Chemical States Of Pt Research Articles

Improved naphthalene photodegradation rate of CN/Pt-P25 photocatalyst by effectively tuning Pt chemical states via H2 secondary annealing

Photocatalytic technology holds promising prospects for remediating naphthalene pollution in water bodies. In this work, the CN/Pt-P25 photocatalyst was successfully prepared via photodeposition combined with co-pyrolysis methods, and employed for naphthalene photodegradation under simulated sunlight. The chemical state of Pt was found to have a significant impact on the photocatalytic activity. H2 secondary annealing effectively tuned Pt chemical states, increasing the proportion of Pt0 species on the CN/Pt-P25 photocatalyst from 41.91 % to 62.24 %. The improved proportion of Pt0 species proportion led to a reduction in the bandgap, which induced changes in the band positions and notably enhancing the separation efficiency of photogenerated electron-hole pairs. Under simulated sunlight irradiation, (H2) CN/Pt-P25 photocatalyst achieved complete naphthalene photodegradation within 100 min. Thus, photocatalysts containing a high proportion of Pt0 species exhibited an improved performance in naphthalene photodegradation. These findings provide new insights into the application of photocatalytic technology for the remediation of PAHs.

The promotion of rare earth on Pt-SiO2-Al2O3 catalyst for NO oxidation in diesel exhaust

The effective oxidation of NO is the key to the catalytic treatment of diesel vehicle exhaust. Improving the NO oxidation ability is mainly to optimize the chemical state of the active site (Pt), followed by increasing the number of active centers. Considering that the atoms with electronegativity weaker than Pt can provide electrons to change the chemical state of Pt, rare earth elements with weak electronegativity are selected as additives to obtain Pt/M-SiO2-Al2O3 (M = Sc, Y, La, Ce, Pr, Nd, Sm, Eu) catalysts by co-impregnation method. Among them, the Pt/La-SiO2-Al2O3 catalyst has the best NO oxidation performance, compared with the Pt-SiO2-Al2O3, the NO conversion rate increased by 28 %. Due to the special outer electron arrangement of La, its electronegativity is the smallest in rare earth, which makes its outer electrons easy to transfer to Pt atoms, and has the strongest electron interaction. Thus, the highest content of Pt0 was detected in CO diffuse reflectance infrared Fourier transform spectroscopy (CO-DRIFTS) and X-ray photoelectron spectroscopy (XPS). In addition, CO chemisorption and transmission electron microscopy (TEM) confirmed that the introduction of La in the catalyst can significantly improve the dispersion of precious metals. Notably, this simple approach of affecting electron interaction by introducing weakly electronegative elements provides a reference for the design of noble metal catalysts with different valence states to solve complex problems.

Durability Estimation for Pt/Carbon-Sphere with the Reduced Graphene Oxide Wall Using the Start/Stop and the Load Fluctuation Tests in Acidic Electrolyte

