Platinum Atoms Research Articles

On the Controlled Loading of Single Platinum Atoms as a Co-Catalyst on TiO2 Anatase for Optimized Photocatalytic H2 Generation.

Single-atom (SA) catalysis is a novel frontline in the catalysis field due to the often drastically enhanced specific activity and selectivity of many catalytic reactions. Here, an atomic-scale defect engineering approach to form and control traps for platinum SA sites as co-catalyst for photocatalytic H2 generation is described. Thin sputtered TiO2 layers are used as a model photocatalyst, and compared to the more frequently used (001) anatase sheets. To form stable SA platinum, the TiO2 layers are reduced in Ar/H2 under different conditions (leading to different but defined Ti3+ -Ov surface defects), followed by immersion in a dilute hexachloroplatinic acid solution. HAADF-STEM results show that only on the thin-film substrate can the density of SA sites be successfully controlled by the degree of reduction by annealing. An optimized SA-Pt decoration can enhance the normalized photocatalytic activity of a TiO2 sputtered sample by 150 times in comparison to a conventional platinum-nanoparticle-decorated TiO2 surface. HAADF-STEM, XPS, and EPR investigation jointly confirm the atomic nature of the decorated Pt on TiO2 . Importantly, the density of the relevant surface exposed defect centers-thus the density of Pt-SA sites, which play the key role in photocatalytic activity-can be precisely optimized.

Stable single platinum atoms trapped in sub-nanometer cavities in 12CaO\xb77Al2O3 for chemoselective hydrogenation of nitroarenes

Single-atom catalysts (SACs) have attracted significant attention because they exhibit unique catalytic performance due to their ideal structure. However, maintaining atomically dispersed metal under high temperature, while achieving high catalytic activity remains a formidable challenge. In this work, we stabilize single platinum atoms within sub-nanometer surface cavities in well-defined 12CaO·7Al2O3 (C12A7) crystals through theoretical prediction and experimental process. This approach utilizes the interaction of isolated metal anions with the positively charged surface cavities of C12A7, which allows for severe reduction conditions up to 600 °C. The resulting catalyst is stable and highly active toward the selective hydrogenation of nitroarenes with a much higher turnover frequency (up to 25772 h−1) than well-studied Pt-based catalysts. The high activity and selectivity result from the formation of stable trapped single Pt atoms, which leads to heterolytic cleavage of hydrogen molecules in a reaction that involves the nitro group being selectively adsorbed on C12A7 surface.

STUDY ON SYNTHESIS AND CHARACTERIZATION OF ELECTROCATALYST CONTAINING PLATINUM, PALLADIUM, NICKEL FOR HYDROGEN EVOLUTION REACTION IN ALKALINE MEDIUM

Several kinds of electrocatalyst based on platinum, palladium, and nickel with glassy carbon substrate were successfully synthesized by electrodeposition method, and then applied for water electrolysis in alkaline media. Surface morphology of materials was investigated with scanning electron microscopy method. Energy-dispersive X-ray spectroscopy was used to find the content of each metal in bimetallic materials. The result showed that the number of noble metals was moderately decreased while the catalytic activities were slightly better than pure metal electrodes. Linear sweep voltammetry measurement was taken in KOH 1M solution to find the overvoltage of hydrogen evolution reaction and cyclic voltammetry method in 0.01M K3[Fe(CN)6]: 0.01M K4[Fe(CN)6] in 0.1M KOH was used to determine the reversible capacity of material electrodes. The linear sweep voltammetry measurements confirmed that the activities of new catalysts are higher than the origin materials. The binary catalyst of Pt-Ni can replace platinum for hydrogen evolution reaction in alkaline medium. Notably, the replacement of platinum atoms with palladium and nickel atoms, and the combination of good properties of them leads to improve the catalytic activity, and in the same time to decrease the catalyst cost. Once again, the electrochemical parameters open up a new prospect for the hydrogen produce.

