pH sensor based on tilted fiber Bragg grating surface plasmon resonance with a polyaniline reaction deposition film layer.

In this paper, we propose a surface plasmon resonance (SPR) fiber-optic pH sensor combined with a tilted fiber Bragg grating (TFBG) by continuously coating gold and polyaniline (PANI) onto the surface of a TFBG. The micron-scale thickness polyaniline film provides the sensor with good sensitivity, and it achieves accurate measurement of pH values ranging from 2 to 12 by utilizing the pH-responsive mechanism of PANI and the surface plasmon resonance characteristics. Experimental results show that within the 2-12 pH range, the sensitivity of the TFBG surface plasmon resonance pH sensor based on PANI coating is 0.50335 nm/pH, and results demonstrate, a linear correlation coefficient between wavelength and pH value reaching 0.96614. This indicates significant potential for future engineering applications in real-world pH measurement using this sensor.

[Role of collagen membrane in modified guided bone regeneration surgery using buccal punch flap approach: A retrospective and radiographical cohort study].

OBJECTIVE: To investigate whether the placement of absorbable collagen membrane increase the stability of alveolar ridge contour after guided bone regeneration (GBR) using buccal punch flap. METHODS: From June 2019 to June 2023, patients who underwent GBR using buccal punch flap simultaneously with a single implant placement in posterior region (from first premolar to second molar) were divided into coverage group, in which particular bone graft was covered by collagen membrane and non-coverage group. Cone beam CT (CBCT) was taken before surgery (T0), immediately after surgery (T1), and 3-7 months after surgery (T2), and the thickness of the buccal bone plate at different levels (0, 2, 4, and 6 mm) below the smooth-rough interface of the implant (BBT-0, -2, -4, -6) was mea-sured after superimposition of CBCT models using Mimics software. RESULTS: A total of 29 patients, including 15 patients in coverage group and 14 patients in non-coverage group, were investigated in this study. At T0, T1, and T2, there was no significant difference in BBT between the two groups (P>0.05). At T1, BBT-0 was (2.50±0.90) mm in the coverage group and (2.97±1.28) mm in the non-coverage group, with corresponding BBT-2 of (3.65±1.08) mm and (3.58±1.26) mm, respectively. At T2, BBT-0 was (1.22±0.55) mm in the coverage group and (1.70±0.97) mm in the non-coverage group, with corresponding BBT-2 of (2.32±0.94) mm and (2.57±1.26) mm, respectively. From T1 to T2, there were no statistically significant differences in the absolute values [(0.47±0.54)-(1.33±0.75) mm] and percentages [(10.04%±24.81%)-(48.43%±18.32%)] of BBT change between the two groups. The thickness of new bone formation in the buccal bone plate from T0 to T2 ranged from (1.27±1.09) mm to (2.75±2.15) mm with no statistical difference between the two groups at all levels. CONCLUSION: In the short term, the GBR using buccal punch flap with or without collagen membrane coverage can effectively repair the buccal implant bone defect. But collagen membrane coverage showed no additional benefit on alveolar ridge contour stability compared with non-membrane coverage.

Effect of Intact Periosteum on Alveolar Ridge Contour Stability after Horizontal Guided Bone Regeneration in the Posterior Region: a Retrospective and Radiographical Cohort Study.

OBJECTIVE: To radiographically evaluate the effect of intact periosteum in guided bone regeneration (GBR) for the treatment of peri-implant ridge defects in posterior region. METHODS: Twenty-eight patients who satisfied the criteria were included in this study. Buccal dehiscence defects were regenerated using demineralised bovine bone mineral (DBBM). Subjects were divided into two groups: the control group (conventional GBR, buccal trapezoidal flap and DBBM with collagen membrane coverage, n = 14) and the test group (modified GBR, buccal pouch and DBBM with collagen membrane coverage, n = 14). CBCT images obtained immediately after and 3 to 7 months following GBR were used to assess buccal bone thickness (BBT) at a level of 0, 2, 4 and 6 mm below the implant platform. RESULTS: Immediately after surgery, BBT at 0 mm and 2 mm below the implant platform presented a significant difference between the two groups (P < 0.05) with significantly thicker buccal bone in the control group in terms of BBT-0 (3.83 ± 1.01 mm) and BBT-2 (4.88 ± 1.15 mm) than in the test group (2.33 ± 0.66 mm and 3.60 ± 1.10 mm, P = 0.000 and P = 0.008, respectively). After 3 to 7 months of healing, the BBT at all levels showed no significant difference between the two groups (P > 0.05), but more bone graft resorption (BBR) in the control group in terms of BBR-0 (2.45 ± 1.14 mm), BBR-2 (2.09 ± 0.94 mm) and BBR-0% (65.37% ± 26.62%) than the test group (BBR-0 1.07 ± 0.51 mm, P = 0.001; BBR-2, 1.22 ± 0.63 mm, P = 0.008; BBR-0% 45.70% ± 15.52%, P = 0.024). CONCLUSION: In the short term, all treatment modalities achieved similar coronal BBT and the intact periosteum had a positive effect on keeping ridge dimensions even.

