Photocatalytic degradation of 2,4-dichlorophenoxyacetic acid by electrospun TiO2 nanofibres synthesised from two different titanium molecular precursors

The evaluation of the photocatalytic properties of electrospun TiO2 nanofibres (TiO2-NFs) synthesised in the same experimental conditions using two distinct precursors, tetraisopropyl orthotitanate (TTIP) and tetrabutyl orthotitanate (TNBT), with morphology and crystalline structure controlled by annealing at 460 °C for 3 h is presented. The presence of circular-shaped TiO2-NFs was corroborated by scanning electron microscopy (SEM). By using X-ray photoelectron spectroscopy (XPS), the chemical binding energies and their interactions of the TiO2 with the different incorporated impurities were determined; the most intense photoelectronic transitions of Ti 2p3/2 (458.39 eV), O 1 s (529.65 eV) and C 1 s (284.51 eV) were detected for TTIP and slightly blue-shifted for TNBT. By using energy-dispersive X-ray spectroscopy (EDS), the chemical element percentages in TiO2 were determined. Using X-ray diffraction, it was found that the annealed electrospun TiO2-NFs presented the anatase crystalline phase and confirmed by Raman scattering. Bandgap energies were determined by diffuse reflectance spectroscopy at room temperature. The photocatalytic degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide under exposure to ultraviolet light was studied using the TiO2-NFs obtained with the two molecular precursors. The results showed that the catalyst, prepared with the TTIP precursor, turned out to be the one that presented the highest photocatalytic activity with a half-life time (t1/2) of 28 min and a degradation percentage of 93%. The total organic carbon (TOC) in the solutions resulting from the 2,4-D degradation by the TiO2-NFs was measured, which showed a TOC removal of 50.67% for the TTIP sample and 36.14% for the TNBT sample. Finally, by using FTIR spectroscopy, the final chemical compounds of the degradation were identified as H2O and CO2.

Recent Progress of Ion-Modified TiO2 for Enhanced Photocatalytic Hydrogen Production

Harnessing solar energy to produce hydrogen through semiconductor-mediated photocatalytic water splitting is a promising avenue to address the challenges of energy scarcity and environmental degradation. Ever since Fujishima and Honda's groundbreaking work in photocatalytic water splitting, titanium dioxide (TiO2) has garnered significant interest as a semiconductor photocatalyst, prized for its non-toxicity, affordability, superior photocatalytic activity, and robust chemical stability. Nonetheless, the efficacy of solar energy conversion is hampered by TiO2's wide bandgap and the swift recombination of photogenerated carriers. In pursuit of enhancing TiO2's photocatalytic prowess, a panoply of modification techniques has been explored over recent years. This work provides an extensive review of the strategies employed to augment TiO2's performance in photocatalytic hydrogen production, with a special emphasis on foreign dopant incorporation. Firstly, we delve into metal doping as a key tactic to boost TiO2's capacity for efficient hydrogen generation via water splitting. We elaborate on the premise that metal doping introduces discrete energy states within TiO2's bandgap, thereby elevating its visible light photocatalytic activity. Following that, we evaluate the role of metal nanoparticles in modifying TiO2, hailed as one of the most effective strategies. Metal nanoparticles, serving as both photosensitizers and co-catalysts, display a pronounced affinity for visible light absorption and enhance the segregation and conveyance of photogenerated charge carriers, leading to remarkable photocatalytic outcomes. Furthermore, we consolidate perspectives on the nonmetal doping of TiO2, which tailors the material to harness visible light more efficiently and bolsters the separation and transfer of photogenerated carriers. The incorporation of various anions is summarized for their potential to propel TiO2's photocatalytic capabilities. This review aspires to compile contemporary insights on ion-doped TiO2, propelling the efficacy of photocatalytic hydrogen evolution and anticipating forthcoming advancements. Our work aims to furnish an informative scaffold for crafting advanced TiO2-based photocatalysts tailored for water-splitting applications.

