Absorption In Visible Light Region Research Articles

Surface-engineered anisotropic g-C3N4 photocatalysts via green-exfoliation for visible light-driven water remediation

This study explores the modification of g-C3N4 (GCN) using extracts of betel (Piper betle) leaves and veld-grape (Cissus quadrangularis) stems. The obtained results indicate that these green extracts can effectively exfoliate the GCN-layers, modifying both the 2D structure and the 3D morphological features of GCN, leading to simultaneous chemical and physical modifications in the system. The FESEM and HRTEM images revealed the exfoliated layers with a spike-like morphology for betel extract-treated GCN (B-GCN) system, while a porous nature, along with curled layer structure, is observed in the veld extract-treated GCN (V-GCN) system. An extended absorption in visible-light region along with a reduced band gap energy is observed for V-GCN (∼2.22 eV) and B-GCN (∼2.29 eV), compared to pristine GCN (∼2.41 eV). These improvements attributed to the anisotropic morphology-induced alterations in the band structure of the systems. A notable carrier recombination resistance is also realized from the PL spectra of the treated-GCNs. The visible light-driven photocatalytic efficiencies of both the pristine and treated-GCNs in degrading methylene blue (MB), rhodamine B (RhB) and their mixture (MB+RhB) are investigated under solar irradiation. The results revealed that the V-GCN and B-GCN exhibited around 100% and over 80% degradation for MB and RhB dye, respectively. Notably, in the case of mixed dyes, the treated-GCN systems demonstrated enhanced degradation compared to pristine. This enhancement can be attributed to their improved band structure resulting from a greater layer exfoliation, morphological changes, and the presence of nitrogen defects in the modified systems. The recycling studies demonstrated that the extract-treated GCN is sable and can remain sustainable for scaled-up photocatalytic applications.

Construction of S-scheme Cs3PMo12O40/MnIn2S4 heterojunction for efficient photocatalytic removal of antibiotics: Degradation pathways, toxicity evaluation and mechanism insight

Developing highly efficient photocatalysts for the removal of antibiotics and heavy metals is of vital importance but remains a great challenge. In this investigation, a novel S-scheme Cs3PMo12O40/MnIn2S4 (CPM/MIS) heterojunction with core-shell structure was fabricated successfully via hydrothermal synthesis/dissolution-precipitation approaches, which was labelled as x CPM/MIS (x = 5, 7, 9 and 11, respectively). In the composites, these 2D MIS nanoflakes were securely and uniformly affixed on the exterior of 3D CPM nanospheres, which was verified through SEM and TEM. These as-produced materials manifested enhanced photocatalytic activity towards antibiotics (tetracycline (TC) and ciprofloxacin (CIP)) degradation and Cr(VI) reduction with visible light, and the removal rates of the optimal 9 CPM/MIS for TC, CIP and Cr(VI) could reach 97.81%, 61.78% and 67.07%, respectively. Of note, these resulting CPM/MIS composites possessed excellent stability and reusability. The outstanding photocatalytic property was attributed to the synergistic effect arising from the advantageous core-shell structure and S-scheme heterostructure. This configuration strengthened robustly interfacial interaction between the constituents, which effectively enhanced light absorption in visible region, promoted the separation and transfer efficiency of photoinduced carriers, and preserved the charge carriers with heightened redox abilities. The ESR spectra and trapping tests confirmed the dominating role of holes and superoxide radical in contaminants removal. Additionally, the high-performance liquid chromatography-mass spectrometry (HPLC-MS) technique was employed to identify the photodegradation pathways of TC. And the product toxicity was evaluated using QSAR prediction. Conclusively, combining the in situ XPS data and analysis of energy band structure, a S-scheme catalytic mechanism was elucidated. This study opens new avenues for systematically designing and fabricating S-scheme heterojunction photocatalysts with outstanding catalytic property for contaminants removal.