Slim the face or not: 3D change of facial soft and hard tissues after third molars extraction: a pilot study.

BACKGROUND: Whether slim the face or not after removed third molars is the concern of some orthodontic treatment candidates. The aim of this article is to explore the volume changes of facial soft and hard tissues after third molars extraction, as well as develop a reproducible clinical protocol to precisely assess facial soft tissue volume change. METHODS: A non-randomized, non-blind, self-controlled pilot study was conducted. 24 adults aged 18-30 had ipsilateral third molars extracted. The body weight change was controlled within 2 kg. Structured light scans were taken under a standardized procedure pre-extraction (T0), three (T1), and six (T2) months post-extraction; CBCTs were taken at T0 and T2. The projection method was proposed to measure the soft tissue volume (STV) and the soft tissue volume change (STVC) by the Geomagic software. The hard tissue volume change (HTVC) was measured in the Dragonfly software. RESULTS: The final sample size is 23, including 5 males (age 26.6 ± 2.5 years) and 18 females (age 27.3 ± 2.5 years). The HTVC was - 2.33 ± 0.46ml on the extraction side. On the extraction side, the STV decreased by 1.396 (95% CI: 0.323-2.470) ml (P < 0.05) at T1, and increased by 1.753 (95% CI: -0.01-3.507) ml (P = 0.05) at T2. T2 and T0 had no difference (P > 0.05). The inter and intra-raters ICC of the projection method was 0.959 and 0.974. There was no correlation between the STVC and HTVC (P > 0.05). CONCLUSIONS: After ipsilateral wisdom teeth extraction, the volume of hard tissue on the extraction side reduces, and the volume of facial soft tissue does not change evidently. However, further research with large sample size is still needed. The STV measurement has excellent repeatability. It can be extended to other interested areas, including forehead, nose, paranasal, upper lip, lower lip and chin, which is meaningful in the field of orthodontics and orthopedics. TRIAL REGISTRATION: ChiCTR, ChiCTR1800018305 (11/09/2018), http://www.chictr.org.cn/showproj.aspx?proj=28868 .

Endoscopic visualization of the inferior alveolar nerve associated with somatosensory changes after impacted mandibular third molar extraction.

The aim of this study is to assess the relationship between somatosensory functional changes and inferior alveolar nerve (IAN) exposure after impacted mandibular third molars (M3M) removal. We recruited 35 patients who underwent impacted M3M extraction near the IAN. The M3Ms were extracted by combined endoscopy, piezosurgery, and contra-angle high-speed turbine handpiece. All IAN canal perforations and exposed regions were recorded and measured by endoscopy after extraction and on cone-beam computed tomography (CBCT) images before extraction. The patients were followed up 1, 7, and 35 days after surgery. A standardized quantitative sensory testing (QST) battery was performed on the lower lip skin. All of 35 cases had exposed IAN on CBCT images, 5 of which had no exposed IAN under endoscopy. For the other 30 cases, the endoscopy-measured IAN length and width were shorter than the CBCT measurements (P < 0.001). The warm and mechanical detection thresholds (MDT) on the operation side were significantly higher than the contralateral side after surgery (P < 0.05). Thermal sensory limen, MDT, and cold pain threshold were strongly correlated with the exposed IAN length and MDT also with the exposed IAN width one day after surgery. In conclusion, it was found that not all exposed IAN in CBCT images were real exposure after surgery. The intraoperative exposed IAN endoscopic measurements were smaller than by CBCT and strongly correlated with some QST parameters.

