Search

Photocatalytic CO2 reduction is considered as a promising strategy for CO2 utilization and producing renewable energy, however, it remains challenge in the improvement of photocatalytic performance for wide‐band‐gap photocatalyst with controllable product selectivity. Herein, the sulfur‐doped In(OH)3 (In(OH)xSy‐z) nanocubes are developed for selective photocatalytic reduction of CO2 to CH4 under simulated light irradiation. The CH4 yield of the optimal In(OH)xSy‐1.0 can be enhanced up to 39 times and the CH4 selectivity can be regulated as high as 80.75% compared to that of pristine In(OH)3. The substitution of sulfur atoms for hydroxyl groups in In(OH)3 enhances the visible light absorption capability, and further improves the hydrophilicity behavior, which promotes the H2O dissociation into protons (H*) and accelerates the dynamic proton‐feeding CO2 hydrogenation. In situ DRIFTs and DFT calculation confirm that the non‐metal sulfur sites significantly weaken the over‐potential of the H2O oxidation and prevent the formation of ·OH radicals, enabling the stabilization of *CHO intermediates and thus facilitating CH4 production. This work highlights the promotion effect of the non‐metal doping engineering on wide‐band‐gap photocatalysts for tailoring the product selectivity in photocatalytic CO2 reduction. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The two-dimensional electrochemical Y2C's low work function and strong charge transfer qualities limit its applicability in catalysis due to its poor catalytic activity. In this paper, based on density functional theory calculations, we use two techniques to increase the HER catalytic activity of the Y2C monolayer: substitution doping (XC) and adsorption doping (XT) of non-metal (X = N, P, O, S, and F). The results showed that the absolute values of hydrogen free energies (ΔGH*) of the substitutional dopants of PC, SC and adsorptive dopants of NT, OT, ST, and PT had increased catalytic activity compared with those of the pristine Y2C monolayer (−0.673 eV). It was highlighted that the adsorption doping of PT can further reduce the adsorption free energy of the pristine Y2C monolayer to −0.19 eV, which is close to the optimal zero value, and the binding energy of the hydrogen atoms on the Y2C surface significantly increased from −0.913 to −0.438 eV, which is more favorable for the desorption of hydrogen atoms. These results demonstrate that the doping of non-metals activates the adsorption of hydrogen atoms on monolayer Y2C and provides a feasible method for hydrogen generation. [ABSTRACT FROM AUTHOR]

Hydrogen is currently recognized as being able to mitigate the overuse of fossil fuels and as a clean energy source in future development. In addition, water electrolysis can work with renewable energy sources to make the hydrogen cycle sustainable. However, hydrogen production efficiency from water electrolysis relies on efficient catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). At present, in order to further develop overall water splitting (OWS) catalysts, non-metal doping has attracted increasing attention. Non-metals can modulate the electronic structure, lattice structure, and surface properties of transition metal-based catalysts, which can be a new strategy to regulate the catalytic activity. Herein, the recent research progresses of non-metallic doping in transition metal-based catalysts are reviewed in this paper. This article summarizes the inherent correlation between the electronic structure and local environmental changes of water electrolysis catalytic materials with different non-metallic elements in the transition metal-based materials. Then, the reasons and related mechanisms for the improved performance of catalysts by nonmetal doping are discussed. The aim of this review is to offer some insights in favour of the role that non-metallic doping owns special advantages in electrocatalytic water splitting. • Non-metals doping is a new strategy to regulate the catalytic activity. • Non-metals can modulate the structure and surface properties of transition metal-based catalysts. • Non-metals doping can regulate inherent correlation between the electronic structure and local environmental. • The effects of non-metal doping on HER, OER and water splitting are discussed. [ABSTRACT FROM AUTHOR]

In this paper, a facile one step synthesis method for the preparation of C-, B-, P- and S-doped g-C 3 N 4 by incorporation of small concentration of doping element precursor into urea during thermal polycondensation is reported leading to much lower doping levels than the ones usually reported. The as-obtained doped g-C 3 N 4 photocatalytic materials are deeply characterized in terms of structural, morphological, surface and optical properties. Doping yields beneficial surface morphology modulation along with improved optical, electronic and photocatalytic properties. In particular, C-doped and S-doped g-C 3 N 4 show, after deposition of gold nanoparticles (<1 wt%), enhanced photocatalytic performance (at least twice as high as the undoped photocatalyst, to achieve ca. 610 μmol/h/g) for the production of H 2 by water splitting under solar light in the presence of low content (1 vol%) of triethanolamine (TEOA) as sacrificial agent. The most remarkable activity results from the incorporation of traces of S dopant, mainly inserted into interplanar hollow cavities. The enhanced activity is attributed to a combination of high surface area, location of the S dopant and small size of the co-catalyst NPs, which induces enhanced visible light harvesting, enhanced charge carrier separation and enhanced proton recombination. This work highlights the benefits of the optimized low-level doping strategy to overcome the main limitations of g–C 3 N 4 –based photocatalysts. [Display omitted] • H 2 production by water splitting with non-metal doped g-C 3 N 4 using low amount (1 vol%)TEOA. • Enhanced H2 production rate induced by trace level (<0.1 wt%) of S-dopant. • Benefits of low-level doping strategy to overcome the main limitations of g-C 3 N 4. • One-pot easy synthesis of non-metal doping of g-C 3 N 4 during thermal polycondensation. • Those photocatalyst exhibit enhanced visible light harvesting properties. [ABSTRACT FROM AUTHOR]

TiO2 semiconductor plays a paramount important as an active photocatalyst mainly due to its photo-induced electron transfer properties. The metastable anatase in particular are widely accepted to have the most photoactive activity in catalytic application as opposed to rutile TiO2. This is majorly due to the significantly lower recombination rate of electron pair possesses by anatase TiO2. Unfortunately, high recombination rate in anatase TiO2 hinders its application as a functional photocatalyst. Therefore, it is crucial to further enhance the photocatalytic activity of anatase TiO2, by modifying its optical properties, morphological properties, and crystal facet. The study aims to provide a benign synthesis method for TiO2 with a co-exposed {001}/{100} anatase TiO2 facet. The synthesis was conducted via one-pot reflux condensation method. A concise evaluation upon the effect of different synthesis heating duration, temperature and doping materials towards the crystal phase, morphology, and photocatalytic performance of TiO2 were conducted. Anatase TiO2 with high percentage of the high-energy {001} facet have the ability to boost the adsorption and photocatalytic performance as opposed to anatase TiO2 dominated with a thermodynamically stable {101} facet. The incorporation of non-metal dopant (HF) acts as surface modifier which leads to the enhancement of {001} facet percentage. This study further evaluates the functionalities of HCl in paving way towards the formation of mid-gap state, hence improving Anatase TiO2 optical properties. The reduction of band gap of the anatase TiO2 can clearly be identified from the shifts in the adsorption band towards higher wavelength. From the findings, it was found that the synergistic effect upon co-doping anatase TiO2 with the two non-metal dopants plays an important role in altering the ratio of exposed facet hence leading towards improving the photocatalytic efficiency of the nanomaterial. To evaluate the photocatalytic performance of the synthesized TiO2, Remazol Brilliant Blue (0.01 g/L) was chosen as the target pollutant. The enhanced photodegradation of co-doped F/Cl-TiO2 was evaluated and it was found that 87.21% and 43.21% of Remazol Brilliant Blue had successfully been degraded within 120 min with irradiation of broad spectrum and blue light (475 nm) respectively. This is mainly attributed to the co-exposed {001}/{100} anatase TiO2 facet presence in the F/Cl-TiO2 sample.

