Recombination Rate Of Charge Carriers Research Articles

Boosting Photocatalytic Hydrogen Evolution by a Light Coupling and Charge Carrier Confinement Strategy

AbstractHigh‐performance photocatalysis requires efficient light absorption and low charge carrier recombination rates. Herein, a light coupling and charge carrier confinement strategy is demonstrated to simultaneously enhance the light absorption efficiency and suppress the charge carrier recombination for high‐performance photocatalysis. The strategy is achieved by the delicate incorporation of catalysts into a dual‐core‐shell structure (e.g., CdS@SiO2@NaYF4:Yb/Tm), in which CdS (catalyst), SiO2, and NaYF4:Yb/Tm serve as shell, outer core, and inner core, respectively. Interestingly, the absorbed light can be confined within the CdS layer through multiple reflections between the CdS and SiO2 interfaces, achieving light confinement. This confinement endows a longer light residence time, enhanced light reabsorption and reutilization efficacy, and a higher concentration of photogenerated charge carriers per unit of time. Moreover, the insulating SiO2 can confine the photogenerated charge carriers within CdS layer, thus shortening their diffusion length for reduced recombination rates. Notably, when employed as the photocatalyst, this dual‐core‐shell structure showed a superb photocatalytic hydrogen evolution rate up to 74.67 mmol g−1 h−1, which is 11 times higher than that of pristine CdS. This work provides a new strategy for the design and synthesis of high‐performance photocatalysts.

Homo-Nuclear Hetero-Atomic Conjugated Reticular Oligomers for Heterojunction: A Novel "Electron Medium" for Panel Photoelectrocatalysis.

A substantial challenge in employing covalent organic frameworks (COFs) for photoelectrochemical (PEC) water splitting lies in improving their solution-processability while concurrently facilitating the transfer of charges and mass to the catalytic sites. Herein, we synthesize a solution-processable conjugated reticular oligomers (CROs), and further embed ruthenium (Ru) into the CRO, forming a CRO-Ru with homo-nuclear hetero-atomic. Thereafter, CRO and CRO-Ru construct an organic-organic heterojunction membrane at the nanoscale. Thisdesign achieves perfect lattice matching, significantly reducing the energy barrier of mass transfer, and effectively lowering the recombination rate of charge carriers. The optimized photocathode, CuI/CRO-Bpy:CRO-Bpy-Ru-1:1+P3HT/SnO2/Pt, exhibits an efficiency of 111.0µAcm-2 at 0.4V versus a reversible hydrogen electrode (RHE). Compared with the original bulk COFs and CROs, the efficiency is significantly improved. The apparent improvements in charge carrier separation and transfer are responsible for the high PEC activity. In the heterojunction, the incorporation of CRO-Bpy-Ru with a longer excited-state lifetime and a substantial built-in electric field has effectively accelerated the photo-induced electron transfer from the conduction band (CB) of CRO-Bpy to the valence band (VB) of CRO-Bpy-Ru, effectively suppressing the recombination of charges. These findings offer significant guidance for the design and optimization of high-performance photoelectrochemical catalysts.

Interface induced photoluminescence enhancement from heterojunction BaMoO4/HEAs phosphors: Experiment, theory and anti-counterfeiting application

The BaMoO4/FeCoNiCrMo (BMO/HEA(Mo)), BMO/FeCoNiCrTi (HEA(Ti)) and BMO/FeCoNiCrTiAl (HEA(Al)) phosphors were synthesized by an integrated technology. The structural characterization showed that except the main lattice phase, only the characteristic peak of high-entropy alloys (HEAs) appeared in BMO/HEAs phosphors and the existence of lattice distortion for [MoO4]2- in BMO. The microstructure analysis confirmed that there is a special interface contact between BMO and HEAs, which makes the metal in HEAs easy to have a certain connection with BMO, which causes the lattice distortion of [MoO4]2- to intensify, thus accelerating the recombination rate of charge carriers in BMO/HEAs phosphors. The BMO/HEAs phosphors have a strong emission peak at 445 nm under the excitation wavelength of 285 nm. Theoretical calculations and experiments confirmed that the luminescence of BMO/HEAs phosphor is caused by the lattice distortion of [MoO4]2-, the interface defect of BMO/HEAs and the recombination of charge carriers. The Mo in HEA(Mo) can accelerate the recombination rate of charge carriers between BMO and HEAs, thus enhancing the luminescence performance of BMO/HEA(Mo) phosphor and exhibit dynamic fluorescence anti-counterfeiting applications. However, the Ti in HEA(Ti) and Al in HEA(Al) can easily separate the charge carriers between BMO and HEAs, thus reducing the luminescence of BMO/HEA(Ti) and BMO/HEA(Al) phosphors.

