TiO2 Nanosheets Research Articles

Crystallization of 2D TiO2 Nanosheets via Oriented Attachment of 1D Coordination Polymer.

Demystifying the molecular mechanism of growth is vital for the rational design, synthesis, and optimization of functional nanomaterials. Despite the promising perspectives and extensive efforts, the growth mechanism of atomically thin TiO2(B) nanosheets remains unclear, hence it is difficult to tune their band and surface structures. Herein, we report an oriented attachment-based crystallization mechanism of TiO2(B) nanosheets from a 1D titanium glycolate coordination polymer through hydrolysis and condensation. With time-tracking experiments, this 1D coordination polymer is found to be an intermediate in the synthesis of TiO2(B) nanosheets by using Ti alkoxides and chlorides as precursors, suggesting the universality of the 1D-to-2D growth mechanism. Such a side-to-side attachment pathway bridges the classical and nonclassical interpretations of crystallization, and meanwhile hints at the possibility of other 1D complexes as potential precursors for 2D materials.

Polydopamine-based surface coating fabrication on titanium implant by combining a photothermal agent and TiO2 nanosheets for efficient photothermal antibacterial therapy and promoted osteogenic activity

Developing titanium-based dental implants with both excellent antibacterial properties and good osseointegration is crucial for the success of the implant operation and the long-term durability of the implant. In this study, a polydopamine-based coating was created by attaching TiO2 nanosheets-cyanine composites onto the titanium surface, enabling the integration of effective photothermal antibacterial therapy with osseointegration. The exceptional dual-photothermal conversion abilities of polydopamine and cyanine in the coating resulted in outstanding photothermal antibacterial and antibiofilm therapy against four types of bacteria. Furthermore, TiO2 nanosheets promoted the adhesion, proliferation and early osteogenic differentiation of osteoblasts. In an infected dental implant model in rats, the developed coating exhibited potent antibacterial activity and remarkable osteogenic differentiation in the bone, leading to increased bone formation around the implants. This innovative approach, combining photothermal therapy with osteogenic two-dimensional nanomaterials, presents a novel method for surface functionalization of implants to achieve effective antibacterial and osseointegration capabilities.

Multidimensional Engineering to Construct Ru/TiO2 Catalysts Enriched with Pores and Ti3+ Defects for Highly Efficient Selective Hydrogenation of Benzene

AbstractStructural engineering, coupled with crystalline phase engineering and surface engineering, serves as a practical and effective strategy for enhancing catalytic performance through the fine design of catalysts in terms of their structure, physical phases and surface defects. In this work, a set of strategies were employed for structural transformation and crystalline phase transition of Ru/TiO2 catalysts, utilizing multidimensional regulation. Ru nanoparticles loaded on a unique TiO2 nanosheet flowers (Ru/TSFs) enriched with pores and Ti3+ defects were prepared by solvothermal and impregnation‐chemical reduction methods. The Ru/TSFs exhibited an outstanding catalytic performance in the reaction of selective hydrogenation of benzene for the preparation of cyclohexene, with a selectivity of 79 % and a maximum yield of 52.8 % along with a benzene conversion of 45.9 % and a good stability. The excellent catalytic performance attributes to the distinctive structure of three‐dimensional nanosheet flowers, which offers a high specific surface area and improvs the effective contact between the catalyst and the reaction substrate. Meanwhile, the porous Ru/TSFs exhibit exceptional hydrophilicity and abundant Ti3+ defects on their surface, which is quite favorable for the desorption of cyclohexene from the reaction system, thus improving the selectivity of cyclohexene. The multidimensional engineering may provide an efficient approach for constructing high‐performance loaded catalysts for potential industrial applications.

