In this research work, atomic and molecular orbitals based analysis has been made to see electronic structure of platinum halides (platinum dichloride, platinum dibromide, platinum diiodide and platinum difluride). Th...In this research work, atomic and molecular orbitals based analysis has been made to see electronic structure of platinum halides (platinum dichloride, platinum dibromide, platinum diiodide and platinum difluride). The geometry optimization and three dimensional (3D) modeling of the above mentioned species have been made on CAChe pro software. The results show: (i) The involvement of three p atomic orbitals is negligible as their summation values are very low in comparison to d orbital and considerably low with respect to s orbital. (ii) The study well support the Landis concepts of sdn-hybridation (here n = 1) as bond angle and contributions of s-orbital and d-orbital of Pt(II) are maximum with negligible contribution of p-orbitals. (iii) These halides also support the cloud-expanding effect with experimental data and also follow the nephelauxetic effect. The result is in good agreement with experiment results that covalent character increases in the order: PtI2 > PtBr2 > PtCl2 > PtF2. (iv) And thus the study will help to fine tune the existing complexes of these halides.展开更多
c-Kit (CD117) is a type IIIa receptor tyrosine kinase (RTK) that plays a key role in regulating the normal physiological processes of cells. In addition, the activation of c-Kit activates the tyrosine kinase signal tr...c-Kit (CD117) is a type IIIa receptor tyrosine kinase (RTK) that plays a key role in regulating the normal physiological processes of cells. In addition, the activation of c-Kit activates the tyrosine kinase signal transduction pathway, which is closely related to the occurrence and development of gynecological tumors, especially ovarian cancer. This article reviews the mechanisms of platinum resistance in ovarian cancer and the research progress of c-Kit in ovarian cancer.展开更多
We demonstrated a one-step hydrothermal polyol reduction technique to produce platinum(Pt)and N-doped carbon quantum dots(N-CDs)co-loaded with reduced-graphene oxide(Pt@N-CDs/RGO).The electrochemical performance of co...We demonstrated a one-step hydrothermal polyol reduction technique to produce platinum(Pt)and N-doped carbon quantum dots(N-CDs)co-loaded with reduced-graphene oxide(Pt@N-CDs/RGO).The electrochemical performance of commercial Pt/C,and Pt@N-CDs/RGO in 0.5 M H_(2)SO_(4) electrolyte was compared under the Pt amount(20wt%).Pt@N-CDs/RGO exhibits ultra-high electroactivity and durability for oxygen reduction reaction(ORR).The electrochemically active surface area(ECSA)can be achieved to 124.8 m^(2)/g,which is 1.65 times higher than that of commercial Pt/C.Pt@N-CDs/RGO shows an onset potential(Eonest)of 1.071 V,a half-wave potential(E_(1/2))of 0.83 V,and a high transfer electron number of 3.97 at 0.4 V.Additionally,Pt@N-CDs/RGO exhibits significant long-term stability with 12 mV offset(1.4%)at E_(1/2)after 1000 cycles.These performance improvements are owed to the edge defects of N-CDs,which enhance the utilization of Pt.The existence of edge defects in N-CDs provides a novel method for promoting the sustainable development of PEMFCs.展开更多
Photodynamic therapy(PDT)has been established as one of the most promising novel cancer therapies with fewer side-effects and enhanced efficacy compared to the currently available conventional treatments.However,its a...Photodynamic therapy(PDT)has been established as one of the most promising novel cancer therapies with fewer side-effects and enhanced efficacy compared to the currently available conventional treatments.However,its application has been hindered by the limitations that photosensitizers(PS)have.The combination of PS with metallic nanoparticles like platinum nanoparticles(PtNPs),can help to overcome these intrinsic drawbacks.In this work,the combination of PtNPs and the natural photosensitizer riboflavin(RF)is proposed.PtNPs are synthesized using RF(Pt@RF)as reducing and stabilizing agent in a one-step method,obtaining nanoparticles with mesoporous structure for UV triggered PDT.In view of possible future UV irradiation treatments,the degradation products of RF,ribitol(RB)and lumichrome(LC),this last being a photosensitizing byproduct,are also employed for the synthesis of porous PtNPs,obtaining Pt@LC and Pt@RB.When administered in vitro to lung cancer cells,all the samples elicit a strong decrease of cell viability and a decrease of intracellular ATP levels.The antitumoral effect of both Pt@RF and Pt@LC is triggered by UV-A irradiation.This antitumoral activity is caused by the induction of oxidative stress,shown in our study by the decrease in intracellular glutathione and increased expression of antioxidant enzymes.展开更多
Exploring platinum single-atom electrocatalysts(SACs)is of great significance for effectively catalyzing the hydrogen evolution reaction in order to maximize the utilization of metal atoms.Herein,ruthenium clusters wi...Exploring platinum single-atom electrocatalysts(SACs)is of great significance for effectively catalyzing the hydrogen evolution reaction in order to maximize the utilization of metal atoms.Herein,ruthenium clusters with several atoms(Rux)supported on nitrogen-doped,cost-efficient Black Pearls 2000(Ru_(x)NBP),were synthesized as initial materials via a simple hydrothermal method.Then,[PtCl_(4)]^(2–)ion was reductively deposited on RuxNBP to obtain a Pt SAC(Pt1/RuxNBP).Electrochemical measurements demonstrate the excellent HER performance of Pt_(1)/Ru_(x)NBP with a 5.7-fold increase in mass activity compared to the commercial Pt/C at 20 mV.Moreover,the cell voltage of the proton exchange membrane electrolyzer with Pt_(1)/Ru_(x)NBP is 20 mV lower compared to that with commercial Pt/C at 1.0 A cm^(−2).Physical characterization and density functional theory calculations revealed that the preserved Pt–Cl bond of[PtCl_(4)]^(2–)and the RuxNBP support co-regulate the 5d state of isolated Pt atoms and enhance the catalytic HER capacity of Pt1/RuxNBP.展开更多
Platinum(Pt)-based single atoms and alloys represent reasonable structures to reduce the cost of electrocatalysts for the oxygen reduction reaction(ORR).However,the poor oxygen adsorption of single Pt atoms and the un...Platinum(Pt)-based single atoms and alloys represent reasonable structures to reduce the cost of electrocatalysts for the oxygen reduction reaction(ORR).However,the poor oxygen adsorption of single Pt atoms and the unfavorable surface microenvironment of alloy electrodes limit their practical applications.To address these issues,we have engineered a synergistic hybrid structure by anchoring PtNi alloys onto defective carbon(DC)modified with Pt and Ni single atoms,followed by surface modification with 2,6-diacetylpyridine(DAP)molecules.The mass activity(MA)of the optimized DAP-PtNi/Pt&Ni-SAC electrocatalyst reaches 1678.9 mA mg_(Pt)^(-1),which is 10.21 times that of commercial JM Pt/C(164.5 mA mg_(Pt)^(-1)).Moreover,after 20,000 accelerated durability tests(ADTs),DAP-PtNi/Pt&Ni-SAC shows only a 7.9%loss in MA,demonstrating its outstanding stability.Structural characterization and theoretical calculations reveal that the interaction of Ni single atoms and PtNi alloys enhances the adsorption stability of O_(2)molecules at Pt single atoms,facilitating a 4-electron ORR pathway.Meanwhile,DAP molecules adsorbed on Pt alloy sites associate with various oxygen-containing intermediates and protons through electrostatic interactions,promoting their combination.This synergistic effect between the intrinsic structure and the electrochemical microenvironment optimizes the ORR pathway in an overall manner,thus improving the kinetics of ORR.展开更多
