TiO2 Nanocubes Research Articles

Synergistic effect of In2O3 nanocuboids and TiO2 nanocubes in electron transport bilayer for carbon-based perovskite solar cells

Bilayer-based electron transport layers (ETLs) are recently emerging due to their benefits in the efficient charge carrier extraction and transportation with diminished interfacial recombination loss. Here, the carbon electrode-based perovskite solar cells (C–PSCs) with mesoscopic bilayer-oriented ETLs using In2O3 nanocuboids and varied concentrations of TiO2 nanocubes were fabricated and their performances were evaluated. In2O3 nanocuboids and TiO2 nanocubes were synthesized through hydro and solvothermal routes respectively. The synthesized samples' structural, morphological, and optical behaviours were characterized by PXRD, FESEM, HRTEM and UV–Vis spectroscopy. With pertinent studies, the impact of all the variants of bilayer-based ETLs on the formation of the perovskite layer was thoroughly investigated. The device based on monolayer ETL has achieved power conversion efficiency (PCE) of 6.9 % with current density (Jsc) of 18.69 mA/cm2. The highest PCE of 10.7 % with Jsc of 22.15 mA/cm2 was achieved for the champion device with the optimized bilayer of In2O3/TiO2 (200 mg/ml). This champion device showed ambient stability (at 35 °C with ∼70 % humidity) of 83 % from its initial PCE for 35 days without any encapsulation. Thus, the suitable morphology of the bilayer-based ETL facilitated the interface passivation by the self-embedding process, which played a significant role in the improvement of the cell performance.

Highly sensitive electrochemical volatile organic compound (Acetone) sensing based on TiO2 Nanocubes @Polyaniline nanostructure

The identification of volatile organic compounds (VOCs) as biomarkers has gained significant attention as a non-invasive point-of-care (POC) diagnostic route. VOC concentrations in the human body offer insights into pathophysiological states and aid in the detection of various diseases. This research article focuses on the synthesis of TiO2 Nanocubes (TNC) and TNC@Polyaniline nanocomposite (TNCP) via sol–gel and in-situ polymerization. Structural and morphological analyses were conducted using XRD, FESEM, and TEM techniques. Additionally, disposable screen-printed carbon electrodes (SPCE) were employed to investigate the electrochemical behaviour. The TNCP/SPCE-based VOC biomarkers exhibited exceptional performance, including a remarkably low detection limit of 0.002 µM and a superior sensitivity of 2869.76 µA mM−1cm−2 within the linear range of 1–1000 μM. These results demonstrate that TNCP holds significant potential as a superior VOC biomarker in biomedical applications, particularly for diabetic diagnosis.

Ultra-small TiO2 nanocubes with highly active (0 0 1) facet for acetone fast detection and diagnosis of diabetes

Early and painless detection of type-I diabetic patients by detecting acetone concentration in their exhaled breath would be a rapid and effective means. TiO2 materials with exposed active (001) facet were synthesized mostly with HF as raw material, and the particle size was relatively large. In this work, (001) and (101) facets co-doped TiO2 nanocubes with particle size < 50 nm were successfully prepared by a simple one-step hydrothermal process assisted by the ionic liquid ([Bmim][BF4]) as the fluorine source and morphology modifier. Due to the exposure of the active (001) facets, the sensor exhibited good gas response to acetone gas at a low operating working temperature (OWT) of 170 °C with a detection limit as low as 30 ppb and a response time of only 2.2 s for 100 ppm acetone gas, and also relatively excellent selectivity, reproducibility, moisture resistance and long-term stability. It is worthy to point that, the changes of acetone concentration were compared in exhaled gas from healthy people and type-I diabetic patients, and the responses to exhaled gas of type-I diabetic patients were also tracked at different time in the same day. This provides significant convenience for early and painless diagnosis of type-I diabetic patients.