Environmental pollution poses a pressing global challenge, demanding innovative solutions for effective pollutant removal. Photocatalysts, particularly titanium dioxide (TiO2), are renowned for their catalytic prowess; however, they often require ultraviolet light for activation. Researchers had turned to doping with metals and non-metals to extend their utility into the visible spectrum. While this approach shows promise, it also presents challenges such as material stability and dopant leaching. Co-doping, involving both metals and non-metals, has emerged as a viable strategy to mitigate these limitations. Inthe fieldof adsorbents, carbon-based materials doped with nitrogen are gaining attention for their improved adsorption capabilities and CO2/N2 selectivity. Nitrogen doping enhances surface area and fosters interactions between acidic CO2 molecules and basic nitrogen functionalities. The optimal combination of an ultramicroporous surface area and specific nitrogen functional groups is key to achievehigh CO2 uptake values and selectivity. The integration of photocatalysis and adsorption processes in doped materials has shown synergistic pollutant removal efficiency. Various synthesis methods, including sol–gel, co-precipitation, and hydrothermal approaches had been employed to create hybrid units of doped photocatalysts and adsorbents. While progress has been made in enhancing the performance of doped materials at the laboratory scale, challenges persist in transitioning these technologies to large-scale industrial applications. Rigorous studies are needed to investigate the impact of doping on material structure and stability, optimize process parameters, and assess performance in real-world industrial reactors. These advancements are promising foraddressing environmental pollution challenges, promoting sustainability, and paving the way for a cleaner and healthier future. This manuscript provides a comprehensive overview of recent developments in doping strategies for photocatalysts and adsorbents, offering insights into the potential of these materials to revolutionize environmental remediation technologies. [ABSTRACT FROM AUTHOR]

Abstract Zinc-Imidazole coordination polymer (ZnImCP) was simply synthesized hydrothermally at relatively low temperature (70 °C) from zinc acetate and imidazole. ZnImCP was treated by sulfide solution to produce sulfur-doped samples (S-ZnImCPs). Structures of the synthesized ZnImCP and S-ZnImCPs were characterized through FTIR, PXRD, and, Raman, SEM/EDX, N2-BET, UV–VIS DRS, and pHpzc analyses. The photocatalytic performances of pristine CP and sulfur modified CPs under visible and ultra-violet irradiations for degrading the cationic methylene blue (MB) and the anionic methyl orange (MO) were investigated considering different initial pH values 4, 7 and 10. Under visible light, the results indicate that these CPs display considerable photocatalytic degradation towards the cationic MB for the initial pH 4 and 7 where degradation increases with sulfur content. While under ultra-violet, results indicate considerable photocatalytic degradation towards both dyes for the initial pH 7 and 10 where degradation increases with sulfur content which indicates the gainful of non-metal dopping. The buffering nature of CPs and the type of radiation considering determined band-gap values effectively influence the degradation mechanisms.

A facile construction of B and P doped carbon nitride as a potential photo-catalyst for splitting water to generate hydrogen or oxygen and BPA removal under visible light. B and P doping are confirmed by a series of characterizations. As the symmetrical π-conjugated rings of g-C 3 N 4 could be destroyed by B and P doping to enhance the visible-light absorbance and n → π∗ electronic transition to provide a new pathway for the directional separation of photoexcited electrons to boost the photocatalytic activity. Significantly, the CN-BP catalyst demonstrates excellent H 2 and O 2 evolution rates of 4.0 mmol H2 h−1 g−1 and 0.3 mmol O2 h−1 g−1 under visible light, which is about ∼3.8 and 21.6 times higher than that of g-C 3 N 4 , respectively. Notably, without sacrificial agent, the CN-BP could remove BPA completely by oxidation to generate 30 μmol h−1g−1 H 2. Both DFT calculations and characteristic results reveal that B and P doped carbon nitride reduce band gap energy, improve light harvesting and separation rate of electron-holes carriers for upgrading the photocatalytic activity. • CN-BP catalyst demonstrates 3.8 and 21.6-fold increased activity for hydrogen and oxygen evolution, respectively. • CN-BP photocatalyst could completely remove BPA to produce 30 μmol H 2 per hour. • B and P doping g-C 3 N 4 could enhance the optical properties by exciting n→ π∗ electronic transition. [ABSTRACT FROM AUTHOR]

In the present research work, iodine-doped iron tungstate has been reported for first time as an active photo-Fenton heterogeneous catalyst for wastewater treatment. In Fenton-like process, the catalytic efficiency of FeWO4 was enhanced greatly by introducing reductive non-metal species (I−) into the crystal lattice. This introduction activated the H2O2 for the generation of hydroxyl radicals which were the most reactive species for the degradation of RhB. The non-metal doping has enhanced the visible light response of transition metal oxide. A hydrothermal method was used for synthesizing novel iodine-doped FeWO4. The prepared sample was characterized through scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, and UV–Visible spectroscopy. The photoactivity of I-FeWO4 was evaluated through the degradation of RhB under sunlight. I-FeWO4 showed 93.8% degradation of RhB after 80 min. [ABSTRACT FROM AUTHOR]

The application of biomass‐based carbon materials in electrochemical sensing was limited due to their few active sites. So N and P double doped biomass pyrolytic carbon materials were designed in this paper. These gained materials were characterized by a series of characterization test techniques, and used as electrode modification to construct electrochemical sensors to detect baicalein (BA) and luteolin (LU). Under the best test condition, the minimum detectability of BA and LU was (7.8±0.25)×10−9 mol/L and (7.6±0.24)×10−9 mol/L (S/N=3), respectively. And the sensor performed well in the Shuanghuanglian oral liquid and the healthy human urine samples. [ABSTRACT FROM AUTHOR]

