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Mesoporous TiO2-BiOBr Microspheres with Tailorable Adsorption Capacities for Photodegradation of Organic Water Pollutants: Probing Adsorption-Photocatalysis Synergy by Combining Experiments and Kinetic Modeling
摘要： Understanding adsorption-photocatalysis synergy helps advance solar-driven photodegradation of organic wastewater pollutants. To evaluate the synergy, mesoporous TiO2(amorphous)-BiOBr microspheres were facilely synthesized as model photocatalysts and characterized by XRD, SEM, TEM/HRTEM, XPS, nitrogen adsorption-desorption, UV-vis DRS, photoluminescence, and FTIR. The characterizations and photodegradation tests suggested that the composites had both adsorption sites and photocatalysis sites on BiOBr phase, while homogeneously distributed TiO2 in BiOBr microplates tailored the size of BiOBr crystallites. Accordingly, surface areas of the composites spanned from 22 to 155 m2/g and adsorption capacities for methyl orange (MO) ranged from 16 to 54 mg/g, controlled by the TiO2 content. In addition to experiments, kinetic modeling that combined adsorption with photocatalysis was developed and aided elucidating the synergy and quantitatively evaluating the composites with extracted rate constants from experimental data. The rate constant of the composite (Ti/Bi = 0.6) was calculated to be 3 times that of the pure BiOBr. Though adsorption promoted MO photodegradation, the capacity of the composite for MO adsorption and photodegradation decreased dramatically during the cycling tests. Nevertheless, this problem did not happen during photodegradation of rhodamine B and phenol on the composite and photodegradation of MO on pure BiOBr. This was explained by possible accumulation of degradation intermediates on the composite surface. This study provides a useful approach to investigate the adsorption-photocatalysis synergy from the perspectives of experiments and kinetic modeling and implies the necessity of scrutinizing the adverse effects of high levels of adsorption on recyclability of the photocatalysts.
关键词： Organic pollutants photodegradation,Kinetic modeling,TiO2-BiOBr microspheres,Tailorable adsorption capacities,Adsorption-photocatalysis synergy
更新于2025-11-14 17:03:37
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Promoting Photoreduction Properties via Synergetic Utilization between Plasmonic Effect and Highly Active Facet of BiOCl
摘要： Exploring highly efficient photocatalysts is an urgent task for achieving efficient solar-to-chemical conversion. Plasmonic effect is widely used in improving the photocatalytic properties via reducing the activation barrier for chemical reactions, enhancing the absorption of the photocatalysts or injecting the hot carriers into the photocatalysts from the plasmon metals. In this work, we design BiOCl-Ag-E with Ag loaded on the edge side of BiOCl. This hybrid structure takes the advantages of highly photocatalytic active (001) facet of BiOCl and the plasmonic effect. The plasmon metal is proposed to provide the (001) facets with more photogenerated charge carriers driving by the internal electric field, which is convinced by the photocurrent response and the detection of active species. Due to the accumulation of more negative charge carriers on (001) facet, BiOCl-Ag-E presents outstanding waste-water cleaning and CO2 photoreduction properties. The methodology of material design in this work paves the way for future design of efficient photocatalysts.
关键词： photocatalyst,synergy effect,surface plasmon resonance,CO2 photoreduction,selective growth
更新于2025-11-14 15:27:09
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Green method by diffuse reflectance infrared spectroscopy and spectral region selection for the quantification of sulphamethoxazole and trimethoprim in pharmaceutical formulations
摘要： An alternative method for the quantification of sulphametoxazole (SMZ) and trimethoprim (TMP) using diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) and partial least square regression (PLS) was developed. Interval Partial Least Square (iPLS) and Synergy Partial Least Square (siPLS) were applied to select a spectral range that provided the lowest prediction error in comparison to the full-spectrum model. Fifteen commercial tablet formulations and forty-nine synthetic samples were used. The ranges of concentration considered were 400 to 900 mg g-1 SMZ and 80 to 240 mg g-1 TMP. Spectral data were recorded between 600 and 4000 cm-1 with a 4 cm-1 resolution by Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The proposed procedure was compared to high performance liquid chromatography (HPLC). The results obtained from the root mean square error of prediction (RMSEP), during the validation of the models for samples of sulphamethoxazole (SMZ) and trimethoprim (TMP) using siPLS, demonstrate that this approach is a valid technique for use in quantitative analysis of pharmaceutical formulations. The selected interval algorithm allowed building regression models with minor errors when compared to the full spectrum PLS model. A RMSEP of 13.03 mg g-1 for SMZ and 4.88 mg g-1 for TMP was obtained after the selection the best spectral regions by siPLS.
