Nanorod Particles Research Articles

Upcycling of Low‐Value Cathode Materials from Spent Lithium‐Ion Battery to High‐Voltage Cathode with Ultrahigh Rate Capability and Reversibility

AbstractLiMn2O4 and LiFePO4 materials are widely applied in electric vehicles and energy storage. Currently, spent LiMn2O4 and LiFePO4 materials recycling is challenged by long process, high energy consumption, and poor recycling economy due to the indispensable metal separation in their recycling. Aiming at this challenge, an upcycling of low‐value cathode materials to high‐value high‐voltage lithium ferromanganese phosphate (LMFP) by simple leaching and hydrothermal reaction is proposed, and the LMFP material with ultrahigh rate capability and reversibility due to its homogenized element distribution, well‐defined nanorods particles, short Fe/Mn─O bond and long average Li─O bond length is regenerated. The initial discharge capacity reaches 144.2 mAh g−1 with 87% capacity retention after 1000 cycles at 1 C. Even cycling at 5 C, a discharge capacity of 136.9 mAh g−1 with 86.4% capacity retention is achieved after 1000 cycles. Kinetics analysis and characterizations of the regenerated LMFP material after cycling further reveal its fast diffusion ability and stable structure. This work sheds light on the potential value of LMFP material regeneration and offers an economic strategy for upcycling of spent low‐value cathode materials.

Controlling pore size during the synthesis of hydroxyapatite nanoparticles using CTAB by the sol–gel hydrothermal method and their biological activities

Abstract Nanorod and nanosphere hydroxyapatite (HAP) particles were synthesized by the sol–gel hydrothermal method. The size of the synthesized HAP nanoparticles was controlled using cetyltrimethylammonium bromide (CTAB) as a templating agent with molar concentrations (HAP + 0.01 M CTAB, HAP + 0.03 M CTAB, and HAP + 0.1 M CTAB). The purity, size, shape, and elemental composition of HAP were determined using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy, which enabled us to determine the nanostructure formation. Further, Brunauer–Emmett–Teller analysis of the samples proves the size of the pores to be 7–10 nm. Thus, by altering the concentration of CTAB, HAP nanorods were induced along the c-axis. The zeta potential values of −34.7 and −28.7 mV confirmed the stability of pure HAP and HAP + 0.01 M CTAB. Further, the biological activities of the HAP nanoparticles were determined. In the anti-microbial activity test, an increase in the inhibition with an increase in the concentration of pure HAP to 0.1 M CTAB + HAP was observed against S. aureus, S. pyrogens, B. subtilis, E. aerogens, K. pneumoniae, and P. vulgaris. About 76% of antioxidant activity was obtained from the experiments. The drug-release behavior of doxorubicin-loaded pure HAP and CTAB-coated HAP also indicates that the % of drug delivery depends on the pores, which further depends on the CTAB concentration. The cytotoxic assay also revealed potential inhibitory effects against human cancer cell lines (MCF-7), with 65% cell viability recorded at a concentration of 500 μg/ml. These findings indicate that the pore size and shape of HAP play significant roles in their biological activities.

Engineering the apparent quantum yield and emission rate of fluorophore molecules by coupling fluorophore dipoles with plasmon modes of gold using low frequency electric fields