In this paper, the effect of substitutional doping of boron (B), carbon (C), nitrogen (N), oxygen (O), and phosphorus (P) at the S-site on the electronic structure of the monolayer TiS2 system is investigated using a first-principles calculation method. The effect of nonmetal doping on the band gap of TiS2 and its mechanism were studied by analyzing the stability, electronic structure, and charge transfer of the system. By calculating the electron cloud overlap population and formation energy, we confirmed that the system is stable, and the Ti–X bond length of the doped system undergoes different degrees of distortion. The properties of the B, C, and N doped system show different properties with different doping concentrations; the band gap of the O-atom system gradually expands with the rise of the doping rate. The hybridization positions of the impurity and the intrinsic atoms are found by comparing the DOS; combined with the charge density difference, we confirmed the interaction of impurity atoms with the system and revealed the bonding process of different systems. [ABSTRACT FROM AUTHOR]

Zinc-Imidazole coordination polymer (ZnImCP) was simply synthesized hydrothermally at relatively low temperature (70 °C) from zinc acetate and imidazole. ZnImCP was treated by sulfide solution to produce sulfur-doped samples (S-ZnImCPs). Structures of the synthesized ZnImCP and S-ZnImCPs were characterized through FTIR, PXRD, and, Raman, SEM/EDX, N2-BET, UV–VIS DRS, and pHpzc analyses. The photocatalytic performances of pristine CP and sulfur modified CPs under visible and ultra-violet irradiations for degrading the cationic methylene blue (MB) and the anionic methyl orange (MO) were investigated considering different initial pH values 4, 7 and 10. Under visible light, the results indicate that these CPs display considerable photocatalytic degradation towards the cationic MB for the initial pH 4 and 7 where degradation increases with sulfur content. While under ultra-violet, results indicate considerable photocatalytic degradation towards both dyes for the initial pH 7 and 10 where degradation increases with sulfur content which indicates the gainful of non-metal dopping. The buffering nature of CPs and the type of radiation considering determined band-gap values effectively influence the degradation mechanisms. [ABSTRACT FROM AUTHOR]

Searching electrocatalysts with excellent hydrogen evolution reaction (HER) performance is very important for developing clean hydrogen energy. Two-dimensional (2D) materials have been widely studied as HER electrocatalysts, however, the basal planes of 2D materials, which dominate the surface area, are usually with poor activity. In this work, we theoretically studied the HER activity of Janus 2H–VSSe with or without non-noble metal element doping. Density functional theory (DFT) calculations suggest that doping As and Si atoms in the S or Se sites of VSSe and the C and Ge atoms in the Se site of VSSe greatly promote the HER performance of the basal plane of VSSe, resulting in hydrogen adsorption free energy close to zero (i.e. −0.022, −0.040, 0.066, 0.065, −0.030, 0.058 eV, respectively), which are better than the Pt catalyst (−0.09 eV). The doped atoms strengthen the interaction between their pz -orbital and the hydrogen s -orbital, resulting in a lower bonding state in energy and higher bind strength for the hydrogen atom. This work opens up a new way to design highly efficient and low-cost catalysts for HER. • VSSe has better activity for HER at the S-edge than Pt but is poor its basal plane. • VSSe can be efficiently activated for HER by doping As, Si, C, or Ge. • A free energy of −0.022 eV has been realized by As doping, better than Pt. [ABSTRACT FROM AUTHOR]

Searching for low-cost and highly-efficient oxygen reduction reaction (ORR) catalysts is crucial to the large-scale application of fuel cells. Herein, by means of density functional theory (DFT) computations, we proposed a new class of ORR catalysts by doping the CrS2 monolayer with non-metal atoms (X@CrS2, X = B, C, N, O, Si, P, Cl, As, Se, and Br). Our results revealed that most of the X@CrS2 candidates exhibit negative formation energy and large binding energy, thus ensuring their high stability and offering great promise for experimental synthesis. Moreover, based on the computed free energy profiles, we predicted that N@CrS2 exhibits the best ORR catalytic activity among all considered candidates due to its lowest overpotential (0.41 V), which is even lower than that of the state-of-the-art Pt catalyst (0.45 V). Remarkably, the excellent catalytic performance of N@CrS2 for ORR can be ascribed to its optimal binding strength with the oxygenated intermediates, according to the computed linear scaling relationships and volcano plot, which can be well verified by the analysis of the p-band center as well as the charge transfer between oxygenated species and catalysts. Therefore, by carefully modulating the incorporated non-metal dopants, the CrS2 monolayer can be utilized as a promising ORR catalyst, which may offer a new strategy to further develop eligible electrocatalysts in fuel cells. [ABSTRACT FROM AUTHOR]

Photocatalysis is recognized to be one of the most promising ways to address energy and environmental issues by utilizing visible light. Graphitic carbon nitride (g-C 3 N 4), with a moderate band gap (∼2.7 eV) has been the flashpoint in environmental photocatalysis as it can work better under visible light, can be synthesized by a facile synthesis process using low-cost materials, thermally and chemically stable. Still the photocatalytic performance of g-C 3 N 4 is not satisfactory because of certain limitations such as insufficient visible light absorption capacity, low electron-hole separation efficiency, high recombination rate, poor surface area. Introduction of doping, band structure engineering, defecting and designing of heterojunction, composites etc. were investigated to amplify its applications. Among all these modifications, elemental doping is a suitable and successful alternative for the enhancement of the photocatalytic activity by changing the optical and electronic properties. This review emphasizes on advancement and trends of elemental doping and its application on photocatalytic organic pollutant remediation in aqueous medium. The fundamental photocatalytic activity of heterogeneous photocatalysis and specifically g–C 3 N 4 –based photocatalysis have been discussed. The benfits of non-metal doping, enhanced photocatalytic performance by doping element, mechanism invloved in doping, advantages of co-doping has been explained. Mono, bi, and tri non-metal doped g-C 3 N 4 and their application for the removal of organic pollutants from water medium by visible light photocatalysis has been summerized. Life cycle assessment (LCA) of photocatalytic system has been highlighted. Future research should focus on the large-scale application of the photocatalysis process considering the economic aspects. A rigorous life cycle assessment for deploying the non-metal doped g–C 3 N 4 –based photocatalysis technology for successful commercial application is recommended. [ABSTRACT FROM AUTHOR]