Lewis Acid Regulation Strategy for Constructing D-A-A Covalent Organic Frameworks with Enhanced Photocatalytic Organic Conversion.

Owing to their excellent photoelectric properties, donor-acceptor (D-A) type photocatalytic covalent organic frameworks (COFs) have attracted significant research interest in recent years. However, the limited D-A structural units of existing COFs restrict the development of novel and efficient photocatalytic COF materials. To solve this problem, we developed a series of D-A-A-type COFs utilizing a Lewis acid regulation strategy, in which Lewis acids act as the coordination centers, and pyridine and cyano groups act as ligands. Lewis acid sites in COFs serve as electron acceptors, facilitating the separation and transfer of photogenerated electron-hole pairs. This process is crucial for photocatalysis because it significantly increases the efficiency of the catalytic reaction by reducing the recombination rate of charge carriers. The developed Lewis acid-activated D-A-A COFs efficiently catalyzed the hydroxylation of various phenylboronic acid compounds under visible light. The developed catalysts are expected to contribute to increasing the fabrication efficiency of industrially important organic materials.

Recent innovations in engineering Zinc Oxide (ZnO) nanostructures for water and wastewater treatment: Pushing the boundaries of multifunctional photocatalytic and advanced biotechnological applications

Owing to its rapid advancement in nanotechnology, latest publications (recent 5 years) related to zinc oxide (ZnO) in various aspects and applications have been reviewed. Trend has shifted to the innovation of pristine ZnO nanostructures functionalized with elemental dopants and heterojunction to improve the photoactivities on micropollutant degradation and heavy metals removal as well as the antibacterial effect towards microorganisms. The fundamentals of improved photoactivities (i.e., low recombination rate of charge carrier and effective charge transfer) and enhanced antibacterial properties (i.e., dissolution of ions and generation of reactive oxygen species) are accentuated. Subsequently, a detailed examination is undertaken to elucidate the key impacts of ZnO on actual wastewater treatment systems. This review concludes with a consolidated overview on the recent advances of ZnO for environmental wastewater decontamination and the future prospects on tailoring ZnO based on their photocatalytic and antibacterial properties to match various expectations from practical applications while minimising the adverse impacts on surrounding environment.

Rod-shaped Cd0.8Mn0.2S and Co3O4 quantum dots construct S-scheme heterojunction for photocatalytic hydrogen evolution

Photocatalytic water splitting for hydrogen production is one of the key pathways to achieving a zero-carbon economy. Cd0.8Mn0.2S has significant potential for photocatalytic hydrogen evolution, but it faces serious challenges due to the recombination of photogenerated charge carriers. To address this issue, we successfully coupled Co3O4 QDs onto Cd0.8Mn0.2S nanorods via ultrasonic self-assembly, constructing a S-scheme heterojunction to reduce charge carrier recombination rates. In this configuration, Co3O4 QDs serves as the electron donor, while Cd0.8Mn0.2S act as the electron acceptor. The Cd0.8Mn0.2S/Co3O4 QDs structure creates a closely spaced interface, providing the shortest possible path for electron transfer. Under 10 W white light irradiation, the Cd0.8Mn0.2S/Co3O4 QDs composite photocatalyst exhibited remarkable hydrogen evolution activity, achieving a hydrogen production rate of 33.39 mmol⋅g⁻¹⋅h⁻¹. This S-scheme heterojunction strategy lays the foundation for the structural design of highly active visible-light photocatalysts.

