives 99 % for WS2/GO/Au respectively. The improved photocatalytic activity by the multicomponent has been demonstrated by nanostructured catalysts with specific morphology due to their exceptional electron transport characteristics. The WS2/GO/Au composite is anticipated to be an encouraging photoelectric material for experimental study in the research area of photocatalysis.

Manipulation of interfacial charge dynamics for metal-organic frameworks toward advanced photocatalytic applications.

Compared to other known materials, metal-organic frameworks (MOFs) have the highest surface area and the lowest densities; as a result, MOFs are advantageous in numerous technological applications, especially in the area of photocatalysis. Photocatalysis shows tantalizing potential to fulfill global energy demands, reduce greenhouse effects, and resolve environmental contamination problems. To exploit highly active photocatalysts, it is important to determine the fate of photoexcited charge carriers and identify the most decisive charge transfer pathway. Methods to modulate charge dynamics and manipulate carrier behaviors may pave a new avenue for the intelligent design of MOF-based photocatalysts for widespread applications. By summarizing the recent developments in the modulation of interfacial charge dynamics for MOF-based photocatalysts, this minireview can deliver inspiring insights to help researchers harness the merits of MOFs and create versatile photocatalytic systems.

Transformations of carbohydrate derivatives enabled by photocatalysis and visible light photochemistry.

This review article highlights the diverse ways in which recent developments in the areas of photocatalysis and visible light photochemistry are impacting synthetic carbohydrate chemistry. The major topics covered are photocatalytic glycosylations, generation of radicals at the anomeric position, transformations involving radical formation at non-anomeric positions, additions to glycals, processes initiated by photocatalytic hydrogen atom transfer from sugars, and functional group interconversions at OH and SH groups. Factors influencing stereo- and site-selectivity in these processes, along with mechanistic aspects, are discussed.

Photo-Fenton degradation of tetracycline antibiotic over MIL-101(Cr)/FeOOH nanocomposite as stable and efficient visible light responsive photocatalyst.

Designing an inexpensive, easily synthesized, stable and efficient photocatalyst is a major challenge in photocatalysis area, especially when photo-reaction is performed in aquatic medium to degrade organic pollutants. To this aim, nano-sized MIL-101(Cr) (MIL = Materials Institute Lavoisier), as chemically tolerant metal-organic framework (MOF), was simply prepared via HF-free hydrothermal synthesis procedure. In order to decorate amorphous FeOOH quantum dots (QDs) on the surface of this MOF, various amounts of FeOOH QDs (i.e., 5, 10, 15 and 20 wt%) were synthesized in the presence of MIL-101(Cr) to prepare MIL-101(Cr)/FeOOH(x%) nanocomposites. Decoration of such iron oxide quantum dots on the surface of MIL-101(Cr) and investigation of its activity in photo-Fenton degradation of tetracycline (TC) antibiotic is reported here for the first time. Among the synthesized nanocomposites, MIL-101(Cr)/FeOOH(15%) demonstrated superior photo-Fenton activity in degradation of TC (80%) at short reaction time under optimum reaction condition using the energy-efficient white LED lamps as visible light source. It was observed that the synergy between any component of this photo-Fenton system such as nanocomposite, hydrogen peroxide and visible light is the main reason for enhancement of TC removal over time. Also, neither MIL-101(Cr) nor FeOOH QDs exhibited poor degradation efficiency, which implies the positive role of the coupling of these materials. Furthermore, the stability and recoverability of MIL-101(Cr)/FeOOH(15%) nanocomposite was investigated in four photo-Fenton cycles, which no significant decrease in TC degradation performance was observed.

A new La(III)-MOF: crystal structure and photodegradation of Rhodamine B

Organic dyes have been widely used in industry but mistreatment of their use and disposal can have negative consequences on human health. A technique based on solid photocatalysts is feasible for remediating organic dyes without additional harmful byproducts or additives. Recently, metal-organic frameworks formed by the metal ions and organic linkers have been studied in the areas of photocatalysis and biomedicine. In this study, the assembly reaction of 2-CNB ligand with La(CH3COO)3 generated a metal-organic framework, [La(2-CNB)(CH3COO)2(H2O)] n (1, 2-CNB = 2-cyanobenzoic acid). Its high degradation efficiency makes 1 an effective photocatalyst for Rhodamine B (RhB) photodegradation under irradiation by UV light, with a degradation efficiency of 97.78% within 90 min.

