Visible Light Absorption Research Articles

Effect of Cherenkov light on cell survival in x-ray irradiation of LINAC based on Monte Carlo simulation and cell survival measurements

Cherenkov radiation is emitted during x-ray irradiation in a linear accelerator (LINAC). Cherenkov light contains many short wavelength components, including ultraviolet (UV) light, which is well-known for its bactericidal effects. A similar phenomenon is probable for human cancer cells. To assess the effect of Cherenkov light on cell death in x-ray irradiation, we employed simulations and UV cell survival data. We measured the survival rates of HeLa cells exposed to 254 nm (UVC) and 310 nm (UVB) light to determine the 50% lethal dose (LD50) required to kill 50% of the cells. For other wavelengths, we utilized literature values to establish the relationship between wavelength and LD50. Due to the broad range of the Cherenkov light spectrum, we need LD50 as a function of wavelength to estimate cell survival solely from Cherenkov light. A Monte Carlo simulation was used to calculate the fluence distribution of Cherenkov light in a 300 mm3phantom comprised of soft tissue, both with and without absorption of visible light. The latter scenario is considered to be most influenced by Cherenkov light. By combining the fluence distribution and the wavelength-LD50 relationship, we determined the distribution of the survival rate. Our findings indicate that, in the absence of absorption, a radiation dose of approximately 90 Gy or greater is necessary for Cherenkov light to have any effect. As a result, the impact of Cherenkov light on cell survival can be considered negligible for typical dose of 2 Gy.

Mn-doped SrTiO3 perovskite: Synthesis and characterisation of a visible light-active semiconductor

This study focuses on the synthesis and characterisation of Mn-doped SrTiO3 using the citric method. As-prepared samples featured a non-porous microstructure with a mean particle size of approximately 5 μm, composed of sintered submicron crystallites. Manganese was successfully incorporated into the perovskite structure as Mn4+, with a homogeneous distribution across the Sr and Ti positions. The doping induced a distinctive dark brown hue, indicating significant visible light absorption. A pronounced band gap shift from 3.32 to 2.92 eV was revealed via Tauc analysis of the Kubelka-Munk function. Both the SrTiO3 and Mn-doped SrTiO3 samples demonstrated a high adsorption capacity exclusively for cationic dye (Methylene Blue) at pH 10, with the Mn-doped sample showing slightly enhanced removal efficiency, reaching a maximum adsorption capacity of 310.7 mg g−1. The selective adsorption at high pH can be attributed to electrostatic interactions between the perovskite surface and MB molecules. This combination of high adsorption capacity and a reduced band gap highlights the material’s potential for photocatalysis applications.

Real-time three-dimensional monitoring and analysis of perovskite solar cell using short wavelength infrared digital holography

The quality and crystallization process of all-inorganic perovskite films play a crucial role in the performance of solar cells. However, traditional detection methods lack three-dimensional depth information and real-time capabilities, hindered by strong visible light absorption, posing challenges to research. Here, a simple digital holography technique is proposed that offers real-time, nondestructive, three-dimensional phase imaging with low absorption characteristics in the short-wave infrared range. The use of short-wave infrared reduces the negative impact of visible light and vibrations in the environment on detection accuracy, while being nearly non-absorbing. The proposed method operates at a speed of 15 Hz, combining a lensless vertical structure, holographic reconstruction algorithm, and phase unwrapping algorithm to achieve real-time three-dimensional observation without image distortion and with low noise of the crystallization process of CsPbBr3 perovskite quantum dots (PQDs)/ethylene-vinyl acetate solution, which crystallizes in 39 s. Subsequently, employing minimum bounding rectangle, field stitching, intensity registration, and sub-pixel level calibration algorithms, real-time characterization is performed on the large-sized droplet of polymethyl methacrylate-matrix-encapsulated CsPbBr3 perovskite quantum dots, which has a crystallization time of 1285 s, without being limited by the field of view. Finally, using this system, the surface quality of the film is assessed, revealing fluctuations at the edge and fabrication defects of the perovskite film. Experimental results demonstrate the potential of short-wave infrared digital holography in enhancing the film formation process and quality inspection. By leveraging this technology, advancements in the development of high-performance all-inorganic perovskite solar cells can be fostered, optimizing global energy output.