Polymer electrolyte fuel cells (PEFCs) are attracting attention as a next-generation power source with low environmental impact. However, PEFCs have significant issues for widespread commercialization, which are high cost and short service life. Increasing Pt utilization in the catalyst layer will reduce the PEFCs cost. We reported new catalyst support with increasing Pt utilization compared to traditional carbon support [1]. Our carbon sphere (CS) support is composed of a SiO2 bead core and a reduced graphene-oxide wall. And it was successful that Pt nanoparticles supported on a CS. The Pt utilization of Pt/CS was ~20% higher than that of commercial Pt/KB. Pt/CS is expected to decrease the cost of electrocatalyst of PEFCs. However, the durability of Pt/CS was not estimated, although the reduced graphene oxide was reported to have a high tolerance for carbon corrosion [2]. In this study, the durability of Pt/CS was estimated by two methods which were start/stop and load fluctuation tests proposed by the Fuel Cell Commercialization Conference of Japan. The preparation method of Pt/CS was followed by our previous study [1]. Durability tests were conducted using a three-electrode cell which was composed of a working electrode, Pt counter electrode, Ag/AgCl reference electrode, and 0.1 M HClO4 electrolyte. This study converted the potentials from Ag/AgCl reference to RHE reference.Conditions of the start/stop test were 10,000 cycling between 1.0 V to 1.5 V with 2 s/cycle of the triangular potential waveform. The load fluctuation test was conducted by the potential step at 3 seconds at 0.6 V and 1.0 V with 10,000 cycles. Both test temperatures were 60°C. The Oxygen reduction-reaction (ORR) activity and the electrochemical active surface area (ECSA) were evaluated before and after durability tests.The initial state of Pt/CS showed high ORR activity and almost the same ECSA in comparison with commercial Pt/KB (TEC10E50E). These results agreed with our previous study [1]. After the start/stop test, commercial Pt/KB drastically degraded that ECSA dropped ~80% of the initial state, and the potential at half the value of a linear sweep voltammogram (E 1/2) negative shifted to 0.35 V. In contrast, Pt/CS demonstrated high durability for the start/stop test. Its ECSA was kept at ~84% of the initial state, and the difference of E 1/2 between before and after the start/stop test was 0.06 V. Compared with SEM images after the start/stop test, the shape of carbon support in commercial Pt/KB was collapsed by the carbon corrosion reaction, although that of CS support in Pt/CS was maintained. The difference in durability between Pt/CS and Pt/KB was probably attributed to the number of functional groups at the support surface. Especially number of hydroxyl groups on the surface may affect the stability of the carbon corrosion.In the load fluctuation test, Pt/CS also demonstrated higher stability than commercial Pt/KB. ECSA retention of Pt/CS was ~67%, and it was about five times higher than that of commercial Pt/KB. Pt/CS was kept ~85% of the initial E 1/2 when commercial Pt/KB decreased to 55% of the initial E 1/2. After the load fluctuation test, the Pt particle size immensely differed between Pt/CS and Pt/KB. In Pt/CS, the increase of Pt particle size was limited from 6.7 nm to 8.6 nm. In contrast, the Pt particle size of commercial Pt/KB increased from ~5 nm to 10.4 nm. The results of the XPS analysis indicated the chemical state of Pt in Pt/CS was the difference in Pt/KB, and it probably was affected by a CS as the catalyst support. The difference in catalyst stability of Pt/CS and commercial Pt/KB may be attributed to the strength of the interaction of Pt and the catalyst support.This study estimated the durability of Pt/CS, which had spherical catalyst support with the reduced graphene oxide wall, compared with that of commercial Pt/KB. Pt/CS demonstrated better initial ORR activity, and higher durability about the start/stop and the load fluctuation test than Pt/KB. The above results indicated that the carbon sphere was most likely one of the useful catalyst supports for PEFCs cathode catalysts.[1] T. Saida, et al., Energy & Fuels, 36, 1027-1033 (2022).[2] P. Zhang, et al. Int. J. Electrochem. Sci., 11, 10763-10778 (2016).

Elucidation of the Active Site for the Oxygen Evolution Reaction on a Single Pt Atom Supported on Indium Tin Oxide.

Single-atom catalysts (SACs) have attracted attention for their high catalytic activity and selectivity, but the nature of their active sites under realistic reaction conditions, involving various ligands, is not well-understood. In this study, we use density functional theory calculations and grand canonical basin hopping to theoretically investigate the active site for the oxygen evolution reaction (OER) on a single Pt atom supported on indium tin oxide, including the influence of the electrochemical potential. We show that the ligands on the Pt atom change from Pt-OH in the absence of electrochemical potential to PtO(OH)4 in electrochemical conditions. This change of the chemical state of Pt is associated with a decrease of 0.3 V for the OER overpotential. This highlights the importance of accurately identifying the nature of the active site under reaction conditions and the impact of adsorbates on the electrocatalytic activity. This theoretical investigation enhances our understanding of SACs for the OER.