Mechanism of Co3O4-TiO2 Nanocomposite Formation with Enhanced Photocatalytic Performance

TiO2 nanotubes are tubular structures that have garnered significant attention in materials science and engineering due to their unique properties and diverse applications. In this study, highly ordered and well aligned TiO2 nanotubes were successfully synthesized through anodization of Ti foil in ethylene glycol (C2H6O2) containing ammonium fluoride (NH4F) and hydrogen peroxide (H2O2) at 60 V for 30 minutes. The effectiveness of TiO2 as a photocatalyst under solar light is limited by its wide band gap and high recombination rate of charge carriers. To address these limitations, TiO2 nanotubes were modified with cobalt oxide. The resulting Co3O4-TiO2 nanocomposite was synthesized using a wet impregnation technique, aiming to enhance the photocatalytic performance of TiO2 nanotubes across a broader range of the solar spectrum. The formation of Co3O4-TiO2 nanocomposite is by immersing the TiO2 nanotubes in the metal salt precursor solution of Co(NO3)2 for a certain soaking period. The soaking cycle was repeated a few times to ensure the deposition of cobalt oxide nanostructures on the TiO2 nanotube samples. This diffusion interstitial process via wet impregnation was time dependent, which altered the amount of cobalt loaded on the nanotube's surface. The addition of cobalt significantly improved the photodegradation activity of the nanotubes under visible light, outperforming bare TiO2 nanotubes. This enhancement is likely due to the cobalt acting as shallow traps, which effectively promote the separation of photogenerated charge carriers.

Hydrothermally synthesized Sr-doped In2S3 microspheres for efficient degradation of noxious RhB pollutants in visible light exposure

A series of SrxIn2-xS3 (x = 0, 2, 4, 6 and 8 mol%) microspheres have been prepared at 160°C using hydrothermal approach and examined the impact of Sr doping on its structural, morphological, optical and photocatalytic properties. Structural properties have been investigated using X-ray diffraction (XRD) with Rietveld refinement. Morphology and elemental composition have been analysed using Field emission scanning electron microscopy (FESEM) and Energy dispersive X-ray Spectroscopy (EDX), respectively. Optical band gap energy (Eg) has been determined using Diffuse reflectance Spectroscopy (DRS) and found to range between 2.15 eV to 2.07 eV. Photoluminescence (PL) emission spectra confirm a decrease in charge carrier recombination rate with Sr doping. The negative surface potential has been assessed by the Zeta analyzer, which indicates its suitability for the degradation of cationic dyes such as Rhodamine-B (RhB). Among the SrxIn2-xS3 microspheres, Sr0.04In1.96S3 demonstrated highest photocatalytic efficiency ∼98 % degradation of RhB pollutant (10 ppm) in 240 min. using 10 mg of catalyst per 100 ml. The adsorption kinetics in the presently studied samples obeys the pseudo 2nd order kinetic model. This study highlights the significant impact of Sr doping on the photocatalytic efficiency of SrxIn2-xS3 microspheres, offering promising applications in removal of RhB dye.

Exceptional light harvesting in copper doped CaTiO3 nanocuboids with surface nanosteps for the photo remediation of toxic Cr(VI) ions and dyes

Addressing the rising concerns of water pollution caused by harmful inorganic and organic contaminants is very crucial and photocatalysts with exceptional light harvesting capability are a promising way to tackle these issues. This study investigates the transformation of CaTiO3 into a visible light-active photocatalyst via copper doping. Copper-doped CaTiO3 nanocuboids were synthesized via a one-step solvothermal approach, resulting in the formation of distinctive nanostep substructures on the surface. Morphological analysis revealed the successful incorporation of copper ions into the perovskite matrix, as evidenced by the transition from smooth to rough, uneven surface features. X-ray diffraction confirmed the incorporation of Cu2+ ions into the Ti4+ site, while visible range absorption indicated a reduction in the bandgap. Furthermore, doping decreased the rate of charge carrier recombination and increased their average lifetime, prolonging the duration of active species. This modification facilitating efficient absorption of visible light and increase in the charge separation, leads to enhanced photocatalytic activity. The doped catalyst exhibited exceptional performance in the remediation of hexavalent chromium ions (98.5 % Cr6+ ions reduction to Cr3+ ions in 20 min), methylene blue (99.4 % degradation within 120 min), and eosin yellow (99.8 % degradation within 80 min) pollutants. This research underscores the potential of doping as a viable strategy for tailoring photocatalytic properties and addressing water pollution challenges.

