Abstract The multivalent states of tungsten oxide offer multiple stoichiometric (WO3 and WO2) and nonstoichiometric WOx (2.72 ≤ x < 3) crystal structures. As x decreases in WOx, the reduced oxygen stoichiometry coincides with enhanced electronic conductivity and the emergence of structural channels within the unit cell. Despite these promising properties, most research has focused on WO3 due to the significant challenges in precisely synthesizing the various WOx phases. This study overcomes this limitation by employing a versatile resistive hot-wire oxidation (RHWO) method, enabling the precise engineering of tungsten-to-oxygen ratios and morphologies in WOx phases. Electrochemical characterization of these compounds indicates that energy storage performance is strongly influenced by crystal phase, morphology, and electrolyte cation size. In particular, clear performance distinction emerged between WO2.90 which shows enhanced capacitance (electric double-layer capacitance (EDLC)) due to fine nanostructures, whereas WO2.72 exhibits both capacitive and diffusion-controlled energy storage behavior, attributed to its larger open channels, higher carrier concentration, and larger concentration of W5+ and W4+ oxidation states. These findings highlight the correlation between crystal structure, morphology, redox behavior, and ionic transport in WOx, providing a foundation for advanced energy storage systems and an eco-friendly pathway for practical supercapacitor (SCs) applications.

Abstract This research has successfully prepared three-dimensional leaf-like copper oxide (CuO) nanostructures on micro-sized Cu powder particles via hot water treatment (HWT). This innovative approach has led to the development of a new core–shell, binder-free, and high-surface-area supercapacitor electrode. The synthesis process involved a simple immersion of Cu powder into hot water stabilized at 75 °C for 24 h. The CuO/Cu powder obtained was combined with DI water and then deposited onto a Cu plate and subjected to annealing at 200 °C in a vacuum furnace to produce a binder-less electrode for electrochemical evaluations. Utilizing SEM and EDS, we thoroughly analyzed the morphology and composition of the CuO nanostructures. X-ray diffraction (XRD) analysis was utilized to unveil the crystal structure of the CuO nanostructures, confirming the presence of leaf-like morphology of CuO. Thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller (BET) were employed to measure the mass of the active material and its specific surface area, respectively. The electrochemical properties of CuO nanostructures were examined by cyclic voltammetry (CV) over various scan rates. The electrochemical resistance of the electrode material was observed using electrochemical impedance spectroscopy (EIS). The results from the electrochemical tests indicated that a peak-specific capacitance of around 220 F/g was achieved when the scan rate was set at 5 mV/s using Na2SO4 electrolyte. Furthermore, the capacitance retention rate was about 38% after 1500 consecutive cycles. Our findings indicate that the HWT-grown CuO/Cu nanostructured powder shows promise for pseudo-supercapacitor applications, which could potentially bring about a revolution in the field of energy storage. Graphical Abstract

The synthesis of metal oxide nanostructures commonly requires sophisticated scientific apparatus, complex synthesis processes, and time-inefficient processes, or produces undesirable by-products. We have overcome these challenges by developing a low-cost and time-effective synthesis technique that allows considerable control of growth energetics enabling exploration of crystal phases that occupy small regions of phase space. Here, we report on nanostructures of tungsten oxide WO2.76 (W17O47) synthesized in a single-step process, which takes roughly one minute to grow WO2.76 and an additional roughly 30 min for preparation. The nanostructures were synthesized directly onto tungsten filaments by resistive heating of tungsten wire in an oxygen environment. The nanostructures are rod-shaped with an average diameter of 25 +/- 9 nm. Their physical properties were investigated through an arsenal of experimental probes including scanning electron microscopy, X-ray diffraction, Raman spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. The improved electrochemical performance in comparison to WO3 along with its large dielectric constant suggests that despite WO2.76 being somewhat elusive to researchers, it demonstrates the potential of this compound for functional applications such as supercapacitors and photocatalytic water splitting.