An atmospheric pressure plasma jet(APPJ)approach is developed to prepare platinum nanoparticles(PtNPs)under mild reaction conditions of lower temperatures and without adding chemical reagents.Optical Emission Spectros...An atmospheric pressure plasma jet(APPJ)approach is developed to prepare platinum nanoparticles(PtNPs)under mild reaction conditions of lower temperatures and without adding chemical reagents.Optical Emission Spectroscopy(OES)and X-ray Photoelectron Spectroscopy(XPS)tests revealed that the APPJ contains a large number of high-energy active particles,which can generate solvated electrons in liquid thereby promoting the rapid reduction of Pt(Ⅳ)ions into Pt(0)atoms,and these atoms gradually grow into nanoparticles.After 3 min of treatment,PtNPs exhibit excellent dispersibility with a particle size distribution ranging from 1.8 to 2.8 nm.After 5 min,the particle size increases,and aggregation occurs.The zeta potentials for the two situations were-56.0 mV and-12.5 mV respectively.The results indicate that the treatment time has a significant impact on the dispersion,particle size distribution,and sol stability of the nanoparticles.Furthermore,it reveals the formation mechanism of PtNPs prepared by APPJ,which involves the generation and expansion of nanocrystalline nuclei,and the construction of negatively charged colloidal particles.The overall mechanism highlights the importance of the plasma-liquid interaction in the synthesis of PtNPs,offering a new perspective on the controllable production of nanomaterials using plasma technology.展开更多
A new lifetime control technique-localized platinum lifetime control （LPLC） is introduced. Silicon samples are implanted with 550keV protons at dosages from 1 × 10^13 to 5 × 10^14 cm^-2. Subsequently, plat...A new lifetime control technique-localized platinum lifetime control （LPLC） is introduced. Silicon samples are implanted with 550keV protons at dosages from 1 × 10^13 to 5 × 10^14 cm^-2. Subsequently, platinum diffusion in silicon is performed at 700 or 750℃ for 15 or 30min,respectively. Then the in-diffused platinum into damaged regions of the proton-implanted silicon is investigated by use of deep-level transient spectroscopy （DLTS）. Finally, for all of the LPLC samples, the distribution of the in-diffused substitutional platinum agrees well with the damage distribution resulting from the low-dosage proton implantation. Also, the diodes show a very low leakage current even at elevated temperatures while keeping the major advantages of ion irradiation devices, including low turn-off loss and soft recovery.展开更多
Platinum(Pt)is a critical raw material for automotive catalytic converters due to its high-temperature stability,corrosion resistance and catalytic activity,whereas its limited primary resources and uneven distributio...Platinum(Pt)is a critical raw material for automotive catalytic converters due to its high-temperature stability,corrosion resistance and catalytic activity,whereas its limited primary resources and uneven distribution make it hard to meet the growing demand of platinum.Spent automotive catalyst(SAC)is currently the most important secondary resource of platinum,of which the platinum content is much higher than that of the primary platinum resources.The recovery process of platinum from spent automobile catalyst mainly consists of pretreatment followed by enrichment and refining,involving pyro-and hydrometallurgical techniques,among which enrichment and refining processes are extremely important for platinum recovery from spent automobile catalyst.This paper provides an overview of the technologies for platinum recovery from spent automotive catalyst.The emphasis is placed on the processes of enrichment and refining based on hydrometallurgical techniques.Future directions of research and development of platinum recovery from spent automobile catalyst are also proposed.展开更多
The Polar Urals region of northern Russia is well known for large chromium （Cr）-bearing massifs with major chromite orebodies, including the Centralnoye I deposit in the Ray-Iz ultramafic massif of the Ural ophiolit...The Polar Urals region of northern Russia is well known for large chromium （Cr）-bearing massifs with major chromite orebodies, including the Centralnoye I deposit in the Ray-Iz ultramafic massif of the Ural ophiolite belt. New data on platinum （Pt）-group elements （PGE）, geochemistry and mineralogy of the host dunite shows that the deposit has anomalous iridium （Ir） values. These values indicate the predominance of ruthenium--osmium--iridium （Ru--Os--Ir）-bearing phases among the platinum-group mineral （PGM） assemblage that is typical of mantle-hosted chromite ores. Low Pt values in chromites and increased Pt values in host dunites might reflect the presence of cumulus PGM grains. The most abundant PGM found in the chromite is erlichmanite （up to 15 μm）. Less common are cuproiridsite （up to 5 μm）, irarsite （up to 4--5 μm）, and laurite （up to 4 μm）. The predominant sulfide is heazlewoodite, in intergrowth with Ni--Fe alloys, sporadically with pentlandite, and rarely with pure nickel. Based on the average PGE values and esti- mated Cr-ore resources, the Centralnoye I deposit can be considered as an important resource of PGE.展开更多
Network crewn ether polymer with pendant sulfide side ohain in the networkstructure units has been synthesized via ring- opening copolymerization of β-ethylthioethyl glycidyl ether and diethylene glycol bisglycidyl e...Network crewn ether polymer with pendant sulfide side ohain in the networkstructure units has been synthesized via ring- opening copolymerization of β-ethylthioethyl glycidyl ether and diethylene glycol bisglycidyl ether. A kind of active catalyst suitable for this reaction was suggested. The title polymer was found tobe a good ligand for platinous chloride, and the platinous complex could catalyze thehydrosilylation of olefins with triethoxysilane efficiently.展开更多
