Non-metallic Elements Research Articles

Deformation, Fracture and Microstructure of Metallic Materials

Metallic materials are mostly a combination of metallic elements, such as iron, aluminum, magnesium, titanium and manganese, which may also include small amounts of non-metallic elements, such as carbon, nitrogen and oxygen [...]

Air Quality Impacts on the Giant Panda Habitat in the Qinling Mountains: Chemical Characteristics and Sources of Elements in PM2.5

The wild giant panda habitat is inaccessible and far away from the main areas of human activity, so environmental pollutants entering the habitat are mainly the result of external migration and spread through the atmospheric advection and diffusion processes and particulate matter deposition. To research the variation, transmission route, chemical characteristics, and source of PM2.5 in the habitat of wild giant pandas, we set up a PM2.5 sampling point near the Shaanxi Foping National Nature Reserve (SFNNR), which is the area with the highest population density of wild giant pandas in the Qinling Mountains. The 12-month average concentration of PM2.5 was 11.3 ± 7.9 μg/m3 from July 2021 to June 2022, and the 12-month average concentration did not exceed the limit value set in the standard. In the results of our analysis of element concentrations, As and Pb were much lower than the limit standard. Si, S, P, and Cl accounted for 99.60% of nonmetallic elements, while the proportion of the six metallic elements, Na, Mg, Al, K, Ca, and Fe, was 96.27%. According to the analysis results of enrichment factor (EF) and pollutant emission sources, there were four sources for the total elements in PM2.5, which were mainly distributed in the areas around the reserve. These included dust, coal combustion, biomass burning, and traffic-related emissions, which contributed 55.10%, 24.78%, 11.91%, and 8.22% of the total element mass in PM2.5, respectively. Additionally, Pb, Cu, Zn, As, Sc, Co, Ga, Mg, and, especially, Se were severely affected by human activities (coal burning, biomass burning, and traffic-related emissions). In the villages and towns around the wild giant panda habitat, the majority of energy for cooking and heating comes from coal and biomass burning, and older vehicles with high emissions are used more frequently. Therefore, to better protect the health of and reduce the impact of environmental pollution on wild giant pandas, we put forward relevant recommendations, including upgrading the energy structure of towns and villages near the habitat to increase the proportion of clean energy, such as photovoltaic power generation, natural gas, etc.; decreasing the combustion of coal and biomass; encouraging the upgrading of agricultural diesel machines and older vehicles used in these areas; and setting limits on vehicle emissions in areas surrounding the habitat.

Insights into the Modification of Carbonous Felt as an Electrode for Vanadium Redox Flow Batteries.

The vanadium redox flow battery (VRFB) has been regarded as one of the best potential stationary electrochemical storage systems for its design flexibility, long cycle life, high efficiency, and high safety; it is usually utilized to resolve the fluctuations and intermittent nature of renewable energy sources. As one of the critical components of VRFBs to provide the reaction sites for redox couples, an ideal electrode should possess excellent chemical and electrochemical stability, conductivity, and a low price, as well as good reaction kinetics, hydrophilicity, and electrochemical activity, in order to satisfy the requirements for high-performance VRFBs. However, the most commonly used electrode material, a carbonous felt electrode, such as graphite felt (GF) or carbon felt (CF), suffers from relatively inferior kinetic reversibility and poor catalytic activity toward the V2+/V3+ and VO2+/VO2+ redox couples, limiting the operation of VRFBs at low current density. Therefore, modified carbon substrates have been extensively investigated to improve vanadium redox reactions. Here, we give a brief review of recent progress in the modification methods of carbonous felt electrodes, such as surface treatment, the deposition of low-cost metal oxides, the doping of nonmetal elements, and complexation with nanostructured carbon materials. Thus, we give new insights into the relationships between the structure and the electrochemical performance, and provide some perspectives for the future development of VRFBs. Through a comprehensive analysis, it is found that the increase in the surface area and active sites are two decisive factors that enhance the performance of carbonous felt electrodes. Based on the varied structural and electrochemical characterizations, the relationship between the surface nature and electrochemical activity, as well as the mechanism of the modified carbon felt electrodes, is also discussed.

Drinking water quality and inflammatory bowel disease: a prospective cohort study.