A New Strategy for Photo‐Electrochemical Reduction of Carbon Dioxide Using a Carbazole‐BODIPY Based Metal‐Free Catalyst

AbstractIn this study, a cross‐linked boron dipyrromethene (BODIPY) photocatalyst containing a carbazole donor group designed for photoelectrocatalytic carbon dioxide (CO2) reduction is synthesized and characterized. The BODIPY‐based system, coated onto a platinum surface, is evaluated for its electrochemical and photocatalytic performance under light illumination. Cyclic voltammetry (CV) and chronoamperometry measurements reveals enhanced photocurrent responses, confirming the catalyst's ability to effectively drive CO2 reduction. Gas chromatography/mass spectrometry (GC‐MS) analysis identifies the formation of ethanol (C2H5OH) as a major reaction product, showing that its yield increased with extended reaction times. Additionally, the photocatalyst demonstrates remarkable performance with significantly increasing turnover numbers (TON) and turnover frequencies (TOF) over time, indicating stable and sustained catalytic activity. With a Faradaic efficiency of 34.79% at a potential of ‐1.15 V, this BODIPY system exhibits both high activity and long‐term stability. The combination of efficient electron transfer and visible light absorption by the carbazole‐BODIPY donor‐acceptor structure positions this system as a highly promising candidate for sustainable CO2 conversion applications.

Turning Waste into Treasure: Utilizing Environment-Pollutant Graphite Tailings as Photocatalyst for Photocatalytic Building Materials

Graphite tailings, as solid waste residuals from graphite extraction and refinement, pose serious risks to the surrounding ecological environment and the safety of residents’ lives. However, it is desirable but challenging how to rationalize the utilization of graphite tailings and further to develop their functionality. Herein, we demonstrate a "turning waste into treasure" strategy: capitalizing on the characteristics of graphite tailings in visible light absorption and rich metal catalytic sites, graphite tailings are employed as photocatalysts and fine aggregates to manufacture photocatalytic building materials, achieving sustainable use. Tailings powder from Luobei, Heilongjiang Province is selected as the photocatalyst, we discover that it exhibits photocatalytic degradation capability for methylene blue (MB) in water under visible-light irradiation: the degradation rates reach 70% within one hour and near-complete degradation within two hours, accompanying good recyclability. Structural analysis reveals that the graphite tailings are enriched with Fe2O3 and TiO2. They are capable of forming type-II heterojunction that enable efficient charge separation and transfer processes, transmitting photogenerated electrons to the active catalytic site to accomplish the photocatalytic degradation of MB. Moreover, other tailings, such as those from Jixi, also achieve photocatalytic degradation of MB, and cement specimens made with graphite tailings also bespoke photocatalytic degradation performance. This work is to provide solutions for the reuse of graphite tailings in the field of functional building materials, and to explore the feasibility of transforming graphite tailings from industrial solid waste to photocatalytic building materials.

Cyano-modified Potassium-Sodium Poly(Heptazine Imide) Nanosheets for Photocatalytic Hydrogen Peroxide Reduction Coupled with 5-hydroxymethylfurfural Oxidation

The efficacy of poly(heptazinonimide) (PHI) materials in photocatalytic applications is often constrained by limited visible light absorption and charge separation. In this study, we successfully synthesized cyano-modified potassium-sodium poly(heptazinonimide) (KNPHI) nanosheets using a molten salt method, which significantly enhances photocatalytic performance. The resulting KNPHI nanosheets achieve hydrogen peroxide (H₂O₂) concentrations up to 8.64mM, nearly 1.9 and 123 times greater than that achieved by KPHI and PCN respectively. Notably, integrating cyano groups and potassium-sodium ions within KNPHI enhances visible light absorption, intermediate adsorption and charge separation, as confirmed by experimental characterizations and DFT calculations, thereby improving the oxygen reduction reaction efficiency. Furthermore, the use of KNPHI for 5-hydroxymethylfurfural oxidation, coupled with oxygen reduction reaction pathway, was systematically investigated. These findings offer promising avenues for the development of advanced photocatalysts that support sustainable energy production and green chemical synthesis.