Hot water treatment (HWT) is a versatile technique for synthesizing metal oxide nanostructures (MONSTRs) by immersing metal substrates in hot water, typically in glass beakers. The proximity of substrates to the heat source during HWT can influence the temperature of the substrate and subsequently impact MONSTR growth. In our study, zinc (Zn) substrates underwent HWT at the base of a glass beaker in contact with a hot plate and at four different vertical distances from the base. While the set temperature of deionized (DI) water was 75.0 °C, the substrate locations exhibited variations, notably with the base reaching 95.0 °C. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Raman spectroscopy showed stoichiometric and crystalline zinc oxide (ZnO) nanorods. ZnO rods on the base, exposed to higher temperatures, displayed greater growth in length and diameter, and higher crystallinity. Nanorods with increasing vertical distances from the base exhibited a logarithmic decrease in length despite identical temperatures, whereas their diameters remained constant. We attribute these findings to crucial HWT growth mechanisms like surface diffusion and “plugging”, influenced by temperature and water flow within the beaker. Our results provide insights for optimizing synthesis parameters to effectively control MONSTR growth through HWT.

Tissue-engineering technologies have the potential to provide an effective approach to bone regeneration. Based on the published literature and data from our laboratory, two biomaterial inks containing PLGA and blended with graphene nanoparticles were fabricated. The biomaterial inks consisted of two forms of commercially available PLGA with varying ratios of LA:GA (65:35 and 75:25) and molecular weights of 30,000–107,000. Each of these forms of PLGA was blended with a form containing a 50:50 ratio of LA:GA, resulting in ratios of 50:65 and 50:75, which were subsequently mixed with a 0.05 wt% low-oxygen-functionalized derivative of graphene. Scanning electron microscopy showed interconnected pores in the lattice structures of each scaffold. The cytocompatibility of human ADMSCs transduced with a red fluorescent protein (RFP) was evaluated in vitro. The in vivo biocompatibility and the potential to repair bones were evaluated in a critically sized 5 mm mechanical load-bearing segmental femur defect model in rats. Bone repair was monitored by radiological, histological, and microcomputed tomography methods. The results showed that all of the constructs were biocompatible and did not exhibit any adverse effects. The constructs containing PLGA (50:75)/graphene alone and with hADMSCs demonstrated a significant increase in mineralized tissues within 60 days post-treatment. The percentage of bone volume to total volume from microCT analyses in the rats treated with the PLGA + cells construct showed a 50% new tissue formation, which matched that of a phantom. The microCT results were supported by Von Kossa staining.

Fluoropolymer-doped S-P3MEET films showed better transmittance and work function alignment at the perovskite/HTL interface leading to higher power conversion efficiency.

Chalcogenide nanoparticles have become a very active field of research for their optoelectronic and biological properties. This article shows the production of tellurium dioxide nanoparticles (TeO2 NPs) by pulsed laser ablation in liquids. The produced nanoparticles were spherical with a diameter of around 70 nm. The energy band gap of those nanoparticles was determined to be around 5.2 eV. Moreover, TeO2 NPs displayed a dose-dependent antibacterial effect against antibiotic-resistant bacteria such as multidrug-resistant Escherichia coli (MDR E. coli) and methicillin-resistant Staphylococcus aureus (MR S. aureus). The "naked" nature of the nanoparticle surface helped to eradicate the antibiotic-resistant bacteria at a very low concentration, with IC50 values of ∼4.3 ± 0.9 and 3.7 ± 0.2 ppm for MDR E. coli and MR S. aureus, respectively, after just 8 h of culture. Further, the IC50 values of the naked TeO2 NPs against melanoma (skin cancer) and healthy fibroblasts were 1.6 ± 0.7 and 5.5 ± 0.2 ppm, respectively, for up to 72 h. Finally, to understand these optimal antibacterial and anticancer properties of the TeO2 NPs, the reactive oxygen species generated by the nanoparticles were measured. In summary, the present in vitro results demonstrate much promise for the presently prepared TeO2 NPs and they should be studied for a wide range of safe antibacterial and anticancer applications.