Environmental factors, such as drinking water and diets, play an important role in the development of inflammatory bowel disease (IBD). This study aimed to investigate the associations of metal elements and disinfectants in drinking water with the risk of inflammatory bowel disease (IBD) and to assess whether diet influences these associations. We conducted a prospective cohort study including 22,824 participants free from IBD from the Yinzhou cohort study in the 2016-2022 period with an average follow-up of 5.24years. The metal and disinfectant concentrations were measured in local pipeline terminal tap water samples. Cox regression models adjusted for multi-level covariates were used to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (95% CIs). During an average follow-up period of 5.24years, 46 cases of IBD were identified. For every 1 standard deviation (SD) increase in the concentration of manganese, mercury, selenium, sulfur tetraoxide (SO4), chlorine, and nitrate nitrogen (NO3_N) were associated with a higher risk of IBD with the HRs of 1.45 (95% CI: 1.14 to 1.84), 1.51 (95% CI: 1.24-1.82), 1.29 (95% CI: 1.03-1.61), 1.52 (95% CI: 1.26-1.83), 1.26 (95% CI: 1.18-1.34), and 1.66 (95% CI: 1.32-2.09), whereas zinc and fluorine were inversely associated with IBD with the HRs of 0.42 (95% CI: 0.24 to 0.73) and 0.68 (95% CI: 0.54-0.84), respectively. Stronger associations were observed in females, higher income groups, low education groups, former drinkers, and participants who never drink tea. Diets have a moderating effect on the associations of metal and nonmetal elements with the risk of IBD. We found significant associations between exposure to metals and disinfectants and IBD. Diets regulated the associations to some extent.

Basic Organic and Inorganic Chemistry of Boron Clusters and Its Application to Drug Discovery

In the past, drug discovery using low-molecular-weight compounds was dominated by structural design based on combinations of non-metallic elements such as carbon, nitrogen, oxygen, and halogens. Recent drug discovery efforts have shown extraordinary progress, an example of which is the adoption of non-universal elements. The approval of boron neutron capture therapy (BNCT) using a neutron accelerator in Japan ahead of other countries is still fresh in our memory. Other small-molecule drugs containing boron atoms have also been developed, and boron is becoming widely recognized as a constituent element for drug discovery. It is known that borane (BH3) is unstable because of its electron-deficient bonds; nevertheless, its stability has been improved by the formation of clusters through multimerization. Carborane (C2B10H12), one of the borane clusters, has an icosahedral structure with two carbon atoms and ten boron atoms and exhibits properties that vastly differ from conventional boron compounds. In this symposium review, we will introduce the basic chemistry of carboranes and their application to drug discovery. Boron is an essential element in plant cell wall formation and has extremely low toxicity to humans. I hope that this symposium review will be an opportunity for us to free ourselves from existing prejudices and constraints in drug discovery, and that new modalities that skillfully utilize the characteristics of boron and boron clusters will be developed one after another.

Physico-Chemical Studies on Crude Oil of Western Onshore

Abstract: Crude oil is a complex mixture of hydrocarbons with non-metallic elements such as sulphur, nitrogen, oxygen, and other elements. Hydrocarbons are chemicals that are mostly composed of the elements carbon and hydrogen. Crude oil comprises a variety of hydrocarbon molecules that fall into three categories: alkane, cycloalkane, and aromatic. Crude oil is distinguished by a number of chemical and physical features that play an essential role in the oil industry. These qualities are critical in making decisions in the exploration and production of crude oil. Characteristics like density, specific gravity, API gravity, water content, and sulphur content, to name a few, contribute value to the price of crude before it is transported to markets and refineries, so controlling these parameters significantly saves damage to infrastructure like pipelines and refineries. As a result, the study of physical and chemical properties becomes crucial for the petroleum industry. The current work deals with the investigation of physico-chemical characteristics of crude oil of Western onshore.

Photodegradation of hazardous organic pollutants using titanium oxides -based photocatalytic: A review

Titanium oxide-based photocatalysts (TOBPs) have been widely utilized as potential materials for numerous applications, such as wastewater treatment, water-splitting reactions, carbon dioxide (CO2) reduction and photosynthesis. However, the large bandgap of intrinsic TiO2 limits their absorption toward visible light, which is the central part of the solar spectrum, resulting in low photocatalytic activities under sunlight. To overcome this obstacle, several strategies, such as doping with either metal or non-metal elements or combining with other compounds, are efficient ways to reduce the bandgap of TiO2, leading to effectively extending their absorption toward the visible region and increasing their catalytic performance. In this review, we discussed the application of TOBPs for the photodegradation of hazardous organic pollutants in wastewater to produce quality reused water. The synthesis of TiO2 and the enhancement of photocatalytic activities of TOBPs by different techniques with detailed information were provided. Application of TOBPs for decomposing hazardous organic pollutants such as dyes, phenolic compounds and pharmaceuticals under optimum conditions have been listed. Also, the photodegradation mechanisms of hazardous organic compounds have been investigated. This work also brings ideas for future perspectives and research plan to inhibit the disadvantages and expand the application of TOBPs to remove toxic organic pollutants.