Amorphous MoOX-Stabilized single platinum atoms with ultrahigh mass activity for acidic hydrogen evolution

It is highly desirable to develop Pt single-atom (SA) catalysts with an optimized mass activity for acidic hydrogen evolution reaction (HER), but it remains a significant challenge. In this study, a new Pt SA strongly coupled with amorphous MoOX (Pt-SA/ɑ-MoOx) is rationally designed. The synergistic effect between unsaturated Pt atoms and defective MoOx can significantly lower the reaction barrier contributing to the fast HER reaction kinetics. Hence, Pt-SA/ɑ-MoOx exhibits an ultrahigh mass activity of 52.0 A mgPt−1 at an overpotential of 50 mV, corresponding to better acidic HER activity than those reported previously for Pt SA-based catalysts. Furthermore, Pt-SA/ɑ-MoOx shows Pt-like kinetics with a small Tafel slope of 123 mV dec−1 and outstanding long-term electrochemical stability for 20 h. This developed synthetic method is also extended for the fabrication of other amorphous MoOx-supported SA catalysts (e.g. Ir, Au and Pb). As far as we know, our study reports the first example of the combination of metal SA and amorphous oxide for highly efficient electrocatalysis.

Crystal structures of chlorido-[dihy-droxybis-(1-imino-eth-oxy)]arsanido-κ3 N,As,N']platinum(II) and of a polymorph of chlorido-[dihy-droxybis-(1-imino-prop-oxy)arsanido-κ3 N,As,N']platinum(II).

Each central platinum(II) atom in the crystal structures of chlorido-[dihy-droxybis-(1-imino-eth-oxy)arsanido-κ3 N,As,N']platinum(II), [Pt(C4H10AsN2O4)Cl] (1), and of chlorido-[dihy-droxybis-(1-imino-prop-oxy)arsanido-κ3 N,As,N']platinum(II), [Pt(C6H14AsN2O4)Cl] (2), is coordinated by two nitro-gen donor atoms, a chlorido ligand and to arsenic, which, in turn, is coordinated by two oxygen donor ligands, two hydroxyl ligands and the platinum(II) atom. The square-planar and trigonal-bipyramidal coordination environments around platinum and arsenic, respectively, are significantly distorted with the largest outliers being 173.90 (13) and 106.98 (14)° for platinum and arsenic in (1), and 173.20 (14)° and 94.20 (9)° for (2), respectively. One intra-molecular and four classical inter-molecular hydrogen-bonding inter-actions are observed in the crystal structure of (1), which give rise to an infinite three-dimensional network. A similar situation (one intra-molecular and four classical inter-molecular hydrogen-bonding inter-actions) is observed in the crystal structure of (2). Various π-inter-actions are present in (1) between the platinum(II) atom and the centroid of one of the five-membered rings formed by Pt, As, C, N, O with a distance of 3.7225 (7) Å, and between the centroids of five-membered (Pt, As, C, N, O) rings of neighbouring mol-ecules with distances of 3.7456 (4) and 3.7960 (6) Å. Likewise, weak π-inter-actions are observed in (2) between the platinum(II) atom and the centroid of one of the five-membered rings formed by Pt, As, C, N, O with a distance of 3.8213 (2) Å, as well as between the Cl atom and the centroid of a symmetry-related five-membered ring with a distance of 3.8252 (12) Å. Differences between (2) and the reported polymorph [Miodragović et al. (2013 ▸). Angew. Chem. Int. Ed. 52, 10749-10752] are discussed.