Polymer Electrolyte Membrane Fuel Cell (PEMFC) is one of the most promising energy conversion technologies with zero carbon emission, and has received significant attention especially for automotive applications. State-of-the-art PEMFCs use platinum or platinum-alloy nanoparticles distributed on carbon as the electrocatalyst. However, there are still significant challenges for PEMFCs before widespread commercialization including short lifetime and high initial cost mainly originating from the catalyst related issues. Recent research efforts have focused on approaches that would improve catalyst lifetime, reduce its manufacturing cost, and reduce the amount of platinum used without losing activity. In this work, we present a new core-shell electrocatalyst design that can potentially address the challenges of conventional PEMFC catalysts. The design involves a shell of nanocolumnar Pt thin film coated on carbon support core (Pt-TF/C). Pt-TF layers were deposited on carbon powder by high-pressure sputtering (HIPS) and their oxygen reduction reaction (ORR) activity relevant to PEMFCs was investigated. HIPS is a simple physical vapor deposition technique that is scalable and easily applicable to industrial sputter deposition systems, in which atoms come to the substrate surface at different angles to form columnar structures. Pt-TF/C powder samples with various types of carbon were produced and studied to investigate their ORR performance. Electrochemical characterization of the samples was performed by cyclic voltammetry and rotating disk electrode measurements. The Pt-TF-to-carbon mass ratios were measured by quartz crystal microbalance and thermogravimetric analysis. X-ray diffraction analysis showed the presence of Pt on the carbon support. Our preliminary results on specific activity, mass activity, and electrochemically active surface area indicate a promising electrocatalyst durability.

Background Traditionally, severe bone defects caused by trauma or disease are treated with autologous bone grafts, but can result in additional pain and discomfort for the patient. Bone tissue engineering strategies involving the use of osteoprogenitor cells and novel scaffolds offer hope as an alternative therapy for the treatment of bone defects. We have demonstrated that adipose derived stem cells (ADSCs) grown on graphene nanoparticles with low oxygen content (LOG) results in spontaneous osteoblast differentiation in vitro. Due to the dark nature of the LOG surface, ADSCs cannot be monitored by traditional light microscopy. Hence, the goal of this work was to create fluorescent ADSCs that can be used for studies on LOG surfaces. Objective Determine if fluorescent ADSCs transduced by lentivirus undergo osteogenesis on low-oxygen content graphene (LOG) surfaces. Hypothesis Fluorescently transduced ADSCs behave similarly to non-transduced ADSCs on LOG coated surfaces. Methods Adipose tissue was obtained from human patients undergoing pannulectomies via an approved IRB and patient consent. In vitro expanded ADSCs were transduced at a multiplicity of infection (MOI) of 5 (>90% transduction efficiency) with lentivirus particles encoding green fluorescent protein (GFP), expanded in vitro, characterized by trilineage staining/flow cytometry and used for characterization on LOG surfaces. Results Our data show that ADSCs, obtained from two different human patients, undergo trilineage differentiation normally by histological staining and express positive surface markers (CD29, CD44, CD73, CD90, CD105) and lack expression of negative surface markers (CD34, CD45, CD106, HLA-DR) indicative of stem cells, by flow cytometry. Moreover, these same ADSCs transduced by lentivirus particles, encoding GFP, undergo trilineage differentiation normally and expression of fluorescence is not reduced/lost upon differentiation. GFP expressing ADSCs seeded, grown and visualized on LOG coated surfaces demonstrated spontaneous osteogenesis in the absence of exogenous inducing factors compared to control ADSCs on polystyrene dishes via alizarin red staining and quantitation. Furthermore, addition of dexamethasone, beta-glycerophosphate and ascorbic acid resulted in higher osteogenesis on LOG coated surfaces. Conclusions Based on these data we conclude the following: 1) lentivial transduction of ADSCs does not alter trilineage differentiation potential; 2) GFP expressing ADSCs can be used to continuously monitor cells on LOG coated surfaces; 3) Transduced ADSCs undergo osteogenesis similar to non-transduced ADSCs on LOG coated surfaces; and 4) ADSCs obtained from different human patients behaved similarly on LOG coated surfaces suggesting LOG can be used for regenerative medicine purposes with any human ADSCs.