Single Atom‐Engineered 2D Catalytic Nanosheets for Sonocatalytic Suppression of Orthotopic Clear Cell Renal Cell Carcinoma

AbstractClear cell renal cell carcinoma (ccRCC), a prevalent malignant tumor, exhibits resistance to chemotherapy, necessitating advanced therapeutic approaches. Sonocatalytic therapy has emerged as a promising non‐invasive treatment for solid tumors due to its ability to penetrate deep tissue. Herein, the development of single atomic Au‐doped 2D TiO2 nanosheets are presented with oxygen vacancies (Au‐SA/Def‐TiO2, ASDT) for sonocatalytic treatment of ccRCC. Surface defects on TiO2 nanosheets effectively stabilize Au single atomic sites via the Ti‐Au‐Ti structure, enhancing catalytic properties and facilitating reactive oxygen species (ROS) generation by reducing energy barriers and improving electron (e−) and hole (h+) separation. Additionally, ASDT exhibits peroxidase‐like activities, further augmenting ROS production, leading to significant inhibition of tumor growth in subcutaneous and orthotopic ccRCC models under ultrasound irradiation. This study underscores the efficacy of defect engineering for stabilizing single atoms to boost ROS production and achieve effective tumor eradication by the enhanced sonocatalytic effect.

Photocatalytic H2 evolution over CuCoSe2 nanoparticles decorated TiO2 nanosheets with S-scheme charge separation route

The construction of S-scheme heterojunctions via exploring semiconductors with suitable energy band structures can effectively improve the photocatalytic performance of TiO2. In this work, CuCoSe2/TiO2 heterojunction were prepared using solvent evaporation strategy by their different surface charge properties. The investigation indicates that rates of H2 evolution (rH2) of the system increases significantly from 138.1 (TiO2) to 3773.8 μmol·g−1·h−1 (CuCoSe2/TiO2). It is found that the incorporation of CuCoSe2 can extend the visible light absorption range of the system, increase the electrochemically active surface area, facilitate charge generation and decrease the transfer resistance, reduce the H2 production overpotential and the water contact angle. Further investigation reveals that a bimetallic selenide CuCoSe2 exhibit superior enhancement activity compared to their monometallic selenides (CuSe2, CoSe2) due to the synergistic effect of Co and Cu. Especially, the charge transfer between CuCoSe2 and TiO2 follows S-scheme charge separation route, which can effectively enhance charge separation/migration, reserve e− with strong reducing ability in TiO2, thereby promoting the H2 evolution kinetics. Moreover, the heterojunction also demonstrates exceptional stability throughout the cycle experiment. The present work establishes an experimental basis for the advancement of highly efficient and stable bimetallic selenides related heterojunctions in the field of photocatalytic H2 evolution.

CuS nanoparticle/TiO2 nanosheets heterojuncture boosting paired electrosynthesis of formate

There is still a gap in research on the use of TiO2 as a multiphase catalyst for electrocatalysis. This paper explores the boosting effect of TiO2 nanosheets (NSs) in CuS/TiO2 NSs bifunctional catalysts which enhances their electrocatalytic formate production in both anodic methanol oxidation reaction (MOR) and cathodic carbon dioxide reduction reaction (CO2R). The boosting effect of TiO2 nanosheet is ascribed to the in-built CuS/TiO2 heterojunctions which have abundant heterointerface boundaries, adjusted electrolyte/catalyst environment, improved electrochemical active area as well as facile electron transfer. The cathodic CO2RR with CuS/TiO2 NSs showed a formate Faraday efficiency (FE formate) of 75 % at −0.9 V (vs. RHE), while the anodic MOR exhibited 97 % FE formate at 1.7 V (vs. RHE). Particularly, paired electrolysis of formate was realized in an H-type cell through simultaneous cathodic CO2RR and anodic MOR, achieving a total FE formate of 168.7 % at 10 mA cm−2.

