Self-assembly of nitrogen-doped TiO2 with exposed {001} facets on a graphene scaffold as photo-active hybrid nanostructures for reduction of carbon dioxide to methane

Tailored synthesis of well-defined anatase TiO₂-based crystals with exposed {001} facets has stimulated incessant research interest worldwide due to their scientific and technological importance. Herein, anatase nitrogen-doped TiO₂ (N-TiO₂) nanoparticles with exposed {001} facets deposited on the graphene (GR) sheets (N-TiO₂-001/GR) were synthesized for the first time via a one-step solvothermal synthetic route using NH₄F as the morphology-controlling agent. The experimental results exemplified that GR was uniformly covered with anatase N-TiO₂ nanoparticles (10–17 nm), exposing the {001} facets. The percentage of exposed {001} facets in the N-TiO₂-001/GR nanocomposites was calculated to be ca. 35%. Also, a red shift in the absorption edge and a strong absorption in the visible light range were observed due to the formation of Ti-O-C bonds, resulting in the successful narrowing of the band gap from 3.23 to 2.9 eV. The photocatalytic activities of the as-prepared photocatalysts were evaluated for CO₂ reduction to produce CH₄ in the presence of water vapor under ambient temperature and atmospheric pressure using a low-power 15 W energy-saving daylight lamp as the visible light source—in contrast to the most commonly employed high-power xenon lamps—which rendered the process economically and practically feasible. Among all the studied photocatalysts, the N-TiO₂-001/GR nanocomposites exhibited the greatest CH₄ yield of 3.70 μmol·g_catalyst ^?1, approximately 11-fold higher activity than the TiO₂-001. The enhancement of photocatalytic performance was ascribed to the effective charge anti-recombination of graphene, high absorption of visible light region and high catalytic activity of {001} facets relative to the {101} facets.      

TiO<Subscript>2</Subscript> nanosheets with exposed {001} facets for photocatalytic applications

TiO₂ nanosheets with highly reactive {001} facets ({001}-TiO₂) have attracted great attention in the fields of science and technology because of their unique properties. In recent years, many efforts have been made to synthesize {001}-TiO₂ and to explore their applications in photocatalysis. In this review, we summarize the recent progress in preparing {001}-TiO₂ using different techniques such as hydrothermal, solvothermal, alcohothermal, chemical vapor deposition (CVD), and sol gel-based techniques. Furthermore, the enhanced efficiency of {001}-TiO₂ by modification of carbon materials, surface deposition of transition metals, and non-metal doping is reviewed. Then, the applications of {001}-TiO₂-based photocatalysts in the degradation of organic dyes, hydrogen evolution, carbon dioxide (CO₂) reduction, bacterial disinfection, and dye-sensitized solar cells are summarized. We believe this entire review on TiO₂ nanosheets with {001} facets can further inspire researchers in associated fields.

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Enhancement of Ferromagnetism in Nonmagnetic Metal Oxide Nanoparticles by Facet Engineering

Ferromagnetism in semiconducting metal oxide nanoparticles has been intensively investigated due to their potential applications in spintronics, information storage, and biomedicine. Ferromagnetism can be produced in nonmagnetic metal oxide nanoparticles by a variety of methods or factors, but the saturated magnetization is typically of the order of 10^?4 emu g^?1 and too small to be useful in practice. In this work, it is demonstrated theoretically and experimentally that stronger ferromagnetism can be achieved in undoped nonmagnetic metal oxide semiconductors by exposing some specific polar crystal facets with carvings of special bonds via the interaction with underlying vacancies. In₂O₃ microcubes with completely enclosed {001} polar facets show two orders of magnitude enhancement at room temperature compared to nanoparticles with an irregular morphology. The surface magnetic domains on the {001} facets account for the significantly enhanced ferromagnetism. The technique and concept described here can be extended to other types of metal oxide nanostructures to spur their application to spintronics.     

