TiO2 Nanoclusters Research Articles

Top-down fabrication of active interface between TiO2 and Pt nanoclusters. Part 1: Redispersion process and mechanism

Supported metal nanoclusters (NCs) are regarded as the next generation of catalyst that bridge the nanocatalyst and single-atom catalyst. However, feasible fabrication of thermally stable NCs has remained a daunting challenge. In this paper, the first part of an extended work, we report a simple route to fabricate Pt NCs in size of around 1 nm through redispersion of Pt nanoparticles (NPs) or commercial PtO2 by a calcination treatment. Combining control experiments and detailed DFT simulation, the whole redispersion process was described and evidenced to proceed via a gas-phase trapping way: Under promotion of oxygen atmosphere and high temperature, volatile oxidized Pt monomers were firstly generated and then trapped by surface defects, forming special sites that preferentially induce the growth of clusters on them. The growing clusters have both size- and temperature-dependent stability, resulting a most stable size distribution of around 1 nm when fabricated at 550 °C. This work provides a feasible top-down strategy to fabricate highly dispersed metal clusters.

Top-down fabrication of active interface between TiO2 and Pt nanoclusters. Part 2: Catalytic performance and reaction mechanism in CO oxidation

In this work, following Part 1 that has found a redispersion process from Pt nanoparticles (NPs, about 3.4 nm) to nanoclusters (NCs, about 1 nm) on TiO2 and elucidated its mechanism, we carefully investigated the catalytic performance of the obtained Pt NC catalyst in CO oxidation as well as the corresponding reaction mechanism. The Pt NC catalyst excels than its parent catalyst in terms of both intrinsic and apparent activity. Detailed studies by combining kinetic measurements, isotopic labeling reaction experiments, and low-temperature operando FT-IR unambiguously demonstrated that the Pt NCs deposited on TiO2 can form unique interfacial sites that enable to active O2 at very low temperature, thus the CO adsorbed on TiO2 can diffuses to, and reacts with, the activated oxygen, rendering a high activity at low temperatures. This work is contributory in understanding the origin of the high activity of the supported metal cluster catalysts.

Tailoring surface morphology on anatase TiO2 supported Au nanoclusters: implications for O2 activation.

Strong interaction between the support surface and metal clusters activates the adsorbed molecules at the metal cluster-support interface. Using plane-wave DFT calculations, we precisely model the interface between anatase TiO2 and small Au nanoclusters. Our study focusses on the adsorption and activation of oxygen molecules on anatase TiO2, considering the influence of oxygen vacancies and steps on the surface. We find that the plane (101) and the stepped (103) surfaces do not support O2 activation, but the presence of oxygen vacancies results in strong adsorption and O-O bond length elongation. Modifying the TiO2 surface with supported small Au n nanoclusters (n = 3-5) also significantly enhances O2 adsorption and stretches the O-O bond. We observe that manipulating the cluster orientation through discrete rotations results in improved O2 adsorption and promotes charge transfer from the surface to the molecule. We propose that the orientation of the supported cluster may be manipulated by making the cluster adsorb at the step-edge of (103) TiO2. This results in activated O2 at the cluster-support interface, with a peroxide-range bond length and a low barrier for dissociation. Our modeling demonstrates a straightforward means of exploiting the interface morphology for O2 activation under low precious metal loading, which has important implications for electrocatalytic oxidation reactions and the rational design of supported catalysts.