Atomic Platinum Anchored on Fe‐N‐C Material for High Performance Oxygen Reduction Reaction

Development of highly active and stable catalysts to reduce the amount of Pt or replace Pt with nonprecious transition metal in acid of oxygen reduction reaction (ORR) is still an enormous challenge. Herein, we report anchoring atomic Pt particles on Fe/N‐doped carbon material (Pt1.1FeNC) are, for the first time, synthesized by the photodeposition method. The obtained Pt1.1FeNC electrocatalyst exhibits superior electrocatalytic activity and good stability for four‐electron oxygen reduction reaction (ORR) in an acidic electrolyte. Pt1.1FeNC electrocatalyst shows a half‐wave potential of 0.85 V vs. reversible hydrogen electrode (RHE) in 0.1 m HClO4 (0.83 V of 20 wt.‐% commercial Pt/C). After 10,000 cycles after, the catalysis active only decreases 20 mV. These are mainly due to the synergistic effect between Pt and Fe.

Fundamental Electrochemical Insights of Vertically Aligned Carbon Nanofiber Architecture as a Catalyst Support for ORR

Three-dimensionally (3D) architectured carbon supports have received great attention for fuel cell catalysts. However, the complicated structure makes the assessment of catalytic properties difficult using the conventional rotating disk electrode (RDE) method. This paper reports a systematic study on oxygen reduction reaction (ORR) with ion-beam sputtered Pt catalyst (at Pt loadings of 6.5–43 μg cm−2) on a vertically aligned carbon nanofiber (VACNF) array, consisting of conically stacked graphitic microstructures. The RDE studies reveal that thick 3D architecture of VACNFs exhibits enhanced limiting current density that deviates from the Levich equation for conventional thin-film catalysts. Nevertheless, useful information can be derived from RDE experiments with such systems. Molecular models representing VACNFs have been constructed to explore their capacity as catalyst supports for ORR. Platinum atoms form strong bonds at the open graphitic edges in VACNF, corroborating the role of VACNF in stabilizing Pt. Density Functional Theory (DFT) calculations further elucidate the two-electron and four-electron ORR pathways on the bare VACNF and Pt/VACNF catalysts, respectively. Furthermore, the Pt/VACNF catalysts show enhanced tolerance to methanol oxidation and a higher ability to recover from carbon monoxide poisoning in comparison to the benchmark Pt/C catalysts. These results provide critical insights for developing future high-performance electrocatalyst supports.

Синтез и строение гексабромоплатината циклопропилтрифенилфосфония

Using the interaction of potassium hexabromoplatinate with cyclopropyltriphenylphosphonium bromide in acetonitrile after crystallization from dimethyl sulfoxide, the [Ph 3 PC 3 H 5 ] 2 [PtBr 6 ] complex ( 1 ) has been obtained for the first time (red crystals, m.p. 235 °C). The compound 1 has been characterized by IR-spectroscopy and X-ray analysis. According to the data of X-ray analysis the unit cell crystallographic parameters of compound 1 are: orthorhombic syngony, the symmetry group Pna2 1 ; M 1281.22; cell parameters: a = 14.653(6), b = 18.874(8), c = 15.921(8) Å; a = 90.00 degrees, β = 90.00 degrees, g = 90.00 degrees; V = 4403(3) Å 3 ; ρ (calc.) = 1.933 g/cm 3 , Z = 8, the crystal size is 0.32×0.24×0.16 mm; intervals of reflection indexes –25 ≤ h ≤ 25, –17 ≤ k ≤ 19, –21 ≤ l ≤ 20; total reflections 66507; independent disclosures 10802; μ = 8.733 mm –1 ; R 1 = 0.0344; wR 2 = 0.0755 (all date), R 1 = 0.0484; wR 2 = 0.0807 ( F 2 > 2s( F 2 )); residual electron density 1,28/–2,05 e/Å 3 . In cations, the phosphorus atoms have a distorted tetrahedral coordination (the CPC angles equal 88.6(3)°-122.4(3)°, the P-C bond lengths are 1.541(5)-2.273(7) Å). The platinum atoms are coordinated by six bromine atoms in the anion (the BrPtBr trans -angles are close to 180°, the BrPtBr cis -angles have the values 89.17(4)-108.(3)°, the Pt-Br bond lengths are 2.1618(9)-2.9732(14) Å). Complete tables of coordinates of atoms, bond lengths and valence angles are deposited at the Cambridge Structural Data (№ 1969775; http://www.ccdc. cam.ac.uk).