Conjugated carbon network mediated - Graphdiyne based Cu2MoS4 homojunction for enhanced charge transfer dynamics

The preparation of stable and environment-friendly catalysts with high photocatalytic performance is of practical significance for the application of photocatalytic hydrogen evolution technology. Graphdiyne has a unique sp and sp2 hybrid structure, making it a potential photocatalyst due to its high surface carrier mobility and porous network structure. In this study, a Cu2MoS4 homojunction composite catalyst with conjugated carbon networks as electron transport channels was prepared by in situ solvothermal growth. Graphdiyne provides an additional pathway for photogenerated electron transfer, improving the efficiency of the interface charge separation. Simultaneously, the built-in electric field at the interface of Cu2MoS4 provides a strong driving force for electron transfer. Owing to the significant visible light absorption and effective multichannel transmission of photogenerated electrons, the Cu2MoS4/graphdiyne composite catalyst exhibited astonishing photocatalytic hydrogen evolution activity (11000 μmol g-1), which is 10 times that of Cu2MoS4 homojunction. Further experimental research and theoretical calculations provided effective evidence for the charge transfer pathway. This work provides a new strategy for constructing efficient hydrogen evolution photocatalysts and regulating the migration of photogenerated electrons.

A novel mesoporous Bi2MoO6/g-C3N4 nanocomposite as an effective photocatalyst against toxic organic pollutants

This study used microwave irradiation technique to synthesize a sequence of Bi2MoO6@g-C3N4 nanocomposite as photocatalysts. The two narrow band gap nanomaterials used were g-C3N4 and Bi2MoO6. The nanocomposites were thoroughly characterized by XRD, FESEM, EDS, HRTEM, Raman spectroscopy, UV–visible spectra, PL and XPS. Moreover, using sunlight radiation, two distinct dyes including Malachite Green (MG) and Acid Blue 113 (AB 113) were degraded using as synthesized photocatalyst. The outcomes indicated that the photocatalytic degradation efficiency of Bi2MoO6@ g-C3N4 was higher than that of pure g-C3N4. A 95 % degradation efficiency towards Malachite Green and an 84 % degradation efficiency towards Acid Blue 113 shown the great effectiveness of Bi2MoO6@ g-C3N4. This enhanced efficiency is attributed to the increased visible light absorption, effective charge separation due to the heterojunction interface between Bi2MoO6 and g-C3N4, and the increased surface area facilitating greater active site availability. According to these results, the synthesized Bi2MoO6@ g-C3N4 would be very beneficial for the removal of organic contaminants in a variety of industrial environments.

Cobalt coordinated olefin-linked covalent organic frameworks toward highly efficient photocatalytic hydrogen production

Covalent organic frameworks (COFs) have emerged as a crystalline porous materials for photocatalytic hydrogen production. However, the design of efficient COF-based catalyst for satisfactory solar-to-hydrogen energy conversion is still challenging. Here, cobalt was anchored on the bipyridine moieties in the framework of olefin-linked sp2c-COFdpy by convenient post-metalation (sp2c-COFdpy-Co). Experimental results showed that sp2c-COFdpy-Co exhibited wider visible light absorption region and quicker photogenerated e-/h+ separation efficiency than sp2c-COFdpy. Photocatalytic experiments revealed that sp2c-COFdpy-Co was highly efficient for H2 production after photodeposition of Pt co-catalyst (Pt@sp2c-COFdpy-Co). The optimized Pt@sp2c-COFdpy-Co exhibited a high photocatalytic H2 production rate of 324.4 μmol/h under visible light irradiation in the presence of 1.0 wt% Pt as co-catalyst, which was higher than Pt@sp2c-COFdpy-Fe and Pt@sp2c-COFdpy-Ni, and it was much higher than that of its counterparts and many reported works. This work provides new insights into design of highly efficient COF-based catalyst for photocatalytic H2 production.