Reinforced facilitated transport PEBA membrane by 2D Fe-doped TiO2 macroporous nanosheets for CO2 separation: Utilizing cationic and non-ionic surfactants

In this study, macroporous nanosheets of 2D Fe-Doped TiO2 were synthesized, and subsequently, membranes composed of polyether block amide (PEBA) were prepared. These membranes were incorporated with the nanosheets mentioned above, as well as two distinct types of surfactant. The structure and gas separation properties of the membranes were studied using different methods, including atomic force microscopy (AFM), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), as well as gas permeation analyses and tensile test. The findings indicated that the nanosheets underwent a porous transformation following the doping process. This occurrence improved the bonding between the nanosheets and PEBA chains, consequently boosting the mechanical strength of the membranes embedded with these nanosheets. Incorporating these nanosheets into the membrane (4 wt%) established a more efficient facilitated transport mechanism via Lewis acid centers, resulting in a 12.5 % increase in CO2 permeability and a 136 % rise in the selectivity of CO2/N2 compared to the pure PEBA membrane. Two different surfactants were introduced to the PEBA/FeTiO2 matrix, resulting in varying impacts on membrane structure and performance. The Cetyl trimethyl ammonium bromide (CTAB) as a cationic surfactant led to membrane stiffening and a significant 241 % enhancement in CO2/N2 selectivity at 1 wt%. On the other hand, the Polysorbat (Tween) as a non-ionic surfactant softened the membrane and boosted CO2 permeability by 53 % at 6 wt% compared to the pure membrane.

Ternary Bi2WO6/TiO2-Pt Heterojunction Sonosensitizers for Boosting Sonodynamic Therapy.

Engineering Z-scheme heterojunctions represents a promising strategy for optimizing the separation and migration of charge carriers in semiconductor sonosensitizers for enhanced reactive oxygen species (ROS) generation. Nevertheless, establishing a continuous and directional pathway for ultrasonic-induced charge flow in Z-scheme heterojunctions remains a significant challenge. In this study, we present a ternary Bi2WO6/TiO2-Pt heterojunction sonosensitizer achieved through the precise growth of Pt nanocrystals on a directionally assembled Bi2WO6/TiO2 Z-scheme structure. The construction of the Bi2WO6/TiO2-Pt heterojunction involves directional growth of Bi2WO6 in situ on the highly exposed (001) crystal facet of TiO2 nanosheets, followed by the precise deposition of nano Pt on the edge (101) crystal facet. The Z-scheme Bi2WO6/TiO2 in the ternary heterojunction ensures effective electron separation, while the Schottky TiO2-Pt interface establishes a well-defined charge flow path and robust redox capabilities. Moreover, nano Pt confers the Bi2WO6/TiO2-Pt heterojunction with excellent peroxidase-mimic and catalase-mimic activities, facilitating interactions with endogenous H2O2 to produce the hydroxyl radicals and O2. It effectively alleviates tumor hypoxia and enhances ROS production. This results in significantly higher efficiency in sonodynamically induced ROS generation compared to pure TiO2 or binary Bi2WO6/TiO2 heterojunctions, as confirmed by DFT theoretical calculation and experiments with both in vitro and in vivo anticancer performance. This study offers valuable insights for designing high-performance Z-scheme sonosensitizer systems.

Ambient Deposition of Single Atoms for Enhancement of Nanostructured Metal Oxide Electrode Catalytic Performance