Enhanced visible-light photocatalytic oxidative desulfurization of model fuel over Pt-decorated carbon-doped TiO2 nanoparticles

Modification of photocatalysts to improve their adsorption and photocatalytic activity in the oxidative desulfurization of liquid fuels has been reported by many investigators. In this study, Pt-decorated carbon-doped TiO2 nanoparticles were synthesized by hydrothermal and photo-deposition techniques and were subsequently used in photocatalytic oxidative desulfurization of dibenzothiophene (DBT) in n-heptane as a simulated liquid fuel with methanol as the extracting solvent. Carbon-doped TiO2 was first synthesized by a simple self-doping method. Pt was then loaded by a photo-deposition technique. The synthesized photocatalysts (labeled as YPt-CT where Y is percent Pt loading) were characterized by of X-ray diffraction (XRD), photoluminescence (PL), field emission scanning electron microscopy (FESEM), N2-physisorption, UV-Vis diffusive reflectance spectra (UV-Vis DRS), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), and nitrogen sorption measurements. The removal efficiency of DBT was 98% in the presence of 2 g/l of 0.5Pt-CT catalyst under visible-light irradiation (λ > 400 nm), ambient pressure, and reaction temperature of 40°C.

Titanium dioxide incorporated in cellulose nanofibers with enhanced UV blocking performance by eliminating ROS generation

The preparation of sunblocks with dispersion stability, ultraviolet blocking, and photocompatibility remains a considerable challenge. Plant-derived natural polymers, such as cellulose nanofibers (CNF), show versatile traits, including long aspect ratio, hydrophilic nature, resource abundance, and low material cost. In the present study, a facile and cost-effective strategy is reported for the fabrication of nanostructured inorganic materials by incorporating natural polymers as interspersed, systematically nanosized titanium dioxide (TiO2) particles onto CNF. Among all experiments, the optimized TiO2@CNF3 showed higher ultraviolet blocking performance and less whitening effect. The outstanding performance is attributed to the engineering of equally dispersed nano-sized TiO2 particles on the CNF surface and stable dispersion. Significantly, TiO2@CNF3 exhibited excellent compatibility with avobenzone (80%), an oil-soluble ingredient used in sunblock products, illustrating the photoprotection enhancement under ultraviolet A (UVA) and ultraviolet B (UVB). Moreover, only 14.8% rhodamine B (Rho-B) dye degraded through photocatalytic oxidation process with the TiO2@CNF3, which is negligible photocatalytic activity compared to that of TiO2 (95% dye degraded). Furthermore, commercial inorganic and organic sunblock products with SPF lifetimes of 35+ and 50+ were modified using CNF, significantly enhancing the transmittance performance compared to that of the pure sunblock. However, it was also observed that hydrophilic CNF tended to demulsify the creams due to electrostatic disequilibrium. This CNF-based modified TiO2 system is a new window to replace effective sunblock products in high-value-added applications, such as cosmetics.

A Convenient and Stable Heterogeneous Nickel Catalyst for Hydrodehalogenation of Aryl Halides Using Molecular Hydrogen

Hydrodehalogenation is an effective strategy for transforming persistent and potentially toxic organohalides into their more benign congeners. Common methods utilize Pd/C or Raney-nickel as catalysts, which are either expensive or have safety concerns. In this study, a nickel-based catalyst supported on titania (Ni-phen@TiO2 -800) is used as a safe alternative to pyrophoric Raney-nickel. The catalyst is prepared in a straightforward fashion by deposition of nickel(II)/1,10-phenanthroline on titania, followed by pyrolysis. The catalytic material, which was characterized by SEM, TEM, XRD, and XPS, consists of nickel nanoparticles covered with N-doped carbon layers. By using design of experiments (DoE), this nanostructured catalyst is found to be proficient for the facile and selective hydrodehalogenation of a diverse range of substrates bearing C-I, C-Br, or C-Cl bonds (>30 examples). The practicality of this catalyst system is demonstrated by the dehalogenation of environmentally hazardous and polyhalogenated substrates atrazine, tetrabromobisphenol A, tetrachlorobenzene, and a polybrominated diphenyl ether (PBDE).

Preparation of C/Ho co-doped TiO2 for enhancing the photocatalytic degradation efficiency of tetracycline hydrochloride

A new C/Ho co-doped TiO2 catalyst was synthesized with Ti3C2Tx MXene and the photocatalytic performance was found to be significantly enhanced.

