Single Platinum Atoms Research Articles

Theoretical insight into mercury species adsorption on graphene-based Pt single-atom catalysts.

Mercury emission from coal-fired flue gases is environmentally crucial. Revealing the interaction between mercury (Hg) and functional materials is significant to controlling emission. We conducted an investigation into the adsorption mechanism of mercury species onto graphene-based Platinum (Pt) single-atom catalysts (SACs). Single-atom Pt is the active center for Hg species chemisorption, with an adsorption energy range of 0.555–3.792 eV. In addition, Hg species adsorbed preferentially at lower temperatures. Pt/3N-GN exhibits a higher adsorption ability than Pt/SV-GN. The strong interaction of Hg0 with Pt SACs contributed to atomic-orbital hybridization between them. Further analysis revealed that s, p orbitals of Hg contribute significantly to orbital hybridization with Pt SACs. Moreover, the charge decomposition analysis confirmed that s, p orbitals of Hg hybridized with d, s orbitals of Pt SACs. The net charge transfer from Hg0 to Pt/SV-GN and Pt/3N-GN are 0.059 and 0.097 e−, respectively. The higher the charge transfers, the more intense the electron and orbital interaction between Hg and the surface. Consequently, Pt/3N-GN is a highly effective catalyst for Hg adsorption.

Α-Moc@Cs Carrier Modulated Platinum Single Atoms to Enhance Catalytic Activity in Solar Cells

Α-Moc@Cs Carrier Modulated Platinum Single Atoms to Enhance Catalytic Activity in Solar Cells

Carboxylic acid ligand substituent impacts hydrosilylation activity of platinum single atom catalysts on ceria

Carboxylic acid substitution in 1,10-phenanthroline-5,6-dione ligands bind to surface hydroxy groups and result in higher ligand loading for metal–ligand single-atom Pt catalysts on CeO2, thereby allowing excellent hydrosilylation catalysis.

Tumor microenvironment-activated single-atom platinum nanozyme with H2O2 self-supplement and O2-evolving for tumor-specific cascade catalysis chemodynamic and chemoradiotherapy.

Nanozyme-based tumor collaborative catalytic therapy has attracted a great deal of attention in recent years. However, their cooperative outcome remains a great challenge due to the unique characteristics of tumor microenvironment (TME), such as insufficient endogenous hydrogen peroxide (H2O2) level, hypoxia, and overexpressed intracellular glutathione (GSH).Methods: Herein, a TME-activated atomic-level engineered PtN4C single-atom nanozyme (PtN4C-SAzyme) is fabricated to induce the “butterfly effect” of reactive oxygen species (ROS) through facilitating intracellular H2O2 cycle accumulation and GSH deprivation as well as X-ray deposition for ROS-involving CDT and O2-dependent chemoradiotherapy.Results: In the paradigm, the SAzyme could boost substantial ∙OH generation by their admirable peroxidase-like activity as well as X-ray deposition capacity. Simultaneously, O2 self-sufficiency, GSH elimination and elevated Pt2+ release can be achieved through the self-cyclic valence alteration of Pt (IV) and Pt (II) for alleviating tumor hypoxia, overwhelming the anti-oxidation defense effect and overcoming drug-resistance. More importantly, the PtN4C-SAzyme could also convert O2·- into H2O2 by their superior superoxide dismutase-like activity and achieve the sustainable replenishment of endogenous H2O2, and H2O2 can further react with the PtN4C-SAzyme for realizing the cyclic accumulation of ∙OH and O2 at tumor site, thereby generating a “key” to unlock the multi enzymes-like properties of SAzymes for tumor-specific self-reinforcing CDT and chemoradiotherapy.Conclusions: This work not only provides a promising TME-activated SAzyme-based paradigm with H2O2 self-supplement and O2-evolving capacity for intensive CDT and chemoradiotherapy but also opens new horizons for the construction and tumor catalytic therapy of other SAzymes.

Crystal facet effects of platinum single-atom catalysts in hydrolytic dehydrogenation of ammonia borane

More electron depletion of the Pt center of the Pt1/Co3O4-c surface facilitates overall electron transfer from the B atom to the ammonia borane (AB) molecule, which ensures the highest activity among Pt1/Co3O4-x in the hydrolytic dehydrogenation of AB reaction.