2D MOF based-heterostructure with hierarchical architecture as antibacterial wound dressing

Bacterial infections pose a huge threat to human health due to the inevitable emergency of drug resistance. Metal-organic frameworks (MOFs) consisting of metal ions and organic linkers, as emerging efficient antibacterial material, have the merits of structural flexibility and adjustable physicochemical property. With assistance of photosensitive agents as organic linkers, MOFs have great potential in antibacterial application through photocatalytic therapy by the generation of reactive oxygen species (ROS). However, the limited light use efficiency and short lifespan of ROS are two obstacles for their applications. Inspired by the semiconductor heterostructure in photocatalysis, we rationally design and precisely synthesize MOFs based heterostructures, in which the TiO2 nanoclusters are filled into the pores of Cu-TCPP nanosheets (i.e. TiO2 NCs@Cu-TCPP HSs). And the composite materials possess three-dimensional (3D) hierarchical architectures, which have advantages of large surface area, excellent light-absorbing ability and photocatalytic efficiency. Significantly, this novel material displays >99.99 % antibacterial efficiency against E. coli and S. aureus within 30 min and preserves the excellent antibacterial ability during reusing three times, which is superior to recently reported photocatalystic-based antibacterial materials. Our study provides new insights into the energy band engineering for enhanced antibacterial performance, paving a way for designing advanced clinical wound dressings.

Studying the influence of the addition of nano-titanium dioxide on the rheological, mechanical, thermal, and electrical properties of polycarbonate/wood flour

In this work, the thermal stability of wood flour (WF) was modified using a boric acid treatment. To further understand the impacts of incorporating various proportions of titanium dioxide (TiO2) nanoparticles loaded on polycarbonate (PC)/wood flour. The rheological, mechanical, thermal, electrical, and interfacial properties were studied. Various properties of the resultant PC/WF/TiO2 nanocomposites were then characterized. The viscosity of the nanocomposite was shown to decrease with shear rate and temperature. XRD investigation indicated that, by introducing TiO2 nanoparticles into PC/WF, the amorphous phase decreased, and the degree of crystallinity increased, as compared to bare PC/WF, from 65.78 to 42.29. In addition, the TGA profile showed that the nanocomposites have a higher resistance to thermal degradation than PC/WF alone. It was observed that the char residue resulting from the TGA of PC/WF/10%wt TiO2 increased to 5.69% compared to pure PC/WF (1.32%). It was found that an appropriate amount of TiO2 in PC/WF caused a significant increase in tensile strength, elongation at break, and on impact strength. These were attributed to an increase in the interface of the dispersed phase. The incorporation of nanoparticles enhanced the thermal conductivity of the nanocomposites, which was found to be higher when a TiO2 content of ∼3 wt% was used. The electrical conductivity of the PC/WF/TiO2 nanocomposite (<3 wt%) hindered the movement of free-moving ions, therefore reducing the nanocomposite’s electrical conductivity. However, at > 3 wt% of TiO2, due to the aggregation of nanoparticles, TiO2 nanoclusters formed in the PC/WF composite. Therefore, the additional space so created for the movement of conduction ions at the interface may have resulted in increased ion mobility. This could be the one of explanations for the increased electrical conductivity associated with higher wt% of TiO2. Results showed that treating the PC/WF/TiO2 nanocomposites with boric acid decreased both the rate of heat release and the total heat release.

A neural network parametrized coagulation rate model for

Coagulation is a key factor governing the size distribution of nanoclusters during the high temperature synthesis of metal oxide nanomaterials. Population balance models are strongly influenced by the coagulation rate coefficient utilized. Although simplified coagulation models are often invoked, the coagulation process, particularly for nanoscale particles, is complex, affected by the coagulating nanocluster sizes, the surrounding temperature, and potential interactions. Toward developing improved models of nanocluster and nanoparticle growth, we have developed a neural network (NN) model to describe titanium dioxide (TiO2) nanocluster coagulation rate coefficients, trained with molecular dynamics (MD) trajectory calculations. Specifically, we first calculated TiO2 nanocluster coagulation probabilities via MD trajectory calculations varying the nanocluster diameters from 0.6 to 3.0nm, initial relative velocity from 20 to 700ms-1, and impact parameter from 0.0 to 8.0nm. Calculations consider dipole-dipole interactions, dispersion interactions, and short-range repulsive interactions. We trained a NN model to predict whether a given set of nanocluster diameters, impact parameter, and initial velocity would lead to the outcome of coagulation. The accuracy between the predicted outcomes from the NN model and the MD trajectory calculation results is >95%. We subsequently utilized both the NN model and MD trajectory calculations to examine coagulation rate coefficients at 300 and 1000K. The NN model predictions are largely within the range 0.65-1.54 of MD predictions, and importantly NN predictions capture the local minimum coagulation rate coefficients observed in MD trajectory calculations. The NN model can be directly implemented in population balances of TiO2 formation.