Single-atom decoration represents cutting-edge technology for enhancing heterogeneous catalysis by utilizing the unique capabilities of catalysts at the atomic level. However, the high surface energy of single atoms often causes them to aggregate, forming nanoparticles [1]. To address this challenge, we first modify the surface structure by synthesizing nanostructured support layers, such as TiO2 nanotubes, TiO2 nanosheets, and NiO nanosponge. Especially TiO2 nanotubes and NiO nanosponge pose relevant support layers due to their favorable attributes, including a high surface-to-volume ratio, abundance, and excellent chemical stability, while TiO2 nanosheets serve as model system. Vertically aligned, well-ordered, self-organized oxide nanostructures can be conveniently fabricated through anodization, allowing precise control over the geometry of the nanotubes and nanopores [2,3]. Well-defined atomic-scale defects on the surface of the supports are generated to immobilize single-atom co-catalysts. Therefore, defect engineering techniques typically require high-temperature thermal reduction. We present more gentle defect-engineering approaches, including room-temperature sonochemical treatment or UV-light irradiation. By combining these approaches, we are able to effectively trap Pt and Ir single atoms.We present a direct method utilizing UV-light radiation to induce point defects, specifically Ti3+ and oxygen vacancies (VO) onto the surface of TiO2 nanosheets and efficiently decorate them with Pt single atoms [4]. Our findings demonstrate that sonochemically treated TiO2 nanotubes provide a remarkable substrate for single-atom decoration from dilute solutions, resulting in promising performance in H2 evolution catalysis and renewable energy conversion. Additionally, the role of V single-atom decoration in ultrasonic treatment of support materials is investigated.Thermal annealing in a reductive atmosphere induces the formation of numerous defects, facilitating the anchoring of single Ir atoms onto the surface of annealed NiO nanostructures. Additionally, the novel ultrasound-driven method stabilizes these Ir atoms within the porous structure. By employing both approaches, we effectively trap Ir single atoms, thereby enhancing the efficiency of the oxygen evolution reaction in electrocatalysis [5].The characterization of the electrodes is conducted using microscopy techniques (FESEM, TEM, and HAADF-STEM) and spectroscopy (XPS and ToF-SIMS) [6]. Gas chromatography is employed to evaluate the H2 photocatalytic performance of TiO2 electrodes, while linear sweep voltammetry is utilized to assess the H2 and O2 electrochemical activity of NiO electrodes [5]. Our findings highlight the significant enhancement of photo- and electrocatalytic efficiency of nanostructured oxide electrodes modified with highly stable single-atom co-catalysts by gentle treatments.

2D TiO2 Nanosheets Decorated Via Sphere-Like BiVO4: A Promising Non-Toxic Material for Liquid Phase Photocatalysis and Bacterial Eradication.

An in-depth investigation was conducted on a promising composite material (BiVO4/TiO2), focusing on its potential toxicity, photoinduced catalytic properties, as well as its antibiofilm and antimicrobial functionalities. The preparation process involved the synthesis of 2D TiO2 using the lyophilization method, which was subsequently functionalized with sphere-like BiVO4 through wet impregnation. Finally, we developed BiVO4/TiO2 S-scheme heterojunctions which can greatly promote the separation of electron-hole pairs to achieve high photocatalytic performance. The evaluation of concentration- and time-dependent viability inhibition was performed on human lung carcinoma epithelial A549 cells. This assessment included the estimation of glutathione levels and mitochondrial dehydrogenase activity. Significantly, the BiVO4/TiO2 composite demonstrated minimal toxicity towards A549 cells. Impressively, the BiVO4/TiO2 composite exhibited notable photocatalytic performance in the degradation of rhodamine B (k=0.135 min-1) and phenol (k=0.016 min-1). In terms of photoinduced antimicrobial performance, the composite effectively inactivated both gram-negative E. coli and gram-positive E. faecalis bacteria upon 60 minutes of UV-A light exposure, resulting in a significant log 6 (log 10 CFU/mL) reduction in bacterial count. In addition, a 49 % reduction of E. faecalis biofilm was observed. These promising results can be attributed to the unique 2D morphology of TiO2 modified by sphere-like BiVO4, leading to an increased generation of (intracellular) hydroxyl radicals, which plays a crucial role in the treatments of both organic pollutants and bacteria. This research has significant potential for various applications, particularly in addressing environmental contamination and microbial infections.

Construction of S-scheme NiCoSe2/TiO2 heterojunction for efficient photocatalytic H2 evolution

In this work, TiO2 nanosheets and NiCoSe2 nanoparticles were synthesized via a hydrothermal method respectively, then NiCoSe2 was combined with TiO2 using a solvent evaporation strategy to form heterojunction for efficient photocatalytic H2 evolution. The investigation demonstrates that the H2 evolution rate of 5 %-NiCoSe2/TiO2 can reach up to 4976 μmol·g−1·h−1 in the sacrificial agent of 20 vol% triethanolamine (TEOA) solution under a 300 W Xe lamp irradiation, which is approximately 35.5 times higher than that of TiO2 (140 μmol·g−1·h−1). Besides, the composite exhibits excellent stability after undergoing five consecutive cycles. The prominent H2 evolution activity of this system can be attributed to the abundant redox active sites provided by the bimetallic selenides, as well as the enhanced light harvesting ability and photocurrent response, reduced electrochemical impedance especially the improved electron-hole (e--h+) pairs separation due to the formed S-scheme charge transfer route between TiO2 and NiCoSe2.This work demonstrates the promising application potential of bimetallic selenides in photocatalytic H2 evolution.