Abstract Localized surface plasmons produced by gold and silver nanostructures have been utilized to enhance the intensity of fluorophore molecules. The issue with using nanostructure plasmons for fluorescence enhancement is their short-range nature (5–50 nm from the nanostructures), which limits accessibility to a few molecules. In addition, fluorophore dipoles needed to be aligned with the plasmon electric fields to maximize the fluorescence enhancement. To address these issues, we used low-frequency electric fields (<5 MHz) and commercially available nanorod and nanosphere samples and studied their effectiveness in enhancing the fluorescence of fluorophore-labeled short single-stranded DNA molecules (22 bases). We demonstrated that DNA molecules and nanorod particles can effectively be manipulated around the charging frequency of DNA molecules (∼3 MHz). Nanorod particles enhanced the fluorescence emission rate by ∼50-fold. When the 3 MHz electric field was introduced, the emission rate increased to over 700-fold. We also found that the introduction of a 3 MHz electric field aided the enhancement of the intrinsic quantum yield fluorophore molecules, which resulted in over a 1000-fold fluorescence enhancement. This enhancement was due to the very high electric produced by polarized DNA dipoles at 3 MHz, which resulted in a torque on fluorophore dipoles and subsequently aligning the fluorophore dipole axis with the plasmon electric field. At a fundamental level, our results demonstrate the role of the low-frequency electric field in the fluorophore–plasmon coupling. These findings can directly be applied to many fluorescence detection systems, including the development of biosensors.

Hydrothermal synthesis and photoluminescent properties of (Ca/Sr)2P2O7: Eu2+ pyrophosphate-based blue-emission phosphors

In this work, the luminescent properties of blue-emission (Ca/Sr)2P2O7: Eu2+ phosphors prepared by hydrothermal synthesis method are extensively investigated. The Rietveld refinement verified that Eu2+ was successfully doped into the phosphors. The SEM results showed that the samples of Ca2P2O7 and Sr2P2O7 were composed of tetragonal particles and short nanorods particles, respectively. Under ultraviolet excitation, the blue emission peak of the sample had a small full width half maximum (FWHM), with Ca2P2O7 (λem = 417 nm, FWHM = 24 nm), Sr2P2O7 (λem = 420 nm, FWHM = 28 nm). The quantum efficiencies of Ca2P2O7: Eu2+ and Sr2P2O7: Eu2+ were 70.13 % and 69.26 %, respectively. Under the temperature of 480 K, the luminescence intensity of Ca2P2O7: 0.03Eu2+ and Sr2P2O7: 0.03Eu2+ phosphors decreased to 30.02 % and 82.47 % of the initial intensity. Therefore, (Ca/Sr)2P2O7: Eu2+ phosphors with narrow-band blue emission have potential applications in Light emitting diodes and transparent display.

Unraveling the electro-oxidation steps of methanol on a single nanoparticle by in situ nanoplasmonic scattering spectroscopy

Understanding the mechanism of methanol oxidation reaction (MOR) remains a challenge in the development of direct methanol fuel cells. Large-scale investigations of the MOR encounter issues related to mass transfer and averaging effects. To address these limitations, exploring the MOR on the surfaces of individual nanocatalyst and precisely identifying the reaction steps can yield valuable insights into the underlying pathways. In this study, we employed in situ nanoplasmonic resonance scattering spectroscopy to dynamically monitor the MOR process on single gold nanorod particles (GNPs) and Pt-coated gold nanoparticles (Pt-GNPs). We observed the evolution of metal hydroxides, which was assumed as the active species. Notably, the dynamic behavior of the surface atomic layers revealed the rate-determining steps for both the GNPs and Pt-GNPs, indicating competitive adsorption of intermediates on the nanocatalyst surface. The resulting inherent reaction mechanism highlights the thermodynamics-dependent catalysts’ redox processes and their surface adsorptions, which holds significance for advancing highly active MOR catalysts.

Biosynthesis of Ag-doped ZnO nanorods using template Bacillus sp. and polyethylene glycol via sol-gel-hydrothermal methods for antifungal application