Background Degenerative bone diseases caused by trauma, cancer, or aging imposes a global health care burden every year. Treatment strategies include directing stem cell differentiation through osteogenesis, thereby creating new bone material for repairment. We previously identified that adult mesenchymal stem cells (MSCs) cultured on graphene nanoparticles spontaneously supports osteoblast development in vitro. However, the osteo-genetic signaling of MSCs in the presence of graphene is largely unknown. Therefore, this study sought to measure genetic expressions of MSCs cultured on graphene using focused PCR arrays. Methods MSCs were extracted from human adipose tissue (hAD-MSCs) and human bone marrow (hBM-MSCs) and expanded in growth media. For experimental conditions, hAD-MSCs and hBM-MSCs were seeded on a graphene surface and cultured for either 7 or 21 days. At each time point, cells were extracted for total RNA and reverse transcribed to cDNA before loading onto RT2 Profiler PCR Human Osteogenesis Array (Qiagen, Hilden, Germany). Gene expressions of both cell lines were compared either over time (day 7 as the control to day 21 as the treated group) or between both cell lines at each time point (hAD-MSCs to hBM-MSCs at day 7 or day 21). Results were analyzed using Qiagen Gene Globe software to determine the relative fold change in comparison to the control. Fold changes were considered statistically significant at p < 0.05. Results We examined expression of four transcriptional genes known to control stem cell fate: DLX5, RUNX2, SOX9, and SP7. In hAD-MSCs, RUNX2 was up-regulated while SOX9 and SP7 were down-regulated, suggesting RUNX2 to be a master regulator in hAD-MSCs. In contrast, all genes were down-regulated in hBM-MSCs. However, when hBM-MSCs were compared to hAD-MSCs, all genes were up-regulated at both time points. Interestingly, the fold changes at day 7 were more robust compared to that observed at day 21, suggesting transcriptional regulation of osteogenesis in hBM-MSCs occurs at an earlier time point. Secondly, we examined common markers of osteogenesis including ALPL, BGLAP, PHEX, and SPP1. In hAD-MSCs, ALPL, BGLAP, and PHEX were upregulated, while SPP1 was down-regulated.In hBM-MSCs, ALP, PHEX, and SPP1 were up-regulated, overall suggesting osteo-genetic signaling by graphene occurs in both cell types. Conclusion hAD-MSCs and hBM-MSCs cultured on graphene showed significant changes in osteogenic gene expressions. These cells were cultured in absence of any chemical inducers, suggesting graphene nanoparticles alone commits osteo-genetic signaling of MSCs. We also observed that osteogenesis of hBM-MSCs may occur at an earlier time point than hAD-MSCs. Lastly, we identified DLX5 as a novel osteogenic regulator supported by graphene. Overall, we show that MSCs isolated from two independent tissue sources spontaneously express osteogenic genes in the presence of graphene.

Defects within the long bones of patients from serious complications can carry extensive damage. The design and implantation of a biofabricated biocompatible implant into the nonunion plays an important role in promoting bone and vasculature. Microcomputed tomography (micro-CT) is a fundamental apparatus for evaluating biomaterial-osteo remodeling and regeneration. It can provide information about the biocompatibility of an implant as well as the 3D microarchitecture and distribution of tissue in the region of interest (ROI). This study was performed to evaluate the in vivo biocompatibility, and osseointegration of novel biofabricated graphene-based scaffolds. Two scaffold iterations of poly (lactic-co-glycolide) (PLGA) [Mix 1 - 50:50+65:35] and [Mix 2 50:50+75:25] were blended with two forms of graphene. A 5mm segmental femur defect created in 6-8 week old female Sprague Dawley rats was used as the test model. Defects were monitored radiographically at days 7, 14, 21, 30 and 60. Rats were sacrificed at 60 days post-treatment and their femurs were harvested for micro-CT and histological analyses. Micro-CT provided visualization of full femur prior to histology and helped to define ROI which facilitated proper orientation for sectioning. Subsequently, the bone volume to tissue volume ratios for each bone were compared at four different thresholds in order to capture the new trabecular and cortical bone throughout the defect. All of the rats were weight bearing within 3 days of surgery. Evaluation of the decalcified samples using hematoxylin/eosin and Masson Trichrome staining demonstrated healthy osseointegration of the implant with the natural tissue. There was no evidence of any adverse reaction at the surgery site, confirming the in vivo biocompatibility of the polymer and the nanoparticles. This study demonstrates that implants fabricated with blended PLGA polymers containing graphene-based nanoparticles can be used safely in weight-bearing rodent bone defects. Implants can be used to deliver mesenchymal stem cells and growth factors as therapeutic modalities.