Dimensionality-dependent photocatalytic activity of TiO2-based nanostructures: nanosheets with a superior catalytic property

TiO₂-based nanostructures usually possess excellent photochemical properties. However, the relationship between their dimensionality and photocatalytic activity was rarely investigated. In this study, a series of TiO₂-based nanostructures in various dimensionalities (such as nanosheets, nanotubes) were obtained by hydrothermal treatment of P25, and the process of structural evolution was also systematically investigated by TEM, BET, Raman, and XRD analysis. Much higher rate constant (3.7 × 10^?2 min^?1) for the degradation of rhodamine B was found for nanosheets, comparing with those of three-dimensional P25 nanoparticles (0.59 × 10^?2 min^?1) and one-dimensional nanotubes (0.85 × 10^?2 min^?1). It is found that the hydrothermally prepared TiO₂-based nanosheets possess small thickness (ca. 5 nm) and plentiful surface hydroxyl groups, and the reason why TiO₂-based nanosheets possess superior photocatalytic activity is also discussed in detail from the microstructure and surface chemical states. In addition, TiO₂-based nanosheets exhibit good reusability in the cyclic experiments, implying a potential application for photocatalytic degradation of organic pollutants.     

Graphdiyne-hybridized N-doped TiO<Subscript>2</Subscript> nanosheets for enhanced visible light photocatalytic activity

In this study, graphdiyne (GD)-hybridized nitrogen-doped TiO₂ nanosheets with exposed (001) facets (GD-NTNS) have been prepared via a hydrothermal reaction and utilized as photocatalyst for the photodegradation of rhodamine B (RhB) under visible light illumination. The resultant GD-NTNS composites exhibit superior visible light photocatalytic activity than that of the bare TiO₂ nanosheets (TNS) and nitrogen-doped TiO₂ nanosheets (NTNS). The enhanced photoactivity can be attributed to the synergistic effects of GD and nitrogen doping with efficient electron transfer and strong visible light absorption. It has been revealed that ^·O^2? and h⁺ are the major species for the enhanced photoactivity under visible light. Our work will facilitate the potential for future design of hybrid materials for practical applications beyond photocatalysts.     

A Photoresponsive Rutile TiO2 Heterojunction with Enhanced Electron–Hole Separation for High‐Performance Hydrogen Evolution

Rutile titanium dioxide (TiO₂) is a promising photocatalyst due to its high thermodynamic stability and few intragrain defects. However, it has not yet achieved photocatalytic activity comparable to that of anatase TiO₂ owing to its higher recombination rate of electron–hole pairs. To effectively separate the electron–hole pairs in rutile TiO₂, a facet heterojunction (FH) structure to prolong the lifetime of the photogenerated electrons is proposed. Ultrathin TiO₂ nanosheets with different facets are coated in situ onto TiO₂ nanorod (NR) substrates, where FHs are built among the nanosheets as well as between the nanosheets and NR substrates. The as‐prepared rutile TiO₂, with an FH structure (FH‐TiO₂), serves as an effective photocatalyst for water splitting. More than 45 and 18 times higher photogenerated current density and H₂ production rate, respectively, are obtained compared to those of pure rutile TiO₂ NRs. Moreover, FH‐TiO₂ delivers a 0.566 mmol g^?1 h^?1 H₂ production rate even in pure water. This study offers important insights into the rational design of rutile TiO₂ structures for highly efficient photocatalytic reactions.     

Low Temperature Synthesis of Large‐Size Anatase TiO2 Nanosheets with Enhanced Photocatalytic Activities

TiO₂ nanosheets have continuously been intriguing due to their high surface activities as photocatalyst but still challenging to synthesis large‐scale 2D nanostructures. A special microstructure evolution of TiO₂, ripening in aqueous solution at low temperature (≈4 °C), is found for the first time, i.e., from the initial aperiodic atom‐networks gradually into low crystallized continuous spongy structure with small crystal facets and ultimately forming large‐size anatase nanosheets with exposed (101) and (200) facets. Based on this finding, the synthesized anatase TiO₂ nanosheets possess monodispersed large‐scale 2D nanostructure so as to exhibit appreciable quantum size effects and remarkable enhanced optical absorption capacity. Using photocatalytic reduction of Cr (VI) to Cr (III) as the probe reaction to evaluate photocatalytic activities of the TiO₂ nanosheets, the reductivity of Cr (VI) achieves 99.8% in 15 min under irradiation of 200–800 nm light. At the same time, an in situ Cr (III)‐doping occurs spontaneously and triggers pronounced visible light driven photocatalysis, reducing 99% of Cr (VI) in 100 min under irradiation of 400–800 nm light.     