关键词： green analytical method,diffuse reflectance infrared Fourier transform spectroscopy,interval partial least squares (iPLS),chemometrics,synergy partial least squares (siPLS),high performance liquid chromatography
更新于2025-09-23 15:22:29
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Mechanically Enhanced Electrical Conductivity of Polydimethylsiloxane-Based Composites by a Hot Embossing Process
摘要： Electrically conductive polymer composites are in high demand for modern technologies, however, the intrinsic brittleness of conducting conjugated polymers and the moderate electrical conductivity of engineering polymer/carbon composites have highly constrained their applications. In this work, super high electrical conductive polymer composites were produced by a novel hot embossing design. The polydimethylsiloxane (PDMS) composites containing short carbon fiber (SCF) exhibited an electrical percolation threshold at 0.45 wt % and reached a saturated electrical conductivity of 49 S/m at 8 wt % of SCF. When reducing the sample thickness from 1.0 to 0.1 mm by the hot embossing process, a compression-induced percolation threshold occurred at 0.3 wt %, while the electrical conductivity was further enhanced to 378 S/m at 8 wt % SCF. Furthermore, the addition of a second nanofiller of 1 wt %, such as carbon nanotube or conducting carbon black, further increased the electrical conductivity of the PDMS/SCF (8 wt %) composites to 909 S/m and 657 S/m, respectively. The synergy of the densified conducting filler network by the mechanical compression and the hierarchical micro-/nano-scale filler approach has realized super high electrically conductive, yet mechanically flexible, polymer composites for modern flexible electronics applications.
关键词： compression-induced percolation threshold,synergy,electrical conducting network,hybrid filler,forced assembly
更新于2025-09-23 15:22:29
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Revisiting cocatalyst/TiO2 photocatalyst in blue light photothermalcatalysis
摘要： Coupling heat into photocatalysis (PC) has been found more efficient than PC for removal of volatile organic compounds (VOC). Therein, photothermal synergy induced photothermalcatalysis (PTC) sometimes tells different stories from PC. In this work, we revisit ST-01 TiO2 photocatalyst as photothermalcatalyst under blue light at 333 K and further investigate the role of surface grafted cocatalyst (CrxO, CoxO, CuxO, Pt) in catalytic removal of gaseous acetaldehyde pollutant. By comparison on the amount of cocatalyst, for PC, more CrxO cocatalyst (3 wt%) is favored for higher removal efficiency of acetaldehyde. For PTC, less CrxO cocatalyst (0.3 wt%) is favored. By further comparison on the type of cocatalyst, for PC, hole cocatalyst (CrxO and CoxO) gives inferior performance to that of electron cocatalyst (CuxO and Pt). For PTC, hole cocatalyst gives superior performance to that of electron cocatalyst. The difference between PC and PTC lies in synergistic effect between defect-related blue-light absorption, cocatalyst induced interfacial charge transfer and matched surface red-ox reaction rate. This work may provide new insight into the design and development of photothermalcatalyst for VOC removal.
关键词： Cocatalyst,VOC removal,Photothermal synergy,Photocatalytic,Photothermalcatalytic
更新于2025-09-23 15:21:01
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Application of Co-Mo bimetal/carbon composite in dye-sensitized solar cells and its research on synergy mechanism
摘要： Bimetal/carbon aerogels have many advantages, such as nano-scale properties, low density, large specific surface area, and high porosity, but their application in dye-sensitized solar cells (DSSCs) as a counter electrode (CE) instead of noble metal Pt is relatively rare. In this paper, a low-cost sodium alginate was used to obtain a Co-Mo bimetal/carbon composite through a simple and controlled carbonization process. Using them as CEs of ZnO-based DSSCs, the filling characteristics of dye can be effectively improved. When the Co2+/Mo2+ molar ratio is 1:3, the photoelectric conversion efficiency of Co-Mo bimetal/ carbon composite–based DSSCs is close to the photoelectric conversion efficiency of Pt based, which is considered to be the result of the synergy of the carbon and two metal ions.
关键词： Counter electrode,Bimetal/carbon composite,Synergy,Dye-sensitized solar cells,Aerogel
更新于2025-09-23 15:19:57
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Synergy of adsorption and photocatalysis on removal of high-concentration dye by Ag/AgCl/Bi6O4(OH)4(NO3)6·H2O nanocomposite using Bi12O17Cl2 as bismuth source
摘要： Novel basic bismuth nitrite nanocomposite-Ag/AgCl/Bi6O4(OH)4(NO3)6·H2O has been applied to remove high-concentration methyl orange (MO). The nanocomposite was prepared by a two-step method with Bi12O17Cl2 as bismuth source. XRD, TEM, HRTEM and IR analyses were performed to clarify the composition and microstructure. TEM and HRTEM images reveal that the nanocomposite is consisted of plate-stacking Bi6O4(OH)4(NO3)6·H2O ultrathin nanosheets, where monodispersed AgCl (3-7 nm) and Ag (10-120 nm) nanoparticles are uniformly distributed. Influences of contact time, MO concentration and solution pH on adsorption capacity have been studied. Adsorption capacity is 349 mg g-1 at natural state, 740 mg g-1 at pH=3, and 141 mg g-1 at pH=9. Visible-light photocatalytic performance was evaluated by degradating high-concentration MO of 500 mg L-1 at natural state, 1500 mg L-1 at acidic condition, and 300 mg L-1 at the alkaline condition. Combining with distinct composition and structure of the nanocomposite, removal mechanism is proposed based on the synergy of adsorption and photocatalysis.
