Nitrogen-doped Titanium Research Articles

Visible light-assisted efficient degradation of Rhodamine B by N-TiO2/Mn-HPMo/Ag ternary composites

In this paper, Ag nanoparticles were deposited on the surface of nitrogen-doped titanium dioxide coupled with manganese-substituted phosphomolybdic acid composites (N-TiO2/Mn-HPMo) using photoreduction method to construct ternary photocatalysis-Fenton composite catalyst (N-TiO2/Mn-HPMo/Ag), and the degradation performance of the catalyst was evaluated with Rhodamine B (RhB) as the target pollutant. The results showed that the N-TiO2/Mn-HPMo/Ag ternary composite catalyst had remarkable visible light activity, and the degradation efficiency of RhB could reach 96.3% in 20 min under visible light. Meanwhile, UV–vis diffuse reflectance spectroscopy illustrated the promotion effect of Ag deposition on the visible light response of N-TiO2/Mn-HPMo. The behavior of photogenerated charges was also characterized by Surface Photovoltage Technique, which further demonstrated that Ag deposition not only extended the light absorption range but also enhanced the separation efficiency of photogenerated charges. This work provides favorable information for the construction of efficient catalysts with high activity under visible light.

Thermo-photocatalytic oxidation of benzene under visible light over nitrogen-doped titania grafted with Cu and Pt

Nitrogen-doped titania (TiO2-N) was synthesized and tested, both in unmodified form and with grafted Cu and Pt particles, in the reaction of photocatalytic oxidation of benzene under visible light irradiation at temperatures of 40, 100 and 140 °C. The results obtained indicate additional thermal activation of the reaction over Pt-containing samples with the maximum difference between the total and thermal activities at 100–120 °C. As modifiers, both platinum and copper separately improve the photoactivity of TiO2-N, but when used together, their effects do not add up, and the photocatalyst behaves like a Pt-modified sample.

Photoelectrochemical Water Oxidation Using Cobalt Phosphate‐Modified Nitrogen‐Doped Titania Nanotube Arrays

Water Splitting In article number 2200229, Kazuhiko Maeda, Hyunwoong Park, and co-workers accomplished stable photoelectrochemical water oxidation driven by sunlight to yield oxygen gas with cobalt phosphate-modified, nitrogen-doped titania nanotube arrays, which can absorb visible light with wavelengths as long as 580 nm.

Efficient photocatalytic degradation of organic pollutants over TiO2 nanoparticles modified with nitrogen and MoS2 under visible light irradiation

Investigate the use of visible light to improve photocatalytic degradation of organic pollutants in wastewater. Nitrogen-doped titania and molybdenum sulfide nanocomposites (NTM NCs) with different weight ratios of MoS2 (1, 2, and 3 wt.%) synthesized by a solid state method applied to the photodegradation of methylene blue(MB) under visible light irradiation. The synthesized NTM composites were characterized by SEM, TEM, XRD, FT-IR, UV–Vis, DRS and PL spectroscopy. The results showed enhanced activity of NTM hybrid nanocrystals in oxidizing MB in water under visible light irradiation compared to pure TiO2. The photocatalytic performance of NTM samples increased with MoS2 content. The results show that the photodegradation efficiency of the TiO2 compound improved from 13 to 82% in the presence of N-TiO2 and to 99% in the presence of MoS2 containing N-TiO2, which is 7.61 times higher than that of TiO2. Optical characterization results show enhanced nanocomposite absorption in the visible region with long lifetimes between e/h+ at optimal N-TiO2/MoS2 (NTM2) ratio. Reusable experiments indicated that the prepared NTM NCs photocatalysts were stable during MB photodegradation and had practical applications for environmental remediation.

Structural effects of nitrogen-doped titanium oxide supports on stabilization of ruthenium active species in carbon dioxide hydrogenation to formate

A single atom Ru catalyst supported on a N-doped TiO2 was investigated for the conversion of CO2 to formate by hydrogenation. N-dopant sites induced a strong binding environment to Ru single-atom catalysts (SACs), resulting in a stable and atomically isolated dispersion state of Ru SACs upon metalation. Consequently, Ru/MN-TiO2 exhibited enhanced catalytic stability, which incorporated both substitutional (Ns) and interstitial (Ni) dopant sites, retaining 42 % of its original relative activity after the fifth recycle test. In contrast, Ru/N-TiO2, which contained only Ni-dopants, showed a lower stability, retaining only 19 % of its initial activity after the fifth run, and Ru/TiO2 was fully deactivated after the third run. Density functional theory calculations revealed that the stronger binding ability of the Ns sites to the Ru species compared with that of the Ni sites and the bare surface of the TiO2 structure improved the catalytic stability during hydrogenation.