Flower-like tin oxide-supported platinum（Pt/SnOx） with a hierarchical structure was synthesized by a hydrothermal method and characterized by XRD,SEM,TEM,high resolution TEM,XPS and nitrogen adsorption.The flower-li...Flower-like tin oxide-supported platinum（Pt/SnOx） with a hierarchical structure was synthesized by a hydrothermal method and characterized by XRD,SEM,TEM,high resolution TEM,XPS and nitrogen adsorption.The flower-like Pt/SnOx microspheres of 1 μm in diameter were composed of staggered petal-like nanosheets with a thickness of 20 nm.Pt nanoparticles（NPs） of 2-3 nm were well dispersed on the SnOx nanosheets.The catalyst was tested in the catalytic oxidation of gaseous formaldehyde（HCHO） at room temperature,and exhibited enhanced activity compared to Pt NPs supported on commercial SnO and ground SnOx.HCHO removal of 87%was achieved over the hierarchical Pt/SnOx after 1 h of reaction,which was 1.5 times that over the ground SnOx-supported Pt（Pt/g-SnOx）,and the high activity was maintained after six recycles,showing the high stability of this catalyst.HCHO decomposition kinetics was modeled as a second order reaction.The reaction rate constant for Pt/SnOx was 5.6 times higher than Pt/g-SnOx.The hierarchical pore structure was beneficial for the diffusion and adsorption of HCHO molecules,and the highly dispersed Pt NPs on the SnOx nanosheets were the active sites for the oxidative decomposition of HCHO into CO2 and H2O.This study provided a promising approach for designing efficient catalysts for indoor HCHO removal at ambient temperature.展开更多
Total platinum-group elements （PGEs） abundances in basalts from the spreading axis of Mariana Trough ranged from 0.418 × 10^9 to 1. 022 × 10^-9, and primitive mantle-normalized PGE patterns are of positive...Total platinum-group elements （PGEs） abundances in basalts from the spreading axis of Mariana Trough ranged from 0.418 × 10^9 to 1. 022 × 10^-9, and primitive mantle-normalized PGE patterns are of positive slope showing the relative enrichment of PPGE （ platinum, palladium, rhodium） and gold relative to IPGE. Compared with other mantle-originated rocks, these basalts have lower PGE contents and wider ranges of primitive mantle-normalized ratios of palladium content to iridium one, palladium content to platinum one and palladium content to gold one exhibiting relative platinum and iridium depletion. Characteristics of PGE patterns indicated that the studied Mariana Trough basalts originated from low partial melting, and the MORB mantle beneath the spreading center had been contaminated by the are-island mantle. In the aspect of trace elements, Mariana Trough basalts showed the enrichment of LILE, lead and LREE, indicating that they had been influenced by subduetion compositions. All these demonstrated that Mariana Trough basalts are products of partial melting from a mixed mantle （ the contamination of MORB mantle by are-island mantle）.展开更多
Chromitites associated with intensely altered dunites and harzburgites from fourteen dif ferent localities in the Islahiye ophiolites(SE Anatolia)is reported here for the first time.These chromitites were observed as ...Chromitites associated with intensely altered dunites and harzburgites from fourteen dif ferent localities in the Islahiye ophiolites(SE Anatolia)is reported here for the first time.These chromitites were observed as lenticular and banded bodies with disseminated and massive textures and containing magnesiochromite grains with the following composition:CrO=58.91–59.74 wt%,Al_(2)O_(3)=10.85–11.20 wt%,and TiO=0.09–0.13 wt%.The Mg#[Mg/(Mg+Fe)]values of magnesiochromite from the Islahiye ophiolite range between 0.52 and 0.60 and their Cr#[Cr/(Cr+Al)]values vary from 0.7802 to 0.7844.These contents vary with a constant pattern,coincident with the estimated parental liquids that have originated from the derivative of a single bulk of boninitic magma together with Al,Ti-poor,and Cr-rich initial contents.The chromitites are serpentinised in almost all parts of the study area,and harzburgite and dunite can be observed in different locations.Although the overall composition of platinum group elements(PGE)in most examined chromitites varies between 97 and 191 ppb,three chromitites from the Islahiye region present enrichments in overall PGE(up to 214 ppb).The mineralogical and geochemical features of chromitites from the Islahiye region exhibit a robust similarity to podiform chromitites in the mantle fragment of supra–subduction zone type ophiolitic bodies.The estimated parental magmas of the investigated chromites are consistent with the diff erentiation of arcrelated melts and do not suggest an oceanic spreading centre tectonic environment.The Islahiye chromites are enriched in IPGE(Ir,Os,Ru),with the occasional presence of Ru and Ir and higher Os contents in chromite.Furthermore,we did not find any platinum group minerals(PGM)associated with the serpentine silicate sample matrix,which would have stated a secondary enrichment in PGEs.All chromitites in the investigated region have high Cr and low Ti values,are defined as magnesiochromite and were crystallised from a characteristic boninitic magma.展开更多
Dust samples collected from the Beijing metropolitan area （China） were evaluated to determine the distribution and the concentration of platinum group elements （PGEs）. The dust particles that were smaller than 100...Dust samples collected from the Beijing metropolitan area （China） were evaluated to determine the distribution and the concentration of platinum group elements （PGEs）. The dust particles that were smaller than 100 mesh size fraction （150 μm） were analyzed after aqua regia digestion. Concentrations ofPt, Rh, and Pd were found to be between 3.96 and 356.3 ng/g, 2.76 and 97.11 ng/g, and 0.1 and 124.9 ng/g, respectively, in the urban areas of Beijing, whereas for the background samples collected from the suburbs of Beijing, the concentrations of Pt, Pd, and Rh were very low and ranged from 0.1 to 0.9 ng/g, 0.5 to 1.4 ng/g, and 0.8 to 2.2 rig/g, respectively. The distributions of PGEs in road dust were an accurate reflection of the levels of pollution and were found to match with the local traffic conditions. A strong positive correlation was established among all the dements found in road dust. This suggests that emissions of abraded fragments from vehicle exhausts may be the source of the high concentration of Pt, Rh, and Pd in road dust along the main roads of Beijing.展开更多
Background:The optimal time to save a person who has had a sudden cardiac arrest is within the first few minutes of the incident.Early compression and early defibrillation should be performed at this time.Timeliness i...Background:The optimal time to save a person who has had a sudden cardiac arrest is within the first few minutes of the incident.Early compression and early defibrillation should be performed at this time.Timeliness is the key to successful CPR; as such,Prof.He proposed the 'platinum 10 min' system to study early CPR issues.This paper systematically evaluates the success rates of heartbeat restoration within the 'platinum 10min' among patients suffering from sudden cardiac arrest.Methods:The clinical data of outpatients suffering from a cardiac arrest were retrieved from the China Knowledge Network(January 1975-January 2015),the Chongqing VIP database(January 1989-January 2015),and the Wanfang database(January 1990-January 2015).The success of the cardiopulmonary resuscitation(CPR) performed at different times after the patients had cardiac arrests was analyzed.Two researchers screened the literature and extracted the data independently.A