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Synthesis of bismuth molybdate photocatalysts for CO2 photo-reduction
摘要： To explore the possibilities of bismuth molybdate in CO2 photo-reduction to chemicals and fuels, two types of bismuth molybdate namely Bi2MoO6 and Bi3.64Mo0.36O6.55 were synthesized via hydrothermal treatment by adjusting the pH of reaction solution. Bi2MoO6 is constituted by MoO6 octahedra while Bi3.64Mo0.36O6.55 is constructed by MoO4 tetrahedra. Different structure causes quite different properties, like electron binding energy, photoluminescence character, band edge position, optical and electrochemical properties. Comprehensively speaking, Bi2MoO6 made the most of solar energy and showed relatively more efficient charge migration and separation efficiency, contributing to its higher activity for CO2 photo-reduction. After irradiating for 5 h, the yields of CO gas over the both samples were 85.5172 (Bi2MoO6) and 57.3259 (Bi3.64Mo0.36O6.55) μmol/g, respectively. Last, the photocatalytic reduction mechanism was analyzed.
关键词： CO2 reduction,Bi3.64Mo0.36O6.55,Photocatalysis,Bi2MoO6
更新于2025-09-23 15:23:52
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Photocatalytic treatment of palm oil mill effluent by visible light-active calcium ferrite: Effects of catalyst preparation technique
摘要： Palm oil mill effluent (POME) is a serious and expensive environmental problem in Malaysia. In this paper, CaFe2O4 is introduced as a novel photocatalyst for the degradation of POME under visible light irradiation. Two synthesis routes, auto-combustion and co-precipitation, and two calcination temperatures 550 °C and 700 °C were used to produce four CaFe2O4 catalysts AC550, AC700, CP550 and CP700. CP550 exhibited the greatest photocatalytic degradation at 56% chemical-oxygen-demand (COD) removal after 8 h of irradiation which dropped to 49% after three consecutive cycles indicating reasonable conversion and high recyclability. BET analysis indicated CP550 had the highest SBET (27.28 m2/g) and pore volume (0.077 cm3/g) which dropped precipitously for CP700 upon increasing the calcination temperature to an SBET of 9.73 m2/g and pore volume of 0.025 cm3/g due to annealing which created a smoother surface area as evidenced by the SEM images. UV–Vis DRS indicated CP550 had the highest band-gap (1.52 eV) which is likely due to the presence of a highly crystalline pure CaFe2O4 phase compared to the other products which existed as a mixture of Fe oxidation states evidenced by the XRD data. The PL spectra for all catalysts indicated significantly lower recombination rate for both CP550 and CP700. Introduction of IPA into the reaction mixture to eliminate hydroxyl radicals resulted in a diminishing of COD removal from 56% to 7% proving hydroxyl radicals to be the primary reactive species responsible for photodegradation of POME.
关键词： Co-precipitation,POME,Photocatalysis,Visible light,Calcium ferrite,Auto-combustion
更新于2025-09-23 15:23:52
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Synthesis of g-C3N4/N-doped CeO2 composite for photocatalytic degradation of an herbicide
摘要： In photocatalysis, surface engineered CeO2 could be vital due to oxygen vacancies arise from multiple valency, i.e. Ce3+ and Ce4+. This study reports photocatalytic properties of g-C3N4/CeO2 composite synthesized by a facile method in the presence of l-arginine. Physicochemical properties of g-C3N4/CeO2 material were analyzed through various characterization techniques such as XRD, UV–Vis, physisorption, etc., and correlated with its photocatalytic activity. Observed bandgap of the synthesized composite material was in the visible region, around 2.8 eV which is less than that of typical ceria, but higher than bandgap of exfoliated g-C3N4. On the further side, N doping into CeO2 was confirmed through XPS analysis. It is estimated that synthesis method aided for the N doping, which further played key role in lowering the bandgap of g-C3N4/CeO2 composite. Finally, Photocatalytic activity of g-C3N4/CeO2 composite was analyzed through degradation of an herbicide i.e. diuron, and the study revealed the good performance of the catalyst.