Bone regeneration using titanium plate stabilization for the treatment of peri-implant bone defects: A retrospective radiologic pilot study.

AIM: To 3-dimensional radiographically assess the effect of titanium plate in guided bone regeneration (GBR) for the treatment of peri-implant ridge defects in esthetic zone. MATERIAL AND METHODS: Nineteen patients with buccal peri-implant defects in the maxillary esthetic zone were treated with GBR using xenograft, autogenous bone, and collagen membrane. Subjects were divided into two groups: control (conventional GBR, 10 patients with 16 implants) and test (GBR with an adjunctive titanium plate; nine patients with 15 implants). Cone-beam computed tomography (CBCT) images obtained immediately after and 5-7 months following GBR were used to assess buccal crestal bone level (BBL) and buccal bone thickness (BBT) at different implant levels. RESULTS: Thirty-one implants in 19 patients were evaluated. Titanium plate exposure occurred in three cases (33.33%) of the test group. After 5-7 months, the mean BBL was located 1.48 ± 0.71 mm coronal to the platform in the test group and 0.90 ± 3.03 mm coronal to the platform in the control group (p = 0.03). The mean over all BBT (BBT-M) was 4.16 ± 0.48 mm in the test group and 2.38 ± 0.97 mm in the control group (p < 0.01). More resorption occurred in the control group than in the test group regarding mean BBL (3.00 ± 3.11 mm vs. 0.78 ± 0.79 mm, respectively; p = 0.04), BBT-M change (1.87 ± 1.59 mm vs. 0.56 ± 0.33 mm, respectively; p = 0.02), and percentage change in BBT-M (40.69 ± 24.01% vs. 11.53 ± 5.86%, respectively; p < 0.01). CONCLUSION: In the short-term, titanium plate-enhanced GBR maintained ridge dimensions better than conventional GBR did.

A three-in-one alveolar process reconstruction protocol for maxillary molar sites with severe residual bone height deficiency: A proof-of-concept pilot study.

BACKGROUND: Implant placement in maxillary molar sites with severe height deficiency often requires multiple surgeries, which was time-consuming, invasive, and subject to serious postoperative complications. PURPOSE: To introduce and assess a three-in-one technique (extraction, alveolar ridge preservation [ARP], and sinus elevation) for augmenting deficiency maxillary molar alveolar ridges. MATERIAL AND METHODS: Fourteen patients with severe posterior maxillary ridge height deficiency underwent extraction, sinus elevation via an intrasocket window and ARP using sticky bone and then covered with acellular dermal matrix (ADM). Primary closure was intentionally not obtained. Cone-beam computed tomography and periapical radiography were used to measure dimensional ridge changes over time. Bone biopsies were taken at implant placement 7-21 months after surgery, which proceeded without additional grafting. Peri-implant soft tissue was assessed after 8-12 months of functional loading. RESULTS: Maxillary molar sites (13 first molars, 1 second molar) with a mean sinus floor height of 1.73 ± 0.86 mm and mean buccal plate thickness of 1.62 ± 1.15 mm were elevated and grafted. Immediately after surgery, the mean sinus floor height was 14.03 ± 1.97 mm and the alveolar thickness at virtual implant platform level was 12.99 ± 1.88 mm. After 5-9 months healing, those measurements decreased by 2.45 ± 1.73 mm (p = 0.000) and 3.88 ± 3.95 mm (p = 0.006), respectively. Healed ridges were composed of 18.74% ± 4.34% mean vital bone and 19.08% ± 9.10% mean residual graft. After 8-12 months of functional loading, the peri-implant tissue appeared healthy, and there was a mean marginal bone loss of 0.12 ± 0.11 mm. CONCLUSIONS: For maxillary first molar sites with severe sinus floor height deficiency, this minimally invasive three-in-one treatment allows for uncomplicated implant placement and short-term functional stability.

Cryoablation treatment of oral and maxillofacial tumors: Five case reports.