Photocatalytic hydrogen under visible light by nitrogen-doped rutile titania graphitic carbon nitride composites: an experimental and theoretical study

Photocatalytic hydrogen under visible light by nitrogen-doped rutile titania graphitic carbon nitride composites: an experimental and theoretical study

Investigation of the Photoinduced Antimicrobial Properties of N-Doped TiO2 Nanoparticles under Visible-Light Irradiation on Salmonella Typhimurium Biofilm

The aim of the present study was to investigate the photoinduced properties of nitrogen-doped titanium dioxide (N-TiO2) against the Salmonella ser. Typhimurium bacterial biofilm, under visible-light irradiation. The capability of N-TiO2 nanoparticles working as multipurpose materials with antimicrobial applications, as well as environmental ones, was therefore investigated. The sol–gel method was used to synthesize N-TiO2 particles, which were then characterized by Fourier-transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), Brunauer–Emmett–Teller (BET) analysis of surface area, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS), and transmission electron microscopy (TEM). The results showed that the particles formed were nano-sized and had the expected Ti-O bonds and the presence of elemental N. The as-produced N-TiO2 nanoparticles (NPs) were tested for their antimicrobial activity. The antibacterial photocatalytic testing was performed under visible-light irradiation, on Salmonella Typhimurium biofilm. To form the biofilm, stainless steel (ss) coupons were incubated with three different strains of Salmonella Typhimurium bacteria for 48 h at 15 °C in tryptone soy broth (TSB). After the biofilm’s formation, the coupons were placed on a horizontal, rectangular, batch, equipped with a vis-LED irradiation source reactor in the presence of N-TiO2 NPs. After 1, 2, and 3 h of irradiation, sampling of the bacterial population was assessed. The results showed an evident inhibition of proliferation under light irradiation when the N-TiO2 was present, compared to the non-irradiated NPs. It is noteworthy that, during the first 2 h, the TiO2 NPs specimens tended to attract more bacteria on their surface then the control specimens, due to their higher available surface area, which worked as a shelter. There were ~6% viable (remaining) Salmonella cells after the first hour of visible-light irradiation with N-TiO2 NPs.

The microstructure and photocatalytic properties of nitrogen-doped nano titanium dioxide loaded on porous ceramics

Nitrogen-doped nano TiO2 powder was prepared using the solvothermal method. The nano TiO2 powder was loaded on the porous ceramic carriers with a different aperture through the vacuum impregnation method using polyvinyl alcohol as a binder. The effects of deionized water content and carrier pore size on the microstructure and photocatalytic activity of nitrogen-doped nano TiO2 powder and supported TiO2 were investigated. The results show that, when introducing 25% deionized water, the nitrogen-doped nano TiO2 powder obtains a good crystallinity, small grain size, and high photocatalytic properties because of adequate hydrolysis of tetrabutyl titanate. The photocatalytic activity of nitrogen-doped nano TiO2 powder is improved by distorting the lattice and inhibiting grain growth. The nano TiO2 powder can be tightly loaded on the surface of the strut or hole-wall of porous ceramic carriers. The absorption and photocatalytic activity of supported TiO2 are demonstrably improved as the macropore provides the transmission channel, and the micropore realizes a good absorbing effect. The 20 PPI carrier with high porosity and suitable strength is beneficial to promote the photocatalytic property of supported TiO2. Moreover, the supported TiO2is easily recycled and reused.

Enhanced Photodegradation of Rhodamine B Using Visible-Light Sensitive N-TiO2/rGO Composite