Preparation of PbBiO2I ultrathin nanosheets with rich oxygen vacancies for enhanced visible-light-driven photocatalytic activities

Photocatalytic oxidation technology is deemed as a prospective approach to settle the global environmental crisis. Nevertheless, the photocatalytic performance is limited by the insufficient solar light harvesting ability and disappointing charge carrier separation efficiency of photocatalysts. Herein, PbBiO2I ultrathin nanosheets with tunable oxygen vacancy (OV) concentrations were successfully fabricated via ionothermal process. The crystal structure, morphology and photoelectrochemical properties of the acquired catalysts were systematically studied. The photocatalytic degradation results demonstrate that rich oxygen vacancy (ROV) PbBiO2I possesses the highest photocatalytic degradation activity, which is about 2.9 and 35.0 times higher than those of deficient oxygen vacancy (DOV) PbBiO2I and bulk PbBiO2I in rhodamine B (RhB) degradation. The enhanced visible-light absorption region arising from bulk oxygen vacancy and surface oxygen vacancy can serve as highly active sites for catalytic reaction. This contributes to enriching electrons to accelerate oxygen molecular activation and boost charge separation. Additionally, superoxide radicals (O2•-) and holes (h+) are proved to be the major reactive species during photocatalytic process. By which, a feasible photocatalytic mechanism was primarily proposed. This research can offer a new avenue for developing bismuth-based defective photocatalyst in the field of environmental remediation.

Daul Z-scheme heterojunction BiOBr/Bi2O2.33/g-C3N4 for enhanced visible-light-driven tetracycline hydrochloride degradation

The construction of heterojunction photocatalysts with superior visible light photocatalytic performance is an effective strategy to addressing antibiotic pollution. A dual Z-scheme heterojunction BiOBr/Bi2O2.33/g-C3N4 was synthesized via hydrothermal and calcination methods, exhibiting exceptional degradation TC-HCL efficiency under visible light irradiation. The well-designed heterojunction was comprehensively supported by SEM, XPS, XRD and other series of characterization. Moreover, the BBCN50 heterojunction demonstrated an optimal degradation efficiency of 97.0% in 60 min compared to BB and CN with efficiencies of 90.8% and 70 respectively. The superior photocatalytic performance is attributed to the significantly broadened visible light absorption region and enhanced migration and separation of photogenerated electron-hole pairs facilitated by the fabricated heterojunction. Moreover, cyclic interpretation and free radical capture research have confirmed both the high stability of catalyst and its Z-type charge transfer mechanism.

Carbon Dots Modification Surface of Titanium Dioxide and Their Photocatalytic Activity

This work, we develop the efficient visible-light-responsive titanium dioxide photocatalyst using carbon dots as a sensitizer (C-dots/TiO2). C-dots was synthesized via a simple one-pot reaction by microwave-assisted pyrolysis method using orange juice as carbon precursors. C-dots/TiO2 samples were prepared by a facile route. Moreover, the micro-structure and optical properties of as-prepared C-dots/TiO2 have been evaluated using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and ultraviolet–visible diffuse reflection spectroscopy (DRS). The modification surface of TiO2 with carbon dots enhanced the light absorption in visible region. The photocatalytic properties of as-prepared pure TiO2 and C-dots/TiO2 were also explored indigo carmine decolorization under visible light. The photocatalytic results revealed that the C-dots/TiO2 exhibited higher catalytic performance than the pure TiO2 under visible light.

Novel two-dimensional square-AlAs: Direct semiconductor coupled with high electron-hole mobility ratio toward sunlight-driven water-splitting