Platinum single-atom catalyst with self-adjustable valence state for large-current-density acidic water oxidation

The design of active acidic oxygen evolution reaction (OER) catalysts is of paramount importance to achieve efficient large-current-density industrial hydrogen fuel production via water electrolysis. Herein, we develop a Pt-based catalyst with high electrochemical activity for the OER in acidic conditions under a large current. We achieve this by modulating the electronic structure of Pt into a high-valence, electron-accessible Pt1(2.4+δ)+ (δ ​= ​0–0.7) state during the reaction. This electron-accessible Pt1(2.4+δ)+ single-site catalyst can effectively maintain a large OER current density of 120 ​mA ​cm−2 for more than 12 ​h in 0.5 ​M ​H2SO4 at a low overpotential of 405 ​mV, and it shows a high mass activity of ∼3350 A gmetal−1 at 10 ​mA ​cm−2 current density and 232 ​mV overpotential. Using in situ synchrotron radiation infrared and X-ray absorption spectroscopies, we directly observe in an experiment that a key (∗O)–Pt1–C2N2 intermediate is produced by the potential-driven structural optimization of square pyramidal Pt1–C2N2 moieties; this highly favors the dissociation of H2O over Pt1(2.4+δ)+ sites and prevents over-oxidation and dissolution of the active sites.

Microstructures and Proton Networks of Ionomer Film on the Surface of Platinum Single Atom Catalyst in Polymer Electrolyte Membrane Fuel Cells

Microstructures and Proton Networks of Ionomer Film on the Surface of Platinum Single Atom Catalyst in Polymer Electrolyte Membrane Fuel Cells

Versatile Synthesis of Hollow Metal Sulfides via Reverse Cation Exchange Reactions for Photocatalytic CO2 Reduction.

Herein, we explore a general Cu2-x S nanocube template-assisted and reverse cation exchange-mediated growth strategy for fabricating hollow multinary metal sulfide. Unlike the traditional cation exchange method controlled by the metal sulfide constant, the introduction of tri-n-butylphosphine (TBP) can reverse cation exchange to give a series of hollow metal sulfides. A variety of hollow multinary metal sulfide cubic nanostructures has been demonstrated while preserving anisotropic shapes to the as-synthesized templates, including binary compounds (CdS, ZnS, Ag2 S, PbS, SnS), ternary compound (CuInS2 , Znx Cd1-x S), and quaternary compound (single-atom platinum anchored Znx Cd1-x S; Znx Cd1-x S-Pt1 ). Experimental and density functional theory (DFT) calculations show that the hollow metal sulfide semiconductors obtained could significantly improve the separation and migration of photogenerated electron-hole pairs. Owing to the efficient charge transfer, the Znx Cd1-x S-Pt1 exhibited outstanding photocatalytic performance of CO2 to CO, with the highest CO generation rate of 75.31 μmol h-1 .

Guaiacol Hydrodeoxygenation over Iron–Ceria Catalysts with Platinum Single-Atom Alloy Clusters as a Promoter

Guaiacol Hydrodeoxygenation over Iron–Ceria Catalysts with Platinum Single-Atom Alloy Clusters as a Promoter

Accelerated Anti-Markovnikov Alkene Hydrosilylation with Humic-Acid-Supported Electron-Deficient Platinum Single Atoms.

The hydrosilylation reaction is one of the largest‐scale applications of homogeneous catalysis, and Pt homogeneous catalysts have been widely used in this reaction for the commercial manufacture of silicon products. However, homogeneous Pt catalysts result in considerable problems, such as undesired side reactions, unacceptable catalyst residues and disposable platinum consumption. Here, we synthesized electron‐deficient Pt single atoms supported on humic matter (Pt1@AHA_U_400), and the catalyst was used in hydrosilylation reactions, which showed super activity (turnover frequency as high as 3.0×107 h−1) and selectivity (>99 %). Density functional theory calculations reveal that the high performance of the catalyst results from the atomic dispersion of Pt and the electron deficiency of the Pt1 atoms, which is different from conventional Pt nanoscale catalysts. Excellent performance is maintained during recycle experiments, indicating the high stability of the catalyst.