Ni-doped TiO2 nanocubes wrapped by CNTs for synergic photocatalytic CH4 conversion

Direct conversion of CH4 to high valued chemicals under mild conditions is attractive but full of challenges. Here, we present a ternary composite that consists of Ni-doped TiO2 nanocubes (NCs) and CNTs as a new kind of catalyst (denoted as CNTs-Ni@TiO2 NCs) for CH4 photocatalytic conversion to C1 oxygenated products at 30 °C. Using H2O2 as an oxidant, a high C1 oxygenated products yield and selectivity of 1.43 mol/(molNi·h) and 95.6% can be reached in 2 h at 30 °C. The superior photocatalytic performance resulted from the synergistic effects of TiO2 NCs, Ni species, and CNTs such as enhanced visible light absorption, improved electron/hole separation and charge transfer property, and lowered C-H bond cleavage energy required for CH4 activation, were carefully studied. Good reusability of the catalyst was studied by recycle experiments. Possible reaction mechanism based on the radical routes were carefully discussed by combining in-situ Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, electron spin resonance spectroscopy, radical scavenger experiments and density functional theory calculation.

Morphology and crystal–plane dependence of CeO2–TiO2 catalysts: Activity and mechanism for the selective catalytic reduction of NOx with NH3

CeO2–TiO2 catalysts with four different morphologies were successfully synthesized by a hydrothermal method and tested for selective catalytic reduction of NOx with NH3 (NH3–SCR). For the four catalysts, CeO2–TiO2 nanocubes (CT–NC) and nanorods (CT–NR) preferentially exposed {100} and {110} facets, respectively; furthermore, nanosheets (CT–NS) and nanospheres (CT–NH) mainly exposed {111} facet. Interestingly, CT–NH catalyst showed the best NH3–SCR performance and the NOx conversion exceeded 97% at 325 °C. Through a series of characteristic methods manifested that the short–range ordered structure of Ce–O–Ti in CT–NH catalyst provided stronger surface acidic sites to promote the high–temperature activity. Moreover, the abundant Ce3+ species and appropriate reduction ability on {111} facet of CT–NH catalyst also caused outstanding deNOx activity. Reaction mechanism study showed that the Langmuir–Hinshelwood (L–H) mechanism and Eley–Rideal (E–R) mechanism existed simultaneously on all catalysts in NH3–SCR reaction. Meaningfully, two types of E–R mechanism were present on CT–NH catalyst, while L–H mechanism was dominant.

Adsorption of NO2 and subsequent formation of nitrate species in the dark on TiO2 nanoparticles exhibiting different morphologies: An in-situ FTIR study

Nitrogen oxides (NOx) are among the major air pollutants, which are responsible for the photochemical smog and haze formation and can cause acid rain. The selective catalytic reduction (SCR) process is a promising method to control the NOx emission from various stationery and mobile resources. The chemisorption of NO2 is regarded as the crucial step in this heterogeneous catalytic process. Here, the adsorption and formation of nitrate species on TiO2 nanoparticles (NPs) with different morphologies, designated as TiO2 trigonal, TiO2 nanowires, TiO2 nanocubes was examined in the dark using an in-situ FTIR spectroscopy, under NO2 as the feeding gas. The N2O4 formation is the initial step as soon as TiO2 NPs are subjected to NO2 adsorption, that is simultaneously transformed into other nitrate species via intramolecular disproportionation reaction. However, TiO2 NPs with different morphologies displayed a distinguished trend towards the stability and formation of various nitrate species. In particular, formation of NO+ was noticed only in TiO2 nanowires and TiO2 nanocubes (10mL_HF/40 h). Also, NO2 was detected in TiO2 trigonal shaped NPs, TiO2 nanocubes (4mL_HF/24 h), and TiO2 nanocubes (10mL_HF/24 h). The formation of different NO3- species, including monodentate, bidentate, and bridged NO3- (m-, b-, br-NO3-) were also observed. This study provides valuable information to modify the TiO2-based supports for the selective catalytic reduction technology.