Double addition of phenylacetylene onto the mixed bridge phosphinito-phosphanido Pt(i) complex [(PHCy2)Pt(μ-PCy2){κ2P,O-μ-P(O)Cy2}Pt(PHCy2)](Pt-Pt).

The reaction of the dinuclear phosphinito bridged complex [(PHCy2)Pt(μ-PCy2){κ2P,O-μ-P(O)Cy2}Pt(PHCy2)](Pt-Pt) (1) with phenylacetylene affords the η1-alkenyl-μ,η1:η2-alkynyl complex [(η1-trans-(Ph)HC[double bond, length as m-dash]CH)(PHCy2)Pt(μ-PCy2)(μ,η1:η2-PhC[triple bond, length as m-dash]C)Pt{κP-P(O)Cy2}(PHCy2)] (4) displaying a σ-bonded 2-phenylethenyl ligand and an alkynyl (μ-κCα:η2) bridge between the platinum atoms. Complex 4 was shown to form in two steps: initially, the attack of the first molecule of phenylacetylene gives the σ-acetylide complex [(PHCy2)(η1-PhC[triple bond, length as m-dash]C)Pt1(μ-PCy2)Pt2(PHCy2){κP-P(OH)Cy2}](Pt-Pt) (5) featuring an intramolecular π-type hydrogen bond between the POH and the C[triple bond, length as m-dash]C triple bond; fast reaction of 5 with a second molecule of phenylacetylene results in the oxidative addition of the terminal C-H bond of the second alkyne to Pt1 that, after rearrangements, leads to 4. When left in solution for two weeks, complex 4 spontaneously isomerizes completely to [(PHCy2)(η1-trans-(Ph)HC[double bond, length as m-dash]CH)Pt(μ-PCy2){κ2P,O-μ-P(O)Cy2}Pt(η1-PhC[triple bond, length as m-dash]C)(PHCy2)] (7) displaying a 2-phenylethenyl ligand and a phenylethynyl group both σ-bonded to the metal. Density functional calculations at the B3LYP/LACV3P++**//DFT/LACVP* level were carried out to study the thermodynamics of the formation of all considered complexes and to trace the mechanism of formation of the observed products.

Cisplatin adducts of DNA as precursors for nanostructured catalyst materials.

The synthesis and characterisation of novel metal-modified DNA precursors for fuel cell catalyst development are described. Material precursors in the form of metal–DNA complexes were prepared through the reaction of DNA with cisplatin at various loadings and spectroscopically tested to confirm the platinum binding mode and the degree of complexation. The surface morphology of the DNA–metal material was analysed by Scanning Transmission Electron Microscopy (STEM), which revealed the extent of platinum nanocluster formation, with low metal loadings leading to observation of individual platinum atoms. Electrochemical measurements showed a greater electrocatalytic activity for the hydrogen evolution reaction (HER) with increased platinum loadings, shifting the half wave potential, E1/2, away from the glassy carbon limit towards that of a bulk Pt electrode. This is explained further by Tafel plots, from which a change in the mechanism of the apparent rate limiting step for proton reduction from a Volmer to a Heyrovsky mechanism is postulated as the platinum loading increases.

Novel luminescent homo/heterometallic platinum(ii) alkynyl complexes based on Y-shaped pyridyl diphosphines.