The design of new monolayered atomic motifs always attracts enormous attention due to their interesting properties induced by unique crystal phases and promising catalytic applications in low dimensional devices. Herein, we propose a novel square-AlAs monolayer based on ab initio density functional theory calculations, whose good stability is confirmed from the perspectives of energy, dynamics, thermodynamics, and mechanics. Electronic structure calculations reveal that the newly predicted square-AlAs monolayer is a direct-gap semiconductor with a bandgap of 1.39 eV, which is sensitive to in-plane strain, meanwhile the strain induced changes in bandgap allow advantageous modulations of optical absorption in visible-light region. Unfortunately, the unfavorable hydrogen evolution reaction (HER) band edge levels make square-AlAs not suitable for photocatalytic water-splitting in spite of the appropriate bandgap, high electron-hole mobility ratio and strong visible light absorption. However, a favorable effect caused by strain engineering is revealed by the fact that the square-AlAs can meet the requirement of photocatalytic water-splitting under the suitable biaxial loading. Particularly, compared to pure AlAs, the Gibbs free energy of hydrogen adsorption indicate that Boron-doping can effectively decrease the HER overpotential. Moreover, the external potential provided by photoexcited electrons for oxygen evolution reaction (OER) is quite positive, which can serve as a free and pollution-free driving force to drive OER to proceed spontaneously for pure AlAs or reduce the OER overpotential to a very low value (0.15 V) for Boron-doped AlAs, overmatching widely used IrO2 catalyst.

Boosting the sonophotocatalytic performance of BiOCl by Eu doping: DFT and an experimental study

Bismuth oxychloride (BiOCl) has a unique layered structure and uneven charge distribution, resulting in an internal electric field under polarization, which promotes the efficient separation and migration of photogenerated carriers. BiOCl could be a candidate for sonophotocatalysts. However, the low utilization of visible light limits the application of BiOCl in photocatalysts. In this study, the photocatalytic performance of rare earth element (Nd, Sm, Eu, Er and Er)-doped BiOCl was studied by density functional theory (DFT) and experimentally to screen high-performance catalysts. The band structure, density of states, and optical properties were calculated by the DFT method to predict the photocatalytic activity of rare earth-doped BiOCl. The built-in electric field formed in Eu-doped BiOCl inhibiting electron and hole recombination can be observed. Subsequently, the activity of the photocatalyst and sonophotocatalysts was evaluated. The results show that the photocatalytic and sonophotocatalytic activity of Eu-doped BiOCl is improved, which is consistent with the theoretical prediction. Combining theoretical calculations with experiments, the sonophotocatalytic activity of Eu-doped BiOCl is enhanced, mainly due to the synergistic effect of inhibiting carrier recombination, and expansion to the visible light absorption region.

Graphitic carbon nitride modified by 5-sulfonic-8-hydroxyquinoline and Fe (III) ions as visible-light photocatalyst to efficiently reduce nitroaromatic compounds

In this study, a new graphitic carbon nitride (CN) catalyst was synthesized by combining 5-sulfonic-8-hydroxyquinoline (SQ) and Fe (III) ions. Photocatalysis reduction of nitroaromatic compounds was employed to evaluate the catalytic performance of the synthesized catalyst. Compared to the pristine CN, the optimized CN-SQ-2-Fe photocatalyst showed enhanced absorption in visible light region, which promoted photogenerated charge transfer and separation. Herein, we also developed a green and efficient photocatalysis route to convert nitrophenols (NPs) into aminophenols (APs) using CN-SQ-2-Fe photocatalyst. The visible light, separation of photogenerated charges and carrier transportation of the optimized sample CN-SQ-2-Fe were significantly improved in comparison with the pristine CN and the modified samples of CN-Fe and CN-SQ-2. Accordingly, the CN-SQ-2-Fe showed a high conversion (96%) of p-nitrophenol (p-NP) to p-aminophenol (p-AP) under visible light irradiation for 2 h and possessed high photocatalytic durability. Different NP compounds were also studied under the condition of photocatalysis reduction and demonstrated high conversion (>97%). Finally, a possible mechanism was proposed for the photocatalytic reduction of p-NP by CN-SQ-2-Fe. This work provides an effective approach to prepare graphitic carbon nitride (CN) modified by 5-sulfonic-8-hydroxyquinoline (SQ) and Fe (III) ions, which is a potential visible light driven photocatalyst for the reduction of nitrobenzene derivatives.