Poly aniline (PANI) loaded hierarchical Ti1−xSbxO2 rutile phase nanocubes for selective room temperature detection of benzene vapor

Benzene is one of the aromatic yet hazardous hydrocarbons that are deceptive under their sweet odor. Even in low ppm concentration, benzene vapor in ambient surroundings have been proven to be a major human carcinogen, primarily responsible for leukemia. Often found along with traces of toluene and xylene which have similar molecular structures, selective detection of low concentration benzene, particularly at room temperature is a major challenge. In this work, using the idea that transition from uni-faceted to bi-faceted crystal growth shall induce a change in morphology from spherical to cubical; antimony doped rutile TiO2 nanocubes were synthesized and employed in benzene vapor detection. While the PANI loaded antimony doped (0.03) TiO2 nanocubes showed an enhanced 80% response to 2 ppm benzene in air at room temperature, it was selective (up to 7 times more) against 2 ppm toluene and xylene vapor. The sensors were highly stable against humidity and also reusable for a considerable span of time. The role of specificity in exposed cubical facet has been explained for eliminating cross-sensitivity in benzene detection phenomenon.

Intriguing CeO2–TiO2 hybrid nanostructured photoanode resulting up to 46% efficiency enhancement for dye-sensitized solar cells

The harvesting of electrical energy from sunrays with low cost, clean form and prosperity is an excellent progression. In this context, significant advancement has been made in the solar energy area in terms of cell's design to enhance efficiency. Light scattering may benefit solar cells in this aspect by extending the travelling distance of light within the photoelectrode film. In this work, dextran templating high-surface-area contained CeO2 nanoparticles (~22 nm) were employed to improve the power conversion efficiency (PCE) of a TiO2-based dye-sensitized solar cell (DSSCs). Various physicochemical techniques were investigated to characterize the synthesized CeO2 nanoparticles. Synthesized cubic CeO2 nanoparticles were further explored as an additional layer on the top of the synthesized anatase TiO2 nanocube based film to fabricate CeO2–TiO2 hybrid photoanode, encouraging light scattering in DSSCs. A comparative study was undertaken to understand the effect of the CeO2 layer on the synthesized and standard anatase TiO2. The overall power conversion efficiency obtained for hybrid photoanode-based DSSC is 8.92%, ~46% higher than that of TiO2 nanocubes-based photoanode, with a considerably improved open-circuit voltage of 0.83 V under 1 SUN AM 1.5 . In addition, the PCE enhancement is observed only ~8% using standard TiO2 based photoanode under the same condition. The photovoltaic performance highlights that dextran templating CeO2 nanoparticle exhibits a significant impact as the light scattering layer and heterojunction formation when incorporating on top of the anatase TiO2 nanocube resulting in a hybrid photoanode enhancing the PCE of DSSCs. This alternative approach could facilitate the performance of TiO2 based DSSCs towards improving efficiency.

Renewable Poly(butene 2, 5-furan dicarboxylate) Nanocomposites Constructed by TiO2 Nanocubes: Synthesis, Crystallization, and Properties

Poly(butene 2,5-furan dicarboxylate) (PBF) is an emerging bio-based polyester with excellent thermal and tensile properties. It is expected to replace its petroleum-based homologous polyester, polybutylene terephthalate (PBT). However, the crystallization rate and strength of PBF need to be improved. In this study, PBF/TiO2 nanocomposites were synthesized by the in-situ polymerization of 2,5-furandicarboxylic acid (FDCA), butanediol, and rutile/anatase TiO2 nanocubes, with a size of 50 nm. The amount of nano-TiO2 added was 1–9‰ of the mass ratio of FDCA. As a result, a series of PBF/TiO2 nanocomposites with high molecular weights was obtained. The crystallization rate of the nanocomposites was significantly improved compared to that of pure PBF. The isothermal and non-isothermal crystallization of the nanocomposites were tested, and the temperature and rates of crystallization were compared. The shortest half-crystallization time was less than 1 min. It is evident from the results that the crystallization rate of the composite increases with an increase in the nano-TiO2 content and reaches a maximum at a nano-TiO2 content of 7‰. In addition, the elongation at break and impact strength of the nanocomposites increased by 118% and 200%, respectively, compared to that of neat PBF. In the range of 200–400 nm, the lowest UV transmittance of nanocomposites is only 5%, which is highly beneficial for the application of PBF in the field of film packaging.