Mini‐Review: Progress on the Controllable Synthesis of Micro/Nanoscale Bi2S3 Functional Materials

AbstractBismuth sulfide (Bi2S3) with micro/nanostructures as an important semiconductor material has attracted considerable attention due to its high ionic conductance, high photoelectric conversion efficiency, and large absorption coefficient, which is widely applied in the areas of photocatalysis, energy conversion, sensors, biomedicine, and pollutant disposal. Up to now, various strategies are reported for the morphology‐controlled synthesis of micro‐nanoscale Bi2S3 and Bi2S3‐based materials via manipulating the thermodynamics and kinetics in the chemical fabricating process. However, the Bi2S3 with designed shapes still remains to be developed to well adapt these diverse usages. To conclude, the designed preparation strategies, advanced applications, current challenges, and future expectations of Bi2S3 are discussed to provide some potential suggestions for further promotion of Bi2S3 functional materials.

Carbazole-involved conjugated microporous polymer hollow spheres for selective photocatalytic oxidation of benzyl alcohol under visible-light irradiation

Conjugated microporous polymers (CMPs) have been considered a type of promising visible-light-driven, organic photocatalysts. However, apart from designing high-performance CMPs from a molecular perspective, little attention is paid to improving the photocatalytic properties of these polymers through macrostructural regulation. Herein, we prepared a kind of hollow spherical CMPs involving carbazole monomers and studied their performance on the selective photocatalytic oxidation of benzyl alcohol under visible light irradiation. The results demonstrate that the introduction of a hollow spherical structure improves the physicochemical properties of the as-designed CMPs, including the specific surface areas, optoelectronic characteristics, as well as photocatalytic performance, etc. In particular, the hollow CMPs can more effectively oxidize benzyl alcohol compared to pristine ones under blue light illumination, and produce >1 mmol of benzaldehyde in 4.5 h with a yield of up to 9 mmol·g−1·h−1, which is almost 5 times higher than that of the pristine ones. Furthermore, such hollow architecture has a similar enhanced effect on the oxidation of some other aromatic alcohols. This work shows that the deliberate construction of specific macrostructures can better arouse the photocatalytic activity of the as-designed CMPs, which will contribute to the further use of these organic polymer semiconductors in photocatalysis areas.

Carbazolic Conjugated Microporous Polymers for Photocatalytic Organic Transformations.

Heterogeneous photocatalysis have been deemed as a versatile and colorful platform for exploring efficient transformation systems. Henceforth, the design of photocatalysts underpins a wide range of research interests. By virtue of synthetic versatility, stability, non-toxicity, purely organic properties, tunable semiconductive structures, and remarkable visible-light absorbance, conjugated microporous polymers (CMPs) have emerged as an attractive new class of semiconductor materials that show great potential for tackling important energy and environmental challenges. Over the past decade, immense efforts have been devoted toward the construction of CMPs-based photocatalysts for versatile photocatalytic transformations. This review aims to summarize the latest representative advances in the field of carbazolic CMPs, focusing on various design strategies for the construction of tailor-made skeletons that have direct impact on their charge dynamics and thus photocatalytic performances, especially on their specific photocatalytic efficiency for organic transformations. Scrutinizing the photocatalytic features and elucidating the related design principles, it is fully described how structure modification of polycarbazoles could have an effect on optical properties, and thus on photocatalytic performance. Furthermore, the bottlenecks that need to be addressed, and the future research directions of CMPs are identified in the area of photocatalysis.

Nanocrystalline Ni-Zn spinel ferrites: size-dependent physical, photocatalytic and antioxidant properties.

The physical properties of nanomagnetic particles are expected to be highly dependent on their size. In this study, besides the promising applications of nanocrystalline Ni-Zn spinel ferrites in the area of photocatalysis and free radical scavenging, we present a detailed study with appropriate scientific explanations on the role of size change in modifying and tuning the microstructural, optical and magnetic properties. Three nanostructured Zn0.3Ni0.7Fe2O4 samples of different particle sizes were prepared via the chemical co-precipitation method. Crystallographic phase purity and formation of the spinel cubic phase for all the samples were tested by X-ray diffraction studies. The magnetic properties of the as-synthesized ferrite nanoparticles have been examined thoroughly at 5 K and 300 K. Emergence of superparamagnetic behavior has been observed for the sample with the smallest size ferrite nanoparticles (ZNF-1). The photocatalytic efficiency of all the nanocatalysts was tested on methylene blue (MB) dye and the smallest sized nanocatalyst (ZNF-1) was identified as the most efficient catalyst in degrading MB dye under light illumination. The degradation efficiency was found to decrease with increasing mean particle size of the prepared samples. The antioxidant properties of the prepared ferrite samples were also studied. Here, too, the ZNF-1 sample with the smallest sized nanoparticles exhibited maximum scavenging of free radicals compared to other samples. Hence, the present study clearly demonstrates that smaller-sized Ni-Zn spinel ferrites are efficient materials for tuning the physical properties as well as for use in photocatalytic and antioxidant applications.