Molybdenum carbides (MoC) are regarded as promising candidates for electrocatalytic hydrogen evolution reaction (HER) as their stabilities, high conductivities. Non-metallic doping is a robust way to enhance the HER activity of MoC in experiments, yet the systematic theoretical study is still lacking. In this work, we investigate the surface doping effect on HER activity of C-terminated γ -MoC(100) by density functional theory (DFT). The thermodynamical stability and realistic catalytic surface of doped surfaces, including mono- and co-doping by three elements (N, P and S) with various doping ratios, are verified by formation energies and surface Pourbaix diagrams, respectively. According to the hydrogen adsorption ability on different coverage and the calculated exchange current densities (i 0) of the doped surfaces, the surfaces doping in range of (P% > 60% and N% > 5%), (60% < N% <85% and P% < 25%), and (60% < N% < 85% and S% < 25%), show larger i 0 (i 0 > 4 mA/cm2). Especially the N/P co-doping γ -MoC(100), their larger i 0 in greater range enables their promising excellent performance in hydrogen evolution in experiments. The improved HER activities of doped MoC(100) are ascribed to suitable hydrogen adsorption abilities tuned by suitable p z -band centers and the charge redistribution. Our DFT simulations provide more insight and guidance for improving the HER performance of electrode catalysts using non-metallic doping effects. [Display omitted] • N/P co-doped MoC(100) at any ratio shows high exchange current density for HER. • N and P doping will downshift p z -band center and tune hydrogen adsorption ability. • The charge redistribution domains the oscillation character of Δ G H in P-doped surfaces. [ABSTRACT FROM AUTHOR]

• Facile synthesis, cost effective surface modifiers, single step fabrication process. • Step by step mechanism and surface evolution during electrodeposition is presented. • Electrochemical performance of gCN was improved with 5% P- doping. • 7.5 X current & 0.10 V potential shift outlined electrocatalytic Tryptophan oxidation. • Wide applicability of modified sensor is shown by testing TRP in 12 real samples. Tryptophan (TRP) is an essential amino acid that is crucial for human growth and must be obtained through a dietary source or nutritional supplements. Both, the overconsumption or deficiency induces clinical symptoms. Therefore, a sensitive and selective method for quantifying TRP in dietary products, nutritional supplements, and clinical samples is essential. In this work, we have electrodeposited phosphorous doped graphitic carbon nitride (P-gCN) for developing a TRP voltammetric sensor. Outlining the benefits of electrodeposition over drop-casting, the developed P-gCN | GCE sensor demonstrated 7.83 times more sensitivity and a negative shift of ∼0.10 V for TRP electro-oxidation compared to unmodified electrode implying its remarkable electrocatalytic activity. The sensor featured a detection-limit of 7.1 nM and showcased excellent stability, repeatability and reproducibility. The practical utility of the sensor was manifested by estimating TRP in over 12 real samples including, food products, nutritional supplements and clinical samples (urine and human blood serum). [ABSTRACT FROM AUTHOR]

Basing on the unique advantages of uniform and rapid volumetric heating of microwave irradiation, microwave hydrothermal method has been used to fabricate Br/Bi2WO6 for streamlining the preparation procedure and enhancing the photocatalytic activity. The results indicated that Br was successfully introduced into the lattice of Bi2WO6, which improved the absorption ability of visible light. Moreover, Br/Bi2WO6 exhibited smaller size and the enhanced separation efficiency of photogenerated carriers as compared with Bi2WO6. Br/Bi2WO6 exhibited superior reusability and photocatalytic activity of Rhodamine B (RhB) and tetracycline (TC). Furthermore, the enhanced photocatalytic activity of Br/Bi2WO6 was mainly ascribed to the increased specific surface area, wide UV–vis light absorption range, and high separation efficiency of photogenerated charge carriers originating from Br doping and microwave heating. [ABSTRACT FROM AUTHOR]

Rationally designing high-activity catalyst for oxygen evolution reaction (OER) is of primary importance due to its sluggish kinetic process in water splitting. Herein, we report a metallic (V) and nonmetallic (F) double doping in Co 3 O 4 with nanoneedles structure, which is synthesized through facile oil bath and annealing. Electrochemical measurements show that the Co 3 O 4 dopped with fluorine and vanadium (F 0.2 -V-Co 3 O 4 -350) only needs a low overpotential of 320 mV to afford a current density of 10 mA cm−2, which is superior to commercial RuO 2. The excellent electrocatalytic performance can be attributed to double doping of vanadium and fluorine which have strong electron absorption effect to optimize the density of electrons in Co 3 O 4. Besides, nanoneedles structure can enlarge exposure of active sites. And its great durability is evaluated through 2000 cycles CV test. Furthermore, the optimal ratio of fluorine to vanadium and different annealing temperatures of the target catalyst are explored reasonably. [Display omitted] • The double doping of V and F has strong effect on the density of electron in Co 3 O 4. • F 0.2 -V-Co 3 O 4 -350 only needs an overpotential of 320 mV at 10 mA cm−2. • The optimal ratio of F to V and annealing temperature have been explored. • The trace introduction of both metallic and nonmetallic can improve OER activity. [ABSTRACT FROM AUTHOR]

Non-metals B, N, P and I were doped into titanium dioxide (TiO2) to form photocatalyst particles. TiO2 doped with various ratios of B, N, P and I were thus formed and these photocatalyst particles were bonded to fix each other in a column system under sunlight as a result of the photocatalytic degradation of bisphenol A (BPA). The doped TiO2 was characterized by X-ray diffraction (XRD), UV-visible absorption spectroscopy, and X-ray photoelectron spectroscopy (XPS) to elucidate the mechanism of doping reaction. Doping with B, N, P and I to form the photocatalyst greatly red-shifted the absorption wavelength, increasing the effectiveness of the photocatalyst in reducing BPA. XPS analysis following doping revealed the bonding of B, N, P, I and other functional groups of the surface of the photocatalyst. Results of an experiment that involved the photocatalysts revealed that BPA degradations of 88%, 94%, 93% and 100% in 66.5 min under sunlight using B, N, P, and I-doped titanium dioxide, respectively. The doped photocatalysts were all superior to the undoped titanium dioxide. [ABSTRACT FROM AUTHOR]