meta-analysis was conducted using Stata 12.0.A total of 57 papers met the inclusion criteria,including 29,269 patients.Of these patients,1,776 had their heartbeats successfully restored.The results showed high heterogeneity(χ~2=3428.85,P<0.01,I2=98.4%).The meta-analysis was conducted using a random-effects model.The combined effect size was 0.171(0.144-0.199).Results:1) The success rate of heartbeat restoration did not differ among the four emergency treatment methods that patients received:the methods described in the 2000 Guidelines for CPR and Emergency Cardiovascular Care,that described in the 2005 version,2010 version,and another CPR method.2) The patients were divided into five groups based on the time when CPR was performed:the ?1min group,the 1-5min group,the 5-10 min group,the 10-15 min group and the >15min group.The CPR success rates of these five groups were 0.247(0.15-0.344),0.353(0.250-0.456),0.136(0.109-0.163),0.058(0.041-0.075),and 0.011(0.004-0.019),respectively.The CPR success rates did not differ between the patients in the ?1min group and the 1-5min group.This success rate was higher for the patients in the 1-5min group than those in the 10-15 min group,those in the 10-15 min group,and those in the >15min group.The CPR success rate was higher for the patients in the 5-10 min group than those in the 10-15 min group and those in the >15min group.The CPR success rate was higher for the patients in the 10-15 min group than those in the >15min group.In addition,the patients were divided into two groups based on whether CPR was performed within the first 10 min after the cardiac arrest occurred:the ?10min group and the >10min group.The CPR success rate was higher for the patients in the ?10min group [0.189(0.161-0.218)] than those in the >10min group [0.044(0.032-0.056)].3) Differences were not found between the CPR success rates among the patients in the telephone guidance group [0.167(0.016-0.351)] and those in the ?1min,1-5min,5-10 min,10-15 min,and >15min groups.4) The CPR success rates did not differ among in the patients in the witness + public group [0.329(0.221-0.436)],those in the ?1min group,and those in the 1-5min group.However,this success rate was higher in the patients in the witness + public group than those in the 5-10 min,10-15 min,and >15min groups.Conclusion:The success rate of heartbeat restoration did not differ among patients receiving CPR based on different guidelines.The success rate of CPR lies in its timeliness.The participation of the general population is the cornerstone of improving CPR.Providing complete emergency treatment equipment and perfecting comprehensive measures can improve the success rate of CPR among patients within the platinum 10 min.CPR research in China must be improved.展开更多
Fabrication of novel electrode architectures with nanostructured ultrathin catalyst layers is an effective strategy to improve catalyst utilization and enhance mass transport for polymer electrolyte membrane fuel cell...Fabrication of novel electrode architectures with nanostructured ultrathin catalyst layers is an effective strategy to improve catalyst utilization and enhance mass transport for polymer electrolyte membrane fuel cells (PEMFCs).Herein,we report the design and construction of a nanostructured ultrathin catalyst layer with ordered Pt nanotube arrays,which were obtained by a hard-template strategy based on ZnO,via hydrothermal synthesis and magnetron sputtering for PEMFC application.Because of the crystallographically preferential growth of Pt (111) facets,which was attributed to the structural effects of ZnO nanoarrays on the Pt nanotubes,the catalyst layers exhibit obviously higher electrochemical activity with remarkable enhancement of specific activity and mass transport compared with the state-of-the-art randomly distributed Pt/C catalyst layer.The PEMFC fabricated with the as-prepared catalyst layer composed of optimized Pt nanotubes with an average diameter of 90(±10) nm shows excellent performance with a peak power density of 6.0W/mgPt at 1 A/cm^2,which is 11.6%greater than that of the conventional Pt/C electrode.展开更多
Platinum was electrodeposited onto a polyaniline-modified carbon fiberelectrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in thelevel of platinum utilization currently achieved i...Platinum was electrodeposited onto a polyaniline-modified carbon fiberelectrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in thelevel of platinum utilization currently achieved in electrocatalytic systems. This electrodepreparation consists of a two-step procedure: first electropolymerization of aniline onto carbonfiber and then electrodeposition of platinum. The catalytic activity of theplatinum-polyanihne-modified carbon fiber electrode (Pt/PAni/C) was compared with that of a barecarbon fiber electrode (Pt/C) by the oxidation of methanol. The maximum oxidation current ofmethanol on Pt/PAni/C is 50.7 mA centre dot cm^(-2), which is 6.7 times higher than 7.6 mA centredot cm^(-2) on the Pt/C. Scanning electron microscopy was used to investigate the dispersion of theplatinum particles of about 0.4 um.展开更多
China is extremely poor in mineral resources of Platinum Group Metals (PGMs), productive output of PGMs from mineral resource is 2.5 tons per year. At the same time, China is the biggest PGMs consumption country in th...China is extremely poor in mineral resources of Platinum Group Metals (PGMs), productive output of PGMs from mineral resource is 2.5 tons per year. At the same time, China is the biggest PGMs consumption country in the world, the mineral resource of PGMs is critical shortage, it shows the importance of recycling the secondary resource of PGMs. Sino-Platinum Metals Resource (Yimen) Co., Ltd. is the leader in recycling of PGMs from secondary resource, and has made outstanding contributions to China PGMs secondary resources recycling. This article elucidates the current situation of secondary resources recovery and development of metallurgical technology for PGMs.展开更多
文摘In this research work, atomic and molecular orbitals based analysis has been made to see electronic structure of platinum halides (platinum dichloride, platinum dibromide, platinum diiodide and platinum difluride). The geometry optimization and three dimensional (3D) modeling of the above mentioned species have been made on CAChe pro software. The results show: (i) The involvement of three p atomic orbitals is negligible as their summation values are very low in comparison to d orbital and considerably low with respect to s orbital. (ii) The study well support the Landis concepts of sdn-hybridation (here n = 1) as bond angle and contributions of s-orbital and d-orbital of Pt(II) are maximum with negligible contribution of p-orbitals. (iii) These halides also support the cloud-expanding effect with experimental data and also follow the nephelauxetic effect. The result is in good agreement with experiment results that covalent character increases in the order: PtI2 > PtBr2 > PtCl2 > PtF2. (iv) And thus the study will help to fine tune the existing complexes of these halides.