One step co-deposition of Ni0.96S and Ag2S on TiO2 nanosheets for enhanced photocatalytic H2 generation with superior stability

Introduction of co-catalysts to construct heterojunctions is one of the important strategies to improve the photocatalytic hydrogen production activity of semiconductor catalysts. Here, Ni0.96S and Ag2S co-decorated TiO2 composites were prepared by a simple one-step solvothermal method, whose photocatalytic H2 production activities were evaluated and related H2 evolution mechanism was explored. The 5%Ni0.96S-8%Ag2S/TiO2 ternary composite exhibited much enhanced photocatalytic activity with the photocatalytic hydrogen evolution rate (HER) of 23.67 mmol·h−1·g−1, which is 131.5 fold higher than that of the pure TiO2. Even higher HER, 29.45 mmol·h−1·g−1, was obtained in the presence of 40 mL glycerol. The photocatalytic HERs of the 5%Ni0.96S-8%Ag2S/TiO2 catalyst under visible light (λ > 420 nm) and simulated solar light (AM1.5) were 353.78 and 935.24 µmol·h−1·g−1, respectively. The apparent quantum efficiency (365 nm) is as high as 13.9%. Remarkably, the catalyst exhibited excellent photocatalytic cycling stability and durability, beneficial to practice applications. The improved photocatalytic activity of the composite can be attributed to much improved charge carrier transfer/separation, optimized energy band structure and enhanced visible light absorption caused by synergistic effect of Ni0.96S and Ag2S.

Mesh-supported V2O5-WO3/TiO2 nanosheet array catalysts for efficient removal of NOx

Mesh-supported V2O5-WO3/TiO2 nanosheet array catalysts for efficient removal of NOx

Nitrogen-Doped TiO2- x(B)/MXene Heterostructures for Expediting Sulfur Redox Kinetics and Suppressing Lithium Dendrites.

Practical application of lithium-sulfur (Li-S) batteries is severely impeded by the random shuttling of soluble lithium polysulfides (LiPSs), sluggish sulfur redox kinetics, and uncontrollable growth of lithium dendrites, particularly under high sulfur loading and lean electrolyte conditions. Here, nitrogen-doped bronze-phase TiO2(B) nanosheets with oxygen vacancies (OVs) grown in situ on MXenes layers (N-TiO2- x(B)-MXenes) as multifunctional interlayers are designed. The N-TiO2- x(B)-MXenes show reduced bandgap of 1.10eV and high LiPSs adsorption-conversion-nucleation-decomposition efficiency, leading to remarkably enhanced sulfur redox kinetics. Moreover, they also have lithiophilic nature that can effectively suppress dendrites growth. The cell based on the N-TiO2- x(B)-MXenes interlayer under sulfur loading of 2.5mg cm-2 delivers superior cycling performance with a high specific capacity of 690.7 mAh g-1 over 600 cycles at 1.0 C. It still has a notable areal capacity of 6.15 mAh cm-2 after 50 cycles even under a high sulfur loading of 7.2mg cm-2 and a low electrolyte-to-sulfur (E/S) ratio of 6.4 µL mg-1. The Li-symmetrical battery with the N-TiO2- x(B)-MXenes interlayer showcases a low over-potential fluctuation with 21.0mV throughout continuous lithium plating/stripping for 1000h. This work offers valuable insights into the manipulation of defects and heterostructures to achieve high-energy Li-S batteries.