We previously reported the development of an osteogenic bone filler scaffold consisting of degradable polyurethane, hydroxyapatite, and decellularized bovine bone particles. The current study was aimed at evaluating the use of this scaffold as a means of local antibiotic delivery to prevent infection in a bone defect contaminated with Staphylococcus aureus . We evaluated two scaffold formulations with the same component ratios but differing overall porosity and surface area. Studies with vancomycin, daptomycin, and gentamicin confirmed that antibiotic uptake was concentration dependent and that increased porosity correlated with increased uptake and prolonged antibiotic release. We also demonstrate that vancomycin can be passively loaded into either formulation in sufficient concentration to prevent infection in a rabbit model of a contaminated segmental bone defect. Moreover, even in those few cases in which complete eradication was not achieved, the number of viable bacteria in the bone was significantly reduced by treatment and there was no radiographic evidence of osteomyelitis. Radiographs and microcomputed tomography (µCT) analysis from the in vivo studies also suggested that the addition of vancomycin did not have any significant effect on the scaffold itself. These results demonstrate the potential utility of our bone regeneration scaffold for local antibiotic delivery to prevent infection in contaminated bone defects.

The use of synthetic materials for biomedical applications is ever expanding. One of the major requirements for these materials is biocompatibility, which includes prevention of immune system responses. Due to the inherent complexity of their structural composition, the polyurethane (PU) family of polymers is being used in a variety of medical applications, from soft and hard tissue scaffolds to intricate coatings on implantable devices. Herein, we investigated whether two polymer materials, D3 and D7, induced an immune response, measured by their effects on a dendritic cell (DC) line, JAWS II. Using a lactate dehydrogenase cytotoxicity assay and Annexin V/PI staining, we found that the PU materials did not induce cytotoxicity in DC cells. Using confocal microscopy, we also showed that the materials did not induce activation or maturation, as compared to positive controls. This was confirmed by looking at various markers, CD80, CD86, MHC class I, and MHC class II, via flow cytometry. Overall, the results indicated that the investigated PU films are biocompatible in terms of immunotoxicology and immunogenicity and show great promise for use in regenerative medicine.

Cesium formadinium methylammonium triple-cation (CsFAMA) lead mixed-halide perovskites have been reported to promote unique photovoltaic properties with high efficiency and minimal hysteresis effects. Perovskite film quality is a vital parameter for improving the performance of perovskite solar cells (PSCs). Here, we report the growth of CsFAMA perovskites with microscale grains passivation grain boundaries by mixing HC(NH2)(2)I (FAI) and CH3NH3Br (MABr) in isopropanol (IPA) as a post-treatment step to cause controlled Ostwald ripening, leading to secondary grain growth. Compared to the conventional preparation of perovskite films with a free organic halide antisolvent, this mixed-cation mixed-halide post-treatment created higher quality perovskite films in terms of morphology, electronic properties, energy level alignment, and carrier recombination, with the band gap adjusted at the optimal concentration. Treatment with the single cation and single halide presented by FAI and/or MABr in IPA treatment was also investigated, and the results showed that multiple band gap perovskite structures were obtained, which could be beneficial for band gap engineering. This method of perovskite preparation was tested in an inverted planar configuration with a hole transport layer (HTL) based on sulfonated poly(thiophene-3-[2-(2-methoxy-ethoxy)ethoxy]-2,5-diyl) (SP3MEET). The efficiency of the PSCs was dramatically boosted from 13.80% with the organic halide-free antisolvent to 17.62% when the mixed-cation mixed-halide approach was used. In addition, the PSCs treated with the mixed-cation mixed-halide solution exhibited excellent reproducibility, with a high fill factor and eliminated hysteresis. The CsFAMA photovoltaic device based on the single organic cation and single halide treatment approach showed power conversion efficiency of 15.82 and 15.90% for the FM and MABr-treated films, respectively. Characterization of the S-P3MEET as HTLs found that good optoelectronic and morphological properties lead to improve the performance of the inverted PSC. However, with further research to align the energy levels at the S-P3MEET/perovskite interface, greater improvements in the PSCs are expected.

