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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Titanium dioxide materials were synthesized using two different methods. The samples were characterized by X-ray diffraction (XRD), UV–Visible diffusion reflectance spectroscopy (UV-Vis DR), Raman spectroscopy, N2 adsorption/desorption, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron spectroscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Although both kind of materials were found to have mesoporous structure and anatase crystalline phase, one of them was obtained from a synthesis method that does not involve the use of surfactants, and therefore, does not require calcination at high temperatures. This implies that the synthesized solid was self-doped with carbon species, coming only from the same source used for titanium. Then, the relationship between the presence of these species, the final calcination temperature, and the photocatalytic activity of the solids was studied in terms of the degradation and mineralization of an Acid Orange 7 aqueous solution, under visible radiation. A photosensitizing effect caused by the non-metal presence, that allows the solid to extend its absorption range, was found. Hence, a novel route to prepare C-modified photoactive mesoporous TiO2, simpler and cheaper, where neither a template nor an external carbon source is used, could be performed. [ABSTRACT FROM AUTHOR]

Cu nanoparticle‐connected ZIF‐8/reduced graphite oxide (RGO) composite was successfully prepared through a facile hydrothermal reaction using sulfate in this paper. The crossover mechanism of metal nanoparticles loading and RGO decoration to enhance the photocatalytic efficiency of pristine ZIF‐8 was studied. The results showed that the prepared Cu‐S@ZIF‐8/RGO has a strong ability to take advantage of sunlight, indicating an appreciable application prospect. RGO can act as a base to support the whole structure and serve as an electron sink to accept photoexcited electrons, realizing the formation of reactive oxygen species (ROS) and inhibition of electron–hole pair recombination. Cu nanoparticles act as connectors between ZIF‐8 and RGO to transfer electrons and realize the formation of partial ROS on its surface. The doped sulfate radical can promote to extend the utilization of the wavelength range by generating surface states. Cu‐S@ZIF‐8/RGO showed the best photocatalytic activity in simulated sunlight for eliminating rhodamine B and 4‐chlorophenol among all the prepared samples, the structure kept intact even in the presence of different kinds of anions. The crossover study of metal loading and RGO decoration can develop a new way for only UV‐responsive metal–organic frameworks to remove organic contaminants under sunlight irradiation. [ABSTRACT FROM AUTHOR]