[Display omitted] • Efficient conversion of cellulose to biochar through pyrolysis was demonstrated. • Effects of various conditions of temperature and non-metal modification were assessed. • Conditions inhibitory to polycyclic aromatic hydrocarbons (PAHs) were determined. • Heteroatom modification was found to effectively remove PAHs from biochar. Biochar production from cellulose biomass is an alternative solution in the search for clean and renewable biofuel. However, the rational design of cellulose biochar (CLBC) for polycyclic aromatic hydrocarbons (PAHs) reduction by integrating pyrolysis process parameters and introducing heteroatoms as inhibitors remains to be studied. Therefore, exogenous heteroatoms (N, B, S, SB, NB, and NS) were used to modify CLBC for the first time. CLBC300 pyrolyzed at 300 °C in a CO 2 atmosphere achieved the highest concentrations of PAHs (4982 ± 271 ng g−1), compared with that of CLBC700 (3615 ± 71 ng g−1) formed in a N 2 atmosphere without heteroatom doping. The results showed that binary nitrogen- and sulfur-doped CLBC exhibited remarkable PAH-removal performance of 99 % with the lowest toxic equivalency (TEQ) value of 9 ng g−1. Overall, this study presents novel insights into the development of a heteroatom-based modification approach for reducing CLBC-borne PAHs and creating value-added products from cellulose biomass. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cost-effective Cu 3 Se 2 and S-doped Cu 3 Se 2 thin films were fabricated using a simple chemical bath deposition process. • S doping enhances the efficiency of photoelectrochemical water oxidation to produce oxygen. • S doping increased the band gap indicating band edge bending as well as increased surface area. • These properties make the S-doped Cu 3 Se 2 semiconductor a promising candidate for large-scale PEC water-splitting applications. The utilization of fossil fuels to meet ever-increasing energy demands is causing a significant threat to the Earth's climate and its inhabitants. To address this issue, photoelectrochemical (PEC) water splitting has emerged as a promising solution to produce oxygen (O 2) and hydrogen (H 2) in a cost-effective, environmentally friendly, clean, and renewable manner. In this study, we present the development of cost-effective Cu 3 Se 2 and S-doped Cu 3 Se 2 thin films on Fluorine-doped Tin Oxide (FTO) substrates using a chemical bath deposition (CBD) process to enhance the efficiency of PEC water oxidation to produce oxygen. The X-Ray Diffraction (XRD) pattern confirms the presence of a single-phase tetragonal Cu 3 Se 2 crystal structure with a noticeable shift in the characteristic (2 1 1) reflection towards a higher 2θ value, from 38.1° to 38.4°, indicating the successful doping of S in the Cu 3 Se 2 thin films. To further validate successful S doping in the Cu 3 Se 2 crystal lattice, X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray (EDX), Fourier transform infrared (FTIR), and Raman Spectroscopy were employed. TEM reveals a granular structure with an average particle size of 7–8 nm, which is consistent with the crystallite size determined by XRD. Furthermore, the valence band and conduction band edge positions are found to be 1.56 and −0.57 eV, respectively. The presence of S increased the band gap of Cu 3 Se 2, from 1.97 to 2.15 eV, thus confirming the bending of the band edge upon doping. The specific surface areas (SSA) of pristine and S-doped Cu 3 Se 2 were determined to be 5.03 and 111.48 m2g−1, respectively, showing a twenty-two-fold increase upon doping. The PEC performance of the materials was evaluated through chopped chronoamperometry (CA), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and Mott-Schottky (M-S) analysis. The S-doped Cu 3 Se 2 , prepared under optimum conditions, exhibited a photocurrent density difference of 880 µA cm−2, which was 6 times greater than for the pristine Cu 3 Se 2 thin film. The results of S-doped Cu 3 Se 2 indicate a negative slope, implying p-type conductivity, and a lower flat band potential value of 0.33 V vs. RHE. Our approach provides a green and cost-effective solution to fabricate S-doped Cu 3 Se 2 thin films for producing hydrogen and oxygen using CBD. [ABSTRACT FROM AUTHOR]

Abstract: Photocatalytic activity of TiO2 under visible light irradiation can be improved by doping with nonmetal atoms. However, inter-band energy states formed upon substitutional or interstitial doping can act as recombination centers, hindering the separation of the charge carriers. In this work, sol-gel synthesized TiO2 was doped with different loadings of boron, namely 0.25, 0.5, 1, 2, and 4 wt. %, and superficially modified by the deposition of Au nanoparticles (0.5, 1.0, and 1.5 wt. %). Particle size of doped TiO2 decreased with the increase of boron loading, while surface area increased accordingly. B2O3 was segregated from TiO2 when boron loading surpassed 1 wt. %. Light absorption of the doped materials was slightly blue shifted as the boron loading increased, more likely because of the quantization effect. Tiny and well dispersed Au nanoparticles were efficiently deposited on the B-TiO2 materials. Au nanoparticle size (3-5 nm) showed no modification as Au loading increased, although deposition rate slightly decreased with the boron loading. The complete mineralization of sulfamethoxazole under UV-A/visible light irradiation was obtained using the (0.5 wt. %) Au/(0.25 wt. %) B-TiO2 material. Electrochemical characterization showed how inter band energetic states increased the separation of the photo-produced charge carriers, while Au nanoparticles hampered the recombination rate via the electron trap effect. Photocatalytic materials displayed high stability. Photoactivity dropped when tap water was tested, because of the dissolved components in the liquid matrix. Some intermediates were identified via LC-MS/MS analysis, which displayed lower antibiotic activity than the parent compound.Sol-gel synthesized TiO2 was doped with boron, and superficially modified by deposition of Au nanoparticles. The complete mineralization of sulfamethoxazole under UV-A/visible light irradiation was obtained using the (0.5 wt. %) Au/(0.25 wt. %) B-TiO2 material. Inter band energetic states speed up the separation of the photo-produced charge carriers, while Au nanoparticles hamper the recombination rate via the electron trap effect Boron doped TiO2 is efficiently synthesized by the sol-gel reaction in a wide range of B loadings.Boron doping impacted on the physical, chemical and optical properties of TiO2.Doping increased separation of charge carriers while Au NPs acted as electron traps.Outstanding visible light driven photocatalytic performance of the Au/B-TiO2 materials.High stability of the Au/B-TiO2 materials and low activity in tap water. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO2) is an efficient photocatalyst for removing organics in photocatalytic wastewater treatment, but its low photoactivity limits its practical applications in a visible-light-driven chemical reaction. Many efforts have been made in the activation of the visible light absorption property on TiO2 photocatalyst. In this paper, a thorough review of current non-metal doping methods of TiO2 to improve photocatalyst activation under visible light is presented. The focus of this study is on doping non-metals onto TiO2 by several methods to enhance its visible light photoactivity. Besides, the resultant characteristics of the chemical structure, physical structure, and optical properties of the doped photocatalysts are discussed. This review enables a better understanding of current advantages and disadvantages that can arise during the production of non-metal-doped TiO2 and its applications. The annealing and hydrothermal methods are found to be more efficient in preparing doped photocatalysts with respect to time and costs. When choosing between these two approaches, the hydrothermal method can be applied using a variety of precursors, whereas the annealing methods are restricted only to solid form precursors. Thus, the hydrothermal method is a more favorable method of non-metal doping of TiO2. However, studies should focus on the effects of different factors involved in each synthesis/preparation method to determine optimal preparation conditions. [ABSTRACT FROM AUTHOR]