Tuning the optoelectronic properties of graphene monoxide by electric field, strain and heterostructure with Cd[formula omitted] ([formula omitted]=S, Se or Te)

Hydrogen production via photocatalytic water splitting has become a promising technique for developing clean and sustainable energy system. Low-dimensional carbon-based materials are under focus to develop high efficiency visible-light photocatalysts. Among the various 2D graphene-based materials, graphene oxides (GO) attracted attention in recent years. Recently identified GO such as graphene monoxide (GMO) shows promising electronic structure characteristics such as direct band gap behavior, high optical absorption, and well-dispersed band edges to use them in higher efficiency optoelectronic applications. Nevertheless, its valence band edge is distant from the water oxidation potential, and band gap value exceeds the ideal band gap required to effectively harvest solar energy, which minimizes its practical application in photocatalytic water splitting. Here, using hybrid density functional theory calculations, we are exploring the effect of applied electric field/strain on the photocatalytic water splitting and photovoltaic properties of GMO. We found that even after applying an electric field or strain, GMO retains the desirable direct band gap behavior, well-dispersed bands at the band edges, and high optical absorption in the visible range. Further, the band alignment analysis suggests that the application of compressive strain enhances the efficiency of photocatalytic water splitting by straddling the band edges with water redox potentials. Additionally, we explored the optoelectronic properties of GMO by designing its heterostructure with CdS, CdSe, and CdTe monolayers. Remarkably, the studied heterostructures demonstrated superior optical absorption in the visible spectrum and a low recombination rate of charge carriers by separating them across different layers with type-II band alignment; suggesting that these heterostructures will be efficient candidates for visible energy photocatalytic water splitting and higher-efficiency solar cells.

Fabrication of Z-scheme Fe2O3/g-C3N4 nanocomposite with improved visible light induced photodegradation of pharmaceutical pollutants and photoelectrochemical water oxidation

The photodegradation and photoelectrochemical performance of Fe2O3 catalyst is an encouraging visible-light induced catalyst owing to its less harmfulness, cheap and ecofriendly. However, owing to its quick charge carriers recombination rate and less lifespan of charge carriers obstructs its catalyst application. Therefore, it has been lately established that the construction of heterojunction with other semiconductor might be a possible method to improve its catalytic activity. Herein, a novel Z-scheme Fe2O3/g-C3N4 heterostructure catalyst has been synthesized by a simple hydrothermal technique and studied its photoelectrochemical and photodegradation activity. The addition of g-C3N4 greatly improves the light absorption ability light, reduced charge recombination rate and progress the charge transportation. The composite catalyst exhibited the superior photodegradation performance (97.8 %) of sulfamethoxazole antibiotic remedy within 30 min of visible light illumination. •OH and •O2– radicals show a key role for dye degradation activity, and proposed a possible photodegradation charge carrier transfer mechanism based on a potential band structures of composite catalyst. Furthermore, the prepared catalysts are further used to examine the photoelectrochemical properties for hydrogen generation. The Fe2O3/g-C3N4 nanocomposite photoelectrode exhibited enriched photocurrent density (0.764 mA/cm2) than g-C3N4 (0.271 mA/cm2) and Fe2O3 (0.370 mA/cm2) photoelectrodes, which ∼ 2.8 and ∼2.1 folds greater photocurrent density than pure photoelectrodes. Electrochemical impedance spectroscopy analysis revealed that the composite electrode has minimal charge transfer resistance and greater electron transfer ability. Therefore, the current study presents a facile formation of Z-scheme catalyst and offers a sustainable method to eradicate water impurities and hydrogen generation by renewable solar energy.

Engineering of g-C3N4 for Photocatalytic Hydrogen Production: A Review.

Graphitic carbon nitride (g-C3N4)-based photocatalysts have garnered significant interest as a promising photocatalyst for hydrogen generation under visible light, to address energy and environmental challenges owing to their favorable electronic structure, affordability, and stability. In spite of that, issues such as high charge carrier recombination rates and low quantum efficiency impede its broader application. To overcome these limitations, structural and morphological modification of the g-C3N4-based photocatalysts is a novel frontline to improve the photocatalytic performance. Therefore, we briefly summarize the current preparation methods of g-C3N4. Importantly, this review highlights recent advancements in crafting high-performance g-C3N4-based photocatalysts, focusing on strategies like elemental doping, nanostructure design, bandgap engineering, and heterostructure construction. Notably, sophisticated doping techniques have propelled hydrogen production rates to a 104-fold increase. Ingenious nanostructure designs have expanded the surface area by a factor of 26, concurrently extending the fluorescence lifetime of charge carriers by 50%. Moreover, the strategic assembly of heterojunctions has not only elevated charge carrier separation efficiency but also preserved formidable redox properties, culminating in a dramatic hundredfold surge in hydrogen generation performance. This work provides a reliable and brief overview of the controlled modification engineering of g-C3N4-based photocatalyst systems, paving the way for more efficient hydrogen production.