文摘c-Kit (CD117) is a type IIIa receptor tyrosine kinase (RTK) that plays a key role in regulating the normal physiological processes of cells. In addition, the activation of c-Kit activates the tyrosine kinase signal transduction pathway, which is closely related to the occurrence and development of gynecological tumors, especially ovarian cancer. This article reviews the mechanisms of platinum resistance in ovarian cancer and the research progress of c-Kit in ovarian cancer.
文摘We demonstrated a one-step hydrothermal polyol reduction technique to produce platinum(Pt)and N-doped carbon quantum dots(N-CDs)co-loaded with reduced-graphene oxide(Pt@N-CDs/RGO).The electrochemical performance of commercial Pt/C,and Pt@N-CDs/RGO in 0.5 M H_(2)SO_(4) electrolyte was compared under the Pt amount(20wt%).Pt@N-CDs/RGO exhibits ultra-high electroactivity and durability for oxygen reduction reaction(ORR).The electrochemically active surface area(ECSA)can be achieved to 124.8 m^(2)/g,which is 1.65 times higher than that of commercial Pt/C.Pt@N-CDs/RGO shows an onset potential(Eonest)of 1.071 V,a half-wave potential(E_(1/2))of 0.83 V,and a high transfer electron number of 3.97 at 0.4 V.Additionally,Pt@N-CDs/RGO exhibits significant long-term stability with 12 mV offset(1.4%)at E_(1/2)after 1000 cycles.These performance improvements are owed to the edge defects of N-CDs,which enhance the utilization of Pt.The existence of edge defects in N-CDs provides a novel method for promoting the sustainable development of PEMFCs.
基金funded by the Horizon Europe Project"PERSEUS"(No.101099423)financed by the Ministry of Universities under application 33.50.460A.752by the European Union NextGenerationEU/PRTR through a contract Margarita Salas from Universidade de Vigo.
文摘Photodynamic therapy(PDT)has been established as one of the most promising novel cancer therapies with fewer side-effects and enhanced efficacy compared to the currently available conventional treatments.However,its application has been hindered by the limitations that photosensitizers(PS)have.The combination of PS with metallic nanoparticles like platinum nanoparticles(PtNPs),can help to overcome these intrinsic drawbacks.In this work,the combination of PtNPs and the natural photosensitizer riboflavin(RF)is proposed.PtNPs are synthesized using RF(Pt@RF)as reducing and stabilizing agent in a one-step method,obtaining nanoparticles with mesoporous structure for UV triggered PDT.In view of possible future UV irradiation treatments,the degradation products of RF,ribitol(RB)and lumichrome(LC),this last being a photosensitizing byproduct,are also employed for the synthesis of porous PtNPs,obtaining Pt@LC and Pt@RB.When administered in vitro to lung cancer cells,all the samples elicit a strong decrease of cell viability and a decrease of intracellular ATP levels.The antitumoral effect of both Pt@RF and Pt@LC is triggered by UV-A irradiation.This antitumoral activity is caused by the induction of oxidative stress,shown in our study by the decrease in intracellular glutathione and increased expression of antioxidant enzymes.
文摘Exploring platinum single-atom electrocatalysts(SACs)is of great significance for effectively catalyzing the hydrogen evolution reaction in order to maximize the utilization of metal atoms.Herein,ruthenium clusters with several atoms(Rux)supported on nitrogen-doped,cost-efficient Black Pearls 2000(Ru_(x)NBP),were synthesized as initial materials via a simple hydrothermal method.Then,[PtCl_(4)]^(2–)ion was reductively deposited on RuxNBP to obtain a Pt SAC(Pt1/RuxNBP).Electrochemical measurements demonstrate the excellent HER performance of Pt_(1)/Ru_(x)NBP with a 5.7-fold increase in mass activity compared to the commercial Pt/C at 20 mV.Moreover,the cell voltage of the proton exchange membrane electrolyzer with Pt_(1)/Ru_(x)NBP is 20 mV lower compared to that with commercial Pt/C at 1.0 A cm^(−2).Physical characterization and density functional theory calculations revealed that the preserved Pt–Cl bond of[PtCl_(4)]^(2–)and the RuxNBP support co-regulate the 5d state of isolated Pt atoms and enhance the catalytic HER capacity of Pt1/RuxNBP.