Synthesis of Ag-ZnO nanorods (Ag-ZnO NR) utilizing biological materials, specifically the extracellular enzymes of Bacillus sp. Combined with polyethylene glycol (PEG) as a nanorod pattern template has been proposed. Polyethylene glycol (PEG) of varying relative molecular mass (Mr): 6000, 8000, and 10000 was used. Characterization of Ag-ZnO NR with ultraviolet spectroscopy (UV–vis) revealed absorption at (λmax) = 300 - 330 nm, a blue shift region that was identical to the growth of the Ag-ZnO crystal nucleus. Infrared spectroscopy (FT-IR) profile of Bacillus sp. revealed high intensity at wave number 1600 -1650 cm−1, indicating the amine NH strain in the extracellular enzyme Bacillus sp.; 1430 – 1387 cm−1, indicating -CH3 strain, and 1050 cm−1 indicating CO in PEG. X-ray diffraction (XRD) showed high intensity at 2θ: 31.75°; 34.41°; 36.25° indicates hexagonal wurtzite ZnO (ICDS-ZnO 2017). In contrast, Ag-doped ZnO exhibited high intensity at 2θ: 38. 07°; 44.28°; 66.35° (ICDS-Ag) with crystallite size of 21.85 nm. Scanning electron microscope (SEM) revealed nanorod and spherical particles of 198.96 nm of Ag-ZnO NR PEG-10000. The antifungal effectiveness that was measured based on the number of free radicals •O2 and •OH in the photocatalytic reaction using a p-benzoquinone scavenger reached 85±0.7 %. The highest antifungal activity was detected with an inhibition zone of 3.65-3.04 mm. This finding is very promising for the green synthesis of ZnO and its application as future antifungal application in textile industries.

CuS/SnS quantum dot-nanorod composites: Ferromagnetic and gigantic dielectric characteristics

In this study, new CuS/SnS nanocomposites were simply synthesized by coprecipitation route for capacitive energy storage applications. The results of the XRD analysis confirmed the formation of hexagonal CuS and orthorhombic α-SnS phases. The TEM images of CuS/SnS (1:1) and CuS/SnS (1:3) composites showed the formation of quantum dot particles (2–3 nm) besides nanorods particles (length 56–80 nm and diameter 9–16 nm). The TEM images of CuS/SnS (3:1) sample illustrated the formation of only quantum dot particles (2–3 nm). Infrared band gap energies of 0.8, 0.95 and 1.25 eV were measured for CuS/SnS (1:1), CuS/SnS (3:1) and CuS/SnS (1:3) composites, respectively. CuS/SnS (1:1) composite has a wide hysteresis loop until magnetic field of ±3500 Oe with magnetization (Ms) and coercivity (Hc) values of 0.009 emu/g and 1000 Oe, respectively. For CuS/SnS (1:3) composite, the hysteresis loop possesses a semi-ferromagnetic shape with measured magnetization value of 0.018 emu/g and Hc of 551 Oe. The ferromagnetic order can be attributed to defects as well as the surface interface interaction between CuS and SnS particles. Remarkably, CuS/SnS composites exhibit a giant dielectric constant (>106) with low temperature dependent, making them promising compositions for capacitive energy storage applications. At room temperature, CuS/SnS (1:1), CuS/SnS (3:1) and CuS/SnS (1:3) composites possess colossal dielectric constant values of ∼2.9 × 106, 5.5 × 105 and 6.3 × 106 at frequency of 42 Hz, respectively.

Alternative dental impression fillers made of nanorod glutinous rice flour particles through precipitation

In this work, nanorod particles were synthesized from a locally available source, glutinous rice flour, using sodium hydroxide (NaOH) through a simple precipitation process. The synthesized nanofillers were then presented as an alternative organic filler for dental impression application to support the making of a diagnostic and working model. Dynamic Light Scattering, Scanning Electron Microscope, Fourier Transform Infrared Spectroscopy, x-ray Diffraction, Energy Dispersive Spectroscopy, Thermogravimetric Analysis, and Differential Scanning Colorimeter were used to characterize the fillers. The particle size measurement, morphology interaction, and composition of glutinous rice flour nanorod particles were also investigated. The cell viability using 3T3L1 cells was assessed to determine the safety of nanorod particles using the MTT assay and trypan blue solution. All treated samples exhibit a change in particle morphology from polyhedral to rod. Additionally, a decrease in crystallinity, dehydration, and gelatinization temperature was observed. The functional group interacting with sodium hydroxide also changes slightly after size reduction. The samples treated with 3000 centrifugation speed without surfactant addition showed changes from the control sample’s 3931.71 nm to the smallest average width particle size of 73.26 nm with an average length of 865.15 nm. All of the treated samples with NaOH and NaOH-surfactant additions met the non-cytotoxicity acceptance criteria in the range of 73.54%–99.58%, according to the cell viability results. The incorporation of 15 wt% of the synthesized nanorod fillers resulted in a 20 μm continuous line as the impression materials specimen, yielding a satisfactory detail reproduction test result. In conclusion, nanorod particles with biocompatible properties have been successfully manufactured and can potentially be used in the future as an alternative dental impression filler materials.