Oral and maxillofacial anatomy and function are important and complex. They are involved in facial expressions, chewing, language, breathing, and other functions. It is therefore important to choose the optimal treatment plan for oral and maxillofacial tumors. For patients with who cannot tolerate surgery or who refuse surgery or radiotherapy can be treated with cryoablation. Cryoablation can maintain local tissue integrity and organ function and protect facial integrity. It is a repeatable treatment that, if necessary, can be followed by traditional antineoplastic therapies. This study introduces five cases with severe basic diseases who cannot tolerate or have refused surgery or radiotherapy. The patients were diagnosed as having oral and maxillofacial tumors. These patients experienced painful local swelling or breaking of the tumor. All patients received cryoablation combined with other treatments. Local control of the tumors and improved function and quality of life were achieved. In clinical work, for patients with severe basic diseases who cannot tolerate or refuse surgery or radiotherapy, cryoablation has unique advantages, and this approach is expected to become a widely used treatment for oral and maxillofacial tumors.

Implications of Virtual CBCT-Based Immediate Implant Planning for Maxillary and Mandibular First Molars.

The purpose of his study was to investigate the projected ridge-implant dimensions derived from virtual superimposition of implants on intact first molars mimicking immediate implantation in the mandible (Md1) and maxilla (Mx1) using cone-beam computed tomography (CBCT). The CBCT records of 41 patients (19 males and 22 females) with Md1 or Mx1 were collected. Ten-millimeter-long cylindrical implants with different diameters were virtually positioned at prosthetically ideal angles into interradicular septum using CBCT software. Radiographic alveolar ridge height (ARH), alveolar ridge width (ARW), gap distance, and vertical distance from the implant platform to the alveolar crest were measured. Twenty Mx1s (48.8%) and 21 Md1s (51.2%) were included. The mean ARH values were 7.13 ± 4.32 and 15.64 ± 1.80 mm for Mx1 and Md1, respectively; 87.8% of mesiobuccal sites had gap distance of >2 mm when 6-mm-diameter implants were used. Increasing implant diameter from 6 to 9 mm decreased the percentage of sites with ARW > 2 mm from 80.5% to 41.5% buccally and from 86.4% to 26.8% lingually. The mean vertical distance from the implant platform to the alveolar crest was 1.41 ± 1.09 mm buccally and 1.11 ± 1.10 mm lingually. Immediate implant placement of first molars, especially in the maxilla, requires stringent presurgical evaluation. Implants no wider than 6 mm placed into the interradicular septum may meet acceptable running room and alveolar plate thickness criteria if the jumping distance is grafted. Further clinical trials are needed to confirm these findings in this virtual study.

Alveolar Ridge Preservation in Severely Damaged Molar Socket Using a Polylactic Acid Membrane Without Primary Wound Closure: A Case Series.

PURPOSE: Untreated severely damaged molar sockets often complicate implant placement. This study evaluated membrane degradation, soft tissue healing, and alveolar crest dimensional changes after alveolar ridge preservation (ARP) in severely damaged molar sockets using a polylactic acid membrane (PLA) and xenograft without primary wound closure. MATERIALS AND METHODS: A total of 14 damaged molar sockets in 12 patients were grafted with deproteinized bovine bone mineral, which was covered with a PLA membrane without primary wound closure. Wound healing was evaluated at set times. Three sets of CBCT data taken before surgery, at 1 to 2 weeks, and at 6 to 12 months after surgery were reconstructed and superimposed to analyze dimensional changes of the alveolar crest with volumetric imaging software. RESULTS: Two weeks after ARP, no degradation of PLA membrane was present, and the xenograft had either no exfoliation (7 sites, 50%) or mild exfoliation (6 sites, 42.9%). One to 2 months following ARP, the membrane was partially degraded in 6 sites (42.9%) and completely degraded in 8 sites (57.1%). Nine sites (64.3%) presented with mild graft particle exfoliation, and four sites (28.6%) had granulation tissue covering the bone graft. All sites were fully covered by keratinized mucosa by 6 to 12 months. Compared with baseline measurements, the vertical bone graft height decreased by 2.2 ± 2.2 mm, and central alveolar ridge thickness measured at the level of the virtual implant platform decreased by 5.0 ± 5.1 mm after 6 to 12 months. CONCLUSION: The exposed PLA membrane maintains some barrier function for at least 3 to 4 weeks after ARP in severely damaged molar extraction sites. This technique allowed for implant placements without additional grafting. Future studies should include histologic assessment of the augmented bone and nongrafted control sockets.