Electronic metal-support interaction via defective-induced platinum modified BiOBr for photocatalytic N2 fixation

Designing atomic-scale catalytic sites to facilitate N2 adsorption and transport of photogenerated electrons to the target active sites offers new opportunities to achieve highly-efficiently photocatalytic N2 reduction reactions. Herein, Pt was photodeposited on BiOBr along with formation of oxygen vacancies (OVs) under ultraviolet light. The modulation of chemical states of Pt and the formation of electron metal-support interactions (EMSI) between BOB and Pt facilitated the charge transfer between the modifiers (i.e. Pt and OVs) and the support (i.e. BiOBr). The production rate of ammonia on Pt and OVs co-modified BiOBr reached 23.8 μmol g−1 h−1, which was much higher than that either on OVs-BiOBr or pristine BiOBr. Density functional theory (DFT) calculations showed that EMSI effect led to a significant charge redistribution between Pt and BOBr carriers, whereby Pt doping could significantly reduce energy barrier of N2 hydrogenation process to facilitate photocatalytic N2 reduction.

Modulating Pt Interaction in Au@Pt Nanoparticle/WO3 Photocatalysts for Enhanced Production of Peroxodisulphate

Production of peroxodisulphate (S2O82–) on powdered photocatalysts is a promising way to obtain high-value-added chemicals using solar energy; however, it is still suffering from low efficiency. In the present work, we fabricated bimetallic Au core and Pt shell nanoparticle-loaded WO3 (Au@Pt/WO3) photocatalyst for enhanced production of S2O82–, which is 1.7 times that of Pt nanoparticle-loaded WO3 (Pt/WO3), and was reported to be the best catalyst for S2O82– production. A further study demonstrated that the electronic interaction of Pt was successfully modulated by the core–shell nanoparticle architecture, and the core–shell nanoparticle structure between Au and Pt improved the formation of the surface chemical state of Pt to be metallic Pt, proposed as the active site for oxygen reduction. Besides, the core–shell nanoparticle structure also exposed a large amount of Pt on the surface of the substrate. As a result, Au@Pt/WO3 showed significantly enhanced photocatalytic activity of S2O82– with a quantum efficiency of 5.2% at 420 nm, whereas Pt–Au bimetallic alloy nanoparticle-loaded WO3 with a large amount of surface PtOx and exposed both Au and Pt on the surface showed very low activity. This work provides insights into the bimetallic Pt nanoparticle-loaded WO3 for enhanced photocatalytic activity.

Photo-controlled chemical states and the optimal size of Pt for enhancing the photo- and electrocatalytic hydrogen evolution reaction

The development of low-Pt catalysts is important for the large-scale application of Pt-based catalysts. Catalytic reactions mainly occur on the surface or interface of a material, and thus the surface properties of the catalyst will strongly affect their catalytic activity; this phenomenon has attracted widespread attention. Here, a series of Pt NPs with different chemical states and particle sizes were obtained by changing the light source wavelength, light time, and other conditions of light deposition synthesis. The Pt-TiO 2 catalyst has excellent potential in both photocatalytic hydrogen evolution (4.5 mmol·g −1 ·h −1 ) and electrocatalytic hydrogen evolution (26 mV@10 mA cm −2 ). We also found that the photocatalytic activity is more sensitive to the chemical state of Pt and that reducing the catalyst size can improve the electrocatalytic activity. This work not only provides a green and effective method to adjust the chemical state of precious metals on metal oxides but also helps to understand the impact of surface states on the catalytic process. A series of Pt NPs with different chemical states and sizes were embedded in TiO 2 (B) via a modified photochemical reduction method. The optimized Pt-TiO 2 (B) bifunctional catalyst exhibited excellent p-HER and e-HER catalytic activity. • A series of Pt NPs with different chemical states and particle sizes were obtained by a photochemical strategy. • The optimized Pt-TiO 2 catalyst has excellent potential in both p-HER (4.5 mmol g −1 h −1 ) and e-HER (26 mV@10 mA cm −2 ). • The p-HER is more sensitive to the chemical state of Pt, and reducing the catalyst size improves the e-HER. • This work provides a new idea to promote catalytic activity by adjusting the catalyst’s state and size.