Open-circuit photopotential characterization of photoelectrochemical activities of Au-modified TiO2 nanorods

The open circuit potential (OCP) of a semiconductor electrode can be used to quantify the transient photopotential (Ep), which represents wavelength-dependent charge accumulation and relaxation kinetics of a photoelectrode. Here OCP responses of a plasmonic Au@TiO2 nanorods (NRs) photoelectrode can be quantified without causing electrochemical corrosion of Au. The photogenerated charge accumulation kinetics data based on the wavelength-dependent growth rates of |Ep| can resolve the plasmonic effects on photoelectrochemistry (PEC) of Au@TiO2 NRs. Data fitting with Kohlrausch-Williams-Watts (KWW) stretched exponential kinetics model illustrates the complex charge relaxations at the Au/TiO2 Schottky contact, from which long relaxation lifetimes with broad lifetime distributions can be obtained. This is attributed to the abundant deep defects in the nanostructure TiO2, which has been strongly confirmed by reducing the oxygen vacancies using a post-thermal annealing treatment. Single-particle dark-field scattering (DFS) spectrum is measured with a tunable wavelength light source to support visible light activities of PEC characteristics of Au@TiO2 NRs. Light scattering spectra of >200 single Au@TiO2 NRs particles are collected to compare directly with PEC responses of OCP of the ensemble Au@TiO2 NRs.

Insights into the Role of Nanorod-Shaped MnO2 and CeO2 in a Plasma Catalysis System for Methanol Oxidation.

Published papers highlight the roles of the catalysts in plasma catalysis systems, and it is essential to provide deep insight into the mechanism of the reaction. In this work, a coaxial dielectric barrier discharge (DBD) reactor packed with γ-MnO2 and CeO2 with similar nanorod morphologies and particle sizes was used for methanol oxidation at atmospheric pressure and room temperature. The experimental results showed that both γ-MnO2 and CeO2 exhibited good performance in methanol conversion (up to 100%), but the CO2 selectivity of CeO2 (up to 59.3%) was much higher than that of γ-MnO2 (up to 28.6%). Catalyst characterization results indicated that CeO2 contained more surface-active oxygen species, adsorbed more methanol and utilized more plasma-induced active species than γ-MnO2. In addition, in situ Raman spectroscopy and Fourier transform infrared spectroscopy (FT-IR) were applied with a novel in situ cell to reveal the major factors affecting the catalytic performance in methanol oxidation. More reactive oxygen species (O22-, O2-) from ozone decomposition were produced on CeO2 compared with γ-MnO2, and less of the intermediate product formate accumulated on the CeO2. The combined results showed that CeO2 was a more effective catalyst than γ-MnO2 for methanol oxidation in the plasma catalysis system.

Gemini ionic liquid-based surfactants: efficient synthesis, surface activity, and use as inducers for the fabrication of Cu2O nanoparticles.