Ridge Volume Stability of Maxillary Anterior Implants Placed with Simultaneous Lateral Guided Bone Regeneration during Healing: a Radiographic Analysis.

OBJECTIVE: To assess bone volume stability and identify critical bone graft thickness for guided bone regeneration (GBR) simultaneous to implant placement in the maxillary anterior region. METHODS: Eighteen patients were included in the study and received placement of one maxillary anterior implant combined with GBR using deproteinised bovine bone mineral (DBBM) and resorbable collagen membrane. The multilevel buccal bone thickness (BT) was measured by CBCT 1 to 2 weeks and 5 to 8 months post-implantation (at implant uncovering surgery). RESULTS: Significant buccal alveolar crest collapse (ACCb 1.20 to 1.70 mm) occurred during the mean healing period of 5.3 months (P = 0.000). A greater percentage of ACCb occurred at the coronal aspect of the implant, with 59.24% ± 19.22% at the implant platform and 34.10% ± 30.50% 6.0 mm below the implant platform, respectively. Linear regression analysis demonstrated that if BT was 1.8 to 2.0 mm at the implant platform at uncovering surgery, then it was estimated to have been 4.1 to 4.5 mm immediately post-implantation. CONCLUSION: ACCb after maxillary anterior implant placement with simultaneous GBR occurred more coronally than apically. Excessive alveolar ridge augmentation, up to 4.0 mm of hard tissue buccal to the implant platform, should be achieved at the time of surgery to compensate for this potential resorption.

[Three-dimensional finite element analysis of Kirschner wire fixation configuration for supracondylar fracture of humerus fracture in children].

OBJECTIVE: To establish a new mechanical model of distal humerus in children with epiphysial cartilage, stimulate supracondylar humerus fracture and perform three dimensional finite elements, and study effect of pins numbers, pin tract, outlet height and pin configurations on stability of fixation. METHODS: Three dimensional computed tomography (CT) data of 6-year-old boy with distal humerus was downloaded from picture archiving and communications systems software (PACS), the data of picture was imported into Simpleware and SolidWorks 2016 software to establish distal humerus fracture in children contained ossific nucleus of the capitellum (ONC) and distal cartilage. Normal extense supracondylar humerus fracture model was established to stimulate configurations of crossed and lateral pinning fixation, 30 N was added on the direction of flexion extension and varus valgus, while 50 N was added on the direction of internal and external turning. Stability was analyzed by displacement degree of distal fracture. RESULTS: Among 2-pin configurations, 2-crossed pins were more stable against rotation forces which could resist rotation stress over 2 585 Nmm/ °, while low position through ONC of 2-divergent lateral pins were more stable, which could resist stress of 45 N /mm and 190 N /mm during the test of resistant strains and varus-valgus stress. The third pins was added into the more stable lateral 2-pins, the stability in all directions were increased obviously, and 3 crossed pins is the most stable, stress of flexion-extension, varus-valgus and internal-external turning were 198 N /mm, 395 N /mm and 6 251 Nmm/ °. CONCLUSION: Two-divergent lateral pins could provide enough stability for supracondylar humerus fracture in children. In two-crossed pins, the upper border of MDJ could provide the best stability. Three-crossed pins could offer the best stability against both translation and rotation forces.

Reduced State of the Graphene Oxide@Polyoxometalate Nanocatalyst Achieving High-Efficiency Nitrogen Fixation under Light Driving Conditions.