Boosting photocatalytic hydrogen evolution via regulating Pt chemical states

As a cocatalyst, chemical states of Pt have significant effects on hydrogen evolution activity of photocatalysts, but the effects have not been elucidated. Herein, we report an effective strategy to greatly improve hydrogen production via regulating the chemical states of Pt. A highly efficient C3N4 photocatalyst with high Pt0 proportion (denoted as 1.0%-Pt/CN-BH-H) is successfully prepared. Under visible-light condition (λ ≥ 420 nm), 1.0%-Pt/CN-BH-H (Pt0 proportion is 60.1%) affords ∼2.316 mmol h−1 g−1 of hydrogen, approximately four-fold higher than that obtained by a photodeposited sample 1.0%-Pt/CN-P (Pt0 proportion is 8.2%, ∼0.605 mmol h−1 g−1 of hydrogen). Atmospheric treatment increases the amount of Pt0 species by causing electrons transfer from N element to Pt2+ in 1.0%-Pt/CN-BH-H, as proved by in situ experimental investigation and DFT calculations. Mass formation of the Pt0 species facilitates charge separation. In addition, Pt0 has a lower hydrogen adsorption energy than that of Pt2+; therefore, photocatalysts containing Pt0 show an improved hydrogen-evolution performance.

Synthesis of Pt-based TS-1 catalysts for selective hydrogenation to produce C15–C18 alkanes from the FAME: Effect of rare-earth metal additives

Green biodiesel is a clean, renewable, and environmental-friendly biofuel, which is commonly produced through catalytic conversion of lipids. The properties of Pt-based catalyst carriers and additives are important factors determining the production of green biodiesel. Herein, titanium silicalite-1 (TS-1) with a large specific surface area was synthesized by a hydrothermal crystallization process, and the rare-earth metal additives including LaOx, CeOx, PrOx, and YOx were used to modify Pt/TS-1 on the fatty acid methyl ester (FAME) hydrotreatment to enhance the selectivity of C15–C18 alkanes. It is shown that the addition of rare-earth metals decreases the particle size of Pt, increases the content of Pt0 species, and changes the major reaction pathway from hydrodecarbonylation (DCO)/hydrodecarboxylation (DCO2) to hydrodeoxygenation (HDO). The Pt–Ce/TS-1 showed the best catalytic performance on the FAME hydrotreatment due to its smaller active metal particle size, more amounts of weak acid, abundant oxygen vacancies, and more content of low chemical states of Pt. The liquid yield, efficiency of deoxygenation, and selectivity of C15–C18 alkanes were 75.7%, 100%, and 97.3% over Pt–Ce/TS-1. The heating value of upgraded liquid products from Pt–Ce/TS-1 reached 49.1 MJ/kg. This work provides a new idea for Pt-based TS-1 catalysts in the preparation of green hydrocarbon biodiesel.

Self-Assembly Ultrathin Fe-Terephthalic Acid as Synergistic Catalytic Platforms for Selective Hydrogenation

Self-Assembly Ultrathin Fe-Terephthalic Acid as Synergistic Catalytic Platforms for Selective Hydrogenation

Understanding the role of tungsten on Pt/CeO2 for vinyl chloride catalytic combustion

Spherical CeO2 synthesized by the hydrothermal process was used as support to prepare Pt/WO3/CeO2, and the effects of tungsten (W) contents on activity, stability and polychlorinated by-products were investigated to understand the role of W for vinyl chloride (VC) catalytic oxidation. The introduction of 12 wt% W to Pt/CeO2 (P12WC) exhibits the highest catalytic activity with 90% conversion of VC at 250 °C, meanwhile the stability improves and the polychlorinated by-products in the tail gas significantly decrease due to the removal of dissociated Cl species in the formation of HCl. The beneficial effects of W on Pt/CeO2 are closely related to the chemical state of Pt, redox and surface acid sites distribution. The doped W not only makes Pt disperse evenly on the support with the high valence, but also weakens the interaction between Pt and CeO2 by the formation of Pt–O–W and Pt–O–W–O–Ce species, which facilitates oxygen mobility. In addition, the modification of W species also significantly increases the surface acidity amount and changes the distribution of acid sites.