Discovery of green and novel synthetic routes for nanoparticles (NPs) has drawn a lot of interest due to the distinct nano size and unusual features as well as applications of such particles. Ionic liquid-based surfactants (ILBSs) and gemini ionic liquid-based surfactants (GILBSs) have become some of the best choices to be used as inducers or dispersing agents for the fabrication of nanoparticles. This work involves the synthesis, spectroscopic characterization, and surface property evaluation of three novel GILBSs (4a-c), which incorporate the imidazolium cation as the polar head with an ethylene spacer. The simple synthetic route includes, first, alkylating imidazole-N1 with the as-prepared fatty alkyl chloroacetates followed by quaternization of two equivalents of imidazole-N2 with ethylene dibromide. Investigations into the compounds' surface characteristics and thermodynamic parameters were carried out. The prepared GILBSs, 4a-c, were then used as inducers at various concentrations for the preparation of cuprous oxide nanoparticles. The size and shape of the produced NPs were examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis in each case to study the effect of concentration on the NP morphology and to determine the best concentration for the NPs fabrication. The XRD patterns of the produced Cu2O NPs contain distinguishable peaks, which refer to crystalline Cu2O. Also, TEM images show that the obtained Cu2O is present in form of well dispersed nanorod particles with sizes about 55 and 23 nm at concentrations of 60 and 200 ppm, respectively.

An effective strategy for preparing transparent ceramics using nanorod powders based on pressure-assisted particle fracture and rearrangement

Achieving full densification of some ceramic materials, such as Y2O3, without sintering aids by spark plasma sintering (SPS) is a great challenge when plastic deformation contributes limitedly to the densification as the yield stress of the material at an elevated temperature is higher than the applied sintering pressure. Herein, we demonstrate that particle fracture and rearrangement is an effective strategy to promote the densification during the pressure-assisted sintering process. Specifically, Y2O3 nanocrystalline powders composed of nanorod and near-spherical particles were synthesized and sintered at various temperatures by the SPS. The results show that the relative density of the ceramics prepared by the nanorod powders is higher than the density of the ceramics from the near-spherical powders after 600 °C due to the fracture and rearrangement of the nanorods at low temperatures, which leads to the decrease of particle size and the increase of density and homogeneity. Based on this novel densification mechanism, ultrafine-grained Y2O3 transparent ceramics with good optical and mechanical properties were fabricated successfully from the nanorod powders.

Improvement of physicochemical properties of ternary nanocomposites based on hydroxyapatite/CuO/graphene oxide for biomedical usages

The nanocomposites (NCs) based on hydroxyapatite (HAP) could be improved into biologically safe and effective antibacterial materials. Combining HAP with copper oxide (CuO) and graphene oxide (GO) in a ternary nanocomposite (TNC) increased the human osteoblast viability in vitro to about 98.3% ± 3%. The structure was also analyzed with XRD, FTIR, XPS. The average roughness (Ra) decreased from 68.2 to 42.4 nm, while the root mean square roughness (Rq) changed slightly from 55.5 to 54.4 nm. The TEM investigation showed a decrease in the diameter and length of nanorod particles from 14 to 37 nm to 11 and 34 nm. In addition, the nano strip particles decreased from 17 to 14 nm in diameter, while a change in length was from 151 to 139 nm in diameter and length, respectively. The nanorods belong to HAP, while nanostrips belong to CuO. The polarization resistance decreased from 108 to around 44.5 (ohm.cm2). The antibacterial activity was done against the gram-negative E. coli, and the gram-positive S. aureus where inhibition zones reached 17.1 ± 1.3 and 14.3 ± 0.7 mm, respectively. The enhancement in cell viability and antibacterial behavior indicate the biocompatibility of the biomaterials for biomedical applications.