Anchoring single platinum atoms onto nickel nanoparticles affords highly selective catalysts for lignin conversion

Due to the highly complex polyphenolic structure of lignin, depolymerization without a prior chemical treatment is challenging, and new catalysts are required. Atomically dispersed catalysts are able to maximize the atomic efficiency of noble metals, simultaneously providing an alternative strategy to tune the activity and selectivity by alloying with other abundant metal supports. Here, we report a highly active and selective catalyst comprising monodispersed (single) Pt atoms on Ni nanoparticles supported on carbon (denoted as Pt 1 Ni/C, where Pt 1 represents single Pt atoms), designed for the reductive depolymerization of lignin. Selectivity toward 4-n-propylsyringol and 4-n-propylguaiacol exceeds 90%. The activity and selectivity of the Pt 1 Ni/C catalyst in the reductive depolymerization of lignin may be attributed to synergistic effects between the Ni nanoparticles and the single Pt atoms. • An efficient single-atom alloy catalyst for lignin-first biorefining is disclosed • The catalyst shows high activity in lignin deconstruction to afford aromatic monomers • Key structural and mechanistic features of the catalyst are provided Alloying noble metal atoms with non-noble metals allows the atomic efficiency of the noble metal to be maximized. Chen et al. describe single-atom catalysts for reductive lignin depolymerization based on platinum single atoms anchored onto nickel nanoparticles and supported on carbon, which are highly efficient, with the structure of the catalysts determining the selectivity of the reaction.

Synergistic effect between platinum single atoms and oxygen vacancy in MoO2 boosting pH-Universal hydrogen evolution reaction at large current density

Single-atomic or cluster-based precious metals provide an effective pathway to minimize the cost of catalysts. However, its stability at large current density is still a major hurdle to satisfy practical requirements for electrocatalytic Hydrogen evolution reaction (HER). Herein, we successfully anchored Pt single atoms (Pt SAs) in the oxygen vacancies (Ovac) of Molybdenum dioxide (MoO2) as advanced HER electrocatalyst. Experimental and theoretical calculations results reveal that the Ovac can not only stabilize Pt SAs, but also modulate the electronic structure of the active site, enabling Pt SAs/MoO2 to exhibit superior HER activity in a wide pH electrolyte at large current density. Especially, the 1.1 wt% Pt SAs/MoO2 deliver ultralow overpotentials (9.3, 14, and 16 mV at 10 mA cm−2) and small Tafel slopes (28.78, 36.86, and 65.18 mV dec-1) in acidic, alkaline, and neutral electrolytes, respectively. Moreover, it displays significantly enhanced mass activity of up to 28, 32, and 56 times compared to the benchmark 20 wt% Pt/C catalyst, and outstanding long-term durability (~200 h) at large current density of −1000 mA cm−2. The significantly improved HER performances are mainly ascribed to the synergistic catalytic effects of between Pt SAs and Ovac in MoO2. These impressive findings can provide insights into the rational design of electrocatalysts that used for future clean energy utilization.

Nanotubular OMS-2 Supported Single-Atom Platinum Catalysts Highly Active for Benzene Oxidation

The cryptomelane-type octahedral molecular sieve (OMS-2) exhibits excellent catalytic activity for the oxidation of volatile organic compounds (VOCs) due to its unique structure, and single-atom catalysts (SACs) have recently attracted much attention in heterogeneous catalysis. Herein, we adopted the hydrothermal redox reaction of KMnO4 and HCl aqueous solution at 120 °C for 12 h to first synthesize the nanotubular OMS-2 support and used the vitamin C and NaBH4 reduction methods to prepare the OMS-2-supported single-atom Pt and PtNP catalysts for benzene oxidation, respectively. It was found that the OMS-2-supported single-atom Pt catalyst with a Pt loading of 0.0383 wt % (0.0383Pt1/OMS-2) exhibited the best catalytic performance for benzene oxidation (a 90% benzene conversion was achieved at 189 °C and 20 000 mL g–1 h–1 (space velocity)), which was associated with its high surface oxygen vacancy density, good low-temperature reducibility, and strong benzene adsorption ability. It was also shown that benzene could be dissociated more readily over the supported single-atom Pt1 catalyst than over the supported PtNP catalyst, and the phenolates or benzoquinone as well as methyl groups, lipid, and vinyl species were the main intermediates in the oxidation of benzene over 0.0383Pt1/OMS-2. The results of this study are useful in developing the high-performance single-atom catalysts that can be applied for the oxidative removal of VOCs.