Enhancement of photocatalytic NO oxidation by Ag-sulfide on TiO2 mixed with Na-ZSM-5

Enhancing NO oxidation performance is pivotal for integrating photocatalysts with wet scrubbers in continuous flow systems. Despite the recent development of various catalysts, such as MOFs, our goal was to simplify the composition by using photocatalyst + zeolite catalyst, bringing us closer to a catalyst that can be practically applied. In this study, we have utilized Ag2S doping and Na-ZSM-5 mixing to improve the photocatalytic NO oxidation performance. Results showed that Ag2S doping improved visible light absorbance and NO oxidation, despite the observed fluctuations in NO conversion being attributable to mass transfer limitations. Mixing with Na-ZSM-5 compensated for the mass transfer limitations and improved its average NO conversion from 19 to 34 %. The Na-ZSM-5 increased the NO adsorption capacity considerably to 0.67 mmol g−1, which reduced the fluctuations in the catalytic performance; subsequently, the diffusion of NO led to its oxidation. Detailed analyses using NO-TPD and DRIFTS further elucidated these improvements, highlighting the significance of optimizing both oxidation reaction and mass transfer rates in the photocatalytic process. We believed that the composite of Ag2S-TiO2 + Na-ZSM-5 could simplify the ways to improve the photocatalytic NO oxidation performance and make it closer to practical applications.

Water process/treatment by a S-scheme Fe2O3/TiO2 heterojunction photocatalyst for excellent antibiotic degradation/CO2 reduction/H2 production; process optimization and mechanistic insights

A facile synthesis approach was employed to fabricate a binary Fe2O3/TiO2 nanocomposite (FeTi4-400) for enhanced photocatalytic hydrogen (H2) production, cephalexin degradation and CO2 reduction under visible light irradiation. Compared to pristine TiO2, FeTi4-400 exhibited improved visible light absorption and promoted charge carrier separation, leading to increased H2 production rate and CO2 conversion into CH4 and CO. This improvement can be attributed to the formation of an S-scheme heterojunction, along with the desirable properties of FeTi4-400, including visible light activity, high surface area, and strong CO2 adsorption. The photocatalyst achieved a maximum H2 production rate of 649 μmol/g·h−1, exceeding that of pure TiO2. Similarly, the highest CO production rate of 16.44 μmol/g·h−1 was attained with FeTi4-400. Furthermore, FeTi4-400 achieved excellent cephalexin degradation (96 %) under optimal conditions, with a degradation rate constant of 0.01 min−1. A plausible cephalexin degradation pathway over FeTi4-400 is proposed. Transient photocurrent measurements and EIS analysis corroborated a significant enhancement in photocatalytic activity for FeTi4-400, attributed to the efficient separation of photogenerated electron-hole pairs. Stability studies demonstrated consistent cephalexin degradation by FeTi4-400 over five consecutive cycles without noticeable photocatalyst deactivation. This work presents a novel strategy for fabricating low-cost, efficient, and readily synthesized nanomaterials for applications in solar energy conversion and environmental remediation.

Boosting the photocatalytic benzylamine oxidation and Rhodamine B degradation using Z-scheme heterojunction of NiFe2O4/rGO/Bi2WO6