Based on the utilization of jarosite residue: The lithium storage performance of α-Fe2O3 materials synthesized from different iron solution systems

• The anion in iron salt has a great impact on the morphology of the prepared α -Fe 2 O 3 . • α -Fe 2 O 3 prepared from sulfate has a high capacity but large fluctuations. • α -Fe 2 O 3 prepared from chloride shows a low capacity but good cycling stability. In this work, three kinds of iron simulation solution systems (FeCl 3 , FeSO 4 , and Fe 2 (SO 4 ) 3 solutions) are prepared and used as an iron source for synthesizing α -Fe 2 O 3 electrode materials by the one-step sucrose-assisted thermal decomposition method. The microstructure and lithium storage performance of the as-prepared α -Fe 2 O 3 materials are systematically studied by XRD, SEM, TGA, FT-IR, XPS, CV, EIS, and discharge/charge measurements. The results demonstrate that the α -Fe 2 O 3 samples prepared from FeSO 4 simulation solution or Fe 2 (SO 4 ) 3 simulation solution are composed of interconnected nanorods particles and contain a certain amount of undecomposed SO 4 2− ; while the α -Fe 2 O 3 sample prepared from FeCl 3 simulation shows irregular particle morphology (with the size ranging from hundreds of nanometers to several microns) and contains a small amount of Cl − . The two α -Fe 2 O 3 samples prepared from sulfate simulation solution exhibit high lithium storage activity but experience large capacity fluctuation during cycling. In contrast, the α -Fe 2 O 3 sample prepared from the FeCl 3 simulation solution gives a lower reversible capacity but much better cycling stability. After 400 cycles at 500 mA g −1 , the α -Fe 2 O 3 samples prepared from FeSO 4 , Fe 2 (SO 4 ) 3 , and FeCl 3 simulation solutions deliver reversible capacities of 947, 1071, and 628 mA h g −1 , respectively. The results reported in this work could provide clues for the structural design and performance modification of Fe-based oxides as anode materials for lithium-ion batteries.

Magnetic Particles Nanorod of ZnO/CuFe2O4 Prepared by Green Synthesized Approach: Structural, Optical and Magnetic Properties, and Photocatalytic Activity

In this study, magnetically separable ZnO/CuFe2O4 nanorod particles were synthesized by the green synthesis approach, using rambutan peel extract (Nephelium lappaceum L.) as a capping agent. The samples were evaluated as photocatalyst for the degradation of Rhodamine B dye driven by solar light irradiation. The XRD patterns represented the specific peaks of ZnO and CuFe2O4 in the ZnO/CuFe2O4 composite. SEM and TEM images showed the rod-like shape of the ZnO/CuFe2O4 composite synthesized using 3 mL (ZCuE3N) of rambutan peel extract. ZCuE3N sample has an increase in photocatalytic activity up to 98.8% in the degradation of Rhodamine B under solar light irradiation for 2 h. Magnetic measurement by VSM revealed that ZnO/CuFe2O4 composite was superparamagnetic. ZnO/CuFe2O4 composites remained stable in an air atmosphere and exhibited promise as a reusable photocatalyst as it can be easily separated from the solution by an external magnetic field.

Nanorod Particles Synthesized from Glutinous Rice Flour Precipitation for Alternative Dental Impression Fillers

Nanorod Particles Synthesized from Glutinous Rice Flour Precipitation for Alternative Dental Impression Fillers

Enzymatic activity of individual bioelectrocatalytic viral nanoparticles: dependence of catalysis on the viral scaffold and its length.

The enzymatic activity of tobacco mosaic virus (TMV) nanorod particles decorated with an integrated electro-catalytic system, comprising the quinoprotein glucose-dehydrogenase (PQQ-GDH) enzyme and ferrocenylated PEG chains as redox mediators, is probed at the individual virion scale by atomic force microscopy-scanning electrochemical atomic force microscopy (AFM-SECM). A marked dependence of the catalytic activity on the particle length is observed. This finding can be explained by electron propagation along the viral backbone, resulting from electron exchange between ferrocene moieties, coupled with enzymatic catalysis. Thus, the use of a simple 1D diffusion/reaction model allows the determination of the kinetic parameters of the virus-supported enzyme. Comparative analysis of the catalytic behavior of the Fc-PEG/PQQ-GDH system assembled on two differing viral scaffolds, TMV (this work) and bacteriophage-fd (previous work), reveals two distinct kinetic effects of scaffolding: An enhancement of catalysis that does not depend on the virus type and a modulation of substrate inhibition that depends on the virus type. AFM-SECM detection of the enzymatic activity of a few tens of PQQ-GDH molecules, decorating a 40 nm-long viral domain, is also demonstrated, a record in terms of the lowest number of enzyme molecules interrogated by an electrochemical imaging technique.