The nitrogen (N2) reduction to generate ammonia (NH3) is a prerequisite for inputting fixed nitrogen (N) into a global biogeochemical cycle. Developing highly efficient photocatalysts for N2 fixation under mild conditions is still a challenge. Herein, we first report three kinds of reduction states of graphene oxide (GO)@polyoxometalate (POM) composite nanomaterials, which have outstanding photocatalytic N2 fixation activities in pure water without any other electronic sacrificial agents and cocatalysts at atmospheric pressure and room temperature. A lot of experiments show that the remarkable photocatalytic N2 fixation performance of these three nanocatalysts is due to three factors that doping the reduced POMs (also called heteropoly blues) into the reduce GO (rGO) reduces the aggregation state of rGO (from 5 to 2 nm), resulting in rGO exposing many active sites to enhance the N2 adsorption amount, these three nanocatalysts possess a wide absorption spectrum and strong reducibility, which facilitate absorb light energy exciting abundant photoelectrons to activate N2, and rGO can effectively suppress the electrons recombination and rapidly transfer electrons to the absorbed N2 to accelerate NH3 production. Among them, r-GO@H5[PMo10V2O40] (PMo10V2) exhibits the highest NH3 generation efficiency of 130.3 µmol L-1 h-1, which is improved by 65.9 and 97.3% compared to the reduced PMo10V2 (rPMo10V2) and PMo10V2. Introduction of POMs provides a new perspective in the design of high-performance photocatalytic N2 fixation nanomaterials.

High-Throughput Sequencing Analysis of Microbial Profiles in the Dry Socket.

PURPOSE: The aim of this study was to explore and describe the microbial profiles of dry socket (DS) and identify the key microbial population as a possible disease-related factor. MATERIALS AND METHODS: Bacterial samples were collected from patients who underwent surgical mandibular third molar extraction and were divided in 3 groups: the disease (D) group composed of patients who were diagnosed with DS; the treated (T) group composed of patients from the D group who received treatment; and the control (C) group composed of patients who did not have adverse reactions after tooth extraction. Bacterial DNA was extracted and the V3 and V4 hypervariable regions of the bacterial 16S rRNA gene were amplified and subjected to sequencing. Sequence data were analyzed using alpha and beta diversity indices. RESULTS: In total, 772,169 high-quality sequences were detected from 31 samples. Using a 97% similarity level, 531 operational taxonomic units were detected. In addition, 10 phyla, 23 classes, 38 orders, 63 families, and 116 genera were found. Composition of the microbial community in the D group differed considerably from that of the T and C groups. Furthermore, a specific microbial pattern, which included Parvimonas, Peptostreptococcus, Prevotella, Fusobacterium, Slackia, Oribacterium, and Solobacterium species, appeared abundantly in the D group compared with the T and C groups. Moreover, Parvimonas, Peptostreptococcus, Prevotella, and Fusobacterium species had important roles in discriminating the D group from the other 2 groups. CONCLUSION: These results suggest differences in the microbial community composition among DSs, normal-healing sockets, and post-treated sockets. These results provide better insight into the development of DS and enhance the understanding of DS. Nonetheless, further studies are necessary to investigate and confirm how these differential bacteria contribute to the development of the disease.

Polyoxometalates in dye-sensitized solar cells.

Dye-sensitized solar cells (DSSCs) are the third generation of photovoltaic cells developed by Grätzel and O'Regan. They have the characteristics of low cost, simple manufacturing process, tunable optical properties, and higher photoelectric conversion efficiency (PCE). With an ever increasing energy crisis, there is an urgent need to develop highly efficient, environmentally benign, and energy-saving cell materials. Polyoxometalates (POMs), a kind of molecular inorganic quasi-semiconductor, are promising candidates for use in different parts of DSSCs due to their excellent photosensitivity, redox, and catalytic properties, as well as their relative stability. Following a brief introduction to the development of DSSCs and the potential virtues of POMs in DSSCs, we attempt to make some generalizations about the energy level regulation of POMs that is the underlying theoretical basis for their application in DSSCs, and then we summarize the research progress of POMs in DSSCs in recent years. This is organized in terms of the properties of POMs, namely, electron acceptor, photosensitivity, redox and catalysis, based on the accumulation of our research into POMs over many years. Meanwhile, in view of the fact that the properties of POMs depend primarily on their electronic structural diversity, we keep this point in mind throughout the article with a view to revealing their structure-property relationships. Finally we provide a short summary and remarks on the future outlook. This review may be of interest to synthetic chemists devoted to designing POMs with specific structures, and researchers engaged in the extension of POMs to photoelectric materials.

An unprecedented {CuTe} core incorporated in a 36-tungsto-4-silicate polyoxometalate with visible light-driven catalytic hydrogen evolution activity.