Novel Sb-SnO2 Electrode with Ti3+ Self-Doped Urchin-Like Rutile TiO2 Nanoclusters as the Interlayer for the Effective Degradation of Dye Pollutants.

Stable and efficient SnO2 electrodes are very promising for effectively degrading refractory organic pollutants in wastewater treatment. In this regard, we firstly prepared Ti3+ self-doped urchin-like rutile TiO2 nanoclusters (TiO2-x NCs) on a Ti mesh substrate by hydrothermal and electroreduction to serve as an interlayer for the deposition of Sb-SnO2 . The TiO2-x NCs/Sb-SnO2 anode exhibited a high oxygen evolution potential (2.63 V vs. SCE) and strong ⋅OH generation ability for the enhanced amount of absorbed oxygen species. Thus, the degradation results demonstrated its good rhodamine B (RhB), methylene blue (MB), alizarin yellow R (AYR), and methyl orange (MO) removal performance, with the rate constant increased 5.0, 1.9, 1.9, and 4.7 times, respectively, compared to the control Sb-SnO2 electrode. RhB and AYR degradation mechanisms are also proposed based on the results of high-performance liquid chromatography coupled with mass spectrometry and quenching experiments. More importantly, this unique rutile interlayer prolonged the anode lifetime sixfold, given its good lattice match with SnO2 and the three-dimensional concave-convex structure. Consequently, this work paves a new way for designing the crystal form and structure of the interlayers to obtain efficient and stable SnO2 electrodes for addressing dye wastewater problems.

Titanium Dioxide Nanocluster Modified Lignite-Based Nanoporous Carbon for Capacitive Deionization

With the development of capacitive deionization (CDI) technology, low-cost and high-performance capacitive deionization electrode materials have received great attention. Herein nanoporous carbon (NPC) was prepared using lignite as the carbon source in this work. The as-prepared NPC has a hierarchical nanoporous structure with micro-, meso- and macro-sized pores. Its specific surface area can reach 3581 m2 g−1. Then TiO2 nanoclusters modified NPC composites were fabricated for better CDI performance due to their synergistic electrochemical behaviour and properties. The results show that the size of TiO2 nanoclusters is 3–5 nm. TiO2 nanoclusters are uniformly dispersed in the composites which retain the hierarchical nanoporous structure and possess high specific surface area up to 3703 m2 g−1. Compared with NPC, the performance of xTiO2@NPC was significantly improved. The specific capacitance of 10TiO2@NPC is 193.45 F g−1 with 95% capacity retention after 5000 cycles. Its CDI adsorption capacity is up to 11.23 mg g−1, which is 1.55 times of NPC (7.24 mg g−1). It provides promising candidate materials for low-cost, industrial CDI applications with high performance through a facile method.

Synthesis and evaluation of photocatalytic properties of Na–TiO2/Sr4All4O25:Eu,Dy phosphor composites