关键词： Adsorption,Photocatalysis,Synergy,High-concentration methyl orange,Ag/AgCl/Bi6O4(OH)4(NO3)6·H2O
更新于2025-09-23 15:19:57
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Improved breakdown strength of Poly(vinylidene Fluoride)-based composites by using all ball-milled hexagonal boron nitride sheets without centrifugation
摘要： Hexagonal boron nitride (h-BN) is an ideal candidate to endow ferroelectric polymers with high energy density ((cid:1)(cid:2)) due to its intrinsic high breakdown strength ((cid:3)(cid:4)) of 800 kV/mm. Generally, it is believed that only boron nitride nanosheets (BNNSs) could remarkably improve (cid:3)(cid:4) of composite. Nevertheless, low-yield and time-consuming preparation procedures of BNNSs greatly limits the application of h-BN. To overcome this challenge, in this study, all ball-milled h-BN (B-BN) sheets were entirely used to enhance (cid:3)(cid:4) of poly(vinylidene fluoride) (PVDF) without any further centrifugation. (cid:3)(cid:4) of composites increased as ball-milling time increases at filler content of 8 wt%. Remarkably, PVDF with h-BN ball-milled for 16 h (B16-BN) possesses an impressive (cid:3)(cid:4) value of 506.8 kV/mm, which is 2.86 times that of neat PVDF (272.4 kV/mm) and even 1.33 times higher than that of PVDF/h-BN composites (380.6 kV/mm). (cid:3)(cid:4) of PVDF/B16-BN composites is close to that of PVDF/OH-BNNSs composites at same filler content, suggesting that the centrifugation is not a necessary procedure. Besides, improved dielectric loss, calculated (cid:1)(cid:2), mechanical properties and in-plane thermal conductivity can also be achieved for PVDF/B16-BN composites. These improved properties of PVDF/B16-BN composites indicate that the employment of B16-BN can avoid the weakness of low-yield and time-consuming preparation procedure of BNNSs and broaden its applications in the field of energy storage. Finally, the improved dispersion of OH-BN as well as synergy effect (f) on (cid:3)(cid:4) between OH-BN and OH-BNNSs were discussed to better understand these improved properties of PVDF/B16-BN composites.
关键词： Breakdown strength,No centrifugation,Synergy effect,Hexagonal boron nitride
更新于2025-09-19 17:13:59
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Electrons and Phonons Cooperate in the Laser-Induced Desorption of CO from Pd(111)
摘要： Femtosecond laser induced desorption of CO from a CO-covered Pd(111) surface is investigated with ab initio molecular dynamics with electronic friction that incorporates effects due to the excited electronic and phononic systems, as well as out-of-phase coadsorbate interactions. Our simulations show evidence of an important electron-phonon synergy in promoting CO desorption that has largely been neglected in other similar systems. At the saturated coverage of 0.75 ML, effects due to CO-CO interadsorbate energy exchange are also important. Our dynamics simulations, in concert with site-specific desorption energy calculations, allow us to understand the large coverage dependence of the desorption yields observed in experiments.
关键词： electron-phonon synergy,Pd(111),desorption,femtosecond laser,CO,electronic friction,ab initio molecular dynamics
更新于2025-09-16 10:30:52
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Influences of synergy effect between laser and arc on laser-arc hybrid welding of aluminum alloys
摘要： Researchers generally believe that synergy effect between laser and arc enables laser-arc hybrid welding to acquire obvious advantages of efficiency and quality in welding aluminum alloys. However, influences of physical essence of the synergy effect on welding process were not clear. In this study, basic principle of the synergy effect and its influences on welding process were obtained by spectral analysis of hybrid plasma plume and high-speed photographic analysis of welding process. First, the principle of the synergy effect is that laser interacts with arc to render electron energy level to transition. This process emits more photons, which enhance the heat input to the weld materials. The synergy effect is quantified by spectral intensity. It increases with the laser power, and decreases with the arc current and laser-arc distance. It is proportional to the cross section of weld, especially the upper, and beneficial to improve the welding energy utilization. Secondly, the amount of spatter in laser-arc hybrid welding is significantly less than that of arc welding. The bigger weld pool, the downward melt flow, and the reduced droplet transfer force generated by the synergy effect make the transferring droplets more easily absorbed by the weld pool, which stabilizes the transfer process and reduces the generation of spatter. The research results are beneficial for understanding hybrid welding mechanism and optimizing the welding process.
关键词： Synergy effect,Laser-arc hybrid welding,Welding penetration,Welding energy utilization,Spatter
更新于2025-09-12 10:27:22