We report an unprecedented {CuII14TeIV10} core containing the novel µ,µ-/µ6-TeIVO32- mode and TeIVO44- embedded within a 36-tungsto-4-silicate POT shell, which constitutes the first example of a tellurous copper cluster in POMs. The structure-stabilizing and templating effects of tellurite anions are crucial for this assembly. Moreover, its visible light-driven catalytic H2 evolution activity and related quenching mechanism are demonstrated, and extensive stability studies are presented.

Dimethyltin-functionalized cyclic selenotungstates based on {Se2W12} units.

Two dimethyltin-functionalized selenotungstates have been obtained: K4Na14[Sn(CH3)2Se6W24O94]·16H2O (1) and K8Na18[Sn(CH3)2Se6W40O145(H2O)2]Cl2·41H2O (2). They both remain cyclic selenotungstates based the on {Se2W12} units, where (CH3)2Sn2+ moieties were first introduced into "pure" POMs wheels.

Ag/AgxH3-xPMo12O40 Nanowires with Enhanced Visible-Light-Driven Photocatalytic Performance.

Photocatalysis, a promising technology platform to address the environmental problems, has been attracting considerable attention. In this paper, Ag/AgxH3-xPMo12O40 (simplified as Ag/AgHPMo12) nanowires have been synthesized by a facile solid reaction route and in situ photodeposited method. The results of SEM and TEM indicate that the diameters of AgHPMo12 nanowires are about 45 ± 10 nm, and Ag nanoparticles with diameters in the range of 5-15 nm are uniformly anchored on the surface of AgHPMo12 nanowires. The Ag content in the Ag/AgHPMo12 composite was manipulated by the light irradiation time (Ag/AgHPMo12-x; x stands for the irradiation time; x = 2, 4, 6, 8 h, respectively). With increasing irradiation time, the light absorption of as-synthesized samples in the visible region was gradually enhanced. The Ag/AgHPMo12-4 exhibits the best photocatalytic performance for the degradation of methyl orange and reduction of Cr2O72- under visible-light (λ > 420 nm) irradiation. The study of the photocatalytic mechanism reveals that both Ag and AgHPMo12 can be excited by visible light. The photoinduced electrons were transferred from AgHPMo12 to metallic Ag, and combined with the Ag plasmonic holes. The Ag plasmonic electrons were trapped by O2 to form ·O2-, or directly reduced Cr2O72- to Cr3+. Meanwhile, the ·O2- species and the photogenerated holes of AgHPMo12 were used to oxidize MO or i-PrOH; thus, they showed highly efficient and recyclable photocatalytic performance for removing the organic and inorganic pollutants.

Highly Dispersed Polyoxometalate-Doped Porous Co3 O4 Water Oxidation Photocatalysts Derived from POM@MOF Crystalline Materials.

Rational design of earth-abundant photocatalysts is an important issue for solar energy conversion and storage. Polyoxometalate (POM)@Co3 O4 composites doped with highly dispersive molecular metal-oxo clusters, synthesized by loading a single Keggin-type POM cluster into each confined space of a metal-organic framework (MOF), exhibit significantly improved photocatalytic activity in water oxidation compared to the pure MOF-derived nanostructure. The systematic synthesis of these composite nanocrystals allows the conditions to be tuned, and their respective water oxidation catalytic performance can be efficiently adjusted by varying the thermal treatment temperature and the feeding amount of the POM. This work not only provides a modular and tunable synthetic strategy for preparing molecular cluster@TM oxide (TM=transition metal) nanostructures, but also showcases a universal strategy that is applicable to design and construct multifunctional nanoporous metal oxide composite materials.

A carbon-free polyoxometalate molecular catalyst with a cobalt-arsenic core for visible light-driven water oxidation.

A carbon-free, stable, homogeneous water oxidation catalyst based on the unique hepta-nuclear cobalt-arsenic core ("fused" double-quasi-cubane) and polyoxometalate ligands, Na12[{Co(II)7As(III)6O9(OH)6}(A-α-SiW9O34)2]·8H2O (1), was synthesized, thoroughly characterized and employed to catalyze water oxidation under visible-light-driven conditions.