Abstract: The visible light photocatalytic performance of graphitic carbon nitride (g-C3N4) can be enhanced by tuning its electronic structure and bandgap via metal and nonmetal elements doping. The Fe and S codoped g-C3N4 is synthesized by the polymerization of melamine, iron chloride and trithiocyanuric acid at elevated temperature and characterized as crimped nanosheets with mesoporous structures. The photocatalytic performance of Fe–S codoped g-C3N4 for RhB degradation increases seven times by enhancing visible light adsorption and increasing the mobility of photoinduced electron/hole pair by narrowing its bandgap compared to the pure g-C3N4 nanosheets. The synergetic effect of Fe(III) ion coordinated in the pore centre among three triazine units and S dopant substituted the N in triazine skeleton causes much stronger delocalized HOMO and LUMO and increases the reactive sites, facilitating the migration of photogenerated charge carriers, thus enhances the visible-light driven photocatalytic performance.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Visible light-activated C, N, S-tri-doped mesoporous anatase-brookite heterojunction TiO 2 photocatalyst has been synthesized by a facile hydrothermal method. The XRD and Raman spectra data revealed the formation of mixed anatase and brookite phases. The FE-SEM and TEM images demonstrated the formation of brookite phase with a rod-like structure composed of much smaller particles of anatase phase. N 2 isotherm measurements exhibited that both doped and undoped TiO 2 have mesoporous structure and their surface area measurements were reduced from 62 to 30 cm 2 g −1 after non-metals doping. The photocatalytic oxidation of the ibuprofen (IBF) has been evaluated using prepared photocatalysts under visible light. The photocatalytic activity of the mesoporous C, N and S co-doped TiO 2 photocatalyst dramatically increased, achieving complete IBF degradation with an initial 1st order rate 1.779 μM min −1 for 5 h. The photonic efficiency (ξ) of IBF degradation under visible light with ABH (un-doped) and DABH (doped) photocatalysts are 0.044% and 1.84%, respectively. The reaction rate of doped photocatalyst is greater 40 times than non-doped one. The results demonstrated the advantages of the synthetic approach and the great potential of the driven visible light C, N and S co-doped TiO 2 photocatalysts for the treatment of residual pharmaceuticals in contaminated water under visible light. [ABSTRACT FROM AUTHOR]

In this study, modification of TiO 2 was carried out by doping of non-metal elements (S and N) and various contents of reduced graphene oxide (rGO) for photocatalytic degradation of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS). Among the tested photocatalyst, 0.1wt%rGO/S 0.05 N 0.1 TiO 2 had the best photocatalytic degradation efficiencies for both DMS and DMDS. Reduction of band gap and increment in surface area might be related to the improvement in photocatalytic activity. Examination was followed by the study of various parameters influence, reaction kinetics, and proposed reaction mechanism using 0.1wt%rGO/S 0.05 N 0.1 TiO 2. Dry and 1% relative humidity in gases promoted photocatalytic activity yet higher water vapor contents led to adsorption competition and reduced DMS and DMDS conversion. Langmuir-Hinshelwood kinetics model 4 presented the best suited result for photocatalytic degradation of DMS and DMDS using 0.1wt%rGO/S 0.05 N 0.1 TiO 2. Furthermore, proposed reaction mechanism for each type of pollutant was assembled from byproducts analysis during the reaction. [Display omitted] • rGO elevated specific surface area and electron transfer capacity of photocatalyst. • Enhancement on photocatalytic activity occurred due to formation of chemical defects. • The best DMS and DMDS photocatalytic degradation was done by 0.1 wt%rGO/S 0.05 N 0.1 TiO 2. • SO 2 , CO 2 , HCHO, CH 3 OOH, CH 3 OH, CO, and MSA were detected as products of DMDS. • DMS degradation generated SO 2 , CO 2 , DMDS, DMSO, DMSO 2 , CO, and MSA. [ABSTRACT FROM AUTHOR]

Hematite (Fe 2 O 3) has been widely used as a photoanode in photoelectrochemical water splitting (PEC) for green hydrogen production. Here, for the first time, we investigate how a simple in-situ phosphorus (P) doping strategy improves the overall PEC performance of hematite with a systematic analysis of the various effects on the PEC performance. By introducing enriched FePO 4 regions on the Ti-doped FeOOH surface and subsequent high-temperature annealing via P-doping, meso-porous P,Ti co-doped Fe 2 O 3 (P,Ti-Fe 2 O 3) nanorods were fabricated. P,Ti-Fe 2 O 3 exhibited four-fold and two-fold increased BET surface area and electrical active area, respectively, compared to that of Ti-Fe 2 O 3. Benefiting from the nano-structuring and efficient P doping effects [e.g., increased carrier density (N d =3.48168 ×1020 cm−3), enhanced charge separation (η bulk = 38.7% and η surface = 79.1%), and steeper band bending (W d =3.910 nm)], the resulting P,Ti-Fe 2 O 3 photoanode exhibited 94% improved photocurrent density of 2.50 mA cm−2 compared to that of Ti-Fe 2 O 3 (@ 1.23 V RHE) under 1 sun illumination. With the deposition of the NiFeO x cocatalyst, the NiFeO x /P,Ti-Fe 2 O 3 photoanode exhibited excellent photocurrent density of 3.54 mA cm−2 (@ 1.23 V RHE) with a remarkable cathodic shift (180 mV) of the onset potential, marking the highest value among P doped hematite studies. This study suggests a new paradigm of P doped hematite with mesopores and gradient doping properties affordable in a cost-efficient way, achieving an excellent PEC water splitting performance. [Display omitted] • We first report a novel in-situ P doping method with a pore generation mechanism for hematite via FePO 4 precipitation. • Porous structure, gradient P doping, increased oxygen vacancy, and fast charge transport were obtained in P,Ti-Fe 2 O 3. • The P,Ti-Fe 2 O 3 exhibited ∼100% improved photocurrent density at 1.23 V RHE compared to Ti-Fe 2 O 3. • After co-catalyst deposition, NiFeO x /P,Ti-Fe 2 O 3 showed 3.54 mA cm−2 (at 1.23 V RHE) of photocurrent density. [ABSTRACT FROM AUTHOR]