Sub-micron Sr4Al14O25:Eu,Dy phosphor particles were coated by a TiO2-sol precipitation procedure at 80 °C for 3 h. The effects of Na/H2O2 additives on TiO2 precipitation and stability of the composites over heat treatment conditions were evaluated. The distribution of TiO2 nanoclusters on the sub-micron phosphor support changed from sparse to dense clusters with increasing Na additive. X-ray diffraction and Raman spectroscopy analyses revealed that the anatase and rutile phases dominated in the Na–TiO2/phosphor nanocomposites at 300 °C. Heat treatment at 450 °C was detrimental to the stability of TiO2 anatase phase. Ultraviolet and visible light were utilized for photocatalytic decomposition of methylene blue and toluene volatile organic components in the vicinity of the Na–TiO2/phosphor composites. Optimum photocatalytic performances were obtained in TiO2/phosphor composites with low concentration precipitation additives (1% Na and 0.23 vol% H2O2) heat-treated at 300 °C. Anatase phases and Na+ existence in TiO2/Sr4Al14O25:Eu,Dy phosphor composites improved the light sensitization and overall photocatalytic efficiencies.

Confined growth of TiO2 nanoclusters inside mesopores of core–shell silica spheres with high loading as efficient photocatalysts

Confined growth of TiO2 nanoclusters inside mesopores of core–shell silica spheres with high loading as efficient photocatalysts

Adsorption of Selected Molecules on (TiO2)20 Nano-Clusters: A Density-Functional-Theory Study

In this work, the adsorption energies and some of the main electronic properties of selected biological molecules adsorbed onto a (TiO2)20 cluster were studied. With this aim, Density-Functional Theory (DFT) calculations were performed using SIESTA code. The Perdew–Burke–Ernzerhof (PBE) functional within the Generalized Gradient Approximation (GGA) was used for the exchange and correlation potential. For this study, we chose molecules with very different characteristics and applications in everyday life, including antibiotics, anti-inflammatory drugs, vitamins, and so on. The TiO2 substrate was considered due to its harmlessness and versatility of application in various industries. In particular, we studied the changes in some of the main electronic properties of the molecules after adsorption onto titanium dioxide. For all of the molecules studied here, we observed that this substrate can increase the stability of the adsorbed molecules, with values in the range of 12–150 meV/atom. The reliability of our calculations was verified through additional optimizations with other DFT codes, considering the hybrid functionals B3LYP and M06-L. Our results showed a reasonably good agreement among these three functionals, thereby revealing the possibility of adsorption of the selected biological molecules onto the vertex of the TiO2 nanoclusters. Some of these molecules were considered as possible candidates for the delivery of drugs into the SARS-CoV-2 main protease, promoting the inhibition of this virus. We are not aware of any systematic study that has focused on the adsorption of the selected molecules on a (TiO2)20 substrate within the same framework, including the analysis of the differences in electronic properties through the use of different functionals.

Theoretical and experimental investigation of the electronic and optical properties of pure and interstitial nitrogen -doped (TiO2)n cluster

The structural and electronic properties of pure and nitrogen-doped TiO2 nanoclusters are investigated using density functional theory with vibrational modes. We performed numerical simulation using two methods based on theories at the Quantum Espresso/PBE and Gaussian/B3LYP/631G (d) levels. The properties of a single nitrogen-doped (TiO2)n nanocluster are also computed in this study. In both cases, interstitial and substitutional Nitrogen doping at all accessible sites was examined. For the experiment, Supersonic Cluster Beam Deposition (SCBD) was used to create pure and nitrogen-doped TiO2 films of nanocluster assemblies. Atomic force microscopy, X-ray photoelectron spectroscopy (XPS), UV–Vis spectroscopy, and Raman techniques were used to characterize these samples. The binding energies (Np, O2s, Ti 2p1/2, and Ti 2p3/2) of N-doped TiO2 were estimated using XPS spectral results. The UV–Vis measurement confirmed the previously stated reasoning about the quantum size effect on the band gap of the pure and nitrogen doped TiO2 nanocluster. The theoretical vibrational modes frequencies are calculated using the B3LYP/6-31G (d) functional via the Gaussian16 code's implementation algorithm. The good agreement between simulation and experimental results implies that a significant advantage of interstitial over substitutional positions. N–O vibration modes appeared in interstitial doped TiO2, and each vibration was dependent on a different cluster structure.