Praseodymium doping-induced band structure tunning in bismuth ferrite (Bi1-xPrxFeO3) nanofibers for the enhanced photocatalytic properties

The study investigates the influence of praseodymium (Pr) doping on bismuth ferrite (BiFeO3/BFO) nanofibers and their structural, morphological, magnetic, optical, and photocatalytic properties. A series of bismuth ferrite nanofibers with varying concentration of Pr (Bi1-xPrxFeO3, x = 0.00, 0.05, 0.10, and 0.15 mol%) were successfully synthesized using an electrospinning technique. XRD patterns revealed that structural transformation occurred from rhombohedral to orthorhombic upon effective doping of Pr3+ into BFO nanofibers. The X-ray photoelectron spectroscopy analysis confirmed that Bi, Fe, and O maintained their native oxidation states of +3 and -2, respectively in the bare and doped systems. Furthermore, the optical band gap value was significantly reduced from 2.35 to 2.22 eV as well as the recombination rates of charge carriers in the doped systems, especially in BP0.15O system. The photocatalytic performance of the prepared samples was studied by measuring the decomposition of rhodamine B (RhB) under sunlight irradiation. Outcomes showed that the doped-BFO nanofibers exhibited enhanced photocatalytic performance compared to pure BFO, with the BP0.15O system showing the 98 % degradation in 60 min. This enhancement could be attributed to the presence of Pr-energy levels, which facilitating enhanced separation, and charge transfer to the surface for the effective redox reactions.

Nitrogen‐Rich Carbon Nanodot‐Sensitized TiO2 with MWCNT Composites for Efficient Visible Light Photocatalysis

AbstractTiO2‐based composite photocatalysts are currently being explored to address concerns intrinsic to TiO2, specifically high charge carrier recombination and UV light activation. Among various materials utilized for composite formation, carbon nanomaterials stand out due to their high electron conductivity, charge storage, photosensitization, and surface properties. However, high carbon content in composites has been shown to reduce performance with potential toxicity concerns. To harness the diverse properties of carbon nanomaterials in a single composite while optimizing the carbon content below 1% by weight, multi‐walled carbon nanotubes (MWCNT)/TiO2 sensitized by carbon nanodots (CND) are synthesized. The heterojunction formed between MWCNTs and TiO2 in the binary composite reduced the charge carrier recombination rate compared to TiO2. The addition of CNDs to MWCNT/TiO2 induced visible light absorbance of the resulting ternary composite, due to the forbidden electron transitions undergone in CND aggregates. CND/MWCNT/TiO2 exhibited a fivefold and 1.6‐fold increase in photocatalytic degradation of acid orange 7 and tetracycline under visible light compared to TiO2. This enhancement is attributed to the photosensitizing property of CNDs working in synergy with the charge storage ability of MWCNTs. A plausible charge transfer pathway for the activity of CND/MWCNT/TiO2 is proposed.

Study of structural, elastic, electronic, optical, magnetic and thermoelectric characteristics of Hexafluoromanganets A2MnF6 (A = Cs, Rb, K) cubic double perovskites