Rhodamine B (RhB) is extensively used for dyeing purposes, and cannot be completely removed using traditional water treatment technologies. Here, we report for the first time the photodegradation of RhB using nitrogen-doped titanium dioxide (N-TiO2) on reduced graphene oxide (rGO) composite (N-TiO2/rGO). The work primarily highlights the synergistic effect of the incorporation of N-TiO2 and rGO and its kinetic study for the photodegradation of RhB. The N-TiO2/rGO composite was synthesized by dispersing titanium(IV) isopropoxide and urea, followed by annealing treatment via the hydrothermal method with rGO. Scanning electron microscopy (SEM) images illustrated that N-TiO2 particles with an irregular round shape and white color were dispersed onto the rGO surface. X-Ray diffraction (XRD) patterns revealed that N-TiO2/rGO composite showed an anatase phase of TiO2 with a diffraction peak of 2θ = 25.622°. The gas sorption analysis (GSA) showed that N-TiO2/rGO had surface area, pore volume, and pore size of 53.393 m2/g, 0.096 cc/g, and 3.588 nm, respectively. The thermogravimetric-differential thermal analysis (TG-DTA) showed an anatase phase of TiO2 that appeared at a temperature of 200–500 °C, with a weight loss of 2.50%. According to the ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) study, TiO2, N-TiO2, and N-TiO2/rGO had band gap energies of 3.25, 2.95, and 2.86 eV, respectively. The highest photodegradation of RhB was obtained at the optimum condition in pH 2 with a photocatalyst mass of 20 mg and an irradiation time of 90 min. The photocatalytic activity of N-TiO2/rGO using visible light showed a higher percentage of photodegradation at 78.29%, compared to 44.08% under UV light. The kinetic study of the photodegradation of RhB using N-TiO2/rGO followed the pseudo-second-order model.

Crucible Effect on Phase Transition Temperature during Microwave Calcination of a N-Doped TiO2 Precursor: Implications for the Preparation of TiO2 Nanophotocatalysts

Nitrogen-doped titanium dioxide (N–TiO2) is extensively studied in the literature and widely employed as a visible-light photocatalyst. The preparation of this nanomaterial often involves a final calcination step: in this paper, we used microwave technology as an efficient and environmentally friendly tool for the calcination of a mixed anatase/brookite phase precursor containing organic compounds arising from its synthesis. A wide study was performed, comparing results obtained in quartz fiber-made crucibles, porcelain crucibles, microwave (MW) and conventional heating, and also using a pristine TiO2 as a reference material. Weight percentages of the three main TiO2 polymorphs obtained in different calcination conditions were determined by X-ray powder diffraction (XRPD) data and Rietveld refinements, and the results are discussed. We found that the calcination’s outcome is dramatically affected by the crucible used: while mixed-phase nanomaterials were obtained when using classic porcelain crucibles, only the rutile phase was obtained when working in a quartz fiber crucible at temperatures as low as 250 °C. The direct material’s temperature measurement inside the microwave oven showed that this finding is not due to a microwave effect but to a thermal effect caused by the particular crucible employed that favors better combustion of organics and prompts rutile formation. Nitrogen doping of this material was inferred by ultraviolet–visible–diffuse reflectance spectroscopy (UV–vis–DRS).

Fabrication of nitrogen doped TiO2/Fe2O3 nanostructures for photocatalytic oxidation of methanol based wastewater

An important industrial process that often occurs on the surface of a heterogeneous catalyst using thermochemical or photochemical could help in the oxidation of methanol-based wastewater to formaldehyde. Titania-based photocatalysts have drawn a lot of interest from scientists because they are a reliable and affordable catalyst material for photocatalytic oxidation processes in the presence of light energy. In this study, a straight-forward hydrothermal method for producing n-TiO2@α-Fe2O3 composite photocatalysts and hematite (α-Fe2O3) nanocubes has been done. By adjusting the ratio of n-TiO2 in the prepared composite photocatalysts, the enhancing influence of the nitrogen-doped titania on the photocatalytic characteristics of the prepared materials was investigated. The prepared materials were thoroughly characterized using common physiochemical methods, such as transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX), X-ray photoelectrons spectroscopy (XPS), physisorption (BET), and others, in order to learn more about the structure The results obtained showed that nitrogen-doped titania outperforms non-doped titania for methanol photooxidation. The addition of nitrogen-doped titania to their surfaces resulted in an even greater improvement in the photooxidation rates of the methanol coupled with hematite. The photooxidation of methanol in the aqueous solution to simulate its concentration in the wastewater has been occurred. After 3 h, the four weight percent of n-TiO2@α-Fe2O3 photocatalyst showed the highest rate of HCHO production.

Inactivation of SARS-CoV-2 variants by nitrogen-doped titanium dioxide loaded with metals as visible-light photocatalysts.

We examined the inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by a nitrogen-doped titanium dioxide (N-TiO2) visible-light photocatalyst that was activated via light irradiation in the natural environment and was safe for human use as a coating material. The photocatalytic activity of glass slides coated with three types of N-TiO2 without metal or loaded with copper or silver and copper was investigated by measuring acetaldehyde degradation. The titer levels of infectious SARS-CoV-2 were measured using cell culture after exposing photocatalytically active coated glass slides to visible light for up to 60min. N-TiO2 photoirradiation inactivated the SARS-CoV-2 Wuhan strain and this effect was enhanced by copper loading and further by the addition of silver. Hence, visible-light irradiation using silver and copper-loaded N-TiO2 inactivated the Delta, Omicron, and Wuhan strains. N-TiO2 could be used to inactivate SARS-CoV-2 variants, including emerging variants, in the environment.