Features of wear of DLC-Si coating under microcontact conditions during the formation of secondary structures

Diamond-Like Carbon (DLC) coatings have high wear resistance, hardness, biocompatibility and chemical inertness. Secondary structures, which formed at the track in dry friction conditions, provide friction reduction. Doping DLC with both metallic and non-metallic elements leads to a rearrangement of the structure of graphite clusters, a change in their properties, and facilitates the formation of secondary structures. In the present, the silicon atoms were used to create the compositional structure of DLC surface layers at the level of the crystal lattice. DLC-Si coatings with the thickness of 2 µm were deposited on a (Cr, Al, Si)N layer with the thickness of 3 µm formed on a steel substrate. DLC-Si layer was deposited by plasma-enhanced chemical vapor deposition using acetylene and tetramethylsilane. Nanoindentation in the wear mode was used to study the nanomechanical properties of the surface. Atomic force microscopy was used to visualize the surface morphology and wear traces. In this study, secondary structures were created in a microfriction process using a NanoScratch mode. The surface structures after microfriction was observed by atomic force microscopy, and the specific surface energy was measured. The specific volumetric wear rate of the coatings after microfriction was estimated. During microtribological testing with double squares the specific volumetric wear rate of DLC coatings was 5.39·10-14 m3/N·m for 0.8 %Si and 12.39·10-14 m3/N·m for 10 % Si. When tested in the form of scratches, the specific volumetric wear rate for the coating was for the DLC-0.8 % Si (1.22 – 10.71)·10-14 m3/N·m and for the DLC-10 % (6.17 – 49.55) ·10-14 m3/N·m.

Investigated electronic and structural properties of non-metallic elements doped BP

In order to control the magnetic properties and electronic structures of black phosphorene (BP) monolayer, the structures, electronic and magnetic properties of non-metallic elements doped BP monolayer without or with defects including P vacancy (VP) have been studied by density functional theory (DFT). Defective BP appears ferromagnetic metallicity, and the magnetic moment is 0.086 μB. The magnetism mainly comes from the spin polarization of P atoms near the defect point. For non-metallic elements doped intrinsic BP, system doped with B and N shows P-type semiconductor. C-doped shows non-magnetic metal properties. O doped exhibits magnetic P-type semiconductor. Si and S doped shows ferromagnetic metal properties. The magnetism mainly comes from the spin polarization of P atoms near the defect point, and a small part comes from doped atoms. In the case of non-metallic elements doped defective BP, the results show that flaw-b-C and flaw-s-Si exhibit non- magnetic metallic properties. The flaw-b-S shows P-type semiconductor with indirect band gap of 0.712 eV. Other systems exhibit ferromagnetic metallicity, and the magnetism mainly comes from the spin polarization of P atoms near defect point. Non-metallic elements doped BP monolayer without or with point defects can effectively adjust magnetic properties and electronic structures.

In-situ composition development of Zn/In-doped Ga2O3 nanowire with ultrahigh responsivity and long-term stability for deep-UV photodetector

High-performance deep ultraviolet photodetectors (UV PDs) based on Ga2O3 have been applied widely in civil and military exploration. The incident photon-to-electron conversion efficiency of Ga2O3-based UV PDs could be improved by doping metal or non-metal elements in the lattice. Herein, multi-metallic oxide of InZn co-doped Ga2O3 (InZn-Ga2O3) nanowires is synthesized via the in-situ chemical vapor deposition (CVD) method. The favorable 25%InZn-Ga2O3 exhibits a maximum responsivity of 440.42 A W−1 and a peak external quantum efficiency (EQE) of 2.15 × 105% under 254 nm light illumination at 10 V, which are 1.19 × 104 times higher than that for pure Ga2O3, indicating its enhanced detection ability for deep-UV light and high conversion efficiency from photons to electrons. A high UV/visible rejection ratio of 7.3 × 105 is also obtained, implying a high sensitivity for UV light. Moreover, the responsivity of the InZn-Ga2O3 UV PD remains unchanged after a long period of 8000 s testing. The superior performances of InZn-Ga2O3 UV PD are attributed to the improved crystal quality with decreased oxygen vacancies and elevated conductivity, which facilitate the separation and transfer of photoinduced electron-hole carriers. The DFT calculation and UV–vis spectra results reveal that the InZn-Ga2O3 possesses a narrowed band gap with enhanced light absorption and a decreased work function for the fast escape of electrons. In addition, the ohmic contact between InZn-Ga2O3 and Ag electrode accelerates the transfer and diffusion of photogenerated electrons. The achievements in our work present a multi-metallic oxide nanowire with high performance and an innovative mechanism analysis method for the applications of optoelectronic devices.