Improving the Electrocatalytic Activities and CO Tolerance of Pt NPs by Incorporating TiO2 Nanocubes onto Carbon Supports

AbstractDesigning efficient anode CO‐tolerant electrocatalysts is critical in low‐temperature fuel cell catalysts fueled either by H2/CO or alcohol. We demonstrate that the incorporation of TiO2 nanocubes (TiO2NCs) on Carbon Vulcan supports, followed by the synthesis of Pt NPs at their surface (Pt/TiO2NCs‐C material), led to improvements in performance towards the electrooxidation of carbon monoxide, ethanol, methanol, ethylene glycol, and glycerol in acidic media relative to the commercial Pt/C and Pt/TiO2‐C counterparts employing commercial TiO2. The nanocubes enabled changes in the electronic properties of Pt NPs while contributing to the bifunctional mechanism as compared to Pt/C and Pt/TiO2‐C with commercial TiO2. Fuel cell experiments fed with H2/CO steam showed that Pt/TiO2NCs‐C employing nanocubes was resistant to CO‐poisoning, yielding superior performance in operational conditions. The results reported herein have important implications for developing electrocatalysts with superior performances in PEMFCs.

Photocatalytic activity enhancement for removal of dye molecules based on plasmonic Ag grafted TiO2 nanocubes under visible light driven

Introduction: Finding a novel photocatalyst for photocatalytic degradation operating in the wavelength range from UV to visible light has been considered a great potential for environmental remediation. Herein, TiO2 nanocubics (NCs) decorated Ag nanoparticles (NPs) with various concentrations were developed.&#x0D; Methods: The crystal structure, morphological and chemical characteristics of prepared photocatalysts were thoroughly analyzed by a series of main analyses (X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), and UVVis spectra).&#x0D; Results: The results revealed that a significantly promoting visible-light photocatalytic behavior of TiO2NCs@Ag photocatalyst was observed. The photocatalytic methyl orange (MO) degradation of the as-synthesized Ag anchored TiO2NCs photocatalyst (85% and 62% under UV light and visible light, respectively) exhibited outstanding photocatalytic efficacy compared with pristine TiO2 NCs. The achieved results could be assigned to the synergistic effects between TiO2NCs and Ag- NPs, leading to enhanced charge carrier separation and improved absorption ability in visible-light response.&#x0D; Conclusion: This work facilitates designing and developing high-efficiency heterostructure photocatalysts for practical works related to environmental deterioration.

Titanium Oxide Nanocubes Embedded Molecularly Imprinted Polymer-Based Electrode for Selective Detection of Caffeine in Green Tea

The present study reports the development of a low cost electrode by means of molecularly imprinted polymer (MIP) technique for detection and quantification of caffeine in green tea. The sensing material has been synthesized using the co-polymer of acrylonitrile (AN) and ethylene glycol dimethacrylate (EGDMA) followed by impregnation of TiO2 nanocubes into it. The electrode demonstrated a wide linear range from 5 μM to 120 μM with limit of detection (LOD) being 0.6 μM. The analytical characteristics revealed acceptable selectivity, repeatability, stability and reproducibility of the electrode. Real time application of developed sensor has been ascertained by measuring the caffeine content in different variants of green tea. The partial least square regression (PLSR) and principal component regression (PCR) models have been explored to estimate the predictive ability of the electrode in terms of their caffeine content by correlating the response of the obtained differential pulse voltammetry (DPV) datasets of green tea samples with HPLC data. In case of PLSR technique, an average prediction accuracy of 92.94% is obtained with root mean square error of calibration (RMSEC) value being as low as 0.07. Additionally for PCR, an average prediction accuracy of 93.75% is acquired with RMSEC value being 0.07.

Fabrication of porous TiO2 nanosheets assembly for improved photoreactivity towards X3B dye degradation and NO oxidation