关键词： Graphitic carbon nitride,Photocatalysis,N doping,Herbicide,CeO2
更新于2025-09-23 15:23:52
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Effect of dissolved natural organic matter on the photocatalytic micropollutant removal performance of TiO2 nanotube array
摘要： The TiO2 nanotube array (TNA) is a promising photocatalyst for removal of micropollutants from water, but better understanding on its applicability in complex water matrices is still desired. Therefore this study investigates the effect of dissolved natural organic matter (NOMs) on 4-chloro-2-methylphenoxyacetic acid (MCPA, a typical micropollutant found in many water bodies) removal performance of TNA. The present study shows that although in bulk liquid phase NOMs would undergo photosensitization that can contribute to MCPA removal, the overall effect of NOMs on MCPA removal is detrimental due to the interaction between NOMs and the TNA surface: the total removal of MCPA decreased from 94.3% to 62.0% and 61.8%, in the presence of only 5 mg/L SWR-NOM and UMR-NOM respectively. Acidic pH was found to be able to mitigate the detrimental effect of NOMs (the total removal of MCPA was only decreased from 94.5% to 83.3% and 88.8% under acidic pH, in the presence of 15 mg/L SWR-NOM and UMR-NOM respectively), and the photosensitization effect of NOMs was strengthened; while under alkaline pH conditions the detrimental effect of NOMs completely vanished (the total removal of MCPA increased from 45.7% to 55.7% and 60.5% in the presence of 15 mg/L SWR-NOM and UMR-NOM respectively). Two commonly present co-existing anions, i.e. phosphate and bicarbonate, also mitigate the detrimental effect of NOMs. With 15 mg/L SWR-NOM: the presence of 100 mg/L bicarbonate increased the total removal of MCPA from 49.1% to 65.1%; the presence of 100 mg/L phosphate increased the total removal of MCPA from 49.1% to 62.5%. With 15 mg/L SWR-NOM, the presence of 100 mg/L bicarbonate increased the total removal of MCPA from 45.2% to 56.1%; the presence of 100 mg/L phosphate increased the total removal of MCPA from 45.2% to 62.9%. The photocurrent measurement support that the presence of such anions greatly suppresses the h + scavenging effect of NOMs; while other anions, i.e. chloride, nitrate, sulfate, showed no notable effect.
关键词： Micropollutant,MCPA,TiO2 nanotube array,Photocatalysis,Natural organic matter
更新于2025-09-23 15:23:52
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BiF3 octahedrons: A potential natural solar light active photocatalyst for the degradation of Rhodamine B dye in aqueous phase
摘要： Herein, we report the successful synthesis of BiF3 octahedrons via facile hydrothermal process as potential solar light active catalyst for the photocatalytic degradation of Rhodamine B (RhB) dye in aqueous phase. The synthesized BiF3 octahedrons were characterized by several techniques such as X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectroscopy, UV-diffuse reflectance spectroscopy (UV-DRS), photoluminescence (PL) spectroscopy, thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) techniques in order to observe the structural, morphological, optical and luminescence properties. The synthesized octahedrons possess the high density growth, pure and well-crystalline with cubic phase structure and band gap of 3.98 eV. As a potential solar light active photocatalyst, the synthesized BiF3 octahedrons exhibited ~95.7% degradation of RhB in 50 min. The effect of different process parameters such as pH and catalyst dose on the degradation of RhB was also explored. Interestingly, the synthesized BiF3 octahedrons demonstrated better photocatalytic performance compared to several commercially available photocatalysts such as TiO2 (PC-500), SnO2 and ZnS. Further, it was observed that the degradation of RhB over the prepared BiF3 octahedrons obeyed the pseudo first-order reaction kinetics with rate constant of 0.06393 min-1. The scavenger experiments verified the role of h+, e─, O2 .─, ?OH and ?OHs in the photocatalytic degradation process and a plausible photocatalytic mechanism has also been proposed.
关键词： Rhodamine B,Photocatalysis,Solar-light irradiation,BiF3 octahedrons
更新于2025-09-23 15:23:52
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Effects of Calcination Temperature on Morphology and Structure of CeO2 Nanofibers and their Photocatalytic Activity
摘要： Calcination temperature plays a critical role on morphology and structure of CeO2 nanofibers, thus affecting its photocatalytic activity. CeO2 nanofibers with diameter of 95 nm were successfully fabricated by electrospinning combining with calcination. The calcination temperature was determined by TGA results ranging from 500℃ to 800℃. The morphology and structure of samples obtained with different calcination temperatures, have been characterized by SEM and XRD. Meanwhile, the specific surface area of samples were checked by BET, that was decreased 17 times from 56.3 m2/g to 3.3 m2/g, as the temperature increasing from 500℃ to 800℃. Normally, the higher specific surface area, the more efficiency photocatalytic activity. But it was interesting that the photodegradation rate of methylene blue was increased from 67% to 98% for CeO2 catalyst obtained at 500℃ and 800℃, with 4 times higher kinetic constant reaction rate under UV irradiation for 60 min. It demonstrates that the photocatalytic activity of CeO2 nanofibers catalyst is not directly related to the specific surface area, and increasing the calcination temperature has a positive effect for the photocatalytic efficiency.
关键词： Calcination,Porous Materials,Microstructure,CeO2 Nanofiber,Photocatalysis
更新于2025-09-23 15:23:52
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The mechanical and photocatalytic properties of modified gypsum materials
摘要： Co-modi?ed TiO2 photocatalysts (TiO2-N,C) were added to commercial gypsum to obtain self-cleaning building material. The gypsum/TiO2 composite were also studied towards their mechanical properties. The highest photocatalytic activity was obtained for gypsum samples containing TiO2/N,C photocatalyst treated at 100–300 °C, attributed to high anatase phase participation, relatively high nitrogen and carbon content and high BET surface area (ca. 170–270 m2/g). In this case (300 °C) the model pollutant (azo dye) degradation rate was 85% and 70% after 15 h of UV and vis irradiation, respectively. Higher compressive strength values was observed for gypsum sample loaded with photocatalysts treated at higher temperatures (600–800 °C), attributed to rutile phase presence and large crystallite size. The grinding operation during gypsum/TiO2 composite preparation can contribute towards the increase of compressive strength (even 40%) by reduction of gypsum particle size whereas photocatalyst particles act as the e?ective ?llers of void spaces in gypsum material.
