Photocatalytic degradation of dye and phenolic compounds as textile effluent using UV- TiO2 photocatalysis based on color removal.
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•TiO2 is used as a semiconductor photocatalyst in ...presence of UV light.•TiO2 photocatalytic advanced oxidation process is executed by five steps.•Metal and non-metal co-doping on TiO2 can increase photocatlytic performance.•UV- doped TiO2 photocatalysis is able to mineralize toxic dyes and phenolic compounds.
Treatment of textile wastewater using titanium dioxide (TiO2) photocatalysis has been started from the last decade and reached attention to the researchers because of its versatile application. The variety of applications of TiO2 as a photocatalyst has been taken place because of low operating temperature, biologically inert nature, low energy consumption, water insolubility, ease availability and photoactivity, less toxicity, high chemical stability, suitable flat band potential, narrow band gap and environmentally benign. The successful and efficient application of photocatalysis depends on quality of photocatalyst, nature of pollutants, and source of light, which should be in close contact with each other. The TiO2 photocatalyst is used for the effluent treatment of textile wastewater in the presence of ultraviolet (UV) irradiation. Heterogeneous UV-TiO2 photocatalysis is capable to remove organic pollutants from textile wastewater, which has been widely studied and the technology also being commercialized in many developing countries in the world. This review focuses on the mechanism of UV-TiO2 photocatalysis, modification of TiO2 photocatalyst, and application of doping and co-doping in order to improve the photocatalytic activity in wastewater treatment. In addition, the review conveys comprehensive and fundamental assessments of the photocatalytic activity for the removal of organic dyes and phenolic compounds from textile wastewater.
Abstract
A new facile route to fabricate N‐doped graphene‐SnO
2
sandwich papers is developed. The 7,7,8,8‐tetracyanoquinodimethane anion (TCNQ
−
) plays a key role for the formation of such ...structures as it acts as both the nitrogen source and complexing agent. If used in lithium‐ion batteries (LIBs), the material exhibits a large capacity, high rate capability, and excellent cycling stability. The superior electrochemical performance of this novel material is the result from its unique features: excellent electronic conductivity related to the sandwich structure, short transportation length for both lithium ions and electrons, and elastomeric space to accommodate volume changes upon Li insertion/extraction.
Hydrogen (H2) production from direct seawater electrolysis is an economically appealing yet fundamentally and technically challenging approach to harvest clean energy. The current seawater ...electrolysis technology is significantly hindered by the poor stability and low selectivity of the oxygen evolution reaction (OER) due to the competition with chlorine evolution reaction in practical application. Herein, iron and phosphor dual‐doped nickel selenide nanoporous films (Fe,P‐NiSe2 NFs) are rationally designed as bifunctional catalysts for high‐efficiency direct seawater electrolysis. The doping of Fe cation increases the selectivity and Faraday efficiency (FE) of the OER. While the doping of P anions improves the electronic conductivity and prevents the dissolution of selenide by forming a passivation layer containing P–O species. The Fe‐dopant is identified as the primary active site for the hydrogen evolution reaction, and meanwhile, stimulates the adjacent Ni atoms as active centers for the OER. The experimental analyses and theoretical calculations provide an insightful understanding of the roles of dual‐dopants in boosting seawater electrolysis. As a result, a current density of 0.8 A cm−2 is archived at 1.8 V with high OER selectivity and long‐term stability for over 200 h, which surpasses the benchmarking platinum‐group‐metals‐free electrolyzers.
An ultrahigh activity and selectivity seawater electrolyzer with robust stability is developed via a dual‐doping and synergism optimization of Fe,P‐NiSe2 nanoporous films. The Fe cation increases the selectivity and Faraday efficiency, while the P anion improves the electronic conductivity and prevents the dissolution of selenide.
A controllable and area selective doping process, especially for p-type Molybdenum disulphide (MoS 2 ), is essential for the realization of various p/n junction-based devices. In this work, we ...demonstrate p-type doping of multilayer MoS 2 with phosphorus (P) as a dopant using a CMOS-compatible plasma immersion ion implantation (PIII) technique. Detailed physical characterization including XPS and SIMS, backed with ab-initio DFT calculations, confirms p-type doping in P-implanted MoS 2 that could be due to a combination of surface charge transfer from physisorbed phosphine ions and/or substitutional phosphorus present in the top few (~5) layers. Controlled reduction in current levels and positive V T shifts were observed in channel-doped MoS 2 transistors. Further, selectively doped gated p/n-junction diodes (rectification ~50X) have been demonstrated.
Improving the capacitance of carbon materials for supercapacitors without sacrificing their rate performance, especially volumetric capacitance at high mass loadings, is a big challenge because of ...the limited assessable surface area and sluggish electrochemical kinetics of the pseudocapacitive reactions. Here, it is demonstrated that “self‐doping” defects in carbon materials can contribute to additional capacitance with an electrical double‐layer behavior, thus promoting a significant increase in the specific capacitance. As an exemplification, a novel defect‐enriched graphene block with a low specific surface area of 29.7 m2 g−1 and high packing density of 0.917 g cm−3 performs high gravimetric, volumetric, and areal capacitances of 235 F g−1, 215 F cm−3, and 3.95 F cm−2 (mass loading of 22 mg cm−2) at 1 A g−1, respectively, as well as outstanding rate performance. The resulting specific areal capacitance reaches an ultrahigh value of 7.91 F m−2 including a “self‐doping” defect contribution of 4.81 F m−2, which is dramatically higher than the theoretical capacitance of graphene (0.21 F m−2) and most of the reported carbon‐based materials. Therefore, the defect engineering route broadens the avenue to further improve the capacitive performance of carbon materials, especially for compact energy storage under limited surface areas.