We analyse a detailed investigation of structure, electronic, optical, magnetic and thermoelectric properties of (Cs, Rb, K)2MnF6 double perovskites with cubic Fm3¯m space group. The calculation method was the augmented plane-wave functions plus local orbitals as implemented in the WIEN2k code and the GGA followed by the most accurate GGA-mBJ as exchange potentials. The precision of our K2MnF6, Rb2MnF6 and Cs2MnF6 lattice constant compared with their available experimental data is in the range 1.2 % to 3.6 %. The calculated band gap of K2MnF6, Rb2MnF6 and Cs2MnF6 materials advantages them for use in light-emitting diode technology. These materials exhibit ferromagnetic behavior. The negative formation energy, free Helmholtz energy and the dispersion of phonons confirm their thermal, thermodynamic and dynamic stability. The calculated band gap of K2MnF6, Rb2MnF6 and Cs2MnF6 materials advantages them for use in light-emitting diode technology. The p-type charge carriers, direct band gap, and flat conduction and valence bands make them as good thermoelectric materials. The major contribution to the magnetization comes from the unfilled Mn-3d orbital. The high static dielectric constant reduces the recombination rate of charge carriers and the presence of absorption peaks in the ultraviolet region are advantageous in the exploitation in the optoelectronic field. The flat valence and conduction bands, high p-type conductivity, good thermoelectric parameters, as well as non-toxicity make these compounds mainly attractive in the thermoelectric application.

Enhanced ambient-stability and charge transport property of the CsPbBr3@Polyaniline

Although all-inorganic lead halide perovskites (CsPbX3 (X = Cl, Br, I)) have received widespread attention due to excellent optoelectronic properties, their low carrier mobility and poor stability have limited their application in photodetection. In this study, to alleviate these problems, CsPbBr3@Polyaniline composite is fabricated by passivating CsPbBr3 quantum dots (QDs) into a CSA-doped polyaniline conducting polymer. Notably, polyaniline is employed as a protective layer to block the structure damage of CsPbBr3 QDs against water, light and heat. The contact between polyaniline and CsPbBr3 QDs forms a type II heterojunction for charge transfer, which greatly reduces the recombination rate of charge carriers compared to pristine CsPbBr3 QDs. Benefiting from the high stability and enhanced charge mobility, CsPbBr3@Polyaniline-based photodetector achieves improved photocurrent signal and optical response time. The results demonstrate that the surface passivation could resolve the crucial stability problem and simultaneously facilitate the superior performance of perovskite optoelectronic devices.

Solar light assisted enhanced photocatalytic activity of smart ternary ZnO:TiO2:SnO2 nanocomposites

In the present study, the smart combinations of metal oxide semiconductors (ZnO:TiO2)1-x(SnO2)x (ZTS) with different SnO2 loadings (as x = 0.0, 0.30, 0.25, 0.20, coded as ZTS0, ZTS1, ZTS2, and ZTS3) were synthesized by employing the simple sol-gel technique. The structural, morphological, optical properties and elemental composition were analyzed by using XRD, Raman spectroscopy, FE-SEM, BET, UV–Vis spectroscopy, IC-PMS, XPS and FTIR of ZTS nanocomposite and proved the formation of smart ternary combination of nanocomposites. Systematic investigation through the characterization emphasised that the acute interfacial combination was established between metal oxide semiconductors. The crystallite size was decreased on adding the amount of SnO2 in the pristine ZTS0 nanocomposites from 23.5 nm to 10.5 nm which was confirmed by Scherrer's equation. The optical energy band gap of the obtained ZTS nanocomposites was found to vary from 3.23 to 3.34 eV on adding the amount of SnO2. The performance of the ZTS nanocomposites as photocatalyst was examined towards organic dyes and the results shows highest degradation of MB and MO dyes with ZTS3 achieving 99 % and 97.3 % degradation efficiency with 1 g/L loading dose. The plausible mechanism was suggested considering the visible light absorption spectra and band diagram resulting in supressed of the recombination rate of charge carriers. The smart combination of ZTS nanocomposites makes it an ideal material for excellent photocatalytic activity for degrading organic contaminants in presence of solar light irradiation.

Remarkable improvement in photocatalytic activity of g-C3N4 for NO oxidation through surface hydroxylation