A series of dinuclear platinum(ii) alkynyl complexes [Pt2L2(C[triple bond, length as m-dash]CC6H4R-4)4] (R = H 1, CH32, But3) and unusual tetranuclear Pt(ii)-Ag(i) clusters [Pt2Ag2L(C[triple bond, length as m-dash]CC6H4R-4)6] (R = H, 4; CH3, 5; But, 6), together with novel polymer crystals [Pt2Ag2L(C[triple bond, length as m-dash]CC6H5)6]∞ ([4]∞), were synthesized by a self-assembly reaction between [NBu4]2[Pt(C[triple bond, length as m-dash]CC6H4-R-4)4] and [Ag6L6]6+ (L = 4-(3,5-(diphenylphosphine)phenyl)pyridine). These complexes were characterized by using a range of spectroscopic techniques and complexes 1, 3, 5, and [4]∞ were analysed by X-ray crystallography. Each platinum atom of the Pt(ii)-Ag(i) clusters shows an unusual asymmetric distorted square planar geometry with three alkynyl groups and one bridging L phosphorus atom. Dinuclear complexes 1-3 demonstrate solid-state weak blue luminescence, while tetranuclear Pt(ii)-Ag(i) clusters 4-6 show intense blue-green or yellow-green emission. Furthermore, the crystalline samples of polymer [4]∞ display bright yellow emission (518 nm) that is significantly red-shifted as compared to monomer crystal 4.

MOF derived high-density atomic platinum heterogeneous catalyst for C–H bond activation

A MOF-derived hollow nanobox with high-density under-coordinated atomic Pt sites exhibits excellent performance in direct C–H bond borylation.

Platinum atoms liberate hydrogen from methanol

Fuel-cell automobiles powered with clean-burning hydrogen are slowly being commercialized for private use. The pace could accelerate, benefiting the environment, if hydrogen was supplied not as a high-pressure gas but rather as an inexpensive liquid that was shipped and pumped using today’s vast liquid-fuel infrastructure. A study describing a single-atom catalyst that efficiently strips hydrogen from methanol, a multimillion-metric-ton commodity, nudges that car-fuel scenario a step closer to reality (J. Am. Chem. Soc. 2019, DOI: 10.1021/jacs.9b09431). Ji Su and Gabor A. Somorjai of Lawrence Berkeley National Laboratory and the University of California, Berkeley, and coworkers have developed a procedure for using ascorbic acid and a platinum precursor to anchor isolated platinum atoms on a porous ceria support. The dispersion of the atoms, which maximizes the use of expensive metals, was confirmed via microscopy and spectroscopy; it shows that the atoms remain stable at elevated temperatures for more than 120 hours.

EPR Spectroscopy Study of the Radical Cation Cluster (η⁵-C₅H₅)(CO)₅ReFePt(μ₃-C=CHPh)(η²-Ph₂P(CH₂)₂PPh₂)

The chemical oxidation of the cluster CpReFePt(μ3-C=CHPh)(CO)5(dppe) (Cp = η5-C5H5, dppe = η2- Ph2P(CH2)2PPh2) resulted in a radical cation [CpReFePt(μ3-C=CHPh)(CO)5(dppe)]+• that is sufficiently stable only at low temperature. An electronic structure of the radical cation was studied by EPR and following parameters were obtained by comparison of the experimental and model spectrum: gx = 2.070 gy = 2.0295 gz = 1.997; Ax(31P) = 17 Ay(31P) = 49 Az(31P) = 35 (Gs);Ax(195Pt) = 62 Ay(195Pt) = 45 Az(195Pt) = 105 (Gs). An unpaired electron is seen to be mainly concentrated on the iron atom (85-90%) and partially on the platinum atom (10-15%). Further transformation of the radical cation led to the formation of the binuclear complex Cp(CO)2RePt(μ-C=CHPh)(dppe) and the Fe-carbonyl fragment