Molybdenum Carbide-Based Photocatalysts: Synthesis, Functionalization, and Applications.

As an effective non-noble, molybdenum carbide (MoxC: MoC or Mo2C) has attracted extensive attention and is regarded as a promising research area in the near future owing to its good biocompatibility, high stability, band gap adjustability, rich valence states, and excellent catalytic activity. This Perspective summarizes the recent progress and achievements for the molybdenum carbide-based catalysts. First, the crystal and band structures of molybdenum carbides are generally presented. Second, various modifying strategies for molybdenum carbides are outlined to enhance the photocatalytic performance, including doping engineering, vacancy engineering, morphology and structure engineering, and the establishment of molybdenum carbide-based composite catalysts. Finally, potential applications in the photocatalysis area of molybdenum carbide-based photocatalyst are generalized. Future development trends and perspective for this promising material are also discussed.

Facile hydrothermal synthesis of cerium oxide/rGO nanocomposite for photocatalytic and supercapacitor applications

The unique features of graphene materials make them excellent catalysts for photodegradation and energy applications. In the present work, CeO2/reduced graphene oxide (rGO) nanocomposites were prepared by a simple one-pot hydrothermal method. The nanocomposite is found to have a mesoporous structure with a surface area of 100.129 m2g−1. With the preferentially small surface area of the nanocomposite and the ability of the rGO to act as electron acceptor, the CeO2/rGO photocatalyst supresses the electron-pair recombination during photodegradation, thereby achieving a quick and efficient degradation of Direct Green dye. Under the influence of UV light, the CeO2/rGO degrades 84.1% of the dye which is 1.5 times more efficient than blank CeO2. Further, due to the conducting nature of rGO, the nanocomposites have also been evaluated for their electrochemical performance. It has been found that the addition of rGO results in a high capacitance (410.8 Fg−1 at current density of 1.0 Ag−1) and stability (94% after 500 cycles) of the CeO2/rGO electrode. The present work projects the excellent charge transport capability of rGO based CeO2 nanomaterials for dual applications in the areas of photocatalysis and electrocatalysis.

MXenes as Emerging Materials: Synthesis, Properties, and Applications.

Due to their unique layered microstructure, the presence of various functional groups at the surface, earth abundance, and attractive electrical, optical, and thermal properties, MXenes are considered promising candidates for the solution of energy- and environmental-related problems. It is seen that the energy conversion and storage capacity of MXenes can be enhanced by changing the material dimensions, chemical composition, structure, and surface chemistry. Hence, it is also essential to understand how one can easily improve the structure–property relationship from an applied point of view. In the current review, we reviewed the fabrication, properties, and potential applications of MXenes. In addition, various properties of MXenes such as structural, optical, electrical, thermal, chemical, and mechanical have been discussed. Furthermore, the potential applications of MXenes in the areas of photocatalysis, electrocatalysis, nitrogen fixation, gas sensing, cancer therapy, and supercapacitors have also been outlooked. Based on the reported works, it could easily be observed that the properties and applications of MXenes can be further enhanced by applying various modification and functionalization approaches. This review also emphasizes the recent developments and future perspectives of MXenes-based composite materials, which will greatly help scientists working in the fields of academia and material science.

Incorporation of carbazole and boron-containing dye into conjugated microporous polymers with significant aerobic oxidative photocatalysis

Carbazole-based conjugated microporous polymers (CMPs) as a new type of advanced porous material have created tremendous research curiosities in the area of photocatalysis. Besides, introducing boron-containing dyes into the CMPs framework was rare but will be rather promising due to their unique properties, including strong electron-accepting capability, efficient catalytic behaviour, significant absorption coefficient and high quantum. Herein, we rationally designed and prepared two new CMPs, i.e.Cz-BF2-CMP and Cz-BPh2-CMP with the combination of carbazole and boron-containing dye as electron donor and acceptor motifs, respectively. Due to the efficient D-A effect between carbazole and boron-dye which not only accelerated the interfacial charge transfer efficiency but also improved the separation capability of photogenerated electron-hole pairs, both CMPs exhibited excellent photocatalytic performances in organic transformations such as green synthesis of benzimidazole in aqueous solution and aerobic oxidation of thioether in EtOH.