The nitrogen oxide emissions originating from combustion pose significant risks to the environment. Photocatalysis is considered an efficient and environmentally friendly strategy to alleviate this problem. Graphitic carbon nitride (g-C3N4) is regarded as one of the most promising organic photocatalytic materials for environmental purification. However, its small specific surface area, weak adsorption and high recombination rate of charge carriers result in low intrinsic photocatalytic activity. To overcome these obstacles, a hydrothermal treatment of dicyandiamide-derived g-C3N4 (DCN) at different temperatures (140–200 °C) was employed to enhance the photocatalytic activity for NO oxidation. The experimental results demonstrated a significant improvement in the photocatalytic oxidation removal rate of NO after a hydrothermal treatment. The optimal photocatalyst, DCN-180, treated at 180 °C, demonstrated the highest NO removal efficiency (65.0 %), which is twice the value of pristine DCN (32.5 %). Additionally, the formation of the toxic intermediate NO2 was effectively suppressed during the reaction. Photoelectrochemical tests revealed that DCN-180 exhibited higher photocurrent density and smaller impedance radius compared to the untreated g-C3N4 sample. Moreover, density functional theory (DFT) calculations confirmed that the DCN-180 sample showed a stronger ability to adsorb O2 and NO. The enhanced photocatalytic NO oxidation performance of DCN-180 has been primarily attributed to its enlarged specific surface area (from 10.7 to 35.5 m2 g−1), local polarization effect, reduced interfacial charge transfer resistance, and improved adsorption abilities for NO and O2 molecules. This study provides valuable insights for designing and preparing highly efficient g-C3N4 based photocatalysts through surface modification for photocatalytic NO purification.

Optimizing inorganic SnS/ZrS2 heterojunction solar cells: Numerical analysis and performance insights

The SnS and ZrS2 have emerged as promising photovoltaic materials. This paper gives the first numerical analysis of inorganic SnS/ZrS2 heterojunction solar cells using SCAPS-1D. The study focuses on the effect of several parameters, such as thickness, doping charge carrier concentration, and energy bandgap, on fundamental solar cell properties in both the window and active layers. Our findings show that a variety of parameters influence solar cell performance, including built-in voltage, minority charge carrier lifetime, depletion breadth, charge carrier collection length, photogenerated current, and recombination rate. The maximum efficiency (η) attained in our simulated devices was 32.13 %, with FF of 84.51 % and Voc of 0.796 V. To achieve this efficiency, particular SnS parameters were used, such as a band gap of 1.00 eV, thickness of 5.0 μm, and doping charge carrier concentration of 1020 cm−3. In ZrS2, characteristics such as a band gap of 1.2 eV, thickness of 0.2 μm, and doping charge carrier content optimized 1020 cm−3 contribute to the observed efficiency. Our simulation results indicate that inorganic SnS/ZrS2 heterojunction devices have potential for solar device production that is cost-effective, large-scale, and high-efficiency. High performance enables a new path toward clean energy.

B and N Codoped Cellulose-Supported Ag-/Bi-Doped Mo(S,O)3 Trimetallic Sulfo-Oxide Catalyst for Photocatalytic H2 Evolution Reaction and 4-Nitrophenol Reduction.

Cellulose plays a significant role in designing efficient and stable cellulose-based metallic catalysts, owing to its surface functionalities. Its hydroxyl groups are used as anchor sites for the nucleation and growth of metallic nanoparticles and, as a result, improve the stability and catalytic activity. Meanwhile, cellulose is also amenable to surface modifications to be more suitable for incorporating and stabilizing metallic nanoparticles. Herein, the Ag-/Bi-doped Mo(S,O)3 trimetallic sulfo-oxide anchored on B and N codoped cellulose (B-N-C) synthesized by a facile approach showed excellent stability and catalytic activity for PHER at 573.28 μmol/h H2 with 25 mg of catalyst under visible light, and 92.3% of the 4-nitrophenol (4-NP) reduction was achieved within 135 min by in situ-generated protons. In addition to B and N codoping, our use of the calcination method for B-N-C preparation further increases the structural disorders and defects, which act as anchoring sites for Ag-/Bi-doped Mo(S,O)3 nanoparticles. The Ag-/Bi-doped Mo(S,O)3@B-N-C surface active site also stimulates H2O molecule adsorption and activation kinetics and reduces the photogenerated charge carrier's recombination rate. The Mo4+ → Mo6+ electron hopping transport and the O 2p and Bi 6s orbital overlap facilitate the fast electron transfer by enhancing the electron's lifetime and photoinduced charge carrier mobility, respectively. In addition to acting as a support, B-N-C provides a highly conductive network that enhances charge transport, and the relocated electron in B-N-C activates the H2O molecule, which enables Ag-/Bi-doped Mo(S,O)3@B-N-C to have appreciable PHER performance.