Two Carbon Dioxide Molecules Consecutively Reduced by Metal-Free B2O2– Anions

Compared with transition metals, nonmetallic elements have always been considered to have low reactivity toward carbon dioxide. However, in recent years, main-group compounds such as boron-based species have gradually attracted increasing attention due to their prospective applications in different kinds of reactions. Herein, we report that metal-free anions B2O2- can promote two CO2 reductions, producing the oxygen-rich product B2O4-. In most of the reported CO2 reduction reactions mediated by transition-metal-containing clusters, transition metals usually provide electrons for the activation of CO2; one oxygen atom in CO2 is transferred to metal atoms, and CO is released from the metal atoms. In sharp contrast, B atoms are electron donors in the current systems and the formed CO is liberated directly from the activated CO2 unit. The synthesis of novel-metal-free gas-phase clusters and investigation of their reactivity toward carbon dioxide as well as reaction mechanisms can provide a fundamental basis in practice for the rational design of active sites on metal-free catalysts.

Selenium in Peptide Chemistry

In recent years, researchers have been exploring the potential of incorporating selenium into peptides, as this element possesses unique properties that can enhance the reactivity of these compounds. Selenium is a non-metallic element that has a similar electronic configuration to sulfur. However, due to its larger atomic size and lower electronegativity, it is more nucleophilic than sulfur. This property makes selenium more reactive toward electrophiles. One of the most significant differences between selenium and sulfur is the dissociation of the Se-H bond. The Se-H bond is more easily dissociated than the S-H bond, leading to higher acidity of selenocysteine (Sec) compared to cysteine (Cys). This difference in acidity can be exploited to selectively modify the reactivity of peptides containing Sec. Furthermore, Se-H bonds in selenium-containing peptides are more susceptible to oxidation than their sulfur analogs. This property can be used to selectively modify the peptides by introducing new functional groups, such as disulfide bonds, which are important for protein folding and stability. These unique properties of selenium-containing peptides have found numerous applications in the field of chemical biology. For instance, selenium-containing peptides have been used in native chemical ligation (NCL). In addition, the reactivity of Sec can be harnessed to create cyclic and stapled peptides. Other chemical modifications, such as oxidation, reduction, and photochemical reactions, have also been applied to selenium-containing peptides to create novel molecules with unique biological properties.

Indicators of restoration strategies in land uses: metallic and non-metallic elements

Land management practices can have an impact on the environmental quality of soil and contribute to identifying the source of its pollution. The objective of this study was to determine presence of metallic and non-metallic elements as indicators of land use impact (livestock management, restoration strategies and without management practices) in the Monte Caldera communal lands located in Cerro de San Pedro, San Luis Potosi, Mexico. Eighteen samples were collected at depths of 0-10 cm and 10-20 cm for each land use. Total concentrations of Zr, Sr, U, Th, Pb, As, Rb, Cr, V, Ti, Zn, and Cu were determined by X-ray fluorescence. Mean concentrations ranged in the following order: Ti>Zr>Rb>V>Sr>Zn>Cr>Pb> Cu>Th>U>As, with concentrations for Ti, Cr, Th, U and As exceeding technical reference values for phytotoxic soils. Significant differences were evidenced by ANOVA between land use (Th, Pb, Rb, Cu) and soil depth (U, Pb, and As). Land use practices associated with restoration resulted in a positive environmental impact. These findings underscore the need to conduct follow-up studies in the area and further examine the relationship of such practices with other environmental factors. Highlights: Soil management practices can affect the environmental quality of this resource and help diagnose the source of its contamination. It is necessary to evaluate the Impact of land use on livestock management, restoration strategies, and without management or conservation areas. By X-ray fluorescence technique the total concentration of Zr, Sr, U, Th, Pb, As, Rb, Cr, V, Ti, Zn, and Cu was determined. Ti, Cr, Th, U and As exceed the technical reference values for consideration as phytotoxic in soils. Land use associated with reclamation practices is an indicator of a positive influence on improving soil quality.