Exploring the mechanism of room temperature ferromagnetism in C-doped TiO2 nanoclusters by tuning the defects by different annealing temperature using citric acid as C source

Revealing the mechanism of room temperature ferromagnetism (RTFM) in carbon-doped TiO2 (C–TiO2) is critical to accelerate the development of TiO2-based spintronic devices. Herein, C–TiO2 nanoclusters were prepared by a sol-gel process using citric acid as C source, and the defects and RTFM of the samples were tuned by vacuum annealing at different temperature, and then the mechanism of RTFM induced by C doping is studied. Results revealed that with the increase of annealing temperature, residual organic precursor was gradually removed, and the phase transformed from pure anatase to rutile and brookite, followed by the precipitating of elemental C at 600 °C and 700 °C. Due to the doping of C, defects including substitutional C atoms for Ti sites (CTi), interstitial C atoms (Ci) and oxygen vacancy were introduced into the lattice. The concentration of CTi increases first till 500 °C, and then decreases gradually with the annealing temperature, while that of Ci exhibits opposite trend, and the oxygen vacancy concentration raises continuously. Influenced by the annealing temperature, RTFM of the samples exhibits similar trend to that of CTi, and the saturation magnetization (Ms) reaches the maximum at 500 °C. The RTFM is synergistically induced by CTi and oxygen vacancy, and ferromagnetic p-p coupling interaction trigged by CTi plays a more critical role. The results provide a significant reference for tuning the defects and RTFM in C–TiO2.

Enhanced properties of PVDF nanofibrous membrane with liquid-like coating for membrane distillation

Grafted poly(dimethyl siloxane) (PDMS) or fluorinated chains as liquid-like films have drawn much attention recently to render the substrate self-cleaning and lyophobic characteristics. Herein, novel PVDF nanofibrous membrane with liquid-like coating was facilely fabricated via one-step co-deposition of TiO2 nanoparticles (TiNPs) and a macromolecular coupling agent with PDMS side chains for membrane distillation. The fabricated PDMS-based coating and TiO2 nanoclusters distributed uniformly on the surface rendered the membrane both superhydrophobic (water contact angles as high as 150.4°) and slippery (water sliding angles as low as 4.5°) characteristics. Membrane distillation (MD) experiments showed that the coated membrane is highly effective in mitigating membrane scaling and wetting via hindering foulant deposition and fouling-releasing mechanisms, while simultaneously maintaining a permeability of as high as 34.5 L·m−2·h−1 and a selectivity of >99.99%. These results are competitive when compared with those of typical commercial membranes and related PVDF nanofibrous membranes, which makes the coated membrane a promising candidate for durable MD applications.

Titania coated silica core-shell spheres with dual grain size as efficient photocatalysts

The TiO2 nanoclusters were modified into the pores of silica core-shell particles (SiO2@dSiO2) by the sol-gel method, and the loading amount reached 47%. Based on the Ostwald ripening theory, by simply extending the reaction time, a part of the TiO2 in the pores of the shell was dissolved and then re-deposited on the outer surface of the shell to form a TiO2 layer. Using this method, TiO2 crystalline grains of different sizes were obtained simultaneously inside and outside the shell of silica core-shell spheres. Small-sized crystalline grains were located in the pores of the shell, and they had a strong quantum size effect. The large crystalline grains were located in the TiO2 layer on the outer surface of the shell of SiO2@dSiO2. Due to the formation of larger-sized crystalline grains, the recombination probability of photogenerated electron-hole pairs was reduced. When used as photocatalysts for the degradation of Rhodamine B under UV irradiation, the catalytic activity of SiO2@dSiO2@TiO2 was 5.4 times higher than that of the commercial P25 TiO2 photocatalyst.