基金supported by the National Natural Science Foundation of China under Grant No.22262018the Lanzhou Youth Science and Technology Talent Innovation Project under Grant No.2024-QN-96+1 种基金the Gansu Key Research and Development Program(Industry Field)under Grant No.23YFGA0056Hongliu Outstanding Youth Talents Support Project。
文摘Platinum(Pt)-based single atoms and alloys represent reasonable structures to reduce the cost of electrocatalysts for the oxygen reduction reaction(ORR).However,the poor oxygen adsorption of single Pt atoms and the unfavorable surface microenvironment of alloy electrodes limit their practical applications.To address these issues,we have engineered a synergistic hybrid structure by anchoring PtNi alloys onto defective carbon(DC)modified with Pt and Ni single atoms,followed by surface modification with 2,6-diacetylpyridine(DAP)molecules.The mass activity(MA)of the optimized DAP-PtNi/Pt&Ni-SAC electrocatalyst reaches 1678.9 mA mg_(Pt)^(-1),which is 10.21 times that of commercial JM Pt/C(164.5 mA mg_(Pt)^(-1)).Moreover,after 20,000 accelerated durability tests(ADTs),DAP-PtNi/Pt&Ni-SAC shows only a 7.9%loss in MA,demonstrating its outstanding stability.Structural characterization and theoretical calculations reveal that the interaction of Ni single atoms and PtNi alloys enhances the adsorption stability of O_(2)molecules at Pt single atoms,facilitating a 4-electron ORR pathway.Meanwhile,DAP molecules adsorbed on Pt alloy sites associate with various oxygen-containing intermediates and protons through electrostatic interactions,promoting their combination.This synergistic effect between the intrinsic structure and the electrochemical microenvironment optimizes the ORR pathway in an overall manner,thus improving the kinetics of ORR.
基金partially supported by Natural Science Research Project of Anhui Educational Committee (Nos.KJ2021A1168,KJ2021A1169 and 2024AH050620)University Synergy Innovation Program of Anhui Province (No.GXXT-2022-026)University-Industry Cooperation Practical Education Base Project (No.2022xqjdx04)。
文摘An atmospheric pressure plasma jet(APPJ)approach is developed to prepare platinum nanoparticles(PtNPs)under mild reaction conditions of lower temperatures and without adding chemical reagents.Optical Emission Spectroscopy(OES)and X-ray Photoelectron Spectroscopy(XPS)tests revealed that the APPJ contains a large number of high-energy active particles,which can generate solvated electrons in liquid thereby promoting the rapid reduction of Pt(Ⅳ)ions into Pt(0)atoms,and these atoms gradually grow into nanoparticles.After 3 min of treatment,PtNPs exhibit excellent dispersibility with a particle size distribution ranging from 1.8 to 2.8 nm.After 5 min,the particle size increases,and aggregation occurs.The zeta potentials for the two situations were-56.0 mV and-12.5 mV respectively.The results indicate that the treatment time has a significant impact on the dispersion,particle size distribution,and sol stability of the nanoparticles.Furthermore,it reveals the formation mechanism of PtNPs prepared by APPJ,which involves the generation and expansion of nanocrystalline nuclei,and the construction of negatively charged colloidal particles.The overall mechanism highlights the importance of the plasma-liquid interaction in the synthesis of PtNPs,offering a new perspective on the controllable production of nanomaterials using plasma technology.
文摘A new lifetime control technique-localized platinum lifetime control （LPLC） is introduced. Silicon samples are implanted with 550keV protons at dosages from 1 × 10^13 to 5 × 10^14 cm^-2. Subsequently, platinum diffusion in silicon is performed at 700 or 750℃ for 15 or 30min,respectively. Then the in-diffused platinum into damaged regions of the proton-implanted silicon is investigated by use of deep-level transient spectroscopy （DLTS）. Finally, for all of the LPLC samples, the distribution of the in-diffused substitutional platinum agrees well with the damage distribution resulting from the low-dosage proton implantation. Also, the diodes show a very low leakage current even at elevated temperatures while keeping the major advantages of ion irradiation devices, including low turn-off loss and soft recovery.
基金financially supported by the Natural Science Foundation of Anhui Province(No.2108085J26)the National Natural Science Foundation of China(Nos.51904003 and U1703130)+1 种基金the Key Research and Development Plan of Anhui Province(No.2022n07020004)the Open Foundation of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(No.CNMRCUKF2208)。
文摘Platinum(Pt)is a critical raw material for automotive catalytic converters due to its high-temperature stability,corrosion resistance and catalytic activity,whereas its limited primary resources and uneven distribution make it hard to meet the growing demand of platinum.Spent automotive catalyst(SAC)is currently the most important secondary resource of platinum,of which the platinum content is much higher than that of the primary platinum resources.The recovery process of platinum from spent automobile catalyst mainly consists of pretreatment followed by enrichment and refining,involving pyro-and hydrometallurgical techniques,among which enrichment and refining processes are extremely important for platinum recovery from spent automobile catalyst.This paper provides an overview of the technologies for platinum recovery from spent automotive catalyst.The emphasis is placed on the processes of enrichment and refining based on hydrometallurgical techniques.Future directions of research and development of platinum recovery from spent automobile catalyst are also proposed.
文摘The Polar Urals region of northern Russia is well known for large chromium （Cr）-bearing massifs with major chromite orebodies, including the Centralnoye I deposit in the Ray-Iz ultramafic massif of the Ural ophiolite belt. New data on platinum （Pt）-group elements （PGE）, geochemistry and mineralogy of the host dunite shows that the deposit has anomalous iridium （Ir） values. These values indicate the predominance of ruthenium--osmium--iridium （Ru--Os--Ir）-bearing phases among the platinum-group mineral （PGM） assemblage that is typical of mantle-hosted chromite ores. Low Pt values in chromites and increased Pt values in host dunites might reflect the presence of cumulus PGM grains. The most abundant PGM found in the chromite is erlichmanite （up to 15 μm）. Less common are cuproiridsite （up to 5 μm）, irarsite （up to 4--5 μm）, and laurite （up to 4 μm）. The predominant sulfide is heazlewoodite, in intergrowth with Ni--Fe alloys, sporadically with pentlandite, and rarely with pure nickel. Based on the average PGE values and esti- mated Cr-ore resources, the Centralnoye I deposit can be considered as an important resource of PGE.
文摘Network crewn ether polymer with pendant sulfide side ohain in the networkstructure units has been synthesized via ring- opening copolymerization of β-ethylthioethyl glycidyl ether and diethylene glycol bisglycidyl ether. A kind of active catalyst suitable for this reaction was suggested. The title polymer was found tobe a good ligand for platinous chloride, and the platinous complex could catalyze thehydrosilylation of olefins with triethoxysilane efficiently.