Anatase TiO₂ crystal facet growth: mechanistic role of hydrofluoric acid and photoelectrocatalytic activity

This work reports a facile hydrothermal approach to directly grow anatase TiO(2) crystals with exposed {001} facets on titanium foil substrate by controlling pH of HF solution. The mechanistic role of HF for control growth of the crystal facet of anatase TiO(2) crystals has been investigated. The results demonstrate that controlling solution pH controls the extent of surface fluorination of anatase TiO(2), hence the size, shape, morphology, and {001} faceted surface area of TiO(2) crystals. The theoretical calculations reveal that {001} faceted surface fluorination of anatase TiO(2) can merely occur via dissociative adsorption of HF molecules under acidic conditions while the adsorption of Na(+)F(-) is thermodynamically prohibited. This confirms that the presence of molecular form of HF but not F(-) is essential for preservation of exposed {001} facets of anatase TiO(2). Anatase TiO(2) crystals with exposed {001} facets can be directly fabricated on titanium foil by controlling the solution pH ≤ 5.8. When pH is increased to near neutral and beyond (e.g., pH ≥ 6.6), the insufficient concentration of HF ([HF] ≤ 0.04%) dramatically reduces the extent of surface fluorination, leading to the formation of anatase TiO(2) crystals with {101} facets and titanate nanorods/nanosheets. The anatase TiO(2) nanocrystals with exposed {001} facets exhibits a superior photoelectrocatalytic activity toward water oxidation. The findings of this work clarify the mechanistic role of HF for controlling the crystal facet growth, providing a facile means for massive production of desired nanostructures with high reactive facets on solid substrates for other metal oxides.     

Synergistic Interlayer and Defect Engineering in VS2 Nanosheets toward Efficient Electrocatalytic Hydrogen Evolution Reaction

A simple one‐pot solvothermal method is reported to synthesize VS₂ nanosheets featuring rich defects and an expanded (001) interlayer spacing as large as 1.00 nm, which is a ≈74% expansion as relative to that (0.575 nm) of the pristine counterpart. The interlayer‐expanded VS₂ nanosheets show extraordinary kinetic metrics for electrocatalytic hydrogen evolution reaction (HER), exhibiting a low overpotential of 43 mV at a geometric current density of 10 mA cm^?2, a small Tafel slope of 36 mV dec^?1, and long‐term stability of 60 h without any current fading. The performance is much better than that of the pristine VS₂ with a normal interlayer spacing, and even comparable to that of the commercial Pt/C electrocatalyst. The outstanding electrocatalytic activity is attributed to the expanded interlayer distance and the generated rich defects. Increased numbers of exposed active sites and modified electronic structures are achieved, resulting in an optimal free energy of hydrogen adsorption (?G_H) from density functional theory calculations. This work opens up a new door for developing transition‐metal dichalcogenide nanosheets as high active HER electrocatalysts by interlayer and defect engineering.     

Synthesis and photo activity of flower-like anatase TiO2 with {001} facets exposed

Developing photocatalysts with specific morphology promises good opportunities to discover the geometry-dependent properties. Herein, flower-like anatase TiO₂ assemblies with dominant {001} facets exposed were successfully synthesized via a simple, economical hydrothermal route with titanium sulfate and hydrofluoric acid. Their surface morphology and structure were investigated by scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, X-ray diffraction, and Brunauer-Emmet-Teller N₂ gas adsorption-desorption isotherms. The optical property and the photo-induced charge carriers of the flower-like TiO₂ were studied by UV-vis diffuse reflectance spectroscopy and transient photovoltage technique. The flower-like TiO₂ particles exhibited a good photocatalytic activity in degrading rhodamine B.     

Vapor‐Phase Hydrothermal Transformation of HTiOF3 Intermediates into {001} Faceted Anatase Single‐Crystalline Nanosheets

For the first time, a facile, one‐pot hydrofluoric acid vapor‐phase hydrothermal (HF‐VPH) method is demonstrated to directly grow single‐crystalline anatase TiO₂ nanosheets with 98.2% of exposed {001} faceted surfaces on the Ti substrate via a distinctive two‐stage formation mechanism. The first stage produces a new intermediate crystal (orthorhombic HTiOF₃) that is transformed into anatase TiO₂ nanosheets during the second stage. The findings reveal that the HF‐VPH reaction environment is unique and differs remarkably from that of liquid‐phase hydrothermal processes. The uniqueness of the HF‐VPH conditions can be readily used to effectively control the nanostructure growth.     