Construction of Single-Atom Platinum Catalysts Enabled by CsPbBr3 Nanocrystals.

Lead halide perovskite nanocrystals (CsPbX3 NCs) have been regarded as promising materials in photocatalysis. Combining metal single atoms with CsPbX3 NCs may be a practical way in exploring perovskite-based catalysts. However, such hybrids have not been achieved experimentally yet, mainly due to the weak interaction between the metal atom and the CsPbX3 surface. Here, we demonstrate that Pt single atoms can be deposited on CsPbBr3 NCs through a photoassisted approach, in which the surface was partially oxidized first, followed by the anchoring of Pt single atoms through the formation of Pt-O and Pt-Br bonds. The deposition of Pt single atoms can significantly change the photophysical properties of CsPbBr3 NCs by inducing the generation of deep trap states in the band gap. The as-prepared Pt-SA/CsPbBr3 can be used as efficient and durable catalysts for photocatalytic semi-hydrogenation of propyne. A CsPbBr3 nanocrystal might be a suitable substrate for anchoring other metal single atoms, such as Cu, Au, Ag, Pd, and so on.

Mechanistic insight into the dispersion behavior of single platinum atom on monolayer g-C3N4 in single-atom catalysts from density functional theory calculations

Single-atom catalysts (SACs) are an effective strategy for the efficient and low-cost utilization of noble metals. However, it remains a huge challenge to obtain atomically dispersed SACs. In this work, the dispersion behavior of single platinum atoms on pristine monolayer g-C3N4 has been investigated by DFT calculations. The calculation results show that the diffusion of single atom Pt on pristine monolayer g-C3N4 has characteristics of anisotropy. More importantly, the migration and aggregation of single atom Pt within the global scope of monolayer g-C3N4 can be effectively avoided, while in the local scope, the migration of single atom Pt is easy, and single atom Pt clustering is inevitable. Significantly, it can be predicted that stable SACs can be synthesized when the coverage of single atom Pt is less than the density of six-fold cavity. Moreover, it is found that the Pt clusters confined in the six-fold cavity of monolayer g-C3N4 are very stable and difficult to migrate on monolayer g-C3N4. And, the larger the size of Pt clusters confined in monolayer g-C3N4, the more difficult to separate a Pt atom from the Pt clusters. These results indicate that the Pt clusters confined in monolayer g-C3N4 have an effective Ostwald ripening mechanism.

Single-atom platinum or ruthenium on C4N as 2D high-performance electrocatalysts for oxygen reduction reaction

Pt/C is a practical electrocatalyst for oxygen reduction reaction (ORR) in metal-air batteries and fuel cells, however, also suffers the drawbacks of high cost and instability, which have propelled people to search for new substitutes, such as single-atom metal electrocatalysts. Herein, C4N was firstly synthesized from 2,3-diyldiamine phenazine via one-step hydrothermal method rather than the traditional way that two monomers react in organic solvent, and then loaded with single-atom metal (Pt or Ru) to form new electrocatalysts. The so-formed M@C4N (M = Pt or Ru) electrocatalysts show more excellent ORR performances with higher half-wave potential and better stability and methanol tolerance as compared with the commercial Pt/C. Specifically, the half-wave potential of 1%Pt@C4N and 0.5%Ru@C4N is 0.861 V and 0.828 V, respectively. Density functional theory calculations reveal that 1%Pt@C4N has stronger adsorption of reactant species and faster kinetics than 0.5%Ru@C4N in ORR pathway.