基金supported by the National Natural Science Foundation of China (51320105001, 51372190, 21573170, 51272199, 21433007)the National Basic Research Program of China (973 program, 2013CB632402)+2 种基金the Natural Science Foundation of Hubei Province (2015CFA001)the Fundamental Research Funds for the Central Universities (WUT: 2015-Ⅲ-034)Innovative Research Funds of SKLWUT (2015-ZD-1)~~
文摘Flower-like tin oxide-supported platinum（Pt/SnOx） with a hierarchical structure was synthesized by a hydrothermal method and characterized by XRD,SEM,TEM,high resolution TEM,XPS and nitrogen adsorption.The flower-like Pt/SnOx microspheres of 1 μm in diameter were composed of staggered petal-like nanosheets with a thickness of 20 nm.Pt nanoparticles（NPs） of 2-3 nm were well dispersed on the SnOx nanosheets.The catalyst was tested in the catalytic oxidation of gaseous formaldehyde（HCHO） at room temperature,and exhibited enhanced activity compared to Pt NPs supported on commercial SnO and ground SnOx.HCHO removal of 87%was achieved over the hierarchical Pt/SnOx after 1 h of reaction,which was 1.5 times that over the ground SnOx-supported Pt（Pt/g-SnOx）,and the high activity was maintained after six recycles,showing the high stability of this catalyst.HCHO decomposition kinetics was modeled as a second order reaction.The reaction rate constant for Pt/SnOx was 5.6 times higher than Pt/g-SnOx.The hierarchical pore structure was beneficial for the diffusion and adsorption of HCHO molecules,and the highly dispersed Pt NPs on the SnOx nanosheets were the active sites for the oxidative decomposition of HCHO into CO2 and H2O.This study provided a promising approach for designing efficient catalysts for indoor HCHO removal at ambient temperature.
基金This study was supported by the National Natural Science Foundation of China under contract No. 40273025the National High Technology Research and Development of China under contract No. 2006AA09Z219+1 种基金the Key Laboratory of Marine Sedimentology and Environmental Geology, the State 0ceanic Administrationthe National Basic Research Program of China under contract No. G2000078503.
文摘Total platinum-group elements （PGEs） abundances in basalts from the spreading axis of Mariana Trough ranged from 0.418 × 10^9 to 1. 022 × 10^-9, and primitive mantle-normalized PGE patterns are of positive slope showing the relative enrichment of PPGE （ platinum, palladium, rhodium） and gold relative to IPGE. Compared with other mantle-originated rocks, these basalts have lower PGE contents and wider ranges of primitive mantle-normalized ratios of palladium content to iridium one, palladium content to platinum one and palladium content to gold one exhibiting relative platinum and iridium depletion. Characteristics of PGE patterns indicated that the studied Mariana Trough basalts originated from low partial melting, and the MORB mantle beneath the spreading center had been contaminated by the are-island mantle. In the aspect of trace elements, Mariana Trough basalts showed the enrichment of LILE, lead and LREE, indicating that they had been influenced by subduetion compositions. All these demonstrated that Mariana Trough basalts are products of partial melting from a mixed mantle （ the contamination of MORB mantle by are-island mantle）.
基金Cukurova University Research Foundation for their support(Project No:FYL-2018-10437,FBA-2021-13093)。
文摘Chromitites associated with intensely altered dunites and harzburgites from fourteen dif ferent localities in the Islahiye ophiolites(SE Anatolia)is reported here for the first time.These chromitites were observed as lenticular and banded bodies with disseminated and massive textures and containing magnesiochromite grains with the following composition:CrO=58.91–59.74 wt%,Al_(2)O_(3)=10.85–11.20 wt%,and TiO=0.09–0.13 wt%.The Mg#[Mg/(Mg+Fe)]values of magnesiochromite from the Islahiye ophiolite range between 0.52 and 0.60 and their Cr#[Cr/(Cr+Al)]values vary from 0.7802 to 0.7844.These contents vary with a constant pattern,coincident with the estimated parental liquids that have originated from the derivative of a single bulk of boninitic magma together with Al,Ti-poor,and Cr-rich initial contents.The chromitites are serpentinised in almost all parts of the study area,and harzburgite and dunite can be observed in different locations.Although the overall composition of platinum group elements(PGE)in most examined chromitites varies between 97 and 191 ppb,three chromitites from the Islahiye region present enrichments in overall PGE(up to 214 ppb).The mineralogical and geochemical features of chromitites from the Islahiye region exhibit a robust similarity to podiform chromitites in the mantle fragment of supra–subduction zone type ophiolitic bodies.The estimated parental magmas of the investigated chromites are consistent with the diff erentiation of arcrelated melts and do not suggest an oceanic spreading centre tectonic environment.The Islahiye chromites are enriched in IPGE(Ir,Os,Ru),with the occasional presence of Ru and Ir and higher Os contents in chromite.Furthermore,we did not find any platinum group minerals(PGM)associated with the serpentine silicate sample matrix,which would have stated a secondary enrichment in PGEs.All chromitites in the investigated region have high Cr and low Ti values,are defined as magnesiochromite and were crystallised from a characteristic boninitic magma.
基金Project supported by the Natural Science Foundation of Beijing (No. 2063025) the Municipal Education Foundation of Beijing (No. KM200610028007)
文摘Dust samples collected from the Beijing metropolitan area （China） were evaluated to determine the distribution and the concentration of platinum group elements （PGEs）. The dust particles that were smaller than 100 mesh size fraction （150 μm） were analyzed after aqua regia digestion. Concentrations ofPt, Rh, and Pd were found to be between 3.96 and 356.3 ng/g, 2.76 and 97.11 ng/g, and 0.1 and 124.9 ng/g, respectively, in the urban areas of Beijing, whereas for the background samples collected from the suburbs of Beijing, the concentrations of Pt, Pd, and Rh were very low and ranged from 0.1 to 0.9 ng/g, 0.5 to 1.4 ng/g, and 0.8 to 2.2 rig/g, respectively. The distributions of PGEs in road dust were an accurate reflection of the levels of pollution and were found to match with the local traffic conditions. A strong positive correlation was established among all the dements found in road dust. This suggests that emissions of abraded fragments from vehicle exhausts may be the source of the high concentration of Pt, Rh, and Pd in road dust along the main roads of Beijing.