Stable Discrete Pt1(0) in Crown Ether with Ultra‐High Hydrosilylation Activity

AbstractObtaining reduced discrete metal atoms that are stable in liquid solvents byin‐situreduction of an ionic metal precursor has been a challenge until recently. A liquid surfactant polydimethylsiloxane‐polyethylene glycol (PDMS‐PEG) enabled the synthesis of stable discrete platinum atoms (Pt1) by reducing Pt(IV) and Pt(II) salts. Here we report the successful preparation of discrete mononuclear platinum atoms (Pt1) in a crown ether, [15]crown‐5, as a structurally much simpler solvent, and the prepared Pt1@[15]crown‐5 was demonstrated for ultra‐high catalytic activity and selectivity in hydrosilylation reactions. A combination of spectroscopic characterizations proves the reduced Pt species is Pt1(0) with partially positive charge.195Pt NMR and DFT calculation indicate the Pt1(0) is stabilized by thepseudooctahedral structure of ([15]crown‐5)PtCl−2H+2involving two adjacent oxygens from the crown ether ring, although the oxygens in the crown ether ring have been known to host and stabilize certain metal cations. The Pt1@[15]crown‐5 shows ultrahigh activity (TOF of 8.3×108 h−1) with excellent terminal adducts selectivity in catalytic olefin hydrosilylation. This catalyst was found to be highly stable under hydrosilylation conditions. For examples, the turnover number (TON) exceeded 1.0×109for hydrosilylation between 1‐octene and (Me3SiO)2MeSiH without showing sign of deactivation; the TON exceeded 2.0×108while the catalyst remained active for a catalytically more demanding reaction between styrene and (Me3SiO)2MeSiH.

Asymmetric Deposition of Platinum Atoms on Gold Nanorods Reduced the Plasmon Field Distortion Induced by the Substrate

New anisotropic bimetallic nanoparticles are prepared on the surface of a substrate with different structures. Unlike the homogenous deposition of Pt on the surface of colloidal gold nanorods (AuNRs), Pt atoms deposit on the surface of AuNRs organized into 2-D arrays binding to a substrate inhomogeneously. Pt ions are chemically reduced and deposit on the surface of AuNR 2-D arrays. Pt atoms deposit initially at the tips of the AuNRs and the magnitude increases over time. After a complete coverage of the tips, the deposition proceeds on the side of the AuNR 2-D arrays. The mechanism of breaking the symmetry of the deposition of Pt on AuNRs is discussed. Individual AuNRs displayed different optical responses depending on the location of the deposited Pt. The experimental optical results are validated theoretically and correlated to the configuration of the Pt layer, imaged by high-resolution electron microscopic imaging. Plasmonic nanoparticles exhibit field distortions when placed on a substrate, which leads to an increased field intensity on the nanoparticle close to the substrate increased at the expense of the intensity of the field intensity on top of the nanoparticles. Interestingly, the plasmon field distortion by the substrate is lowered upon Pt deposition. The prepared nanoparticle 2-D arrays are useful in photocatalysis and optically enhanced catalysis as they compromise an exciting plasmonic metal and a catalytically efficient metal.

Engineering the Atomic Interface with Single Platinum Atoms for Enhanced Photocatalytic Hydrogen Production.

It is highly desirable but challenging to optimize the structure of photocatalysts at the atomic scale to facilitate the separation of electron-hole pairs for enhanced performance. Now, a highly efficient photocatalyst is formed by assembling single Pt atoms on a defective TiO2 support (Pt1 /def-TiO2 ). Apart from being proton reduction sites, single Pt atoms promote the neighboring TiO2 units to generate surface oxygen vacancies and form a Pt-O-Ti3+ atomic interface. Experimental results and density functional theory calculations demonstrate that the Pt-O-Ti3+ atomic interface effectively facilitates photogenerated electrons to transfer from Ti3+ defective sites to single Pt atoms, thereby enhancing the separation of electron-hole pairs. This unique structure makes Pt1 /def-TiO2 exhibit a record-level photocatalytic hydrogen production performance with an unexpectedly high turnover frequency of 51423 h-1 , exceeding the Pt nanoparticle supported TiO2 catalyst by a factor of 591.