Owing to the significantly improved double‐layer capacitance originating from the “self‐doping” defects, defective graphene blocks with high defect density (ID/IG = 2.16), high packing density (0.917 g cm–3), and low specific surface area (29.7 m2 g–1) show an integration of high gravimetric, volumetric, and areal capacitances for supercapacitors.
Asahi et al explore the designs, developments and prospects of nitrogen-doped titanium dioxide as a visible-light-sensitive photocatalyst. They focus on topics such as the materials design for ...visible-light-sensitive photocatalyst, the synthesis and properties of nitrogen-doped titanium dioxide (TiO2), and the detailed analysis of N-doped TiO2.
A synergistic N doping plus PO43− intercalation strategy is used to induce high conversion (ca. 41 %) of 2H‐MoS2 into 1T‐MoS2, which is much higher than single N doping (ca. 28 %) or single PO43− ...intercalation (ca. 10 %). A scattering mechanism is proposed to illustrate the synergistic phase transformation from the 2H to the 1T phase, which was confirmed by synchrotron radiation and spherical aberration TEM. To further enhance reaction kinetics, the designed (N,PO43−)‐MoS2 nanosheets are combined with conductive vertical graphene (VG) skeleton forming binder‐free arrays for high‐efficiency hydrogen evolution reaction (HER). Owing to the decreased band gap, lower d‐band center, and smaller hydrogen adsorption/desorption energy, the designed (N,PO43−)‐MoS2/VG electrode shows excellent HER performance with a lower Tafel slope and overpotential than N‐MoS2/VG, PO43−‐MoS2/VG counterparts, and other Mo‐base catalysts in the literature.
An N‐doping plus PO43− intercalation strategy is used to induce high conversion (ca. 41 %) of 2H‐MoS2 into 1T‐MoS2, which is much higher than single N‐doping or PO43− intercalation (ca. 28 % and ca. 10 %, respectively). A scattering mechanism is proposed to illustrate the synergistic phase transformation from 2H phase to 1T phase, confirmed by synchrotron radiation and spherical aberration TEM.
•Novel SiC/Pyrrolic-N doped carbon material have been synthesized from bamboo.•Inherent SiO2 moieties in natural bamboo has been used as a sacrificial template.•The synergy of SiC and Pyrrolic-N has ...been demonstrated for Faradaic redox reactions.•Natural bamboo-based carbon materials deliver capacitance of 369 F g−1 at 0.5 A g−1.•Bamboo-based carbon materials deliver 100% capacitance retention after 5000 cycles.
It is still challenging to prepare porous carbon materials following a facile, green and universal sacrificial template method from renewable biomass. For this purpose, bio-renewable bamboo is a natural silicon reservoir containing a significant amount of inherent silica that can act as a natural sacrificial template for the formation of porous carbon materials as well as a dopant. Herein, we firstly report the SiC/N dual doped bio-renewable carbon material via a facile, natural sacrificial template method. In this newly developed method, the inherently available SiO2 nanoparticles have been utilized as the natural sacrificial template for creating the multi-porous architecture as well as for the generation of structural defects in the form of SiC nano-species. Additionally, the inherent nitrogen functional groups give rise to the formation of only pyrrolic-N species after pyrolysis. Furthermore, dual doping of SiC and pyrrolic-N species stimulate the faradaic redox reaction during the charge/discharge process and further increase the rate capability at higher current density with excellent electrochemical stability. Hence, the synergistic effect of SiC and N-pyrrolic dually doped carbon network gives rise to the formation of promising electrode material towards supercapacitors. Benefiting from the above unique features, the supercapacitor with the SNAC-1 electrode material delivers excellent capacitive behavior (369 F g−1 at 0.5 A g−1) in 1 M H2SO4 electrolyte with 100% capacitance retention after 5000 charge–discharge cycles. More prominently, the all-solid state, symmetric supercapacitors assembled by SNAC-1 show outstanding capacitance of 162 F g−1 at 0.5 A g−1 and reveal high energy density (∼5.41 W h kg−1 at 0.5 kW kg−1 power density) and excellent cyclic stability. This work provides an ideal sustainable solution from bamboo source to prepare porous SiC/N composites for cost-effective supercapacitor’s electrode materials.
Cesium‐based inorganic perovskites, such as CsPbI2Br, are promising candidates for photovoltaic applications owing to their exceptional optoelectronic properties and outstanding thermal stability. ...However, the power conversion efficiency of CsPbI2Br perovskite solar cells (PSCs) is still lower than those of hybrid PSCs and inorganic CsPbI3 PSCs. In this work, passivation and n‐type doping by adding CaCl2 to CsPbI2Br is demonstrated. The crystallinity of the CsPbI2Br perovskite film is enhanced, and the trap density is suppressed after adding CaCl2. In addition, the Fermi level of the CsPbI2Br is changed by the added CaCl2 to show heavy n‐type doping. As a result, the optimized CsPbI2Br PSC shows a highest open circuit voltage of 1.32 V and a record efficiency of 16.79%. Meanwhile, high air stability is demonstrated for a CsPbI2Br PSC with 90% of the initial efficiency remaining after more than 1000 h aging in air.
Herein, calcium chloride is applied to passivate and dope inorganic CsPbI2Br. It enhances the crystallinity of CsPbI2Br to decrease trap density and prolong carrier lifetime and to raise its Fermi level to lie very close to the conduction band, leading to a high voltage of 1.32 V, and a record efficiency of 16.79% for CsPbI2Br cells.
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