In Situ One-Pot Synthesis of C-Decorated and Cl-Doped Sea-Urchin-like Rutile Titanium Dioxide with Highly Efficient Visible-Light Photocatalytic Activity

Titanium dioxide (TiO₂) that offers high light-harvesting capacity and efficient charge separation holds great promise in photocatalysis. In this work, an in situ one-pot hydrothermal synthesis was explored to prepare a C-decorated and Cl-doped sea-urchin-like rutile TiO₂ (Cl-TiO₂/C). The growth of sea-urchin-like 3D hierarchical nanostructures was governed by a mechanism of nucleation and nuclei growth-dissolution-recrystallization growth from time-dependent morphology evolution. The crystal morphology and the content of Cl and C could be controlled by the volume ratio of HCl to TBOT. Systematic studies indicated that the 0.4Cl-TiO₂/C sample (the volume ratio of HCl to TBOT was 0.4) exhibited the highest visible-light photocatalytic activity for the degradation of rhodamine B, with kinetic rate constant (k) of 0.0221 min^-1, being 6.5 and 3.75 times higher than that of TiO₂ and Cl-TiO₂. The enhanced photocatalytic performance could be attributed to the high charge separation and transfer efficiency induced by Cl-doping and C decoration and the excellent light-harvesting capacity caused by its sea-urchin-like nanostructure. Moreover, the 0.4Cl-TiO₂/C sample exhibited good reusability and excellent structural stability for five cycles. This facile one-pot approach provides new insight for the preparation of a TiO₂-based photocatalyst with excellent photocatalytic performance for potential application in practical wastewater treatment.

Effect of Process Parameters on the Microstructure and Performance of TiO2-Loaded Activated Carbon

In this study, the visible-light-driven photocatalytic regeneration performance of TiO2-loaded activated carbon (TiO2/AC) was effectively improved. By carefully controlling the activation condition at 700 °C for 2 h with a 60% H3PO4 concentration and 3:1 TBT (tetrabutyl titanate) impregnation ratio, 90.5% of methylene blue (50 mg/L) was removed within 2 h by a low-dose TiO2/AC (0.5 g/L), which was much higher than those obtained in previous studies on TiO2/AC. Moreover, the effects of process variables on the microstructure and performance of TiO2/AC were systematically investigated. The results showed that (1) the long period of activation time effectively inhibited the photogenerated charge carrier recombination and enhanced the regeneration performance of samples; (2) the photogenerated charge carrier recombination rate was lowered initially and then increased as the temperature ascended, whereas the pore volume showed an opposite variation tendency, and thus the adsorption and regeneration performances of samples were improved at 500-700 °C and then weakened at 800 °C; (3) the increase of H3PO4 concentration effectively inhibited the charge carrier recombination and had an improvement in the adsorption and regeneration performances of samples; and (4) the photogenerated charge carrier recombination rate and bandgap value of samples decreased initially and then increased with increasing TBT mass ratio, so the regeneration performances of samples were improved initially and then lowered.

Electro-enhanced chlorine-mediated ammonium nitrogen removal triggered by an optimized catalytic anode for sustainable saline wastewater treatment

Electrochemical technology has unique superiorities in chlorine-mediated pollutant oxidation, but has limited application in saline wastewater treatment due to inadequate efficiency and high energy consumption. To promote electrochemical oxidation capacity, a novel but low-cost electrode containing TiO₂/Co-WO₃/SiC was prepared and optimized, achieving highly efficient chlorine-mediated ammonium nitrogen oxidation (98.3 ± 2.2% in 120 min, with initial NH₄⁺-N of 10.2 ± 0.5 mg L^-1) in a simple electrochemical system with supplied current density only at 1.00 mA cm^-2. Comparing with unmodified carbon fiber cloth, the catalytic anode achieved 96.0% nitrogen selectivity, enhanced the system current efficiency by 20.6% and reduced the energy consumption by 54.4%, making the treatment of simulated mariculture wastewater both energy-saving (36.5 ± 2.8 kWh kg^-1 NH₄⁺-N) and cost-effective (1.45 US$ m^-3), comparing with previously reported electrochemical processes (54-622 kWh kg^-1 NH₄⁺-N). The nitrogen content (<1 mg L^-1) in the treated wastewater, containing only 0.18 mg L^-1 NH₄⁺-N, meets the discharge standard of mariculture wastewater. The promoted electrochemical oxidation should be attributed to the chloride derived species (HOCl and ClO^-) and related active species (Cl, ClO, OH, etc.). This easily prepared and reusable catalytic electrode is a promising alternative to conventional anode materials in sustainable electrochemical treatment of saline wastewater.