Fe-and-N co-doped Fe-ZIF-8-NH2(1/10) prepared by molecular-scale cages effect for highly efficient photocatalytic degradation of organic dyes

The amino and iron modified Metal-organic frameworks was successfully synthesized via a skillfully strategy and used as a photocatalyst to decompose organic dyes under visible light irradiation. Results show that 50 mg catalyst can almost degrade 100% MB within just 25 min at a wide pH (3.4–11.9) range. The kinetics constant (k) on Fe-ZIF-8-NH2(1/10) is estimated to be 0.0896 min−1, significantly higher than control samples. Meanwhile, there is little effect of various water sources on catalytic activities, and the rate reaches 97.1% (in Tap water), 88.5% (in Yangtze River water) and 78.1% (in oilfield brine with ultrahigh mineralization). Besides, the Fe-ZIF-8-NH2(1/10) exhibits high stability after 5 cyclic runs, and the ICP detects a small amount of Fe3+ (0.153 mg/L) leaching. Characterization reveals the catalyst has hierarchical porous structure, a rather homogeneous geometric topology and uniformly dispersed active sites. Based on the N 1 s spectrum of XPS, the nitrogen group is successfully loaded in amino mode. Its band gap drops sharply from 5.11 eV to 2.17 eV and the peak of PL spectra is much smaller, and the Fe-ZIF-8-NH2(1/10) possesses stronger absorption in visible light region and the response wavelength is widened to 700 nm. Further, the possible mechanism of photocatalytic degradation of pollutants is also proposed. The h+ is the most effective active species, meanwhile, •O2−, e− and •OH are both apparently participated in the photodegradation process. This study introduces valuable information for constructing high active catalysts on administration of water pollution.

Enhanced tetracycline photocatalytic degradation of FeOx/Fe-Bi2O2CO3 synthesized by one-step hydrothermal method

As an effective method to reduce the antibiotic contamination in water, photocatalysis has been widely investigated. Here, we report a preparation and tetracycline photodegradation of FeOx/Fe-Bi2O2CO3 system. The system consists of FeOx nanoparticles deposited on Fe-doped Bi2O2CO3. We used a simple one-step hydrothermal technique to successfully dope Fe into the Bi2O2CO3 lattice and simultaneously deposit FeOx. Based on experiments and calculations, it is found that incorporation of Fe in Bi2O2CO3 lattice results in a preferential growth of {001} facets, which are the active facets for photocatalytic reactions, and an increased light absorption in visible region. Additionally, FeOx nanoparticles increase light absorption and carriers’ generation via an interfacial charge transfer. Moreover, FeOx acts as cocatalyst to trap photogenerated electrons and holes, reducing the carriers’ recombination. A combination of positive effects from both Fe doping and FeOx deposition increase tetracycline photodegradation performance by two to three times compared to the pristine Bi2O2CO3. Thus, this work provides an easy-to-prepare and enhanced Bi2O2CO3 – based photocatalysts, which could benefit the future development of other materials in the field.

Replacing CC Unit with B←N Unit in Isoelectronic Conjugated Polymers for Enhanced Photocatalytic Hydrogen Evolution.

Three linear isoelectronic conjugated polymers PCC, PBC, and PBN are synthesized by Suzuki-Miyaura polycondensation for photocatalytic hydrogen (H2 )production from water. PBN presented an excellent photocatalytic hydrogen evolution rate (HER) of 223.5µmolh-1 (AQY420 =23.3%) under visible light irradiation, which is 7 times that of PBC and 31 times that of PCC. The enhanced photocatalytic activity of PBN is due to the improved charge separation and transport of photo-induced electrons/holes originating from the lower exciton binding energy (Eb ), longer fluorescence lifetime, and stronger built-in electric field, caused by the introduction of the polar B←N unit into the polymer backbone. Moreover, the extension of the visible light absorption region and the enhancement of surface catalytic ability further increase the activity of PBN. This work reveals the potential of B←N fused structures as building blocks as well as proposes a rational design strategy for achieving high photocatalytic performance.