Mesoporous titania (mp-TiO2) has drawn tremendous attention for a diverse set of applications due to its high surface area, interfacial structure, and tunable combination of pore size, pore orientation, wall thickness, and pore connectivity. Its pore structure facilitates rapid diffusion of reactants and charge carriers to the photocatalytically active interface of TiO2. However, because the large band gap of TiO2 limits its ability to utilize visible light, non-metal doping has been extensively studied to tune the energy levels of TiO2. While first-principles calculations support the efficacy of this approach, it is challenging to efficiently introduce active non-metal dopants into the lattice of TiO2. This review surveys recent advances in the preparation of mp-TiO2 and their doping with non-metal atoms. Different doping strategies and dopant sources are discussed. Further, co-doping with combinations of non-metal dopants are discussed as strategies to reduce the band gap, improve photogenerated charge separation, and enhance visible light absorption. The improvements resulting from each doping strategy are discussed in light of potential changes in mesoporous architecture, dopant composition and chemical state, extent of band gap reduction, and improvement in photocatalytic activities. Finally, potential applications of non-metal-doped mp-TiO2 are explored in water splitting, CO2 reduction, and environmental remediation with visible light. [ABSTRACT FROM AUTHOR]

This paper presents the research of the effects of operating parameters on the photocatalytic degradation of 3,4-dichloroaniline (3,4-DCA) using non-metal doped TiO2-based photocatalysts. The nitrogen- and sulfur-doped in TiO2which was prepared using sol–gel method. The prepared catalyst was characterized using XRD, SEM-EDX, FTIR, XPS, DRS, and BET analysis. The characterization revealed that Ti–N showed lower particle size, higher specific surface area, and low band-gap energy as compared to Ti–S. The photocatalytic degradation of 3,4-DCA using Ti–N showed better activity as compared to Ti–S and undoped TiO2. The findings revealed that various parameters, such as the initial pH of the solution to be degraded, catalyst loading, concentration of solution, and light intensity, exert their individual influence on the photocatalytic degradation of 3,4-DCA. The kinetics of degradation of 3,4-DCA followed two-regime LH model and rate constants were determined. The reaction constant and Langmuir adsorption constants were determined and half-life time which was determined was found to be closer to those determined using two-regime fit. [ABSTRACT FROM PUBLISHER]

Titanium dioxide (TiO 2 ) has been proved to be a leading semiconductor material to removal of environmental pollutants. However, it suffers from low photocatalytic efficiency under visible-light irradiation and narrow light response range because of its intrinsic large band gap. One of the most significant scientific and commercial progresses to date has been the development of visible light active TiO 2 by incorporation of additional components in the TiO 2 structure. In this review, a variety of strategies to improve the photocatalytic efficiency and shift the photocatalysis to visible light range are discussed. The materials are covered in the review including TiO 2 /SiO 2 , TiO 2 /carbon nanotube, TiO 2 -graphene/grapheme oxide, non-metal and/or metal doped TiO 2 . Emphasis is given to highlight current techniques and recent progress in enhancing photocatalytic efficiency of TiO 2 -based materials, which drives the rising of some key strategies involved in the ongoing challenges and potential new directions of TiO 2 photocatalysts. [ABSTRACT FROM AUTHOR]

This study provides valuable insights into chemical doping on MoS 2 is an effective and applicable strategy to separate nitrogen from natural gas. [Display omitted] • DFT computations indicate that B/C-doped 2H–/1T-MoS 2 surfaces can effectively separate N 2 from the CH 4 /N 2 gas mixture. • N 2 adsorption properties on these surfaces were investigated, including adsorption energies and structures, charge transfers, partial density of states (PDOS), etc. • The thermodynamic processes of N 2 on these surfaces were investigated in detail. N 2 removal is of great significance to the industrial production and usage of natural gas. It is necessary to find new methods and materials for separating nitrogen (N 2) from methane (CH 4) with high selectivity and efficiency. Molybdenum disulfide (MoS 2) is a promising two-dimensional material. In this work, density functional theory (DFT) was applied to study the influences of non-mental (B, C, N, O and P) doping in 1H- or 1T'-MoS 2 monolayer on the adsorption behaviors of N 2 and CH 4. The result shows that the interaction between either gas and pristine MoS 2 is very weak, but that between N 2 and MoS 2 can be significantly improved by doping B or C. Nevertheless, the adsorption of CH 4 is insensitive to such doping. The DFT computational results indicate that doping of B or C in MoS 2 is a selective and efficient method to separate N 2 from CH 4. This study provides valuable information for designing novel approaches and advanced materials for N 2 removal from natural gas with high efficiency. [ABSTRACT FROM AUTHOR]

Cadmium sulfide (CdS) has been extensively employed to achieve highly efficient H 2 production under visible-light irradiation due to its features of narrow bandgap and appropriate conduction band position. However, fast carriers recombination and severe photocorrosion inevitably result in low carriers utilization, leading to undesirable photocatalytic performance and poor durability. To address the issues, N heteroatoms were introduced into the lattice of hexagonal CdS NPs to prepare the N-doped CdS (N-CdS) nanocatalyst via a wet chemical precipitation coupled with a hydrothermal process. Due to the synergetic promotion of heteroatom-semiconductor coordination (HSC) interaction to body carriers migration of CdS, their recombination behavior was effectively hampered, resulting obviously increased photocurrent density (~2 times) and significantly improved photoexcited carriers utilization. Thereby, high apparent quantum yield (AQY = 32.41%, λ = 500 nm) was achieved by the optimized N 0.2 -CdS nanocatalyst. Under simulated sunlight (SSL) irradiation, about 3983.4 μmol·h−1·g−1 of HER rate with excellent photostability was achieved at absence of cocatalyst, which raises to about 9-fold greater than that of bare CdS NPs. Moreover, density functional theory (DFT) calculations proved that the energy barrier of water splitting on Cd sites and |ΔG H* | of H 2 generation on S sites were reduced obviously due to the synergetic HSC interaction, which thermodynamically accelerated the H 2 generation. This study provides a simple and green strategy for gaining highly stable CdS photocatalyst with improved HER photoactivity. Heteroatom-semiconductor coordination interaction promotes body carriers migration of CdS nanocatalyst for highly improved HER photoactivity under simulated sunlight irradiation. [Display omitted] • N heteroatoms were introduced into the lattice of hexagonal CdS NPs via a one-step strategy. • Heteroatom-semiconductor coordination (HSC) interaction promotes body carriers migration of CdS. • Increased photocurrent density and improved photoexcited carriers utilization were presented by this doped nanocatalyst. • The decreased energy barriers thermodynamically accelerate the H 2 generation. [ABSTRACT FROM AUTHOR]