The construction of heterojunction photocatalysts with powerful interfacial connections is critical for the actual utilization of photocatalytic technology. In this paper, the heterojunction photocatalyst NiFe2O4/rGO/Bi2WO6 (NFO/rGO/BWO) was prepared by in-situ hydrothermal method. Due to its excellent conductivity, rGO promoted the separation of photogenerated carriers, which was beneficial to the formation of Z-scheme heterojunction between NFO and BWO, and the absorption of visible light was improved by the involvement of rGO and NFO. Among a series of synthesized photocatalysts, 3 % NFO/rGO/BWO had the best photocatalytic activity in the photocatalytic oxidative coupling of benzylamine (BA). After 180 min of illumination, high conversion of 96 % for BA was achieved, which was 2.6 times higher than that of BWO. When it was applied to the degradation of Rhodamine B (RhB), complete degradation could be achieved, and the degradation rate was 5.67 times than that of BWO. The important roles of h+ and •O2– in the reaction were confirmed by electron spin resonance (ESR) analysis and radical capture experiments. The density functional theory (DFT) calculation and bandgap structure of the catalysts verified the existence of Z-scheme heterojunction. Potential reaction pathways for photocatalytic BA coupling and RhB degradation were proposed, respectively.

Plasmonic Silver Nanoparticles Facilitate Electron Emission from Diamond upon Sun‐Like Excitation

AbstractThe development of a stable, non‐toxic material that emits electrons following absorption of visible light may have a major impact on the solar photocatalysis of difficult reactions such as CO2 and N2 reduction, as well as for targeted chemical transformations in general. Diamond is a good candidate, however it is a wide bandgap material requiring deep UV photons ( <227 nm) to promote electrons from the valence band into the conduction band. Embedding silver nanoparticles under the diamond surface allows the photoconductivity of the diamond in the spectral region of the surface plasmon resonance to be increased, while also leading to an enhancement of visible light photoemission. Considering the low intensity of the light sources used in this work and the spectral properties of the enhanced photoconductivity and photoemission a mechanism based on plasmonically enhanced photoconductivity which in turn allows surface states emptied by photoemission to be recharged thus leading to enhanced photoemission in the visible range is proposed.

Improving visible light-driven CO2 conversion to high calorific fuels over sustainable highly crystalline and holey sulphur doped graphitic carbon nitrides

The effectiveness of CO2 reduction through g-C3N4 (CN) is considerably hindered by poor visible light absorption and the high rate of recombination of electron-hole (e−/h+) pairs. An effective method for increasing CO2 photoreduction efficiency is to incorporate non-metal components into the CN to modify its electronic properties and enhance its performance. This research presents the findings of our inquiry into sulfur-doped graphitic carbon nitrides (S–CN) for CO2 reduction through visible light. The XPS study reveals that the substitution of nitrogen atoms in the heptazine ring by sulfur (S) doping significantly influences the electronic configuration of CN, while the UV–visible absorbance spectra reveals that the CN band gap value 2.64 eV has reduced to 2.50 eV after S doping. Therefore, S–CN exhibits exceptional visible-light absorption, separation and migration of photoexcited e−/h+, corroborated by photoluminescence and transient photocurrent response experiments. Besides, S–CN demonstrated remarkable CO2 reduction capabilities without any cocatalyst or sacrificial agent, achieving CO/CH4 formation rates of 25/3 μmolg−1h−1, outperforming traditional CN. Our research highlights the relevance of impeding the e−/h+ recombination process to boost solar energy conversion output, suggesting potential for productive solar fuel generation using g-C3N4.

Parameter influences of FTO/ZnO/Cu₂O photodetectors fabricated by electrodeposition and spray pyrolysis techniques