Photocatalytic degradation of pharmaceuticals from water using nitrogen-doped titanium dioxide coated on fiberglass cloth

Caffeine, carbamazepine, and ibuprofen are pharmaceuticals that were frequently found in natural water, and they can pose a potential threat to aquatic organisms even at low concentrations. Visible light-driven photocatalysis is a green technology that can remove pharmaceuticals from water, and the treated water could be useful for other purposes. The recycling of wastewater is a sustainable option for water management. In this study, the photocatalysts were prepared by the binder-free coating of commercial anatase TiO2 and sol-gel-derived nitrogen-doped TiO2 (moles N/Ti of 1–5) on fiberglass clothes (FGC). Nitrogen was found to be interstitially doped into TiO2 and improved the photocatalytic activity of TiO2 under visible light irradiation. The molar ratio of N/Ti for coating on FGC was optimized through the removal of caffeine in a simple batch reactor. 3N–TiO2-coated FGC (N/Ti molar ratio = 3) was optimum photocatalyst. The curtain waterfall reactor was fabricated to efficiently utilize the energy from visible light source. The 3N–TiO2-coated FGC was used in a curtain waterfall reactor to remove caffeine, carbamazepine, and ibuprofen from the water. The removal efficiencies achieved their acceptable levels for reuse within an irradiation time of 14 h. Total organic carbon results confirmed the mineralization of pharmaceuticals. The photocatalyst can be reused for five cycles (12 h for each cycle) with stable performance although it was kept as a roll before use, which indicates the convenience to transport to the place of use, and the potential to further fit in various shapes of the photocatalytic reactor.

Enhanced Photovoltaic Properties of Dye-Sensitized Solar Cells through Ammonium Hydroxide-Modified (Nitrogen-Doped) Titania Photoanodes

Doping is a unique strategy to modulate the optical and electronic properties of semiconducting materials. This study reports a facile approach to fabricate nitrogen-doped TiO2 (N-doped TiO2) photoanode for DSSC application. A solid-state reaction was employed to synthesize a series of N-doped TiO2 nanoparticles with different volumetric ratios of nitrogen dopant and the TiO2 host. The NH4OH as a nitrogen dopant was combined with P25-TiO2 via grinding followed by calcination at 500°C. The synthesized nanoparticles were extensively characterized by XRD, XPS, EDX, SEM, and TEM techniques. XRD results suggested that the incorporation of nitrogen had not altered the structure of the TiO2 lattice, and the presence of nitrogen was confirmed through the XPS and EDX spectroscopies. SEM and TEM images, obtained before and after N doping, showed that N-doped TiO2 nanoparticles with low amounts of NH4OH (10 and 20 μL) had retained their spherical shapes and sizes while use of higher amounts of the N dopant (30 and 40 μL) had led to agglomeration of nanoparticles. BET and BJH analyses revealed that the optimized N-doped TiO2 with 20 μL of NH4OH (20N-TiO2) possesses the highest average pore diameter of 15.99 nm. Furthermore, the UV-visible spectroscopic analysis confirmed a red shift in the optical absorption edge on N doping and the corresponding bandgap reduced from 3.15 to 2.94 eV with increase in the amount of NH4OH from 0 to 40 μL. Eventually, DSSCs were fabricated using the prepared pure TiO2 and N-doped TiO2 photoanodes, N719 dye,I−/I3−electrolyte, and Pt counter electrode, followed by investigating their performance under simulated irradiation with 100 mW/cm2 intensity with AM 1.5 filter. The photoanode doped with 20 μL of NH4OH (20N-TiO2) exhibited the highest power conversion efficiency (PCE) of about 6.16%, which was 20% higher than that of the control device, with improvedJSC. This enhancement inJSCcould be predominantly attributed to higher dye uptake along with marginal contribution by reduced rate of recombination. Among the reported studies on DSSCs with N-doped P25-TiO2 photoanodes, our method gives the best efficiencies for the DSSCs.

A novel polymer-free everolimus-eluting stent with a nitrogen-doped titanium dioxide film inhibits restenosis and thrombosis in a swine coronary model.

