scholarly journals Structural, morphological and catalytic characteristics of nanostructured palladium catalysts

2021 ◽  
Vol 2086 (1) ◽  
pp. 012203
Author(s):  
P D Pushankina ◽  
I S Lutsenko ◽  
I S Glazkova ◽  
T I Malkov ◽  
M A Mukhanov
Keyword(s):  
Palladium Catalysts ◽  
Active Sites ◽  
High Efficiency ◽  
Active Surface ◽  
Spherical Particles ◽  
Methanol Oxidation Reaction ◽  
Catalyst Synthesis ◽  
Long Term Stability ◽  
Highly Active

Abstract A new method for the highly active palladium catalyst synthesis on the surface of a Pd-23%Ag film has been developed to increase the material activity with respect to reactions involving hydrogen. Comparison of the electrochemical experiments data of classical palladium black and a new developed nanocatalyst demonstrated a significant increase in catalytic activity in the methanol oxidation reaction (up to 17.09 μA cm−2) for electrodes modified with the latter catalyst. The reason for that is an increase in the number of localized potentially more active surface regions due to the creation of a larger number of active sites in comparison with spherical particles. Estimation of resistance to CO poisoning showed high efficiency of nanocatalysts. Chronoamperometric experiment established the long-term stability and activity of the developed catalyst and confirmed the possibility of its practical use.

Hierarchical carbon and nitrogen adsorbed PtNiCo nanocomposites with multiple active sites for oxygen reduction and methanol oxidation reactions

2016 ◽  
Vol 4 (31) ◽  
pp. 12296-12307 ◽  
Author(s):  
Qin Wang ◽  
Qi Zhao ◽  
Yiguo Su ◽  
Geng Zhang ◽  
Guangran Xu ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Methanol Oxidation ◽  
Active Sites ◽  
Reduction Reaction ◽  
Methanol Oxidation Reaction ◽  
Oxidation Reactions ◽  
Carbon And Nitrogen ◽  
Long Term Stability ◽  
Hierarchical Carbon

Hierarchical carbon and nitrogen adsorbed PtNiCo nanocomposites with different morphologies and facets were successfully synthesized via a solvothermal method and showed high electrochemical activity and long-term stability towards the methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR).

scholarly journals Antimicrobial Effects of Biogenic Nanoparticles

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1009 ◽  
Author(s):  
Priyanka Singh ◽  
Abhroop Garg ◽  
Santosh Pandit ◽  
V. Mokkapati ◽  
Ivan Mijakovic
Keyword(s):  
Infectious Diseases ◽  
Metallic Nanoparticles ◽  
Active Surface ◽  
Multidrug Resistant ◽  
Antimicrobial Drugs ◽  
Long Term Stability ◽  
New Antibiotics ◽  
Conventional Antibiotics ◽  
Biogenic Nanoparticles

Infectious diseases pose one of the greatest health challenges in the medical world. Though numerous antimicrobial drugs are commercially available, they often lack effectiveness against recently developed multidrug resistant (MDR) microorganisms. This results in high antibiotic dose administration and a need to develop new antibiotics, which in turn requires time, money, and labor investments. Recently, biogenic metallic nanoparticles have proven their effectiveness against MDR microorganisms, individually and in synergy with the current/conventional antibiotics. Importantly, biogenic nanoparticles are easy to produce, facile, biocompatible, and environmentally friendly in nature. In addition, biogenic nanoparticles are surrounded by capping layers, which provide them with biocompatibility and long-term stability. Moreover, these capping layers provide an active surface for interaction with biological components, facilitated by free active surface functional groups. These groups are available for modification, such as conjugation with antimicrobial drugs, genes, and peptides, in order to enhance their efficacy and delivery. This review summarizes the conventional antibiotic treatments and highlights the benefits of using nanoparticles in combating infectious diseases.

Microfluidic Synthesis and Electrochemical Performance of Ternary Metals Nanoalloy: FePtSn

2018 ◽  
Vol 913 ◽  
pp. 831-837
Author(s):  
Ju Gang Ma ◽  
Jun Mei Wang ◽  
Shuai Li ◽  
Yu Jun Song
Keyword(s):  
Electrochemical Performance ◽  
Active Sites ◽  
Annealing Treatment ◽  
Active Surface ◽  
Catalytic Performance ◽  
Synthesis Process ◽  
Methanol Oxidation Reaction ◽  
X Ray ◽  
Onset Potential ◽  
Surface Areas