Rational construction of Ni(OH)2 nanoparticles on covalent triazine-based framework for artificial CO2 reduction

Artificial photoreduction of CO₂ to chemical fuel is an intriguing and reliable strategy to tackle the issues of energy crisis and climate change simultaneously. In the present study, we rationally constructed a Ni(OH)₂-modified covalent triazine-based framework (CTF-1) composites to serve as cocatalyst ensemble for superior photoreduction of CO₂. In particular, the optimal Ni(OH)₂-CTF-1 composites (loading ratio at 0.5 wt%) exhibited superior photocatalytic activity, which surpassed the bare CTF-1 by 33 times when irradiated by visible light. The mechanism for the enhancement was systematically investigated based on various instrumental analyses. The origin of the superior activity was attributable to the enhanced CO₂ capture, more robust visible-light response, and improved charge carrier separation/transfer. This study offers an innovative pathway for the fabrication of noble-metal-free cocatalysts on CTF semiconductors and deepens the understanding of photocatalytic CO₂ reduction.

Metal-organic frameworks derived C/TiO2 for visible light photocatalysis: Simple synthesis and contribution of carbon species

A series of in-situ carbon-doped TiO₂ (C_x/TiO₂) composites with a porous and crystalline structure were successfully synthesized via one-step and low-temperature calcination of titanium metal-organic framework (MOF), MIL-125(Ti). The resultant materials were comprehensively investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), N₂ adsorption-desorption measurements, UV-vis diffuse reflectance spectrum (DRS), photoluminescence (PL) spectra and photoelectrochemical measurements, and their photocatalytic activities for bisphenol A (BPA) degradation were assessed. Compared with the benchmark TiO₂ photocatalyst (P25), the C_x/TiO₂ composite material with high specific surface, lower band gap, and reduced photogenerated electron hole ratio exhibited outstanding photodegradation activity and durability for BPA, which could be attributed to the combined effect of co-doping of multiple carbon species (substituent carbon and carbonate) and porous structure. During BPA degradation, the holes and superoxide radicals were the primary role oxidative species in the reaction process. Therefore, this new efficient photocatalyst is promising candidate for photodegradation of organic pollutants.

Recent Advances in Synthesis and Applications of Carbon-Doped TiO2 Nanomaterials

TiO2 has been widely used as a photocatalyst and an electrode material toward the photodegradation of organic pollutants and electrochemical applications, respectively. However, the properties of TiO2 are not enough up to meet practical needs because of its intrinsic disadvantages such as a wide bandgap and low conductivity. Incorporation of carbon into the TiO2 lattice is a promising tool to overcome these limitations because carbon has metal-like conductivity, high separation efficiency of photogenerated electron/hole pairs, and strong visible-light absorption. This review would describe and discuss a variety of strategies to develop carbon-doped TiO2 with enhanced photoelectrochemical performances in environmental, energy, and catalytic fields. Emphasis is given to highlight current techniques and recent progress in C-doped TiO2-based materials. Meanwhile, how to tackle the challenges we are currently facing is also discussed. This understanding will allow the process to continue to evolve and provide facile and feasible techniques for the design and development of carbon-doped TiO2 materials.

Photocatalytic hydrogen evolution by co-catalyst-free TiO2/C bulk heterostructures synthesized under mild conditions

Hydrogen production by photocatalytic water splitting is one of the most promising sustainable routes to store solar energy in the form of chemical bonds. To obtain significant H2 evolution rates (HERs) a variety of defective TiO2 catalysts were synthesized by means of procedures generally requiring highly energy-consuming treatments, e.g. hydrogenation. Even if a complete understanding of the relationship between defects, electronic structure and catalytic active sites is far from being achieved, the band gap narrowing and Ti3+-self-doping have been considered essential to date. In most reports a metal co-catalyst (commonly Pt) and a sacrificial electron donor (such as methanol) are used to improve HERs. Here we report the synthesis of TiO2/C bulk heterostructures, obtained from a hybrid TiO2-based gel by simple heat treatments at 400 °C under different atmospheres. The electronic structure and properties of the grey or black gel-derived powders are deeply inspected by a combination of classical and less conventional techniques, in order to identify the origin of their photoresponsivity. The defective sites of these heterostructures, namely oxygen vacancies, graphitic carbon and unpaired electrons localized on the C matrix, result in a remarkable visible light activity in spite of the lack of band gap narrowing or Ti3+-self doping. The materials provide HER values ranging from about 0.15 to 0.40 mmol h-1 gcat -1, under both UV- and visible-light irradiation, employing glycerol as sacrificial agent and without any co-catalyst.