Dispersion and support dictated properties and activities of Pt/metal oxide catalysts in heterogeneous CO oxidation

The source of activity of metal/metal oxides has always been an interesting, important but highly challenging research topic in heterogeneous catalysis. In CO oxidation reaction, this work clarifies dispersion and support dictated activities of Pt including single-atom (Pt1), 2.8 nm (PtNP-S) and 36 nm (PtNP-L) Pt supported on both reducible TiO2 and “inert” Al2O3 supports. The X-ray absorption fine structure (XAFS) shows that chemical state of Pt is affected by both dispersion and support: Pt1 presents fully oxidized state in both Pt1/TiO2 and Pt1/Al2O3; PtNP-S in PtNP-S/TiO2 appear nearly oxidized state while about half of Pt is metallic state in PtNP-S/Al2O3; PtNP-L in both PtNP-L/TiO2 and PtNP-L/Al2O3 exhibit metallic state. All the Pt species supported on TiO2 present much lower apparent activation barriers (Eapp) than that on Al2O3. Moreover, Pt1/TiO2 possesses dozen times of efficiency than PtNP-S/TiO2 although they have similar Eapp values. A truth is finally made clear that a reducible metal oxide with low oxygen vacancy formation energy is critical to endow Pt/metal oxide a high activity and the single-atom dispersion of Pt is the way to maximize the active sites of Pt/metal oxide.

Reversed selectivity of photocatalytic CO2 reduction over metallic Pt and Pt(II) oxide cocatalysts.

The chemical state of Pt in cocatalysts has a major influence on the activity and selectivity of the photocatalytic reduction of CO2; however, the underlying mechanism is unclear owing to the co-existence of different Pt chemical states and mutual transformation between them. In this study, PtO/TiO2 catalysts were prepared through photodeposition and Pt/TiO2 was prepared by the photoreduction of PtO/TiO2 to avoid interference arising from co-existing Pt forms and different loading amounts. These catalysts exhibited completely reversed selectivity for CO and CH4 production during CO2 photoreduction: PtO/TiO2 tended to produce CO (100%), whereas Pt/TiO2 favored the production of CH4 (66.6%). By combining experimental analysis and theoretical calculations, the difference in selectivity was ascribed to the different charge transfer/separation and CO/H adsorption properties of PtO/TiO2 and Pt/TiO2. Photoelectric and photoluminescence (PL) analysis showed that Pt was more advantageous to the photogenerated carrier separation compared with PtO, which was conducive to the multi-electron CH4 reduction reaction. Fourier transform-infrared spectroscopy, temperature-programmed desorption/temperature-programmed reduction, and density functional theory calculations indicated that the adsorption of CO and hydrogen on Pt was stronger than that on PtO, which favored the further reduction of CO to CH4. Based on the above results, a mechanism was proposed to explain the reversed selectivity of the photocatalytic reduction of CO2 over Pt/TiO2 and PtO/TiO2.

Carbon nanotube supported PtO nanoparticles with hybrid chemical states for efficient hydrogen evolution