The synergistic enhancement of photocatalytic activity by Fe3O4–TiO2 nanosheets for rhodamine B degradation

As an advanced oxidation material, Fe3O4-TiO2 nanocomposites have been widely used in wastewater treatment. However, conventional Fe3O4 nanoparticles suffer from drawbacks such as carrier recombination and aggregation, which seriously affect the catalytic activity. In this study, Fe3O4-TiO2 nanosheets with different TiO2 loading rates were synthesized by sol-gel method and solvothermal method. The unique two-dimensional nanostructure of Fe3O4 nanosheets facilitated the deposition of TiO2 nanoparticles, resulting in Fe3O4-TiO2 nanosheets with a high BET specific surface area of 121.67 m2·g−1. Under optimal experimental conditions, the degradation rate of RhB dye in the photocatalytic synergistic Fenton-like system constructed with Fe3O4-TiO2 nanosheets reached 98.12 % within 120 min, significantly surpassing that of single photocatalysis and Fenton-like systems. It was attributed to the unique surface structure of Fe3O4 nanosheets, which provided a larger contact area for TiO2 nanoparticles. It facilitated the effective reduction of Fe3+ to Fe2+ by photogenerated electrons in TiO2, inhibited the recombination of photogenerated electron-hole pairs, and consequently enhanced the degradation rate of RhB dye. Furthermore, Fe3O4-TiO2 magnetic nanosheets exhibited excellent reusability and stability, with the recovery rate and degradation rate of RhB dye remaining above 90 % even after five cycles. More importantly, the catalytic mechanism of Fe3O4-TiO2 nanosheets was elucidated, and •OH identified as the primary reactive species responsible for degrading RhB dye. This work provides a novel research direction for designing and preparing advanced catalytic degradation materials, offering a practical solution to the challenging issue of wastewater treatment.

Enhanced Photocatalytic Performances of SnS2/TiO2 Composites via a Charge Separation Following Z-Scheme at the SnS2/TiO2{101} Facets

The formation of heterojunctions for efficient charge separation has been practiced for the preparation of efficient semiconductor-based photocatalysts for applications such as hydrogen production and environmental remediation. In this study, we synthesized a composite structure with a heterojunction between SnS2 and TiO2 through a microwave-assisted hydrothermal process, in which SnS2 nanoparticles grew on nanocrystalline TiO2 nanosheets preferentially at the exposed {101} facets. Appropriate exposure of the {001} and {101} facets of the TiO2 nanosheet in the composite with a preferential growth of SnS2 nanoparticles at the {101} facets was the origin of the charge separation following a direct Z-scheme mechanism to result in enhanced photocatalytic performances in photodegradation of organic dyes such as methylene blue (MB) and rhodamine B (RhB) compared to that of SnS2 and TiO2 alone. A plot of photodegradation rates vs. SnS2 ratios in the composites gave an overall volcano-shaped curve with a maximum at the SnS2 ratio of about 33% at which small SnS2 nanoparticles were populated at the {101} facets of the TiO2 nanosheets with a high surface area (118.2 m2g−1). Our results suggest the microwave-assisted hydrothermal process can be a good synthetic approach for composite-based photocatalysts with a preferential heterojunction structure.

Hydrothermally synthesized Nb -doped TiO2 nanosheets for efficient removal of methylene blue dye on photocatalytic performance

In this work, Niobium-doped (1%, 3%, and 5%) titanium dioxide (Nb-TiO2) nanosheets were successfully formed via the hydrothermal route and further characterized using TEM, XRD, XPS and UV–vis absorption spectroscopy techniques. Phase purity and structural information of the prepared materials were analysed by XRD measurements. The band gap values ranged from 3.27 to 2.98 eV as Nb doping increased, leading to improved photocatalytic activity by creating new energy levels close to the conduction band. The XPS results confirm the amalgamation of Nb5+ ions into TiO2 without affecting the crystallinity, structure or orientation of the occurrence of oxygen vacancies. In 3% Nb-doped TiO2, the degradation efficiency for removing (Methylene blue) MB dye increased by ∼96% for the removal of MB dye within 70 min in comparison to pure and other doped TiO2 catalysts The better photocatalytic activity of 3% Nb-TiO2 is due to the longer time between electron–hole pairs before they recombine into one pair. Hydroxyl radicals (HO•) and superoxide radicals (O2 •−) are the primary reactive entities responsible for the deterioration of MB dye. Therefore, incorporating Nb into TiO2 nanostructures represents an auspicious material for the decomposition of hazardous and toxic pollutants in aquatic environments.