Porous nanosheet can enhance the adsorption performance and light-harvesting ability of the photocatalyst due to the enlarged surface area and improved multi-reflection of the incident light between nanosheets. In this work, porous TiO2 nanosheets (TiO2-NSs) assembly was obtained by transformation TiO2 nanocubes in NaOH solution via hydrothermal reaction and followed by acid wash and heat treatment. The effect of reaction time (t) -dependent on photocatalytic activity of the obtained TiO2-NSs (St sample) was systematically investigated. It was found that TiO2-NSs exhibits superior catalytic activity for X3B dye degradation and NO oxidation when compared to pristine TiO2 nanocubes (S0 sample). The optimized photoreactivity of TiO2-NSs improved 8.1 and 5.0 times for X3B degradation (S1.5 sample) and NO oxidation (S3.0 sample), respectively. The enhanced photoreactivity of TiO2-NSs assembly is ascribed to the combined effects of enlarged surface area and unique structure of nanosheets assembly which facilitates the absorption of incident light. Both hydroxyl radicals and superoxide radicals are important reactive oxygen species (ROSs) responsible for the degradation of organic dye and NO oxidation. The present study provides a novel way to prepare high efficient semiconductor photocatalyst for water treatment and air purification.

Biomolecules encapsulated TiO2nano‐cubes usingTinospora cordifoliafor photodegradation of a textile dye

In the present research work, novel nano-sized cubes of TiO2 capped with the biomolecules of Tinospora cordifolia leaf extract have been successfully synthesised and characterised. UV–visible absorption spectrum shows the maximum absorption edge at a wavelength of 271 nm. Transmission electron microscope results reveal the development of nano-sized cubes with anatase phase confirmed from selected-area electron diffraction pattern. Further, X-ray diffraction study re-confirms the crystallinity and anatase phase evolution of TiO2. Fourier transmission infrared and energy-dispersive X-ray spectrum spectra elucidate the presence of biomolecules on TiO2 surface. The high photocatalytic activity of green synthesised TiO2 is demonstrated through the degradation of a textile dye, neutral red. A total 93.4% of dye has been removed with high apparent constant value (Kappa = 0.00758 min−1) under 120 min of short UV-light irradiation. Therefore, current work presents simple, low-cost, eco-friendly and hitherto unreported synthesis of TiO2 nano-cubes using Tinospora cordifolia leaf extract that could pave the way towards highly efficient photocatalysts.

The photovoltaic performance of highly asymmetric phthalocyanine-sensitized brookite-based solar cells

Highly asymmetric zinc phthalocyanine derivative (Zn-tri-PcNc) is utilized as sensitizer, meanwhile, brookite TiO2 nanocubes used as photoanode material to fabricate dye-sensitized solar cells (DSSCs). The optimal photovoltaic conversion efficiency of the solar cell reach value of 2.03%, with 160% improvement compared with single anatase cell (0.78%). Zn-tri-PcNc has intense absorption in the UV/blue and the red/near-IR spectral regions. At the same time, brookite nanocubes are benefit to less surfacestate traps and higher voltage. Combining the advantages of the above two approaches can reduce the charge recombination, improve light harvesting capability and prolong the electron lifetime, which leads to improve photovoltaic performance of the phthalocyanine-sensitized solar cell.

Surface Chemistry Directs the Tunable Assembly of TiO2 Anatase Nanocubes into Three‐Dimensional Mesocrystals

An important step in nanocrystal self‐assembly is programming the large‐area organization of nanocrystals into superlattices with tunable packing efficiencies. Here we utilize nanoscale surface chemistry to direct the self‐assembly of TiO2 (anatase) nanocubes into distinct three‐dimensional mesocrystals. High nanocrystal solubility combined with weak electrostatic attraction induced by the pH mediated surface charge was sufficient to organize 3,4‐dihydroxyhydrocinnamic acid (DHCA) functionalized nanocubes into large superstructures with both translational and orientational order. The finding that translational and orientational order of nanocrystal superlattices can be induced by the interplay of thermal energy, steric repulsion, and ionic interactions in a nucleation and growth self‐assembly process offers insight into the importance of the initial nucleation stage in the self‐assembly process and suggests new routes for controlled self‐assembly of nanocrystals.