This study investigates fabrication of transparent conductive glass using fluorine-doped tin oxide (FTO) as a more affordable alternative to indium tin oxide (ITO) in photovoltaic applications. To enhance conductivity, a ZnO layer was deposited on FTO, followed by a Cu2O layer via electrodeposition. The synthesis parameters are varied to determine their effect on the reaction and to identify the optimal conditions. The characteristic of FTO/ZnO/Cu2O studied using XRD, SEM annexed with EDX, IV testing and visible light absorption spectroscopy to disclose its optoelectronic applications. The FTO layers were produced via spray pyrolysis, with optimal deposition achieved at 400 °C and efficiency value 0.0149 %, resulting in a dense, transparent structure. Meanwhile the efficiency of samples at temperatures of 350°C, 450°C, and 500°C are 0.0032 %, 0.0042 %, and 0.0037 %. From the efficiency results, the optimal thickness of the Cu2O layer was obtained at a duration of 30 min, which was 0.0380 %, while the other durations of 1 hour, 2 h, and 3 h were 0.0149 %, 0.0076 %, and 0.0056 %. The best efficiency was obtained at an optimum pH of 10 with a value of 0.0038 %, promoting crystal growth along the (111) plane. While at pH variations of 8, 9, 11, and 12, the efficiency values were 0.0016 %, 0.0083 %, 0.0083 %, and 0.0073 %, respectively. I-V testing of FTO/ZnO:Mg/ Cu2O with varying electrodeposition voltage show that the efficiency of samples at voltage 5 V, 10 V, 15 V, 20 V, and 0.0128, 0.0093, 0.0036, 0.0053 and 0.0383 %. The optimum conditions for fabricated the samples was achieved with a 30-minute electrodeposition duration at 25 V and pH 10, as confirmed through I-V testing. The study highlights the influence of pyrolysis temperature, electrodeposition time, and pH on the optical and electrical properties of the glass, with optimized conditions yielding improved photoresponse performance.

Bi2S3/BiOCl heterojunction-based photoelectrochemical aptasensor for ultrasensitive assay of fumonisin B1 via signal amplification with in situ grown Ag2S quantum dots.

Fumonisin B1 (FB1) is a mycotoxin mainly found in corn, peanuts, and wheat crops, which affects human health.Based on bismuth sulfide/bismuth oxychloride (Bi2S3/BiOCl) composite material, silver sulfide (Ag2S) was grown in situ as a quantum dot sensitization signal, and a photoelectrochemical (PEC) aptasensor was designed by layer upon layer modification to detect FB1. Bi2S3/BiOCl has a wide range of visible light absorption, stable chemical properties, and asimple synthesis method. In the construction process, L-ascorbic acid (AA) is selected to provide electrons and inhibit photogenerated electron-hole (e-/h+) recombination. Under the optimal experimental conditions, the detection range of the fabricated PEC aptasensor was 0.001 ~ 100ng/mL, and the detection limit was 0.016pg/mL. The prepared PEC aptasensor has high sensitivity, stability, and reproducibility. The combination of aptamer and PEC sensor provides a novel method for the application of PEC sensor in mycotoxin detection.

Thermal Bistability of Magnetic Susceptibility, Light Absorption, Second Harmonic Generation, and Dielectric Properties in a Polar Spin-Crossover Iron-Rhenium Chain Material.

The bistability of multiple physical properties driven by external stimuli in a solid is a desired prerequisite for its application in memory devices with convenient data readout. We present a pathway for thermal bistability detectable in four physical properties: magnetic, light absorption, second-harmonic generation (SHG), and dielectric. We report a novel heterometallic (TBA){[FeII(phIN)4][ReV(CN)8]}·(phIN) (1) (TBA = tetrabutylammonium cation, phIN = phenyl isonicotinate) cyanido-bridged chain material. Owing to an appropriate {N6} coordination sphere of Fe(II) centers, 1 reveals a thermal spin crossover (SCO) effect which is complete and cooperative providing a distinct thermal hysteresis loop in magnetic measurements. Moreover, it exhibits simultaneous thermal bistability in (a) visible-light absorption due to the presence of efficient d-d electronic transitions in the low-spin (LS) state, (b) SHG activity as it crystallizes in a polar Cc space group due to the bulky substituent on phIN ligands, and (c) dielectric parameters, including dielectric constant, which can be correlated with subtle changes in polarity between LS and HS (high spin) phases. Thus, we present a remarkable thermally controlled hysteretic behavior in four physical functionalities realized by properly functionalizing an SCO-active coordination compound.

Dual Regulation of Sensitizers and Cluster Catalysts in Metal-Organic Frameworks to Boost H2 Evolution.