Background In the last decade, graphene surfaces have consistently supported osteoblast development of stem cells, holding promise as a therapeutic implant for degenerative bone diseases. However, until now no study has specifically examined the genetic changes when stem cells undergo osteogenic differentiation on graphene. Results In this study, we provide a detailed overview of gene expressions when human mesenchymal stem cells (MSCs) derived from either adipose tissue (AD-MSCs) or bone marrow (BM-MSCs), are cultured on graphene. Genetic expressions were measured using osteogenic RT 2 profiler PCR arrays and compared either over time (7 or 21 days) or between each cell source at each time point. Genes were categorized as either transcriptional regulation, osteoblast-related, extracellular matrix, cellular adhesion, BMP and SMAD signaling, growth factors, or angiogenic factors. Results showed that both MSC sources cultured on low oxygen graphene surfaces achieved osteogenesis by 21 days and expressed specific osteoblast markers. However, each MSC source cultured on graphene did have genetically different responses. When compared between each other, we found that genes of BM-MSCs were robustly expressed, and more noticeable after 7 days of culturing, suggesting BM-MSCs initiate osteogenesis at an earlier time point than AD-MSCs on graphene. Additionally, we found upregulated angiogenic markers in both MSCs sources, suggesting graphene could simultaneously attract the ingrowth of blood vessels in vivo. Finally, we identified several novel targets, including distal-less homeobox 5 ( DLX5 ) and phosphate-regulating endopeptidase homolog, X-linked ( PHEX ). Conclusions Overall, this study shows that graphene genetically supports differentiation of both AD-MSCs and BM-MSCs but may involve different signaling mechanisms to achieve osteogenesis. Data further demonstrates the lack of aberrant signaling due to cell-graphene interaction, strengthening the application of specific form and concentration of graphene nanoparticles in bone tissue engineering. Graphic abstract

Nanocomposites containing mixed metal oxides show excellent phosphate removal results and are better compared to individual metal oxides. In this research, cerium/manganese oxide nanocomposites, embedded on the surface of modified cellulose pine wood shaving, were synthesized by a simple technique that is both eco-friendly and economically feasible. No toxic or petroleum chemicals were employed during preparation. Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), surface area analysis, and attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy were performed to study the shape and size of nanocomposites as well as composition of elements present on the surface of the nanocomposites. Adsorption isotherm (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich) and kinetic studies (pseudo first and second-order, Elovich and Weber-Morris) were carried out to determine the adsorption mechanism for phosphate removal from contaminated water. The maximum adsorption capacity of nanocomposites was found to be 204.09 mg/g, 174.42 mg/g, and 249.33 mg/g for 100 mg, 300 mg, and 500 mg, respectively. The results indicate that the nanocomposites were able to decrease the phosphorus concentration from 10 to 0.01 ppm, below the threshold limit required by EPA guidelines in the USA. We also demonstrated that the media could be regenerated and reused five times without loss of performance.

Effective graft technologies for bone repair have been a primary focus in the field of bone tissue engineering. We have previously fabricated and examined a nanocomposite composed of polyurethane, nano-hydroxyapatite, and decellularized bone particles, which demonstrated osteobiologic characteristics. To evaluate the underlying mechanisms of this biomaterial, human adipose-derived mesenchymal stem cell seeded scaffolds were assessed using a combinatorial approach of transcriptomic and metabolomic analyses. Data from osteogenic and signal transduction polymerase chain reaction arrays and small molecule abundances, measured through liquid chromatography-mass spectrometry, were cross-examined using Integrated Molecular Pathway Level Analysis, Database for Annotation, Visualization, and Integrated Discovery, and ConsensusPathDB online tools to generate a fundamental collection of scaffold-influenced pathways. Results demonstrated upregulation of key osteogenic, cellular adhesion cell signaling markers and indicated that Hedgehog and Wnt signaling pathways were primary candidates for the osteobiologic mechanisms of the scaffold design. The detection of complimentary metabolites, such as ascorbate, further indicates that scaffolds generate intricate cellular environments, promoting cell attachment and subsequent osteodifferentiation.