Strong Surface‐Bound Sulfur in Carbon Nanotube Bridged Hierarchical Mo2C‐Based MXene Nanosheets for Lithium–Sulfur Batteries

In this work, hydroxyl‐functionalized Mo₂C‐based MXene nanosheets are synthesized by facilely removing the Sn layer of Mo₂SnC. The hydroxyl‐functionalized surface of Mo₂C suppresses the shuttle effect of lithium polysulfides (LiPSs) through strong interaction between Mo atoms on the MXenes surface and LiPSs. Carbon nanotubes (CNTs) are further introduced into Mo₂C phase to enlarge the specific surface area of the composite, improve its electronic conductivity, and alleviate the volume change during discharging/charging. The strong surface‐bound sulfur in the hierarchical Mo₂C‐CNTs host can lead to a superior electrochemical performance in lithium–sulfur batteries. A large reversible capacity of ≈925 mAh g ^{? 1} is observed after 250 cycles at a current density of 0.1 C (1 C = 1675 mAh g^?1) with good rate capability. Notably, the electrodes with high loading amounts of sulfur can also deliver good electrochemical performances, i.e., initial reversible capacities of ≈1314 mAh g^?1 (2.4 mAh cm^?2), ≈1068 mAh g^?1 (3.7 mAh cm^?2), and ≈959 mAh g^?1 (5.3 mAh cm^?2) at various areal loading amounts of sulfur (1.8, 3.5, and 5.6 mg cm^?2) are also observed, respectively.     

Heterogeneous nucleation of solidification of cadmium particles embedded in an aluminium matrix

A hypomonotectic alloy of Al-4.5wt%Cd has been manufactured by melt spinning and the resulting microstructure examined by transmission electron microscopy. As-melt spun hypomonotectic Al-4.5wt%Cd consists of a homogeneous distribution of faceted 5 to 120 nm diameter cadmium particles embedded in a matrix of aluminium, formed during the monotectic solidification reaction. The cadmium particles exhibit an orientation relationship with the aluminium matrix of {111}_Al//{0001}_Cd and 110_AlAl//11¯20> _Cd, with four cadmium particle variants depending upon which of the four {111}_Al planes is parallel to {0001}_Cd. The cadmium particles exibit a distorted cuboctahedral shape, bounded by six curved {100}_Al//{20¯23}_Cd facets, six curved {111}_Al/{40¯43}_Cd facets and two flat {111}_Al//{0001}_Cd facets. The as-melt spun cadmium particle shape is metastable and the cadmium particles equilibrate during heat treatment below the cadmium melting point, becoming elongated to increase the surface area and decrease the separation of the {111}_Al//{0001}_Cd facets.The equilibrium cadmium particle shape and, therefore, the anisotropy of solid aluminium-solid cadmium and solid aluminium -liquid cadmium surface energies have been monitored by in situ heating in the transmission electron microscope over the temperature range between room temperature and 420 °C. The anisotropy of solid aluminium-solid cadmium surface energy is constant between room temperature and the cadmium melting point, with the {100}_Al//{20¯23}_Cd surface energy on average 40% greater than the {111}_Al//{0001}_Cd surface energy, and 10% greater than the {111}_Al//{40¯43_Cd surface energy. When the cadmium particles melt at temperatures above 321 °C, the {100}_Al//{20¯23}_Cd facets disappear and the {111}_Al//{40¯43}_Cd and {111}_A1//{0001}_Cd surface energies become equal. The {111}_Al facets do not disappear when the cadmium particles melt, and the anisotropy of solid aluminium-liquid cadmium surface energy decreases gradually with increasing temperature above the cadmium melting point.The kinetics of cadmium solidification have been examined by heating and cooling experiments in a differential scanning calorimeter over a range of heating and cooling rates. Cadmium particle solidification is nucleated catalytically by the surrounding aluminium matrix on the {111}_Al faceted surfaces, with an undercooling of 56 K and a contact angle of 42 °. The nucleation kinetics of cadmium particle solidification are in good agreement with the hemispherical cap model of heterogeneous nucleation.     

Metabolizable Ultrathin Bi2Se3 Nanosheets in Imaging‐Guided Photothermal Therapy

Poly(vinylpyrrolidone)‐encapsulated Bi₂Se₃ nanosheets with a thickness of 1.7 nm and diameter of 31.4 nm are prepared by a solution method. Possessing an extinction coefficient of 11.5 L g^?1 cm^?1 at 808 nm, the ultrathin Bi₂Se₃ nanosheets boast a high photothermal conversion efficiency of 34.6% and excellent photoacoustic performance. After systemic administration, the Bi₂Se₃ nanosheets with the proper size and surface properties accumulate passively in tumors enabling efficient photoacoustic imaging of the entire tumors to facilitate photothermal cancer therapy. In vivo biodistribution studies reveal that they are expelled from the body efficiently after 30 d. The ultrathin Bi₂Se₃ nanosheets have large clinical potential as metabolizable near‐infrared‐triggered theranostic agents.     