关键词： Modi?ed gypsum,Photocatalysis,TiO-N,C,Compressive strength
更新于2025-09-23 15:23:52
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One-pot self-assembly of 3D CdS-graphene aerogels with superior adsorption capacity and photocatalytic activity for water purification
摘要： Graphene-based three-dimensional (3D) aerogel hybrids have recently emerged as a new class of functional materials and applied in many fields. In this work, we assemble the spherical CdS nanoparticles in situ in graphene aerogel (GA) by a facile one-pot hydrothermal method. The resultant CdS-GA hybrids possess a hierarchical porous structure and there is strong electronic interaction between CdS and GA, which enhances the adsorption capacity and photocatalytic activity for the elimination of organic contaminants in water under visible light irradiation, such as rhodamine B (RhB), methylene blue (MB), acid chrome blue K (AcbK), methyl orange (MO), and ciprofloxacin (CIP). The removal efficiencies of CdS-GA for MO, MB, CIP, RhB, AcbK are 15.6, 6.6, 4.4, 2.8, and 2.2 times of pure CdS, respectively. Meanwhile, the resultant CdS-GA hybrids display good reusability. In addition, a photocatalytic mechanism is also discussed. This provides a valuable alternative to explore semiconductor-GA hybrids with outstanding adsorption capacity and superior visible-light induced photocatalytic activity.
关键词： Graphene aerogel,Adsorption,Photocatalysis,Hybrids,CdS nanoparticle,organic contaminants
更新于2025-09-23 15:23:52
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The design of a polyaniline-decorated three dimensional W18O49 composite for full solar spectrum light driven photocatalytic removal of aqueous nitrite with high N2 selectivity
摘要： Photocatalysis using solar energy is the most promising green technology for nitrite removal. However, effective photocatalytic performance is often challenged by the limited light absorption, utilization of expensive noble metals and undesired products (nitrate and ammonium). Here, we report for the first time that a full solar light response polyaniline-decorated three dimensional W18O49 composite (PANI@W18O49), a noble metal-free photocatalyst, possesses excellent photocatalytic activity for aqueous nitrite removal with high N2 selectivity. The prepared sample was thoroughly identified via XRD, Raman, FTIR, SEM, TEM, UV–vis DRS and PL. The catalytic results demonstrated that over 80% N2 selectivity (initial concentration 1.0 mM) was achieved through the PANI@W18O49 without sacrificial agent under 300 W Xe lamp irradiation for 60 min. Such advantages were attributed to the built-in junction between n-type W18O49 and p-type PANI, offering suitable redox levels of electron-hole pairs for NO2? reaction. The modification of PANI also benefited the light harvesting ability and activated carriers migration, the calculated rate constant of PANI@W18O49 is about four times as high as that of W18O49. The current study not only prepared a promising photocatalyst, but also provides new insights into improving the photocatalytic activity and N2 selectivity for nitrite treatment.
关键词： Nitrite,Polyaniline,Tungsten oxide,Full solar spectrum light driven,Photocatalysis
更新于2025-09-23 15:23:52
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Facile synthesis of two-dimensional tailored graphitic carbon nitride with enhanced photoelectrochemical properties through a three-step polycondensation method for photocatalysis and photoelectrochemical immunosensor
摘要： Graphitic carbon nitride (g-C3N4) is an ideal alternative two-dimensional (2D) nanostructure for photocatalysis and photoelectrochemical (PEC) application, while controllably fabricating 2D shaped g-C3N4 nanolayers/nanosheets is still facing challenges. On the basis of temperature-dependent polymorphic characters, herein, a 2D extending g-C3N4 (g-CNS3) is synthesized from dicyandiamide as the precursor by operating the condensation temperature in a continuously three-step thermal polycondensation procedure. The g-CNS3 with film-like morphology showed improved visible-light absorption ability and enhanced PEC performance compared to g-CNS1 synthesized via the traditional one-step thermal polymerization method. Benefiting from its excellent PEC properties, the g-CNS3 exhibited high photocatalytic activity to removal MB with fast kinetics and served as the photoactive layer to construct a PEC immunosensor with high sensitivity and specificity for subgroup J avian leukosis virus detection. A linear range from 102.14 to 103.35 TCID50/mL and a detection limit of 102.08 TCID50/mL were obtained for the PEC immunoassay of the target virus. This work might provide a novel protocol for tailoring shaped 2D g-C3N4 nanosemiconductor with superior properties and shed light on its promising PEC applications.
关键词： Two-dimensional material,Photocurrent response,Graphitic carbon nitride,Photocatalysis,Photoelectrochemical immunosensor
更新于2025-09-23 15:23:52