Synthesizing C–N–P-tridoped TiO2 in a Salix psammophila-activated carbon body to enhance its regeneration performance

Loading TiO₂ into an AC body via Salix psammophila pores. C, N, and P atoms were spontaneously doped into TiO₂ lattices. MB removal ratio decreased by 11% after three trials. The synergistic effect of adsorption and photodegradation was enhanced.

Facile synthesis of oxygen-deficient nano-TiO2 coordinated by acetate ligands for enhanced visible-light photocatalytic performance

Surface oxygen vacancy defects and acetate ligands can synergistically enhance the visible-light photocatalytic activity of nano-TiO₂ for phenol degradation.

Enhanced degradation of ciprofloxacin by graphitized mesoporous carbon (GMC)-TiO2 nanocomposite: Strong synergy of adsorption-photocatalysis and antibiotics degradation mechanism

In order to achieve remarkable synergy between adsorption and photocatalysis for antibiotics elimination from water, in this study, a graphitized mesoporous carbon (GMC)-TiO₂ nanocomposite was successfully synthesized by an extended resorcinol-formaldehyde (R-F) method. In the composite, the lamellar GMC nanosheets possessed large specific surface area and mesoporous structure, and could adsorb and enrich antibiotics effectively. This could not only reduce the antibiotic concentration in water shortly, but also greatly increase the chances for antibiotics to contact with and be degraded by photocatalysts and active species. Interestingly, GMC could also facilitate the transportation of photogenerated electrons to further improve the photocatalytic efficiency of TiO₂, and 15 mg/L ciprofloxacin (CIP) could be totally mineralized in 1.5 h. Meanwhile, the biological inhibition of reaction solution on luminescence bacteria decreased obviously with antibiotics degradation until non-toxicity, reinforcing the thorough elimination of antibiotics. Besides, from the viewpoint of organic chemistry, several plausible CIP degradation pathways were established using HPLC-MS technique, and an interesting intermediate with five-membered ring structure was firstly proposed, which is helpful to deeply understand CIP degradation. Strong synergy between adsorption and photocatalysis, along with quick and efficient antibiotics elimination, double confirm the great potential of GMC-TiO₂ nanocomposite for practical antibiotic wastewater purification.

Growth of SnO2 Nanoflowers on N-doped Carbon Nanofibers as Anode for Li- and Na-ion Batteries

It is urgent to solve the problems of the dramatic volume expansion and pulverization of SnO₂ anodes during cycling process in battery systems. To address this issue, we design a hybrid structure of N-doped carbon fibers@SnO₂ nanoflowers (NC@SnO₂) to overcome it in this work. The hybrid NC@SnO₂ is synthesized through the hydrothermal growth of SnO₂ nanoflowers on the surface of N-doped carbon fibers obtained by electrospinning. The NC is introduced not only to provide a support framework in guiding the growth of the SnO₂ nanoflowers and prevent the flower-like structures from agglomeration, but also serve as a conductive network to accelerate electronic transmission along one-dimensional structure effectively. When the hybrid NC@SnO₂ was served as anode, it exhibits a high discharge capacity of 750 mAh g^-1 at 1 A g^-1 after 100 cycles in Li-ion battery and 270 mAh g^-1 at 100 mA g^-1 for 100 cycles in Na-ion battery, respectively.