Photocatalytic efficiency is closely correlated to visible-light absorption ability, electron transfer efficiency and catalytic center activity of photocatalysts, nevertheless, the concurrent management of these factors to improve photocatalytic efficiency remains underexplored. Herein, we proposed a sensitizer/catalyst dual regulation strategy on the polyoxometalate@Metal-Organic Framework (POM@MOF) molecular platform to construct highly efficient photocatalysts. Impressively, Ni-Sb9@UiO-Ir-C6, obtained by coupling strong sensitizing [Ir(coumarin 6)2(bpy)]+ with Ni-Sb9 POM with extremely exposed nickel site [NiO3(H2O)3], can drive H2 evolution with a turnover number of 326923, representing a record value among all the POM@MOF composite photocatalysts. This performance is over 34 times higher than that of the typical Ni4P2@UiO-Ir constructed from [Ir(ppy)2(bpy)]+ and Ni4P2 POM. systematical investigations revealed that dual regulation of sensitizing and catalytic centers endowed Ni-Sb9@UiO-Ir-C6 with strong visible-light absorption, efficient inter-component electron transfer and high catalytic activity to concurrently promote H2 evolution. This work opens up a new avenue to develop highly active POM@MOF photocatalysts by dual regulation of sensitizing/catalytic centers at the molecular level.

Photo-assisted highly efficient electrocatalytic N2 fixation on nonmetal-metal dual atom catalysts through the reversable evolution of active center

The electrocatalytic reduction naturally abundant dinitrogen (N2) to ammonia (NH3) offers a promising alternative to the harsh Haber–Bosch process. However, developing catalysts for high-performance electrocatalytic N2 reduction reaction (NRR) remains a significant challenge. In this study, density functional theory (DFT) calculations were employed to investigate boron-transition metal atom pairs (B–TM) supported on graphitic carbon nitride (g-C6N6) as dual-atom catalysts for photo-assisted electrocatalysis of NRR. It was demonstrated that B–TM atom pair can be successfully embedded on g-C6N6. Among the considered B–TM@g-C6N6 catalysts, B–Os@g-C6N6 exhibits exceptional catalytic activity for NRR via a consecutive mechanism, with the lowest overpotential of 0.21 V, outperforming the efficiency of widely used noble catalysts. Notably, both B and Os atoms directly participate in N2 activation through σ-donation and π*-backdonation mechanism. Furthermore, the adsorption of intermediates can induce the reversable evolution of the active center, accelerating the NRR. Therefore, these novel characteristics endow B–Os dual atom catalyst with excellent NRR performance. Importantly, B–Os@g-C6N6 also shows suitable band edges and high capability of visible-light absorption, which can assist N2 conversion under visible-light irradiation. This work offers new insights and ideas for designing nonmetal-metal atom pair as dual atom catalyst for the photo-assisted electrocatalytic reduction of N2 to NH3.

Biophotoelectrocatalytic detoxification of Bisphenol A using Bismuth-doped TiO2 Nanotubes photoanode coupled with Laccase-immobilized cathode

Photoelectrocatalytic (PEC) technology has been demonstrated to be an effective method for environmental remediation, but its efficiency in detoxifying persistent pollutants such as bisphenol A (BPA) requires further enhancement. Herein, an enzyme-coupled PEC system for detoxification of BPA was proposed by integrating a Bismuth-doped TiO2 Nanotubes (Bi-TiO2 NTs) photoanode and laccase-immobilized cathode. The results reveal that the doping of Bi into TiO2 enhances the visible light absorption and reduces the recombination of photogenerated electron-hole pairs when exposed to simulated solar irradiation. When the laccase-immobilized cathode was incorporated into the PEC device, the resulting biophotoelectrocatalytic system exhibited excellent degradation performance for BPA, owing to the synergistic effect between enzymatic catalysis and photoelectrocatalysis. A potential degradation pathway for BPA was established through the analysis of intermediate products, and subsequent phytotoxicity assessments revealed a significant reduction in the toxicity of the laccase-coupled PEC-degraded BPA solution. This study highlights that coupling a laccase-immobilized cathode with Bi-doped TiO2 NTs photoanodes serves as an effective method for the detoxification of persistent pollutants.