Short-term outcomes regarding the safety and efficacy of a polymer-free everolimus-eluting stent (EES) with a nitrogen-doped titanium dioxide (N-TiO₂) film in a swine coronary model have been reported. However, the long-term results of the use of this type of stent have not yet been evaluated or compared to those of other polymer-free coronary stents. Therefore, this study aimed to determine the mid- to long-term safety and efficacy of a polymer-free EES with an N-TiO₂ film in a swine coronary model. Polymer-free EES with N-TiO₂ films (n = 30) and polymer-free sirolimus-eluting stents (SES; n = 30) were implanted in 30 pigs. Quantitative coronary analysis and optical coherence tomography were conducted immediately and at 1 (quantitative coronary analysis only), 3, and 6 months after stenting. Histopathologic examinations were performed at 1, 3, and 6 months after stenting. The polymer-free EES group had a lower percentage of neointimal growth than the polymer-free SES group at 3 months (22.5% ± 11.4% vs. 32.1% ± 12.3%; p < 0.001). The polymer-free EES group had a lower fibrin score than the polymer-free SES group at 1 month (1.9 ± 0.45 vs. 2.5 ± 0.54; p = 0.001). The re-endothelialization rates were similar between groups. The polymer-free EES group had a lower percentage of the area of stenosis than the polymer-free SES group throughout the follow-up period. The novel polymer-free EES with an N-TiO₂ film has superior safety and efficacy than the polymer-free SES at the 6-month follow-up in a swine model.

Numerical Simulation of Nitrogen-Doped Titanium Dioxide as an Inorganic Hole Transport Layer in Mixed Halide Perovskite Structures Using SCAPS 1-D

Perovskite solar cells (PSCs) stand out as superior third-generation (III-gen) thin-film energy harvesting structures with high efficiency, optical properties and light transmission ability. However, the need to develop cost-effective, stable and sustainable PSCs is allied to the influence of the absorber layer and charge selective transport layers when achieving semi-transparent (ST) structures. Using SCAPS simulation software that can envisage the conceptuality in devising ST PSCs, this work explores and reports the electrical performance of different methylammonium (MA)-based perovskite structures (FTO/TiO2/PCBM/SnO2/MAPbI3/TiO2:N/PTAA/Spiro-OMeTAD/PEDOT: PSS/Ag). The influence of absorber thickness and defect density is analyzed with optimal parameters. This research reports a novel idea that replaces the polymeric hole transport layer (HTL), such as Spiro-OMeTAD, PEDOT: PSS and PTAA with an air-stable inorganic metal oxide, viz., nitrogen-doped titanium dioxide (TiO2:N). The simulation results depict an attainable power conversion efficiency of 9.92%, 10.11% and 11.54% for the proposed structures with the novel HTL that are on par with polymeric HTLs. Furthermore, the maximum allowable absorber thickness was 600 nm with a threshold defect density of 1 × 1015 cm−3. The optimized electrical parameters can be implemented to develop thin-film light transmission perovskite cells with rational power conversion efficiencies.

Electrochemical Sensor Based on Multi-Walled Carbon Nanotubes and N-Doped TiO2 Nanoparticles for Voltametric Simultaneous Determination of Benserazide and Levodopa

An electrochemical sensor for simultaneous determination of Benserazide (BEZ) and levodopa (L-dopa) was successfully developed using a glassy carbon electrode (GCE) modified with multi-walled carbon nanotube and nitrogen-doped titanium dioxide nanoparticles (GCE/MWCNT/N-TiO2). Cyclic voltammetry and square wave voltammetry were employed to investigate the electrochemical behavior of different working electrodes and analytes. In comparison with unmodified GCE, the modified electrode exhibited better electrocatalytic activity towards BEZ and L-dopa and was efficient in providing a satisfactory separation for oxidation peaks, with a potential difference of 140 mV clearly allows the simultaneous determination of these compounds. Under the optimized conditions, linear ranges of 2.0-20.0 and 2.0-70.0 μmol L-1 were obtained for BEZ and L-dopa, respectively, with a limit of detection of 1.6 µmol L-1 for BEZ and 2.0 µmol L-1 for L-dopa. The method was applied in simultaneous determination of the analytes in pharmaceutical samples, and the accuracy was attested by comparison with HPLC-DAD as the reference method, with a relative error lower than 4.0%.