Exposing {001} Crystal Plane on Hexagonal Ni‐MOF with Surface‐Grown Cross‐Linked Mesh‐Structures for Electrochemical Energy Storage

Hexagonal nickel‐organic framework (Ni‐MOF) [Ni(NO₃)₂·6H₂O, 1,3,5‐benzenetricarboxylic acid, 4‐4′‐bipyridine] is fabricated through a one‐step solvothermal method. The {001} crystal plane is exposed to the largest hexagonal surface, which is an ideal structure for electron transport and ion diffusion. Compared with the surrounding rectangular crystal surface, the ion diffusion length through the {001} crystal plane is the shortest. In addition, the cross‐linked porous mesh structures growing on the {001} crystal plane strengthen the mixing with conductive carbon, inducing preferable conductivity, as well as increasing the area of ion contact and the number of active sites. These advantages enable the hexagonal Ni‐MOF to exhibit excellent electrochemical performance as supercapacitor electrode materials. In a three‐electrode cell, specific capacitance of hexagonal Ni‐MOF in the 3.0 m KOH electrolyte is 977.04 F g^?1 and remains at the initial value of 92.34% after 5,000 cycles. When the hexagonal Ni‐MOF and activated carbon are assembled into aqueous devices, the electrochemical performance remains effective.     

Novel UV–Visible Photodetector in Photovoltaic Mode with Fast Response and Ultrahigh Photosensitivity Employing Se/TiO2 Nanotubes Heterojunction

A feasible strategy for hybrid photodetector by integrating an array of self‐ordered TiO₂ nanotubes (NTs) and selenium is demonstrated to break the compromise between the responsivity and response speed. Novel heterojunction between the TiO₂ NTs and Se in combination with the surface trap states at TiO₂ help regulate the electron transport and facilitate the separation of photogenerated electron–hole pairs under photovoltaic mode (at zero bias), leading to a high responsivity of ≈100 mA W^?1 at 620 nm light illumination and the ultrashort rise/decay time (1.4/7.8 ms). The implanting of intrinsic p‐type Se into TiO₂ NTs broadens the detection range to UV–visible (280–700 nm) with a large detectivity of over 10¹² Jones and a high linear dynamic range of over 80 dB. In addition, a maximum photocurrent of ≈10⁷ A is achieved at 450 nm light illumination and an ultrahigh photosensitivity (on/off ratio up to 10⁴) under zero bias upon UV and visible light illumination is readily achieved. The concept of employing novel heterojunction geometry holds great potential to pave a new way to realize high performance and energy‐efficient optoelectronic devices for practical applications.     

Photocatalytic mechanism of high-activity anatase TiO<Subscript>2</Subscript> with exposed (001) facets from molecular-atomic scale: HRTEM and Raman studies

Anatase TiO₂ with a variant percentage of exposed (001) facets was prepared under hydrothermal processes by adjusting the volume of HF, and the photocatalytic mechanism was studied from atomic-molecular scale by HRTEM and Raman spectroscopy. It was revealed that: 1) From HRTEM observations, the surface of original TiO₂ with exposed (001) facets was clean without impurity, and the crystal lattice was clear and completed; however, when mixed with methylene blue (MB) solution, there were many 1 nm molecular absorbed at the surface of TiO₂; after the photocatalytic experiment, MB molecules disappeared and the TiO₂ lattice image became fuzzy. 2) The broken path of the MB chemical bond was obtained by Raman spectroscopy, i.e., after the irradiation of the light, the vibrational mode of C-N-C disappeared due to the chemical bond breakage, and the groups containing C-N bond and carbon rings were gradually decomposed. Accordingly, we propose that the driving force for breaking the chemical bond and the disappearance of groups is from the surface lattice distortion of TiO₂ during photocatalyzation.     