Emeraldine-based polyaniline (EB-PANI) was synthesized via oxidative polymerization of aniline in aqueous acid. Various aliquots of graphene oxide (GO) aqueous dispersion were added to aniline during polymerization to achieve a mass percent of GO in the PANI:GO nanocomposites of 0%, 0.49%, 2.4%, 4.9%, 7.3%, 9.8%, 12.2%, and 24.5%, respectively. TEM images of the GO taken from different locations showed that most of the GO is either a double layer or multilayer graphene sheet—although some of the locations showed a single-layer graphene sheet. Raman shift of GO presents the G band located at 1591 cm−1 and the D band located at 1321 cm−1. The thermogravimetric analysis (TGA) of the PANI:GO nanocomposite showed the evidence of existing GO in PANI. The X-ray photoelectron spectroscopy (XPS) narrow scans of EB-PANI, GO, and PANI:GO showed a maximum that is assigned to the C–C peak position (284.8 eV). The deconvolution of the C1s peak in EB-PANI reveals the presence of C–N/C=N species (285.8 eV) assigned to the amine and imine nitrogens in polyaniline. The acid-free hole transport layer (HTL) synthesized from PANI:GO composites was used in two different types of organic solar cells (OPVs), i.e., P3HT:PC60BM (1:0.6) and PCDTBT:PC70BM (1:4). The highest power conversion efficiency (PCE) as a function of GO loadings in the PANI:GO nanocomposites for P3HT:PCBM cells was for the nanocomposite PANI:GO-7.5 with an average of ~ 0.2%, where the GO loading was 7.3% w/w. Equivalently, the PCDTBT:PCBM cells exhibited the highest PCE for PANI:GO-7.5 nanocomposite (~ 0.5%), as well.

Phosphate is one of the most costly and complex environmental pollutants that leads to eutrophication, which decreases water quality and access to clean water. Among different adsorbents, biochar is one of the promising adsorbents for phosphate removal as well as heavy metal removal from an aqueous solution. In this study, biochar was impregnated with nano zinc oxide in the presence of glycine betaine. The Zinc Oxide Betaine-Modified Biochar Nanocomposites (ZnOBBNC) proved to be an excellent adsorbent for the removal of phosphate, exhibiting a maximum adsorption capacity of phosphate (265.5 mg. g(-1)) and fast adsorption kinetics (similar to 100% removal at 15 min at 10 mg. L-1 phosphate and 3 g. L-1 nanocomposite dosage) in phosphate solution. The synthesis of these benign ZnOBBNC involves a process that is eco-friendly and economically feasible. From material characterization, we found that the ZnOBBNC has similar to 20-30 nm particle size, high surface area (100.01 m(2) . g(-1)), microporous (25.79 angstrom) structures, and 7.64% zinc content. The influence of pH (2-10), coexisting anions (Cl-, CO32-, NO3- and SO43-), initial phosphate concentration (10-500 mg. L-1), and ZnOBBNC dosage (0.5-5 g. L-1) were investigated in batch experiments. From the adsorption isotherms data, the adsorption of phosphate using ZnOBBNC followed Langmuir isotherm (R-2 = 0.9616), confirming the mono-layered adsorption mechanism. The kinetic studies showed that the phosphate adsorption using ZnOBBNC followed the pseudo-second-order model (R-2 = 1.0000), confirming the chemisorption adsorption mechanism with inner-sphere complexion. Our results demonstrated ZnOBBNC as a suitable, competitive candidate for phosphate removal from both mock lab-prepared and real field-collected wastewater samples when compared to commercial nanocomposites.