Electrochromic properties of nitrogen doped titanium dioxide films

Nitrogen doping is an effective way to improve the electrochromic performance of inorganic materials. However, there is still a lack of systematic studies on the electrochromic properties of nitrogen-doped TiO2 materials. In this work, the N-doped titanium dioxide films (N-TiO2) with different N content were prepared by an ion exchange method combined with hydrothermal approach. The effects of different N doping concentrations on the morphology and electrochromic properties of samples were studied by XRD, XPS, FESEM, HR-TEM and electrochemical methods. It was found that the nitrogen doping has a great influence on the crystal structure of the TiO2, leading to an obvious light transmittance difference in bleaching/coloring states for all the films. The N1-TiO2 film (nitrogen doping concentration was 1 mol/L) shows the best electrochromic performance. The ion diffusion coefficient of N1-TiO2 composite film was 2.28 × 10−9 cm2/s, and the coloring efficiency is 10.61 cm2/C, the coloring and bleaching switching time was 31.13 s and 3.79 s, and the optical modulation amplitude retention rate after 100 cycles can reach 65.43 %, indicating that nitrogen doping with proper amount is indeed an effective method to tune electrochromic properties of TiO2.

Blue light activated photodegradation of biomacromolecules by N-doped titanium dioxide in a chitosan hydrogel matrix

The use of photocatalysis activated by titanium dioxide nanostructured materials is a promising solution for many biomedical applications ranging from drug-free antibacterial to anticancer therapies, as well as for innovative hydrogel-supported phototherapies. This makes the effects of photocatalysis on the structure of biomolecules of a great relevance in order to define the applicability of photocatalytic materials in the biomedical fields. In this work, the effects of nitrogen-doped titanium dioxide (N-TiO2) dispersed in a biocompatible chitosan/PEG hydrogel on myoglobin and bovine serum albumin as target model proteins were investigated. The efficiency of this composite biocompatible material in inducing damages on biomolecules was assessed under blue light illumination by using spectroscopic techniques. N-TiO2 nanoparticles were chosen as photocatalyst to trigger the photocatalytic process by irradiation with a blue light source, instead of higher energy sources, e.g. UV radiation, avoiding UV-related damages on biomolecules. In addition, the present work highlighted several advantages of using the hydrogel as medium for photocatalytic reactions. Firstly, N-TiO2 nanoparticles were well dispersed and stabilized in the hydrogel respect to the correspondent aqueous suspension, and the photocatalytic reactions can occur in a biomimetic and biocompatible environment suitable for biomolecules, such as proteins. Importantly, the chitosan/PEG hydrogel enabled a direct investigation of the effects of photocatalysis on proteins by direct in situ spectroscopic measurements without any need of recovery of the target molecules, nor stirring during the photocatalysis, which could be detrimental for delicate biomolecules structures. Finally, the possibility to run in situ spectroscopic measurements directly in the N-TiO2-loaded hydrogel during the photocatalytic process allowed kinetic studies of photocatalytic process to obtain information of the chemical and structural modifications of proteins over time and not only at the end of the photocatalysis. Therefore, the reported results highlight the possibility of using this system as biomimetic environment to investigate the photocatalysis of proteins in detail overcoming relevant technical aspects that typically limit the study of photocatalysis of biomolecules, opening up the possibility to extend the approach to more complex biomolecular systems.

Improvement of peroxymonosulfate utilization efficiency for sulfamethazine degradation by photo-electron activating peroxymonosulfate: Performance and mechanism

Enhancing the utilization efficiency of oxidant is of great importance for advanced oxidation processes (AOPs). Herein, nitrogen-doped titania dioxide/carbon (NTC7) catalyst was fabricated via pyrolyzing NH2-MIL-125 under nitrogen atmosphere at 700 °C. Excitation of NTC7 under visible light can successfully achieve efficient activation of peroxymonosulfate (PMS) (NTC7 + PMS + Vis). Degradation performance and PMS activation mechanism were systematically investigated using sulfamethazine (SMT) as the target pollutant. It was found that the photo-generated electrons excited from NTC7 under visible light played the dominant role in enhancing the productive consumption of PMS. Its utilization increased by 66 % (Δ[PMS]/Δ[SMT] = 7.0) in NTC7 + PMS + Vis process and the degradation rate was 2.14 times higher than that of NTC7 + PMS process. The ketonic CO groups and structural defects were responsible for the generation of 1O2 in dark activation while radicals (•OH, O2•–) were more inclined to be continuously produced in NTC7 + PMS + Vis process. The involved degradation pathways, intermediates, and toxicity assessment have been studied in detail. This work provides an effective approach to enhance the utilization efficiency of oxidant for pollutant degradation by AOPs.