Engineering the Atomic Interface with Single Platinum Atoms for Enhanced Photocatalytic Hydrogen Production

AbstractIt is highly desirable but challenging to optimize the structure of photocatalysts at the atomic scale to facilitate the separation of electron–hole pairs for enhanced performance. Now, a highly efficient photocatalyst is formed by assembling single Pt atoms on a defective TiO2 support (Pt1/def‐TiO2). Apart from being proton reduction sites, single Pt atoms promote the neighboring TiO2 units to generate surface oxygen vacancies and form a Pt‐O‐Ti3+ atomic interface. Experimental results and density functional theory calculations demonstrate that the Pt‐O‐Ti3+ atomic interface effectively facilitates photogenerated electrons to transfer from Ti3+ defective sites to single Pt atoms, thereby enhancing the separation of electron–hole pairs. This unique structure makes Pt1/def‐TiO2 exhibit a record‐level photocatalytic hydrogen production performance with an unexpectedly high turnover frequency of 51423 h−1, exceeding the Pt nanoparticle supported TiO2 catalyst by a factor of 591.

Identification of characteristic features in scattering cross sections for the electrons colliding with silver, platinum, and gold atoms

A semi-relativistic approach is employed to calculate elastic differential, integral, and momentum transfer cross sections as well as total (elastic plus inelastic) cross sections for the scattering of electrons from silver, platinum, and gold atoms in the energy range 0.1–100 eV. The projectile-target interaction is composed of real (i.e. the sum of static, exchange, and polarization) and imaginary (i.e. absorption) potential. The total optical potential is then used in the solution of the Dirac equation for the scattered electrons. The characteristic features [Ramsauer-Townsend (RT) minimum and shape resonance] which are required for the fundamental understanding of the dynamic processes at the atomic level, are identified in the low energy region. The value of the RT minimum has been correlated with the scattering length to the dipole polarizability of the target atom. The calculated cross sections are compared with available theoretical calculations and experimental measurements in this energy region.

The Role of the Stage of Metal Complex Deposition on Support in the Properties Formation of Supported Platinum Catalysts

The subject of this review is related to the development of research on the mechanism of interaction of platinum complex compounds, primarily, H2[PtCl6], with alumina supports and the role of this interaction in properties formation of the corresponding platinum catalysts. Based on the study of the composition of Pt(IV) chloride complexes adsorbed on the γ-Al2O3 surface, it was proposed that the complexes should be quantitatively discriminated as inner- and outer-sphere complexes in accordance with the nature of their binding with the support. The chloride ligands were found to be dominant in the bound outer-sphere Pt(IV) complexes, and adsorption of the complexes on the surface occurs due to the protonation of the hydroxyl groups of the support without any significant changes in the composition and geometry of the [PtCl6]2– complex anion. The binding of Pt(IV) in the outer-sphere complexes leads (after their reduction with hydrogen) to the formation of Pt particles with a relatively low dispersion containing platinum atoms mainly in a nearly Pt0 state, which are characterized by hydrogenating and dehydrogenating activity. The inner-sphere platinum(IV) complexes are the hydrolyzed forms of the chloride complexes formed by the replacement of chloride ligands by the hydroxyl groups of the support. Their reduction forms finely dispersed platinum particles containing a significant fraction of atoms in the ionic form, which increases the activity of the Pt/Al2O3 catalyst in dehydrocyclizations of n-alkanes. Several approaches were proposed that make it possible to vary the ratio between the outer- and inner-sphere platinum(IV) complexes (increasing the degree of hydrolysis of the complexes, or varying the nature of the surface OH groups of the alumina support) and hence to modify the properties of the catalyst. The possibility of selective synthesis of outer- and inner-sphere platinum(IV) complexes bound with other supports was shown for the Pt/MgAlOx system. Using the structural features of layered aluminum-magnesium hydroxides makes it possible to bind platinum(IV) in the complexes of the given type at high selectivity and to change the electronic state of Pt atoms in Pt particles and their activity in alkane dehydrogenations without changing the chemical composition of the catalyst.