Design and Synthesis of Vanadium‐Titanium‐Incorporated Mesoporous Silica Catalysts for the Oxidative Dehydrogenation of Propane

AbstractA series of vanadium and titanium‐incorporated mesostructured cellular foams (MCF) silica with different vanadium contents were synthesized by direct hydrothermal method, which applied as catalysts for the oxidative dehydrogenation of propane (ODP). Vanadium doping amount significantly affects the distribution and coordination environment of VOx and TiOx species on the MCF silica. With the increasing of V content, the TiOx species incorporated into silica framework were substituted by some framework V species to form more polymeric or small TiO2 nanoclusters. VOx species were incorporated on both silica surface and TiOx species surface. The interaction between highly dispersed VOx and polymerized TiO2 enhanced the C3H6 formation rate. The 3 V5Ti/MCF catalysts showed the highest propylene productivity (4.2 kgpropylene kgcat−1 h−1, at 500 °C) among the xV5Ti/MCF catalysts because of the highest concentration isolated/oligomeric VOx species incorporated on the appropriate polymerized TiO2 surface.

Mobility analysis of nanocluster formation and growth from titanium tetraisopropoxide in a flow tube reactor

In an effort to understand the earliest stages of nanocluster growth in gas phase synthesis systems, we apply a flow tube reactor with a differential mobility analyzer-Faraday cage electrometer system to examine nanocluster formation and growth in the sub-3.0 nm mobility diameter range from the decomposition of titanium tetra-isopropoxide (TTIP) in air. Measured mobility distributions are inverted accounting for the DMA transfer function, tubing losses, and the charging efficiency, estimated from a non-steady state charge model within a bipolar ion source. Measurements reveal two types of species in spectra. First, we detect discrete (narrow) peaks falling in the 0.5 nm–1.5 nm size range which appear at different locations for positive and negative measurement modes. Second, we observe a larger, broadly distributed peak, which is similar in intensity for both positive and negative modes after data inversion, and which increases in intensity (concentration) and peak diameter with increasing precursor flow rate, increasing reactor temperature, and increasing residence time. We conclude that the latter broad peak arises from growing nanoclusters in the reactor. The narrower, sub 1.5 nm peaks, are most likely attributable to specific reactive intermediates from the decomposition of TTIP. We find that increasing TTIP concentration, reactor temperature, or increasing residence time, which furthers the extent of nanocluster formation, leads to the depletion of the sub 1.5 nm ions. Because of the large step size in diameter between neighboring sub 1.5 nm peaks, we also find it is unlikely that these peaks arise from small TiO2 clusters. Therefore, our measurements suggest that nanocluster growth from TTIP is facilitated by surface growth of reactive intermediates from TTIP decomposition, with reactive intermediates detectable via mobility analysis. Furthermore, while nanocluster formation and growth is clearly detected, measurements do not make clear that the nanoclusters are fully oxidized TiO2 nanoclusters for the synthesis temperature range examined.

Covalently Bonded Ir(IV) on Conducted Blue TiO2 for Efficient Electrocatalytic Oxygen Evolution Reaction in Acid Media

The stability of anode electrode has been a primary obstacle for the oxygen evolution reaction (OER) in acid media. We design Ir-oxygen of hydroxyl-rich blue TiO2 through covalent bonds (Ir–O2–2Ti) and investigate the outcome of favored exposure of different amounts of covalent Ir–oxygen linked to the conductive blue TiO2 in the acidic OER. The Ir-oxygen-blue TiO2 nanoclusters show a strong synergy in terms of improved conductivity and tiny amount usage of Ir by using blue TiO2 supporter, and enhanced stability using covalent Ir-oxygen-linking (i.e., Ir oxide) in acid media, leading to high acidic OER performance with a current density of 10 mA cm−2 at an overpotential of 342 mV, which is much higher than that of IrO2 at 438 mV in 0.1 M HClO4 electrolyte. Notably, the Ir–O2–2Ti has a great mass activity of 1.38 A/mgIr at an overpotential 350 mV, which is almost 27 times higher than the mass activity of IrO2 at the same overpotential. Therefore, our work provides some insight into non-costly, highly enhanced, and stable electrocatalysts for the OER in acid media.