Development of surface modified titanium alloy as a promising photocatalyst for textile waste water treatment

TiO2 photocatalyst properties can be enhanced by doping with metals and non-metallic elements or coupling with another semiconductor forming a heterostructure photocatalyst, etc. Doped TiO2 can also be achieved by surface modification of commercially available titanium alloys by plasma electrolytic oxidation (PEO). Herein, Ti-6Al-2Sn-4Zr-6Mo, Ti-10V-2Fe-3Al and Ti-6Al-4V are PEO treated, and the photocatalytic ability of the material was studied. Further, the effect of alpha and beta stabilisers on the polymorphs of TiO2 (anatase and rutile) is investigated. Surface morphology, wettability and optical properties are analysed to determine the material’s photocatalytic ability. All titanium alloys possess a typical PEO porous structure, favouring the adsorption of dyes from the textile wastewater. The EDS and XPS analysis found that the alloying elements such as Fe, V and Mo in the titanium have limited participation in the oxidation reaction. In contrast, Al, Zr, and Sn actively participated in the PEO reaction and doped into the TiO2 lattice. The bandgap of the oxide coatings on Ti-6Al-2Sn-4Zr-6Mo, Ti-10V-2Fe-3Al and Ti-6Al-4 V alloys was found to be 2.92, 2.42 and 2.78 eV, respectively. The charge carrier’s recombination rate and separation efficiency of the PEO-treated Ti-6Al-4V and Ti-10V-2Fe-3Al are better than the PEO-treated pure Ti and Ti-6Al-2Sn-4Zr-6Mo. The PEO-treated Ti-6Al-4V alloy showed the highest MB degradation of 98% under visible light irradiation. The article successfully demonstrated PEO surface-modified commercial titanium alloys as a promising new immobilised photocatalyst for efficient textile wastewater degradation under visible light.

Properties and Analysis of Liquid Alternative Fuels II: Alcohols and Ethers

The importance of alternative fuels and their share in total energy consumption is constantly growing. The reason is, on the one hand, the saving of the gradually decreasing reserves of fossil fuels and also the effort to gradually reduce the emissions of carbon dioxide and other harmful substances. This article is another in a series of articles focused on an overview of the technical requirements and possibilities for testing alternative fuels. These articles aim to provide an overview of the required properties of individual alternative fuels, an overview of the prescribed analytical tests, and explain their relevance. This article focuses on liquid alternative fuels containing ethanol. Ethanol is currently the most widespread alternative oxygen fuel and, at the same time, also a biofuel. In pure form (E100), ethanol is used only exceptionally. Far more often, it is used as a bio-component of gasoline fuels. This article provides an overview of the technical requirements prescribed by legislation and relevant standards for ethanol for blending into gasoline fuels, and fuels containing ethanol. From ethanol-gasoline blends, E5, E10, and E85 are discussed. In addition, E95 fuel is discussed as well. The article also presents prescribed analytical tests for monitoring the quality of these fuels, or fuel components. Generally, in ethanol fuels or pure ethanol according to EN 15376, the composition is mostly analysed by GC. GC analysis determines the content of main and secondary oxygen components and/or the content of other impurities. In addition, the water content, total acidity, chloride and sulfate content, non-volatile impurities content, and the content of selected metallic and non-metallic elements, especially sulfur, are monitored in these matrices. For fuels intended for combustion in gasoline engines (E5, E10, and E85), important monitored parameters are also vapor pressure, oxidation stability, as well as density and corrosion on copper.

Selenium and thyroid diseases.

Selenium, a non-metallic element, is a micronutrient essential for the biosynthesis of selenoproteins containing selenocysteine. In adults, the thyroid contains the highest amount of selenium per gram of tissue. Most known selenoproteins, such as glutathione peroxidase, are expressed in the thyroid and are involved in thyroid hormone metabolism, redox state regulation, and maintenance of cellular homeostasis. Some clinical studies have shown that lack of selenium will increase the prevalence of several kinds of thyroid diseases. Selenium treatment in patients with Graves' orbitopathy has been shown to delay disease progression and improve the quality of life. Selenium supplementation in Hashimoto's thyroiditis was associated with the decreased levels of anti-thyroid peroxidase antibody and improved thyroid ultrasound structure. In thyroid cancer, various selenium supplements have shown variable anticancer activity. However, published results remain the conflicting and more clinical evidence is still needed to determine the clinical significance of selenium. This article reviews the strong association between selenium and thyroid disease and provides new ideas for the clinical management of selenium in thyroid disease.