Highlights: [•] Recent progresses on non-metal doping of transition metal oxides are reviewed. [•] The origins of visible light absorption upon non-metal doping are discussed. [•] Pathways to achieve homogeneous non-metal doping are summarized. [•] An overview on the photocatalytic reactions of non-metal doped materials is presented. [ABSTRACT FROM AUTHOR]

Abstract: Fujishima and Honda (1972) demonstrated the potential of titanium dioxide (TiO2) semiconductor materials to split water into hydrogen and oxygen in a photo-electrochemical cell. Their work triggered the development of semiconductor photocatalysis for a wide range of environmental and energy applications. One of the most significant scientific and commercial advances to date has been the development of visible light active (VLA) TiO2 photocatalytic materials. In this review, a background on TiO2 structure, properties and electronic properties in photocatalysis is presented. The development of different strategies to modify TiO2 for the utilization of visible light, including non metal and/or metal doping, dye sensitization and coupling semiconductors are discussed. Emphasis is given to the origin of visible light absorption and the reactive oxygen species generated, deduced by physicochemical and photoelectrochemical methods. Various applications of VLA TiO2, in terms of environmental remediation and in particular water treatment, disinfection and air purification, are illustrated. Comprehensive studies on the photocatalytic degradation of contaminants of emerging concern, including endocrine disrupting compounds, pharmaceuticals, pesticides, cyanotoxins and volatile organic compounds, with VLA TiO2 are discussed and compared to conventional UV-activated TiO2 nanomaterials. Recent advances in bacterial disinfection using VLA TiO2 are also reviewed. Issues concerning test protocols for real visible light activity and photocatalytic efficiencies with different light sources have been highlighted. [Copyright &y& Elsevier]

Chlorophenols comprise a class of persistent organic pollutants that are hazardous to the environment. In this study, nitrogen- and sulfur-doped zinc ferrite nanoparticles synthesized via co-precipitation and wet impregnation methods were investigated as catalysts for use in the complete degradation of 4-chlorophenol. The doped ferrite nanoparticles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and thermogravimetric analysis. Dielectric studies determined increased dielectric permittivity of ≈80 pF for the doped samples, which is usually in the range of 60–70 pF for ferrites. The superparamagnetic behavior observed in magnetic analyses suggests possible applications in devices for targeted drug delivery and magnetic resonance imaging. The persulfate activated degradation of 4-chlorophenol was investigated using the prepared catalysts under optimized conditions. Complete degradation of the target compound was observed with a reduction in the chemical oxygen demand of 98% even at room temperature (25–30 °C). Phase analysis using X-ray diffraction demonstrated the stability of the catalysts after successive reaction cycles. The catalysts were stable, efficient, and reusable for five consecutive cycles, and negligible amounts of iron were leached out. The results obtained in the present study suggest potential applications of nitrogen- and sulfur-doped zinc nanoferrite catalysts in water treatment techniques for the oxidative removal of persistent organic compounds. • Magnetically recoverable catalysts for persulfate-activated oxidation of 4-chlorophenol. • Oxidizing power of zinc nanoferrites increased with nitrogen and sulfur substitution. • Reaction rate highly dependent on catalyst amount and its composition. • Catalysts reusable with negligible leaching, thereby indicating a heterogeneous mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • Stable nitrogene monolayer has an indirect band gap of 6.023 eV. • AA-, AA′-, and AB-stacked bilayers show good stability with reduced energy gap. • Magnetic semiconductor magnetic nature is induced by C-doping. • B-doping leads to magnetism-free materials, with considerable band gap reduction. • Codoping can be considered of the combined effects of separated C- and B- doping. The (N) nitrogen monolayer (nitrogene) has been predicted to be stable in the buckled hexagonal structure. However the non-magnetic nature and large band-gap may restrict its practical applications. In this paper, the electronic and magnetic properties of the nitrogene monolayer and bilayer doped with carbon (C) and boron (B) are investigated using first-principles calculations. Nitrogene monolayer is a non-magnetic two-dimensional (2D) material with an indirect band-gap of 4.185(6.023) eV determined by the PBE(HSE06) functional. Nitrogene bilayers with different stacking shaps are examined. Results reveal dynamical stability of the AA-, AA′-, and AB-stacked bilayers. Such atomic arrangements depict an energy gap reduction as compared to that of the monolayer. C doping causes strong spin polarization at the vicinities of the Fermi level, giving place to magnetic semiconductor nature. The magnetic properties are produced mainly by the C dopants (0.7 μ B ), and also proximity induced small contributions on the N atoms (0.07 μ B ). In contrast, B doping produces non-magnetic materials with band-gap reduction (∼ 12% and 20.5%) for all considered systems. When the co-doping is treated, the effect on the electronic and magnetic properties can be considered as the combined effects of the separated C doping and B doping. Results presented herein may propose an efficient method to functionalize the nitrogene monolayer and bilayer for practical applications in optoelectronic and spintronic nano devices. [ABSTRACT FROM AUTHOR]

Acesulfame K is a zero-calorie alternative to sugar used worldwide. There is contradictory information on the toxicity of the compound, but its accumulation in the aquatic environment is undeniable. In this study, one-pot sol-gel synthesis was used to obtain nitrogen-doped TiO2 photocatalysts. Doping up to 6.29 wt % of nitrogen caused an increase in the surface area of the catalysts (48.55–58.23 m2∙g−1) and a reduction of the pHPZC value (5.72–5.05). Acesulfame K photodegradation was tested at the initial concentration of 20–100 ppm and the catalyst concentration at the level of 1 g∙L−1. Compared to the pure anatase, 4.83–6.29 wt % nitrogen-doped TiO2 showed an effective photodegradation of Acesulfame K. Ninety percent molecule removal was obtained after ~100 min, ~90 min, and ~80 min for initial concentrations of 20 ppm, 50 ppm, and 100 ppm, respectively. The increased activity of the catalysts is due to the modification of the TiO2 lattice structure and probably the limitation of the photogenerated electron/hole charge carrier recombination. It was shown that the electrostatic interactions between Acesulfame K and the catalyst surface play an important role in the photodegradation efficiency. [ABSTRACT FROM AUTHOR]