Effect of different aromatic groups on photovoltaic performance of 1,1′‐bis (diphenylphosphino)ferrocene functionalized Ni (II) dithiolates as sensitizers in dye sensitized solar cells

AbstractA series of five new heteroleptic 1,1′‐bis (diphenylphosphino)ferrocene (dppf) appended nickel (II) dithiolates namely, [Ni (dppf)(benzylcyanidedithiolate)] (Bz‐Ni), [Ni (dppf)(2‐cyanobenzylcyanidedithiolate)] (CN‐Ph‐Ni) and [Ni (dppf)(pyridine‐2‐cyanidedithiolate)] (2‐Py‐Ni), [Ni (dppf)(pyridine‐3‐cyanidedithiolate)] (3‐Py‐Ni), Ni (dppf)(thiophene‐2‐cyanidedithiolate)] (Th‐Ni) have been prepared and characterized using spectroscopic techniques and in one case by single‐crystal X‐ray diffraction analysis for CN‐Ph‐Ni. The geometry around Ni (II) in CN‐Ph‐Ni is distorted square planar which is fulfilled by two S and two P centers of dithiolate and dppf ligand, respectively. The electronic absorption spectra for sensitizers display major bands between 400 and 550 nm that could be ascribed to an intra‐molecular charge transfer (ICT) between the ferrocene and functionalized dithiolates to engender an efficient charge separated state. All these newly synthesized compounds are used as sensitizers in dye sensitized solar cells (DSSCs). The photovoltaic performances for the five featured sensitizers follow the order 3‐Py‐Ni>2‐Py‐Ni˃CN‐Ph‐Ni˃Bz‐Ni˃Th‐Ni. The assembly fabricated with 3‐Py‐Ni displays Jsc of 13.15 mA cm−2 and Voc of −0.633 with conversion efficiency (η) and incident photon‐to‐current conversion efficiency (IPCE) of 5.05% and 52%, respectively. The relatively slower charge recombination, greater dye loading capacity on TiO2 nano‐particulate and relative smaller total resistance are the possible reasons behind the superior photovoltaic performance of the cell fabricated using the 3‐Py‐Ni as sensitizer. Also, density of states calculations have been performed which suggested that in the best performer 3‐Py‐Ni+(TiO2)30 cell set‐up, the minimum inter‐band excitation energy lies ~1.4 eV. Also, efficient electron coupling between sensitizer and (TiO2)30 results in efficient sensitization of TiO2 nanocluster.

Sub-Nanometer Nanobelts Based on Titanium Dioxide/Zirconium Dioxide-Polyoxometalate Heterostructures.

In addition to offering conformational flexibility, sub-nanometer nanobelts (SNBs) also outperform many larger nanobelts with large size owing to their ultrathin morphologies. However, to date, only a few monocomponent SNBs have been synthesized. This study presents a facile method for synthesizing ZrO2 -PMoO (PMZ) SNBs and TiO2 -PMoO (PMT) SNBs with heterostructures. The SNBs comprise ZrO2 /TiO2 and polyoxometalate (POM) nanoclusters, which are formed via the aggregation and subsequent transformation of nanoclusters. Significantly, these SNBs demonstrate high catalytic activity and stability in oxidative desulfurization reactions at room temperature. The impressive catalytic performance of the SNBs is aided by the POM nanoclusters, which not only coassemble with ZrO2 /TiO2 nuclei to form building blocks of PMZ SNBs/PMT SNBs but also serve as catalytic centers. The catalytic performance is further enhanced by the ZrO2 /TiO2 in the SNBs. Moreover, the proposed synthesis method can be utilized to produce other SNBs. Thus, this method provides valuable insights into the strong performance properties of SNBs created by combining metal oxides and POM nanoclusters into SNBs, which have great potential as redox catalysts.