Effect of B-Doping and Manifestation on TiO2-Supported IrO2 for Oxygen Evolution Reaction in Water Electrolysis.

To commercialize hydrogen production by proton exchange membrane (PEM) electrolysis, the amount of rare and precious metal (iridium) required for anodic oxygen evolution reaction (OER) must be greatly reduced. In order to solve the problem, carrier loading is used to reduce the amount of iridium. Unlike the carrier modified by conventional metal element doping, this work doped the carrier with the nonmetallic element and then prepared IrO2/TiBxO2 composite catalyst using the Adams melting method. B-doped TiO2 supports with different doping amounts show the main phase rutile structure. Among them, the conductivity of B-doped carrier shows an increasing trend with the increase of doping amount, because boron can form holes and negative centers after doping, and more carriers improve the conductivity of the support. In addition, since element B is manifested from inside to outside on the support, B can affect the catalytic process. After the manifestation of element B, the carrier loaded with IrO2 exhibited superior electrocatalytic properties. The voltammetric charge per unit mass of 40IrO2/TiB0.3O2#2 (where #2 represents B after manifestation) reaches 1970 mC (cm2 mg)-1, the corresponding overpotential is 273 mV at a current density of 10 mA/cm-2, and the Tafel slope is 61.9 mV/dec Also, the charge transfer resistance is only 15 Ω. Finally, in the stability test, the composite catalyst is also better than pure IrO2 in the 20 000 s operation. Therefore, element B has an unexpectedly positive effect on the catalytic progress on the surface of the support after its manifestation.

Preparation of FeNi-based nanoporous amorphous alloy films and their electrocatalytic oxygen evolution properties

The progress of this research is the preparation of FeNi alloy thin films by magnetron sputtering. Each step of the experimental process is based on the electrocatalytic performance of the sample, and characterized by many characterizations means such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray energy spectrometry (EDS) and step gauge thickness test for morphology, structure and elemental composition, etc. The analysis of the characterization results is used as a support for the experimental process. Adjustment of various preparation process parameters for material growth and subsequent processing include doping of non-metallic elements and construction of nanostructures. Doping of C elements can make FeNi based alloy films further amorphous. Zn element is used as a pore-forming agent. The two processes of doping and high-temperature vacuum dealloying can make the film obtain a nanoporous structure, which greatly increases the specific surface area. These two strategies reduce the overpotential (η10) of oxygen evolution reaction (OER) of FeNi alloy thin films to 393 mV and 314 mV, which are reduced by 47 mV and 79 mV step by step. The electrochemical properties of the finally obtained alloy film are: overpotential of 314 mV, Tafel slope of 61.8 mV/dec and the stability of only 10% decay at a current density of 10 mA/cm2 for 12 h. In this study, low-cost transition metals were used as the main materials to design OER catalysts, and the catalytic efficiency was comparable to that of commercial noble metal catalysts. The physical preparation methods made each sample have good reproducibility. It provides the experimental basis and theoretical basis for the design and synthesis of new catalytic materials at a higher level.

The Precision Defect Engineering with Nonmetallic Element Refilling Strategy in g-C3 N4 for Enhanced Photocatalytic Hydrogen Production.

Traditional defect engineering and doping strategies are considered effective means for improving H2 evolution, but the uncontrollability of the modification process does not always lead to efficient activity. A defect-induced heteroatom refilling strategy is used here to synthesize heteroatoms introduced carbon nitride by precisely controlling the "introduction" sites on efficient N1 sites. Density functional theory calculations show that the refilling of B, P, and S sites have stronger H2 O adsorption and dissociation capacity than traditional doping, which makes it an optimal H2 production path. The large internal electric field strength of heteroatom-refilled catalysts leads to fast electron transfer and the hydrogen production of the best sample is up to 20.9mmolg-1 h-1 . This work provides a reliable and clear insight into controlled defect engineering of photocatalysts and a universal modification strategy for typical heteroatom and co-catalyst systems for H2 production.

RGO doped S0.05N0.1/TiO2 accelerated visible light driven photocatalytic degradation of dimethyl sulfide and dimethyl disulfide

In this study, modification of TiO2 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/S0.05N0.1TiO2 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/S0.05N0.1TiO2. 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/S0.05N0.1TiO2. Furthermore, proposed reaction mechanism for each type of pollutant was assembled from byproducts analysis during the reaction.