Resonant Concentration-Driven Control of Dye Molecule Photodegradation via Strong Optical Coupling to Plasmonic Nanoparticles.

Photobleaching is one of the basic chemical processes that occur naturally in organic molecules. In this work, we investigate the quantum dynamics of Cy 7.5 dye molecules optically coupled to Au nanorod particles and experimentally demonstrate the decrease of the photobleaching rate in this hybrid system. We discover the effect of a resonance-like behavior not observed before for any type of emitter─the photobleaching rate of the dye molecules reaches a minimum for a suitable number of molecules coupled to the nanoparticle. The manifestation of the effect is the consequence of shifts in the energy levels in the hybrid system caused by the change in the number of molecules coupled to a nanoparticle. The energy shifts are the prerequisite for the effective depopulation of the triplet level, which is responsible for the photodegradation mechanism. The discovered effect paves the way for increasing the efficiency of optoelectronic and photovoltaic devices.

Plasmonic Gold Nanorod Size-Controlled: Optical, Morphological, and Electrical Properties of Efficiency Improved Tin Disulfide Vacuum-Free Hybrid Solar Cells

The different size of plasmonic gold nanorods (NRs) were synthesized by the overgrown seeds method and applied to vacuum-free hybrid solar cells (VFHSCs). Tin disulfide (SnS2) quantum dots were synthesized and used as an n-type material of the device. The synthesized materials were characterized by different techniques such as transmission electron microscopy (TEM), UV-Vis spectroscopy, and atomic force microscopy (AFM). The Au (NRs) had a different of size of NR1 (Width: 4 nm; Length: 12 nm), NR2 (Width: 5 nm; Length: 16 nm), NR3 (Width: 6 nm; Length: 22 nm) which were measured using a TEM technique. The Au NR particles were incorporated into the PEDOT:PSS as a hole transport layer (HTL) of solar cells device. The effects of Au NRs size on the device performance were investigated. A thin film of Zin oxide (ZnO) was used as a buffer layer of the device. The influence of buffer layer thickness on the device’s active layer surface morphology was also studied. At the optimized condition, the highest power conversion efficiency was obtained at about ~3.7%.

One-Pot Synthesis of Ni0.05Ce0.95O2−δ Catalysts with Nanocubes and Nanorods Morphology for CO2 Methanation Reaction and in Operando DRIFT Analysis of Intermediate Species

The valorization of CO2 via renewable energy sources allows one to obtain carbon-neutral fuels through its hydrogenation, like methane. In this study, Ni0.05Ce0.95O2−δ catalysts were prepared using a simple one-pot hydrothermal method yielding nanorod and nanocube particles to be used for the methanation reaction. Samples were characterized by XRD, BET, TEM, H2-TPR, and H2-TPD experiments. The catalytic activity tests revealed that the best performing catalyst was Ni0.05Ce0.95O2−δ, with nanorod morphology, which gave a CO2 conversion of 40% with a selectivity of CH4 as high as 93%, operating at 325 °C and a GHSV of 240,000 cm3 h−1 g−1. However, the lower activation energy was found for Ni0.05Ce0.95O2−δ catalysts with nanocube morphology. Furthermore, an in operando diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis was performed flowing CO2:H2 or CO:H2 mixture, showing that the main reaction pathway, for the CO2 methanation, is the direct hydrogenation of formate intermediate.