Solidification of tin droplets embedded in an aluminium matrix

The solidification behaviour of tin droplets embedded in an aluminium matrix in a rapidly solidified Al-5 wt % Sn alloy has been investigated by a combination of transmission electron microscopy and differential scanning calorimetry. Detailed transmission electron microscopy shows that rapidly solidified Al-5 wt % Sn consists of about 5 μm diameter columnar aluminium grains, with a fine-scale distribution of 20–300 nm sized tin particles embedded within the aluminium grains, and 100–400 nm sized tin particles at the aluminium grain boundaries. The tin particles exhibit two different orientation relationships with the aluminium matrix and a variety of different faceted shapes: {1 1 1}_Al∥{1 0 0}_Sn and 〈¯2 1 1〉_Al∥〈0 1 0〉_Sn, with the main facet parallel to {1 1 1}_Al, and {1 0 0}_Sn; and {1 0 0}_Al∥{1 0 0}_Sn and 〈0 1 1〉_Al∥〈0 1 1〉_Sn, with the main facet parallel to {1 0 0}_Al and {1 0 0}_Sn.In situ heating in the transmission electron microscope shows that the different tin particle shapes are not affected by heat treatment in the solid state, but change into a truncated octahedral shape bounded by {1 1 1}_Al and {1 0 0}_Al facets when the tin particles melt. The {1 0 0}_Al-liquid Sn interfacial energy is about 9% larger than the {1 1 1}_Al-liquid Sn interfacial energy just above the tin particle melting point, and the {1 0 0}_Al/{1 1 1}_Al interfacial energy anisotropy decreases gradually as the temperature increases above the melting point. Differential scanning calorimeter experiments show that the liquid tin droplets solidify in three stages. Firstly, the larger tin droplets at the aluminium grain boundaries solidify by nucleation on catalytic trace impurities, over a temperature range of 170–140 °C. Secondly and thirdly, the smaller tin particles embedded within the aluminium grains solidify by catalytic nucleation on the {1 0 0}_Al and {1 1 1}_Al facets, over the two temperature ranges of 140–128 °C and 128-115°C. Catalytic nucleation of the solidification of tin takes place at special sites such as steps or dislocations on the {1 0 0}_Al and {1 1 1}_Al facets with contact angles of 55° and 59°.     

Enhancement of antibacterial properties of Ag nanorods by electric field

Abstract

The effect of an electric field on the antibacterial activity of columnar aligned silver nanorods was investigated. Silver nanorods with a polygonal cross section, a width of 20–60 nm and a length of 260–550 nm, were grown on a titanium interlayer by applying an electric field perpendicular to the surface of a Ag/Ti/Si(100) thin film during its heat treatment at 700 °C in an Ar+H₂ environment. The optical absorption spectrum of the silver nanorods exhibited two peaks at wavelengths of 350 and 395 nm corresponding to the main surface plasmon resonance bands of the one-dimensional silver nanostructures. It was found that the silver nanorods with an fcc structure were bounded mainly by {100} facets. The antibacterial activity of the silver nanorods against Escherichia coli bacteria was evaluated at various electric fields applied in the direction of the nanorods without any electrical connection between the nanorods and the capacitor plates producing the electric field. Increasing the electric field from 0 to 50 V cm^?1 resulted in an exponential increase in the relative rate of reduction of the bacteria from 3.9×10^?2 to 10.5×10^?2 min^?1. This indicates that the antibacterial activity of silver nanorods can be enhanced by applying an electric field, for application in medical and food-preserving fields.     

Spontaneous Dewetting of Au-Thin Layers on Oxide- and Fluorine-Terminated Single Crystalline Anatase and Efficient Use in Photocatalytic H2 Production

In the present work, the spontaneous dewetting of thin Au layers on single crystalline anatase nanosheets into narrow-disperse Au nanoparticles is investigated. Patterns of the Au particles can be formed on the main facets of anatase that provide a high co-catalytic activity for photocatalytic generation of H₂. Dewetting is distinctly influenced by the respective facets (001) and (101), the deposit thickness, and secondary thermal dewetting, but most strongly by the surface termination of the nanosheets. Fluoride termination not only leads to an enhanced Au-phobic behavior but strongly affects the co-catalytic activity for photocatalytic generation of H₂. While fluoride termination with or without Au decoration is detrimental for hole transfer, the interplay of the Au co-catalyst and surface fluoride yields highly beneficial effect for electron transfer. This results in a three-times higher photocatalytic H₂ production for the F-terminated surface. The findings suggest that dewetting of Au on surface fluorinated TiO₂ is an effective way to modulate surface dewetting and achieve a strongly enhanced photocatalytic activity.