Fabricating polyoxometalates-stabilized single-atom site catalysts in confined space with enhanced activity for alkynes diboration

Effecting the synergistic function of single metal atom sites and their supports is of great importance to achieve high-performance catalysts. Herein, we successfully fabricate polyoxometalates (POMs)-stabilized atomically dispersed platinum sites by employing three-dimensional metal-organic frameworks (MOFs) as the finite spatial skeleton to govern the accessible quantity, spatial dispersion, and mobility of metal precursors around each POM unit. The isolated single platinum atoms (Pt1) are steadily anchored in the square-planar sites on the surface of monodispersed Keggin-type phosphomolybdic acid (PMo) in the cavities of various MOFs, including MIL-101, HKUST-1, and ZIF-67. In contrast, either the absence of POMs or MOFs yielded only platinum nanoparticles. Pt1-PMo@MIL-101 are seven times more active than the corresponding nanoparticles in the diboration of phenylacetylene, which can be attributed to the synergistic effect of the preconcentration of organic reaction substrates by porous MOFs skeleton and the decreased desorption energy of products on isolated Pt atom sites.

Design of carbon supports for metal-catalyzed acetylene hydrochlorination

For decades, carbons have been the support of choice in acetylene hydrochlorination, a key industrial process for polyvinyl chloride manufacture. However, no unequivocal design criteria could be established to date, due to the complex interplay between the carbon host and the metal nanostructure. Herein, we disentangle the roles of carbon in determining activity and stability of platinum-, ruthenium-, and gold-based hydrochlorination catalysts and derive descriptors for optimal host design, by systematically varying the porous properties and surface functionalization of carbon, while preserving the active metal sites. The acetylene adsorption capacity is identified as central activity descriptor, while the density of acidic oxygen sites determines the coking tendency and thus catalyst stability. With this understanding, a platinum single-atom catalyst is developed with stable catalytic performance under two-fold accelerated deactivation conditions compared to the state-of-the-art system, marking a step ahead towards sustainable PVC production.

Platinum single-atoms anchored covalent triazine framework for efficient photoreduction of CO2 to CH4

Achieving maximum atom-utilization efficiency is desirable to facilitate the charge separation and CO2 activation for photocatalytic CO2 reduction. Herein, we report a well-defined positioned synthesis of Pt single atoms in ethylene glycol (EG)-modified covalent triazine framework (Pt-SA/CTF-1) via a photo-deposition method for efficient photoreduction CO2 to CH4 under visible light irradiation. The well-defined coordination structure of Pt–N(C) sites in the Pt-SA/CTF-1 catalyst has been probed by HAADF-STEM and EXAFS. Results show that Pt single atoms confined into CTF-1 not only improved CO2 adsorption and activation but also accelerated the separation and transfer of photogenerated carriers in CTF-1. Consequently, Pt-SA/CTF-1 exhibited superior photoactivity and stability, which significantly surpass the Pt nanoparticles-based CTF-1, affording CH4 as the main reduction product. This work showcases an operable avenue to develop single-metal-atom photocatalysts and a mechanistic insight into photoreduction of CO2 by CTF-based composite.

Platinum single-atom catalyst coupled with transition metal/metal oxide heterostructure for accelerating alkaline hydrogen evolution reaction

Single-atom catalysts provide an effective approach to reduce the amount of precious metals meanwhile maintain their catalytic activity. However, the sluggish activity of the catalysts for alkaline water dissociation has hampered advances in highly efficient hydrogen production. Herein, we develop a single-atom platinum immobilized NiO/Ni heterostructure (PtSA-NiO/Ni) as an alkaline hydrogen evolution catalyst. It is found that Pt single atom coupled with NiO/Ni heterostructure enables the tunable binding abilities of hydroxyl ions (OH*) and hydrogen (H*), which efficiently tailors the water dissociation energy and promotes the H* conversion for accelerating alkaline hydrogen evolution reaction. A further enhancement is achieved by constructing PtSA-NiO/Ni nanosheets on Ag nanowires to form a hierarchical three-dimensional morphology. Consequently, the fabricated PtSA-NiO/Ni catalyst displays high alkaline hydrogen evolution performances with a quite high mass activity of 20.6 A mg−1 for Pt at the overpotential of 100 mV, significantly outperforming the reported catalysts.