文摘Background:The optimal time to save a person who has had a sudden cardiac arrest is within the first few minutes of the incident.Early compression and early defibrillation should be performed at this time.Timeliness is the key to successful CPR; as such,Prof.He proposed the 'platinum 10 min' system to study early CPR issues.This paper systematically evaluates the success rates of heartbeat restoration within the 'platinum 10min' among patients suffering from sudden cardiac arrest.Methods:The clinical data of outpatients suffering from a cardiac arrest were retrieved from the China Knowledge Network(January 1975-January 2015),the Chongqing VIP database(January 1989-January 2015),and the Wanfang database(January 1990-January 2015).The success of the cardiopulmonary resuscitation(CPR) performed at different times after the patients had cardiac arrests was analyzed.Two researchers screened the literature and extracted the data independently.A meta-analysis was conducted using Stata 12.0.A total of 57 papers met the inclusion criteria,including 29,269 patients.Of these patients,1,776 had their heartbeats successfully restored.The results showed high heterogeneity(χ~2=3428.85,P<0.01,I2=98.4%).The meta-analysis was conducted using a random-effects model.The combined effect size was 0.171(0.144-0.199).Results:1) The success rate of heartbeat restoration did not differ among the four emergency treatment methods that patients received:the methods described in the 2000 Guidelines for CPR and Emergency Cardiovascular Care,that described in the 2005 version,2010 version,and another CPR method.2) The patients were divided into five groups based on the time when CPR was performed:the ?1min group,the 1-5min group,the 5-10 min group,the 10-15 min group and the >15min group.The CPR success rates of these five groups were 0.247(0.15-0.344),0.353(0.250-0.456),0.136(0.109-0.163),0.058(0.041-0.075),and 0.011(0.004-0.019),respectively.The CPR success rates did not differ between the patients in the ?1min group and the 1-5min group.This success rate was higher for the patients in the 1-5min group than those in the 10-15 min group,those in the 10-15 min group,and those in the >15min group.The CPR success rate was higher for the patients in the 5-10 min group than those in the 10-15 min group and those in the >15min group.The CPR success rate was higher for the patients in the 10-15 min group than those in the >15min group.In addition,the patients were divided into two groups based on whether CPR was performed within the first 10 min after the cardiac arrest occurred:the ?10min group and the >10min group.The CPR success rate was higher for the patients in the ?10min group [0.189(0.161-0.218)] than those in the >10min group [0.044(0.032-0.056)].3) Differences were not found between the CPR success rates among the patients in the telephone guidance group [0.167(0.016-0.351)] and those in the ?1min,1-5min,5-10 min,10-15 min,and >15min groups.4) The CPR success rates did not differ among in the patients in the witness + public group [0.329(0.221-0.436)],those in the ?1min group,and those in the 1-5min group.However,this success rate was higher in the patients in the witness + public group than those in the 5-10 min,10-15 min,and >15min groups.Conclusion:The success rate of heartbeat restoration did not differ among patients receiving CPR based on different guidelines.The success rate of CPR lies in its timeliness.The participation of the general population is the cornerstone of improving CPR.Providing complete emergency treatment equipment and perfecting comprehensive measures can improve the success rate of CPR among patients within the platinum 10 min.CPR research in China must be improved.
基金financially supported by the National Natural Science Foundation of China(NSFC,Grant no.21503228)the Transformational Technologies for Clean Energy and Demonstration,Strategic Priority Research Program of the Chinese Academy of Sciences(Grant no.XDA21090203)。
文摘Fabrication of novel electrode architectures with nanostructured ultrathin catalyst layers is an effective strategy to improve catalyst utilization and enhance mass transport for polymer electrolyte membrane fuel cells (PEMFCs).Herein,we report the design and construction of a nanostructured ultrathin catalyst layer with ordered Pt nanotube arrays,which were obtained by a hard-template strategy based on ZnO,via hydrothermal synthesis and magnetron sputtering for PEMFC application.Because of the crystallographically preferential growth of Pt (111) facets,which was attributed to the structural effects of ZnO nanoarrays on the Pt nanotubes,the catalyst layers exhibit obviously higher electrochemical activity with remarkable enhancement of specific activity and mass transport compared with the state-of-the-art randomly distributed Pt/C catalyst layer.The PEMFC fabricated with the as-prepared catalyst layer composed of optimized Pt nanotubes with an average diameter of 90(±10) nm shows excellent performance with a peak power density of 6.0W/mgPt at 1 A/cm^2,which is 11.6%greater than that of the conventional Pt/C electrode.
文摘Platinum was electrodeposited onto a polyaniline-modified carbon fiberelectrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in thelevel of platinum utilization currently achieved in electrocatalytic systems. This electrodepreparation consists of a two-step procedure: first electropolymerization of aniline onto carbonfiber and then electrodeposition of platinum. The catalytic activity of theplatinum-polyanihne-modified carbon fiber electrode (Pt/PAni/C) was compared with that of a barecarbon fiber electrode (Pt/C) by the oxidation of methanol. The maximum oxidation current ofmethanol on Pt/PAni/C is 50.7 mA centre dot cm^(-2), which is 6.7 times higher than 7.6 mA centredot cm^(-2) on the Pt/C. Scanning electron microscopy was used to investigate the dispersion of theplatinum particles of about 0.4 um.
基金the National High Technology Research and Development Program of China(863 Program) (2012AA063203)Funded by Science and Technology Department of Yunnan Province (2011AA004)
文摘China is extremely poor in mineral resources of Platinum Group Metals (PGMs), productive output of PGMs from mineral resource is 2.5 tons per year. At the same time, China is the biggest PGMs consumption country in the world, the mineral resource of PGMs is critical shortage, it shows the importance of recycling the secondary resource of PGMs. Sino-Platinum Metals Resource (Yimen) Co., Ltd. is the leader in recycling of PGMs from secondary resource, and has made outstanding contributions to China PGMs secondary resources recycling. This article elucidates the current situation of secondary resources recovery and development of metallurgical technology for PGMs.