The ternary FePtSn alloy nanoparticles (NPs) were synthesized via a simple programmed microfluidic process, showing a great electrochemical performance in methanol oxidation reaction (MOR). The synthesis process exhibited convenient and spatial-temporal kinetics control of the NPs formation for a narrow size distribution, ultra-small (~2nm) and good dispersion features. The morphology, crystal structure and composition of FePtSn NPs were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), powder X-ray diffraction (XRD). FePtSn/C nanocatalyst ink could be further prepared by mixing the as-synthesized or annealed FePtSn NPs with carbon black powder and nafion. Their electrocatalytic performances were tested by the electrochemical work station. By contrast, the annealing treatment made more active sites exposed and facilitated the catalytic performance of FePtSn/C NPs. The electrochemical active surface areas (ECSAs, 42.8m2/g), catalytic activity (If: 588.1 mA/mg-Pt) and electrochemical durability of FePtSn/C nanocatalysts after annealing were greatly improved, comparing with as-synthesized samples and commercial Pt/C nanocatalysts for MOR. In addition, the onset potential of annealed FePtSn/C nanocatalysts was improved, much better than the commercial Pt/C nanocatalysts.

scholarly journals A Review on Improving the Quality of Perovskite Films in Perovskite Solar Cells via the Weak Forces Induced by Additives

2019 ◽  
Vol 9 (20) ◽  
pp. 4393 ◽  
Author(s):  
Jien Yang ◽  
Songhua Chen ◽  
Jinjin Xu ◽  
Qiong Zhang ◽  
Hairui Liu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
High Efficiency ◽  
Power Conversion ◽  
Perovskite Solar Cells ◽  
Term Stability ◽  
Long Term Stability ◽  
Weak Forces

Perovskite solar cells (PSCs) employing organic-inorganic halide perovskite as active layers have attracted the interesting of many scientists since 2009. The power conversion efficiency (PCE) have pushed certified 25.2% in 2019 from initial 3.81% in 2009, which is much faster than that of any type of solar cell. In the process of optimization, many innovative approaches to improve the morphology of perovskite films were developed, aiming at elevate the power conversion efficiency of perovskite solar cells (PSCs) as well as long-term stability. In the context of PSCs research, the perovskite precursor solutions modified with different additives have been extensively studied, with remarkable progress in improving the whole performance. In this comprehensive review, we focus on the forces induced by additives between the cations and anions of perovskite precursor, such as hydrogen bonds, coordination or some by-product (e.g., mesophase), which will lead to form intermediate adduct phases and then can be converted into high quality films. A compact uniform perovskite films can not only upgrade the power conversion efficiency (PCE) of devices but also improve the stability of PSCs under ambient conditions. Therefore, strategies for the implementation of additives engineering in perovskites precursor solution will be critical for the future development of PSCs. How to manipulate the weak forces in the fabrication of perovskite film could help to further develop high-efficiency solar cells with long-term stability and enable the potential of future practical applications.

scholarly journals Novel zero-dimensional lead-free bismuth based perovskites: from synthesis to structural and optoelectronic characterization

2020 ◽  
Vol 1 (9) ◽  
pp. 3439-3448
Author(s):  
Mailde S. Ozório ◽  
Willian X. C. Oliveira ◽  
Julian F. R. V. Silveira ◽  
Ana Flávia Nogueira ◽  
Juarez L. F. Da Silva
Keyword(s):  
Solar Cells ◽  
Conversion Efficiency ◽  
High Efficiency ◽  
Lead Free ◽  
Term Stability ◽  
Long Term Stability ◽  
High Efficiency Solar Cells

Despite high photo-conversion efficiency, the short long-term stability and toxicity issues have prevented lead-based perovskites from becoming the standard in high efficiency solar cells.

Properties of a-Si:H and a-SiGe:H Films Deposited by Photo-Assisted CVD

1986 ◽  
Vol 70 ◽  
Author(s):  
R. E. Rocheleau ◽  
S. C. Jackson. ◽  
S. S. Hegedus ◽  
B. N. Baron
Keyword(s):  
High Efficiency ◽  
Chemical Vapor ◽  
Photovoltaic Cell ◽  
Gas Flows ◽  
Long Term Stability ◽  
Improved Stability ◽  
Deposition Processes ◽  
P Type