Polyacrylic acid/polyethylene glycol hybrid antifouling interface for photoelectrochemical immunosensing of CYFRA 21-1 based on TiO2/PpIX/Ag@Cu2O composite

A photoelectrochemical (PEC) transducer based on composite TiO2/PpIX/Ag@Cu2O was prepared for the detection of CYFRA 21–1. TiO2 nanomaterials were synthesized by hydrothermal method. TiO2/PpIX/Ag@Cu2O composites were obtained by combining protoporphyrin Ⅸ (PpIX) molecules and Ag@Cu2O on TiO2. This composite material has strong absorption in visible light region and excellent photoelectric chemical properties. Ascorbic acid (AA) is a good electron donor, which can remove photogenerated holes in liquid environment to inhibit the recombination of photogenerated electrons and hole pairs, thus enhancing the photocurrent and improving its stability. The results showed that the sensor can quantitatively test CYFRA 21–1 in the range of 0.1 pg/mL∼100 ng/mL. The photoelectric chemical sensor has the advantages of high sensitivity, low detection line limit and wide linear range.

Janus monolayer SiXY (X = P, as and Sb, Y = N, P, As) for photocatalytic water splitting

We theoretically propose a types of Janus monolayers SiPN and SiXY (X = As, Sb; Y = P, As) with high stability, suitable band structures and outstanding light absorption for photocatalytic water splitting. On the basis of the first-principles calculations with the HSE06 functional and EVGW0 + BSE method, we determine that monolayer SiPN has mediocre optical absorption, appropriate STH efficiency, small electronic effective mass, and indirect band gap with value of 2.49 eV. We have also explored the anisotropy-tunable electronic and optical properties under uniaxial strain. Additionally, through replacing the surface atoms in monolayer SiPN, we have built monolayer SiAsP, SiSbP, and SiSbAs, whose band gaps are 2.35 eV, 1.88 eV, and 2.17 eV, respectively. Furthermore, we obtain that monolayer SiAsP, SiSbP, and SiSbAs have smaller effective mass, higher solar to hydrogen (STH) efficiency, as well as better optical absorption in visible-light region. Our work not only propose four Janus monolayers for expanding the instances of two-dimensional Janus semiconductors but also provide a guide for modifying mediocre 2D semiconductor photocatalysts into the high-performance one for photocatalytic water splitting.

Excellent photocatalytic degradation of rhodamine B over Bi2O3 supported on Zn-MOF nanocomposites under visible light

Abstract In this article, Bi2O3@Zn-MOF hybrid nanomaterials were synthesized by supporting Zn-based metal–organic framework (Zn-MOF) through the hydrothermal method. X-ray diffractometer, Fourier transform infrared, scanning electron microscopy, energy-dispersive X-ray, N2 physisorption, X-ray photoelectron spectroscopy, and UV-Vis were used to characterize the physical and chemical properties of Bi2O3@Zn-MOF nanomaterials. The photocatalytic activity of the as-prepared hybrid has been studied over the degradation of rhodamine B (RhB). A catalytic activity of 97.2% was achieved using Bi2O3@Zn-MOF nanocomposite with the loading of 0.18 g Bi2O3, after 90 min of exposure to visible light irradiation, and the high photocatalytic performance was mainly associated with the nanorod structures, larger pore size, and broaden visible light absorption region due to the synergistic effect of the constituting materials. Furthermore, the Bi2O3@Zn-MOF nanocomposite can be reused three times and the degradation rate of RhB was maintained at 77.9%. Thus, the Bi2O3@Zn-MOF nanocomposite can act as a potential photocatalyst for the photodegradation of organic dyes in environmental applications.

Boosted degradation of tetracycline over a novel hierarchical 2D/1D S-scheme heterojunction Bi2O4 @SnS under visible light irradiation