The HER activity can be greatly enhanced due to the favorable hybrid chemical states of Pt with both abundant Pt−O active sites and the Pt−C interaction. Efficient electrocatalysts for hydrogen evolution reaction (HER) in alkaline solution are highly required for water splitting. Here we design an ultra-small PtO x nanoparticle with hybrid Pt chemical states on carbon nanotubes as highly efficient alkaline HER catalyst, which shows a low overpotential of 19.4 mV at 10 mA cm −2 , a high mass activity of 5.56 A mg Pt −1 at 0.1 V, and a stable durability for at least 20 h. The HER performance is better than that of the benchmark 20 wt% Pt/C while the Pt content in the catalyst is only about one tenth of that in Pt/C. It also represents one of the best catalysts ever reported for HER in alkaline solution. Synchrotron radiation X-ray absorption spectroscopy reveals that the efficient and stable alkaline HER performance can be attributed to the favorable design of hybrid chemical states of Pt with carbon nanotubes, which exhibits abundant surface Pt–O as active catalytic sites and forms stable Pt–C interfacial interaction to both anchor the NPs and improve the synergistic effect between catalyst and substrate.

Metallic Pt and PtOx dual-cocatalyst-loaded WO3 for photocatalytic production of peroxydisulfate and hydrogen peroxide

Photocatalytic production of green oxidation reagents as an economical and environmental-friendly process is a promising strategy to replace the traditional production processes. In the present study, a series of 1.0 wt% Pt/WO3 photocatalysts with different surface chemical states of Pt were successfully fabricated. The different surface metallic Pt (Pt0) and oxidized Pt (PtOx) ratios on WO3 showed significant effects on the photocatalytic activities for strong oxidants of peroxydisulfate ( $$ {\text{S}}_{ 2} {\text{O}}_{8}^{2 - } $$ ) and hydrogen peroxide (H2O2) formations. It is proposed that surface Pt0 and PtOx functioned as reduction site for O2 reduction to H2O and oxidation site for H2O oxidation to H2O2, respectively, during the photocatalytic process. As a result, a higher surface composition of Pt0 prepared using photodeposition (PD) method led to the formation of higher amount of $$ {\text{S}}_{ 2} {\text{O}}_{8}^{2 - } $$ . On the other hand, PtOx-loaded WO3 using impregnation (IM) method showed significant formations of $$ {\text{S}}_{ 2} {\text{O}}_{8}^{2 - } $$ and H2O2 simultaneously. This work provided a new idea for the design of noble metal Pt-supported WO3 for efficiently photocatalytic generation of $$ {\text{S}}_{ 2} {\text{O}}_{8}^{2 - } $$ and H2O2.

Study on the dissolution of hollow mesoporous silica nanosphere-supported nanosized platinum oxide in biorelevant media for evaluating its potential as chemotherapeutics

Platinum oxide (PtOx) nanoparticles (NPs) have been shown to possess anticancer activity by releasing ionic Pt species under biological conditions. However, the dissolution kinetics and the changes in the chemical state of Pt during PtOx dissolution have not yet been studied. To fill this gap, we prepared a composite (designated as PtOx@MMT-2) containing PtOx NPs on hollow mesoporous silica nanospheres and studied the dissolution of the material in different biorelevant media. We found that the release of Pt was retarded due to the adsorption of biomolecules on PtOx NPs during the degradation of host silica. The biomolecules adsorption also lowered the accessibility of PtOx NPs, resulting in the reduced catalase-like activity of the NPs. In line with the results, the cytotoxicity of PtOx@MMT-2, which was positively correlated to the amount of Pt uptake, was reduced by biomolecules adsorption. Our findings should be applicable to other metal (oxide) NPs under biological conditions and may provide implications for the design of nanomaterials for practical therapeutic applications.

Surface engineering of nano-ceria facet dependent coupling effect on Pt nanocrystals for electro-catalysis of methanol oxidation reaction