Unraveling the Unique Strong Metal-Support Interaction in Titanium Dioxide Supported Platinum Clusters for the Hydrogen Evolution Reaction.

Strong metal-support interaction (SMSI) is crucial to modulating the nature of metal species, yet the SMSI behaviors of sub-nanometer metal clusters remain unknown due to the difficulties in constructing SMSI at cluster scale. Herein, we achieve the successful construction of the SMSI between Pt clusters and amorphous TiO2 nanosheets by vacuum annealing, which requires a relatively low temperature that avoids the aggregation of small clusters. In situ scanning transmission electron microscopy observation is employed to explore the SMSI behaviors, and the results reveal the dynamic rearrangement of Pt atoms upon annealing for the first time. The originally disordered Pt atoms become ordered as the crystallizing of the amorphous TiO2 support, forming an epitaxial interface between Pt and TiO2. Such a SMSI state can remain stable in oxidation environment even at 400 °C. Further investigations prove that the electron transfer from TiO2 to Pt occupies the Pt 5d orbitals, which is responsible for the disappeared CO adsorption ability of Pt/TiO2 after forming SMSI. This work not only opens a new avenue for constructing SMSI at cluster scale but also provides in-depth understanding on the unique SMSI behavior, which would stimulate the development of supported metal clusters for catalysis applications.

Unraveling the Unique Strong Metal‐Support Interaction in Titanium Dioxide Supported Platinum Clusters for the Hydrogen Evolution Reaction

AbstractStrong metal‐support interaction (SMSI) is crucial to modulating the nature of metal species, yet the SMSI behaviors of sub‐nanometer metal clusters remain unknown due to the difficulties in constructing SMSI at cluster scale. Herein, we achieve the successful construction of the SMSI between Pt clusters and amorphous TiO2 nanosheets by vacuum annealing, which requires a relatively low temperature that avoids the aggregation of small clusters. In situ scanning transmission electron microscopy observation is employed to explore the SMSI behaviors, and the results reveal the dynamic rearrangement of Pt atoms upon annealing for the first time. The originally disordered Pt atoms become ordered as the crystallizing of the amorphous TiO2 support, forming an epitaxial interface between Pt and TiO2. Such a SMSI state can remain stable in oxidation environment even at 400 °C. Further investigations prove that the electron transfer from TiO2 to Pt occupies the Pt 5d orbitals, which is responsible for the disappeared CO adsorption ability of Pt/TiO2 after forming SMSI. This work not only opens a new avenue for constructing SMSI at cluster scale but also provides in‐depth understanding on the unique SMSI behavior, which would stimulate the development of supported metal clusters for catalysis applications.

Preparation and photocatalytic performance of BiOCl nanosheet–TiO2 nanotube array composites

Combining BiOCl with TiO2 nanomaterials is beneficial to enhance the photocatalytic activity and optoelectronic activity. In this paper, BiOCl nanosheet–TiO2 nanotube array composites were synthesized to enhance the photocatalytic degradation performance for methyl orange (MO) of TiO2 under ultraviolet light irradiation. BiOCl nanosheets were deposited on TiO2 nanotube arrays by the straightforward impregnation method. X-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and photocurrent (i–t) were used to evaluate the composites of BiOCl nanosheets–TiO2 nanotube arrays. The results showed that the tetragonal BiOCl nanosheets clustered together on the surface of the TiO2 nanotubes and grew along the (110) crystal plane. The composites outperformed pure TiO2 regarding outstanding structure and overall photocatalytic performance, and the MO photocatalytic degradation rate was 98.5%. For the 30-BiOCl–TiO2, its photocurrent intensity (58 µA) was 4.5 higher than TiO2 (13 µA). The degradation rate of 87% can still be reached after three cycles.