Wheat bran valorisation: Towards photocatalytic nanomaterials for benzyl alcohol photo-oxidation

In this work, we have successfully synthesized a set of titania photocatalytic nanocomposites by the incorporation of different TiO₂ content on wheat bran residues. The obtained catalysts were characterized by different techniques including UV-Vis spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Transmission Electron Microscopy (TEM) while their photocatalytic activity was investigated in the oxidation of benzyl alcohol under UV light irradiation. Benzaldehyde yields were ca. 20%, with conversion in the systems of ca. 33% of benzyl alcohol by using 10%Ti-Bran catalyst, as compared to 33% yield to the target product (quantitative conversion of benzyl alcohol) using commercial pure TiO₂ (P-25). The photocatalytic activity results indicate that designed waste-derived nanomaterials with low TiO₂ content can efficiently photocatalyze the conversion of benzyl alcohol with relative high selectivity towards benzaldehyde.

Surface Modification of Perfect and Hydroxylated TiO2 Rutile (110) and Anatase (101) with Chromium Oxide Nanoclusters

We use first-principles density functional theory calculations to analyze the effect of chromia nanocluster modification on TiO₂ rutile (110) and anatase (101) surfaces, in which both dry/perfect and wet/hydroxylated TiO₂ surfaces are considered. We show that the adsorption of chromia nanoclusters on both surfaces is favorable and results in a reduction of the energy gap due to a valence band upshift. A simple model of the photoexcited state confirms this red shift and shows that photoexcited electrons and holes will localize on the chromia nanocluster. The oxidation states of the cations show that Ti³⁺, Cr⁴⁺, and Cr²⁺ (with no Cr⁶⁺) can be present. To probe potential reactivity, the energy of oxygen vacancy formation is shown to be significantly reduced compared to that of pure TiO₂ and chromia. Finally, we show that inclusion of water on the TiO₂ surface, to begin inclusion of environment effects, has no notable effect on the energy gap or oxygen vacancy formation. These results help us to understand earlier experimental work on chromia-modified anatase TiO₂ and demonstrate that chromia-modified TiO₂ presents an interesting composite system for photocatalysis.

Interfacial charge transfer in functionalized multi-walled carbon nanotube@TiO2 nanofibres

A new insight into photoinduced charge transfer processes across carbon nanotube@TiO₂ interfaces has been gained based on experimental details from transient absorption spectroscopy. We show that photoinduced, interfacial hole transfer to carboxylic acid-functionalized multiwalled carbon nanotubes (oxMWCNTs) from TiO₂ results in hole-doped oxMWCNTs and reduced TiO₂. The latter is inferred from femto- and nanosecond transient absorption spectroscopy performed with oxMWCNT@TiO₂ dispersions and complemented with investigations using methyl viologen and N,N,N',N'-tetramethyl-p-phenylenediamine as an electron scavenger and a hole scavenger, respectively. The results of ultraviolet photoemission spectroscopy (UPS) of the compounds corroborate the findings, highlighting the strong coupling between oxMWCNTs and TiO₂ in these hybrids.

Rapid Screening of Graphitic Carbon Nitrides for Photocatalytic Cofactor Regeneration Using a Drop Reactor

Artificial photosynthesis is the imitation of natural photosynthesis, which promises an efficient way to use solar energy to synthesize organic matters, in which the key step is the coenzyme regeneration (NADH/NADPH). To achieve an efficient regeneration rate, various photocatalysts have been developed, such as g-C₃N₄ and mesoporous carbon nitride (mpg-C₃N₄). Generally, efficiency determination of different photocatalysts requires laborious experiments, high consumption of reagents, and a considerable amount of time. Here, based on the one-step artificial photosystem I method, we processed the analytical experiment in a very simple PDMS well (20 μL, a drop) to achieve a rapid screening of photocatalysts. For comparison, we used two types of graphitic carbon nitrides, few-layer g-C₃N₄ and mpg-C₃N₄. Compared with the slurry systems, firstly, the regeneration rate of mpg-C₃N₄ drop-reactor system is 4.3 times and 7.1 times those of the few-layer g-C₃N₄-slurry system and mpg-C₃N₄-slurry system, respectively. Secondly, this one-drop method reduces the typical verification time from 90 min to 5 min and lowers the liquid volume from 20 mL to 20 μL. Thirdly, this operation is a pump-free and soft lithography technique-free process. The miniaturization of the photocatalytic reaction in the PDMS well improves the regeneration rates, saves samples, and achieves high-throughput screening of multiple photocatalysts.