Highly efficient photocatalytic degradation of tetracyclines (TCs) has drawn increasing interest in the field of environmental remediation. Constructing S-scheme heterojunction is a desirable strategy for booting the photocatalytic activity of the semiconductors. Herein, rod-like Bi2O4 was decorated with SnS nanosheets with excellent light harvesting ability to construct 2D/1D hierarchical S-scheme heterojunction Bi2O4 @SnS. The photocatalytic degradation of TC over Bi2O4 @SnS was carried out under visible-light. S-scheme interfacial charge transfer mode was inferred via in-situ irradiated X-ray photoelectron spectroscopy (XPS). The optimum Bi2O4 @SnS composites 20-SSBO exhibits excellent photocatalytic activity and stability for degradation of TC in both deionized water and natural river water. Within 120 min, the degradation efficiency of tetracycline reaches 91%. The degradation rate constant of TC over 20-SSBO is 3.3 and 10.6 folds that over Bi2O4 and SnS, respectively. The significant enhancement of photocatalytic activity is mainly due to two aspects: On the one hand, the successful construction of S-scheme heterojunction between Bi2O4 and SnS not only effectively promotes the separation and transfer of photogenerated carriers but also preserves electrons with strong reduction ability and photogenerated holes with strong oxidation ability. On the other hand, the 2D/1D hierarchical core-shell structure resulted in increased specific surface area and broadened visible-light absorption region. In addition, environmental factor such as pH, typical inorganic cations and anions, and natural organic matters have less effect on the photocatalytic degradation of tetracycline. The possible photocatalytic degradation pathway of TC was proposed. The S-scheme heterojunction Bi2O4 @SnS have promising application in natural Environmental remediation.

Efficient Photodegradation of Methylene Blue using WLED with Nanosphere Graphitic Carbon Nitride Compared with its Bulk Counterpart

Herein, a simple solvothermal synthesis of graphitic carbon nitride nanosphere (g-CNN) at 180 ºC is reported. The photocatalytic activity of g-CNN was studied under an in-house developed white light emitting diode (WLED) reactor and characterized by FESEM, PXRD, FTIR, EDX, UV-visible spectroscopy and BET isotherm. The g-CNN has absorbance in visible light region and exhibits enhanced photocatalytic activity compared to bulk graphitic carbon nitride (BGCN) for photodegradation of methylene blue, which attributes to its lower surface area. The photocatalytic performance of g-CNN as function of pH of dye solution and catalyst amount were also studied. The g-CNN can be used for three repeated cycles with minimal change in photocatalytic efficiency. The solvothermal synthesis method at relative low temperature introduces terminal oxygen functionalities in g-CNN, which enhance light absorption and accelerate electron transfer results in improvement of photocatalytic efficiency of g-CNN. The results demonstrated the effectiveness of g-CNN as a photocatalyst for the treatment of water using visible light from WLED.

Chiral Lewis Acid-Catalyzed Norrish Type II Cyclization to Synthesize α-Oxazolidinones via Enantioselective Protonation

Chiral Lewis Acid-Catalyzed Norrish Type II Cyclization to Synthesize α-Oxazolidinones via Enantioselective Protonation

Carbon dots cooperatively modulating photocatalytic performance and surface charge of O-doped g-C3N4 for efficient water disinfection

The emergence of widespread microbial contamination and drug-resistant bacteria in the water environment poses a severe threat to public health. Photocatalysis is considered an efficient, energy-saving, and cost-effective disinfection strategy for effectively removing microbial contamination from water bodies. In this paper, a metal-free O-doped g-C3N4/carbon dots (O-CN/CDs) nanosheet photocatalysts are prepared in coordination with various modification strategies, which results in a considerable improvement in photocatalytic disinfection activity compared to bulk g-C3N4 (B-CN). First, O-doping and morphology modulation are achieved simultaneously with hydrothermal treatment, which not only hinders the recombination of photogenerated hole-electron pairs, but also enables the exposure of more active centers. Subsequently, loading of CDs onto O-CN nanosheets by electrostatic self-assembly increases the production of photogenerated hole-electron pairs by expanding the visible light absorption region and promoted the separation of photogenerated carriers by trapping photogenerated electrons. Interestingly, the loading of CDs changes the charge on the surface of the composite photocatalyst from negative to positive, making it easier for the active species to come in contact with bacteria, and thus improving bacterial disinfection performance. Under visible light irradiation, the inactivation efficiency of optimized O-CN/CDs against methicillin-resistant Staphylococcus aureus (MRSA) is log(C/C0) = 4.08, approximately 9 times higher than that of B-CN. The main active species inactivating bacteria are superoxide anions radicals (•O2–) and photogenerated holes, and their attack causes damage to the membrane wall structure and leakage of intracellular components. Additionally, the feasibility of the as-prepared photocatalysts in water disinfection in real environments was confirmed by photocatalytic disinfection experiments in successive recovery cycles and in practical lake water.