Surface engineering of metal-support coupling interaction is significant in the catalytic reactions. Herein, we demonstrate a nano-ceria facet dependent coupling effect on Pt nanocrystals for the electro-catalysis of methanol oxidation in acid electrolyte for fuel cell reaction. It is found CeO2 exposed with different facets have different Pt nanocrystals trapping/coupling ability, and this interplay induces the different surface chemical states of Pt and Ce in terms of the content of Pt(0) and Ce3+, Pt-O-Ce bonding, the oxygen vacancy and electronic states. The CeO2-rods enclosed by (1 1 0) and (1 0 0) facets coupled Pt nanocrystals show much higher catalytic activity and durability than that of CeO2-plates and CeO2-cubes exposed by (1 1 1) and (1 0 0) facets respectively. Specifically, Pt-CeO2-rods exhibit a specific activity of 2.04 mA cm−2, nearly 1.5 and 2.6-fold enhancement than that of Pt-CeO2-cubes and Pt-CeO2-plates. Facet-dependence anti-poisoning and stability are also discovered after 8000 cyclic voltammetry cycles on the proposed catalyst. The weakened poisoning intermediates adsorption ability via bi-functional mechanism and the metal-support interaction induced by different CeO2 support can account for the facet-dependent methanol electro-oxidation performance on Pt-CeO2 catalyst system. The current work demonstrates the significance of assistant catalyst facet/morphology tuning in the fuel cells catalyst design and fabrication.

Formation of Pt3O4 particles on PtO2–CeO2 solid solution

Pt supported on CeO2 has various applications as a catalyst. Because chemical states of Pt are hugely significant in offering improved catalytic performance, it is necessary to understand structures of Pt on CeO2 at high temperatures. In this study, PtO2 and PtO2–CeO2 powders were prepared by precipitation in molten sodium nitrate, and their thermal decomposition in air was examined by X-ray diffraction. When PtO2 powder is heated at 600 °C, the oxide decomposes into Pt phase which is accompanied by a slight Pt3O4 phase. On the other hand, in a heat treatment of a PtO2–CeO2 powder, the formation of Pt phase is hindered and Pt3O4 phase is formed preferentially. These results suggest that supporting Pt on CeO2 contributes not only to maintenance of fine dispersion at high temperatures, but also to formation of the Pt3O4 phase, which might play an important role in catalytic reactions. Observation with transmission electron microscopy and chemical analysis with X-ray photoelectron spectroscopy were performed on the powders before and after the heat treatment to discuss the formation of Pt3O4 particles on a PtO2–CeO2 solid solution.

Birch-Type Reduction of Arenes in 2-Propanol Catalyzed by Zero-Valent Iron and Platinum on Carbon.

Catalytic arene reduction was effectively realized by heating in 2-propanol/water in the presence of Pt on carbon (Pt/C) and metallic Fe. 2-Propanol acted as a hydrogen source, obviating the need for flammable (and hence, dangerous and hard-to-handle) hydrogen gas, while metallic Fe acted as an essential co-catalyst to promote reduction. The chemical states of Pt and Fe in the reaction mixture were determined by X-ray absorption near-edge structure analysis, and the obtained results were used to suggest a plausible reaction mechanism, implying that catalytic reduction involved Pt- and Fe-mediated single-electron transfer and the dehydrogenation of 2-propanol.

The critical role of CeO2 crystal-plane in controlling Pt chemical states on the hydrogenolysis of furfuryl alcohol to 1,2-pentanediol

1,2-pentanediol (1,2-PeD), as a valuable chemicals, can be obtained from the hydrogenolysis of furfural or furfuryl alcohol, but its high and selective synthesis is still challenging. Here, we report the production of 1,2-PeD from furfuryl alcohol over various fine-shaped Pt/CeO2 catalyst and their structure-property relationships. The yield of 1,2-PeD can reach 77% over Pt/CeO2-nanocube, which is the highest among reported catalysts; but the yield is low over Pt/CeO2 nanorods (48.5%). Extensive characterizations reveal that the chemical state of Pt plays key role in the selective production of 1,2-PeD, which is controlled by the surface oxygen vacancies of CeO2 through metal-support interaction. CeO2-nanocube exposed (1 0 0) facet has suitable interaction with Pt (abundant metallic Pt species and small particle size) and therefore results in the best catalytic performance. This work highlights the importance of optimizing the ceria terminal facets in rationally tuning Pt surface states in Pt/CeO2 systems for selective production of 1,2-PeD.