Photocatalytic degradation of clofibric acid by g-C3N4/P25 composites under simulated sunlight irradiation: The significant effects of reactive species

Pharmaceutically emerging micropollutants have become an environmental concern in recent years. In the present paper, the reactive species (RSs)-induced degradation mechanism of clofibric acid (CA) was investigated using a newly sunlight-driven g-C₃N₄/P25 photocatalyst. A very low g-C₃N₄ content of 8.0 weight percent resulted in a 3.36 and a 2.29 times faster reaction rate for CA photodegradation than for pristine g-C₃N₄ and P25, respectively. Electron spin resonance and quenching experiments demonstrated the participation of HO, h⁺, e^-, ¹O₂ and O₂^·- in the photocatalytic system, and the contribution rates were calculated to 73.3%, 15.3%, 5.1%, 6.7% and 33.1%, respectively. According to the pulse radiolysis measurements and the competitive kinetics approaches, the bimolecular reaction rate constants for HO, e^-, and ¹O₂ with CA were (8.47 ± 0.33) × 10⁹ M^-1s^-1, (6.41 ± 0.48) × 10⁹ M^-1s^-1 and (6.6 ± 0.37) × 10⁶ M^-1s^-1, respectively. RSs were found to significantly influence the degradation of CA, and the degradation pathways occurred primarily via e^- reduction, HO addition and ¹O₂ attack reactions on the basis of mass spectrometry and theoretical calculations.

Synthesis of a hierarchical structured NiO/NiS composite catalyst for reduction of 4-nitrophenol and organic dyes

The synthesis approach of the catalyst is simple and facile. The NiO/NiS catalyst is effective and universal towards reduction. NiS facilitates electron transfer for reduction reactions.

Microfluidic Immuno-Biochip for Detection of Breast Cancer Biomarkers Using Hierarchical Composite of Porous Graphene and Titanium Dioxide Nanofibers

We report on a label-free microfluidic immunosensor with femtomolar sensitivity and high selectivity for early detection of epidermal growth factor receptor 2 (EGFR2 or ErbB2) proteins. This sensor utilizes a uniquely structured immunoelectrode made of porous hierarchical graphene foam (GF) modified with electrospun carbon-doped titanium dioxide nanofibers (nTiO2) as an electrochemical working electrode. Due to excellent biocompatibility, intrinsic surface defects, high reaction kinetics, and good stability for proteins, anatase nTiO2 are ideal for electrochemical sensor applications. The three-dimensional and porous features of GF allow nTiO2 to penetrate and attach to the surface of the GF by physical adsorption. Combining GF with functional nTiO2 yields high charge transfer resistance, large surface area, and porous access to the sensing surface by the analyte, resulting in new possibilities for the development of electrochemical immunosensors. Here, the enabling of EDC-NHS chemistry covalently immobilized the antibody of ErbB2 (anti-ErbB2) on the GF-nTiO2 composite. To obtain a compact sensor architecture, the composite working electrode was designed to hang above the gold counter electrode in a microfluidic channel. The sensor underwent differential pulse voltammetry and electrochemical impedance spectroscopy to quantify breast cancer biomarkers. The two methods had high sensitivities of 0.585 μA μM(-1) cm(-2) and 43.7 kΩ μM(-1) cm(-2) in a wide concentration range of target ErbB2 antigen from 1 × 10(-15) M (1.0 fM) to 0.1 × 10(-6) M (0.1 μM) and from 1 × 10(-13) M (0.1 pM) to 0.1 × 10(-6) M (0.1 μM), respectively. Utilization of the specific recognition element, i.e., anti-ErbB2, results in high specificity, even in the presence of identical members of the EGFR family of receptor tyrosine kinases, such as ErbB3 and ErbB4. Many promising applications in the field of electrochemical detection of chemical and biological species will derive from the integration of the porous GF-nTiO2 composite into microfluidic devices.

Microfluidic chip-based one-step fabrication of an artificial photosystem I for photocatalytic cofactor regeneration

We report a one-step strategy for the formation of an artificial photosystem I, with an enhanced coenzyme regeneration rate.

Kinetics stabilized doping: computational optimization of carbon-doped anatase TiO2 for visible-light driven water splitting

Carbon dimers exhibiting strong C–C binding could be ideal kinetics-stabilized dopants enhancing the visible-light activity of TiO₂ for photocatalysis.