ABSTRACTChemical vapor deposition techniques, in particular plasma enhanced CVD, have been used to produce high quality a-Si:H materials. Continuing research is directed toward increased device performance, improved stability, and translation of scale to commercial production. A part of this effort is the evaluation of alternate CVD techniques which in addition to providing technical options for high efficiency and long term stability are likely to lead to improved understanding of the relationships between deposition processes and material properties. A relatively new technique for depositing a-Si:H is photo-CVD which utilizes ultraviolet light to initiate the decomposition of silane or disilane. The best results from both materials properties and device efficiency points of view have been achieved using mercury sensitized photo-CVD. Recently, a 10.5% efficient a-Si:H p-i-n photovoltaic cell, fabricated by photo-CVD, was reported [1]. A limitation in photo-CVD has been preventing deposition on the UV transparent window. In this paper we describe a new photo-CVD reactor with a moveable UV-transparent Teflon film and secondary gas flows to eliminate window fouling. The deposition and opto-electronic characterization of intrinsic a-Si:H and a-SiGe:H and p-type a-SiC:H are described. Finally, preliminary results of p-i-n solar cells are presented.

scholarly journals Highly Active Deficient Ternary Sulfide Photoanode for Photoelectrochemical Water Splitting

2020 ◽  
Author(s):  
Haimei Wang ◽  
Yuguo Xia ◽  
Haiping Li ◽  
Xiang Wang ◽  
Yuan Yu ◽  
...  
Keyword(s):  
Water Splitting ◽  
Active Sites ◽  
High Efficiency ◽  
Theoretical Calculations ◽  
Metal Sulfide ◽  
Surface States ◽  
Photocurrent Density ◽  
Highly Active ◽  
Ternary Sulfide ◽  
Ternary Metal

<div>The exploration of photoanode materials with high efficiency and stability is the </div><div>eternal pursuit for the realization of practically solar-driven photoelectrochemical </div><div>water splitting. Here we develop a novel deficient ternary metal sulfide (CdIn2S4) </div><div>as photoanode, and its PEC performance is significantly enhanced by introducing </div><div>surface S vacancies, achieving a photocurrent density of 5.73 mA cm-2 at 1.23 V vs. </div><div>RHE and 1 Sun and an applied bias photon-to-current efficiency of 2.49% at 0.477 </div><div>V vs. RHE, which, to the best of our knowledge, are the record-high values for a </div><div>single sulfide photon absorber to date. The experimental characterizations and </div><div>theoretical calculations highlight the enhanced effect of surface S vacancies on the </div><div>interfacial charge separation and transfer kinetics, and also demonstrate the </div><div>restrained surface states distribution and the transformation of active sites after </div><div>introducing surface S vacancies. This work may inspire more excellent work on </div><div>developing sulfide-based photoanodes. </div>

Operando Unraveling Photothermal-Promoted Dynamic Active Sites Generation in Spinel NiFe2O4 for Oxygen Evolution

2020 ◽  
Author(s):  
Likun Gao ◽  
Xun Cui ◽  
Zewei Wang ◽  
Christopher Sewell ◽  
Zili Li ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Surface Reconstruction ◽  
Water Oxidation ◽  
Active Sites ◽  
Density Functional ◽  
Diblock Copolymers ◽  
High Current Density ◽  
Active Surface ◽  
Photothermal Effect ◽  
Highly Active

Abstract The ability to develop highly active and low-cost electrocatalysts represents an important endeavor toward accelerating sluggish water-oxidation kinetics. Herein, we report, for the first time, the implementation and unravelling of photothermal effect of spinel nanoparticles (NPs) on promoting dynamic active sites generation to markedly enhance their oxygen evolution reaction (OER) activity via an integrated operando Raman and density functional theory (DFT) study. Specifically, NiFe2O4 (NFO) NPs are first synthesized by capitalizing on amphiphilic star-like diblock copolymers as nanoreactors. Upon the NIR light irradiation, the photothermal heating of the NFO-based electrode progressively raises the temperature, accompanied by a marked decrease of overpotential. Accordingly, only an overpotential of 309 mV is required to yield a high current density of 100 mA cm-2, greatly lower than recently-reported earth-abundant electrocatalysts. More importantly, photothermal effect of NFO NPs not only significantly reduces the activation energy necessitated for water splitting, but also facilitates surface reconstruction into high-active oxyhydroxides at lower potential (1.36 V) under OER conditions, as revealed by operando Raman spectra-electrochemistry. Moreover, the DFT calculation corroborates that these reconstructed (Ni,Fe)oxyhydroxides are electrocatalytically active sites as the kinetics barrier is largely reduced over pure NFO without surface reconstruction. Given the diversity of materials (metal oxides, sulfides, phosphides, etc.) possessing the photo-to-thermal conversion, this effect may thus provide a unique and robust platform to boost highly-active surface species in nanomaterials for fundamental understanding of enhanced performance that may underpin future advances in electrocatalysis, photocatalysis, solar energy conversion and renewable energy production.  

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