Exposing TiO2 (001) crystal facet in nano Au-TiO2 heterostructures for enhanced photodegradation of methylene blue

Abstract This article reports an investigation on the effect of crystal facet of TiO2 in nano Au-TiO2 heterostructures for enhanced photocatalytic degradation of organic dyes. Here, nano Au-TiO2 heterostructures with two distinct TiO2 morphologies, i.e. nanospindles and nanocubes, were successfully prepared and utilized for photodegradation of methylene blue (MB). Based on the photocatalytic experiments, it is found that TiO2 nanospindles exhibited superior photocatalytic performance than TiO2 nanocubes which primarily due to the exposure of (001) crystal facet. It is observed that the exposure of (001) crystal facet was able to increase the photocatalytic reaction rate by four folds. Additionally, integration with Au nanoparticles was also found to have a synergistic effect in photodegradation activity due to the presence of surface plasmon resonance (SPR) effect. According to the result, Au-TiO2 nanospindles was found to be most efficient catalyst for photocatalytic degradation of MB with pseudo-first order reaction rate of 0.1570 min−1.

In-situ Platinum Plasmon Resonance Effect Prompt Titanium Dioxide Nanocube Photocatalytic Hydrogen Evolution.

Herein, Pt-decorated TiO2 nanocube hierarchy structure (Pt-TNCB) was fabricated by a facile solvothermal synthesis and in-situ photodeposition strategy. The Pt-TNCB exhibits an excellent solar-driven photocatalytic hydrogen evolution rate (337.84 μmol h-1 ), which is about 37 times higher than that of TNCB (9.19 μmol h-1 ). Interestingly, its photocatalytic property is still superior to TNCB with post modification Pt (1 wt %) (208.11 μmol h-1 ). The introduction of Pt efficiently extends the photoresponse of the composite material from UV to visible light region, simultaneously boosting their solar-driven photocatalytic performance, which attribute to the porous structure, the sub size TNCB, the SPR effect of Pt NPs and strong interaction of two components. In fact, Pt NPs can enhance collective oscillations on delocalized electrons, which is conducive to capture electrons and hinder the recombination of photogenerated electron-hole pairs, leading to the longer lifetime of photogenerated charges. The fabrication of Pt-TNCB photocatalyst with SPR effect may provide a promising method to improve visible-light photocatalytic activities for traditional photocatalysts.

Effect of Ammonium Salts on the Hydrothermal Synthesis of TiO₂ Nanocubes for Dye-Sensitized Solar Cells.

TiO2 nanocubes were synthesized via hydrolysis condensation of titanium tetra-isopropoxide (TTIP) in aqueous media, followed by hydrothermal treatment with ammonium salts. Various ammonium salts with different alkyl chain such as ammonium hydroxide (NH4OH), tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH) and tetrabutylammonium hydroxide (TBAH) were investigated. The crystalline phase, shape, and morphology of TiO2 nanocubes were studied by XRD, TEM, and SEM analysis. These TiO2 nanocubes were pure anatase phase and tended to assemble with well-ordered and close-packed domains. Both alkyl chain length of ammonium salts and hydrothermal duration affected the TiO2 nanocube formation process. The ammonium salts with longer alkyl chain formed TiO2 nanocubes in shorter hydrothermal time and offered the smallest particle size. The above TiO2 nanocubes were applied as photoanode materials in N719 anchored dye-sensitized solar cells and one of the cells exhibited the maximum power conversion efficiency of 7.85%.

Plasmon-Enhanced Self-Powered UV Photodetectors Assembled by Incorporating Ag@SiO2 Core–Shell Nanoparticles into TiO2 Nanocube Photoanodes

A novel photoelectrochemical self-powered ultraviolet photodetector (UVPD) has been assembled employing Ag@SiO2 core–shell nanoparticles (NPs) incorporated TiO2 nanocubes (NCs) as the photoanode. The incorporation of the plasmonic core–shell NPs can boost the photocurrent of the self-powered UVPD. Finite difference time domain (FDTD) and transient absorption spectroscopy (TAS) were employed to understand plasmonic enhancement processes. By optimizing the incorporated ratio of Ag@SiO2 NPs, the photocurrent of UVPD with 2 wt % Ag@SiO2 NPs reaches the maximum value in view of the enhanced light harvesting and effective inhibition of charge recombination. More importantly, the UVPD with 2 wt % Ag@SiO2 NPs achieves a high on/off ratio of 8212 and a remarkable responsivity of 0.151 A W–1, combined with a rapid response time, prominent spectral selectivity, and photosensitivity linearity response.