MoSi2N4/CrS2 van der Waals heterostructure with high solar-to-hydrogen efficiency

Based on first-principle calculations, electronic properties and photocatalytic performance of MoSi 2 N 4 /CrS 2 heterostructure are studied systematically. Our results show that MoSi 2 N 4 /CrS 2 van der Waals heterostructure possesses an indirect band gap of 1.52 eV. The layer-projected band structures combined with PDOS have confirmed a type-II band alignment, which can effectively reduce the photogenerated carrier recombination. The heterostructure's band edges can cross the redox potential of water decomposition at pH = 0. Compared with two individual monolayers, the optical absorption in visible light region is improved. Moreover, the heterostructure possesses a high solar-to-hydrogen efficiency up to 39.81%. Hence, our results provide useful guidance for MoSi 2 N 4 -based heterostructure design and applications. • MoSi 2 N 4 /CrS 2 vdW heterostructure possesses a type-II band alignment. • MoSi 2 N 4 /CrS 2 vdW heterostructure can be used as photocatalyst for water splitting. • MoSi 2 N 4 /CrS 2 vdW heterostructure has a high STH efficiency (39.81%).

Experimental and theoretical studies on the synergistic effect of P and Se co-doped g-C3N4 loaded with Ag nanoparticles as an affective photocatalyst under visible light irradiation

In this work, in order to improve drawbacks of bare (pure) carbon graphite nitride (g-C3N4), phosphorus-selenium doped carbon nitride was synthesized to enhance light absorption in visible region. Then Ag nanoparticles loaded onto P-Se co-doped g-C3N4, as a result, the surface plasmonic resonance effect was created. In addition, the photocatalytic activity of samples was improved by suppression of charge carriers’ recombination. Synthesized photocatalyst was characterized by XRD, FT-IR, EDS, BET, XPS, FE-SEM, ICP, TEM, and DRS and PL analysis. All prepared samples were applied in the degradation of Rhodamine B as an azo dye under irradiation of visible light. According to the obtained results, the sample of Ag/P-Se co-doped g-C3N4 (3 wt% Ag, 2 wt% P and Se) showed the highest photocatalytic activity for the degradation of Rhodamine B (about 90% after 180 min). This result was about 4 times higher than degradation of dye in the presence of pure g-C3N4. This increase in the photocatalytic activity in Ag/P-Se co-doped g-C3N4is related to the significant decrease in bandgap energy due to the synergistic effects by doping P and Se, as well as the decrement in the recombination rate of electron-holes by depositing Ag nanoparticles. Quantum and Monte Carlo (MC) calculations were used to investigate the structure P-Se co-doped g-C3N4 and the interaction of Ag molecules on its surface under aqueous condition in the Materials Studio 2017 software. Ag created a tendency to form relatively strong interaction with synthesized P-Se co-doped g-C3N4. Also, Monte Carlo adsorption locator module was investigated to test adsorption activity of Rhodamine B on g-C3N4 and P-Se co-doped g-C3N4 loaded with Ag. According to the obtained outcomes, RhodamineB adsorption on P-Se co-doped g-C3N4 loaded with Ag structure was higher than the dye adsorption on g-C3N4 pure. In this structure, Ag atoms led to better dye adsorption on P-Se co-doped g-C3N4 surface (Rhodamine B was adsorbed on P-Se co-doped g-C3N4 surface by Ag atoms with lower than 3 Å). In addition, Rhodamine B was interacted by catalyst via π-π stacking interactions and hydrogen bonding. Furthermore, Ag atoms enhancedRhodamine B adsorption on P-Se co-doped g-C3N4 surface.