High Efficiency for Methanol Electrooxidation of Self-Supporting 3D Nanoporous PdAg Alloy Foams

NANO ◽  
2021 ◽  
Author(s):  
Yanyan Song ◽  
Ying Chen ◽  
Lizhong He ◽  
Yunlong Wu ◽  
Xinhai He ◽  
...  
Keyword(s):  
High Efficiency ◽  
Three Dimensional ◽  
Active Surface ◽  
Atomic Ratio ◽  
Active Surface Area ◽  
Moderate Amount ◽  
Intermediate Products ◽  
Electrocatalytic Performance ◽  
One Step ◽  
Electrochemical Active Surface Area

The self-supporting three-dimensional (3D) nanoporous PdAg alloy (NP–PdAg) foams have been prepared by a simple one-step dealloying melt-spun Al–Pd–Ag ribbons in a 20[Formula: see text]wt.% NaOH aqueous solution at 90∘C for 1.5[Formula: see text]h. The structure is advantageous to the diffusion and removal of the intermediate products and the transmission of the methanol molecules. The NP–PdAg foams exhibit better electrocatalytic performance than the NP-Pd foam toward the methanol oxidation in potassium hydroxide (KOH) solution. The optimal atomic ratio of Pd to Ag in the NP–PdAg foams is 1:1, and its electrocatalytic activity is about 2.6 times that of the NP–Pd foam. The significant improvement in the electrocatalytic performance is attributed to the addition of a moderate amount of Ag. In the whole electrocatalytic process, Ag can provide OHads to oxidize the intermediate products on the surface of active Pd sites into carbon dioxide or other cleaning products. Also, the Ag can increase electrochemical active surface area and the adsorption energy of Pd to methanol molecules and OHads. These significantly prevent the accumulation of poisoning intermediates on the surface of Pd and quickly release more active Pd sites.

Exfoliation of bimetallic (Ni, Co) carbonate hydroxide nanowires by Ar plasma for enhanced oxygen evolution

2020 ◽  
Vol 56 (6) ◽  
pp. 872-875 ◽  
Author(s):  
Hongmei Sun ◽  
Yuanling Miao ◽  
Tao Wu ◽  
Qi Wang
Keyword(s):  
Oxygen Evolution ◽  
Three Dimensional ◽  
Dendritic Structure ◽  
Active Surface ◽  
Oxidation States ◽  
Active Surface Area ◽  
Carbonate Hydroxide ◽  
Ar Plasma ◽  
Electrochemical Active Surface Area ◽  
Thin Nanosheets

Ar plasma exfoliated smooth 1D nanowires of NiCo-LDHs into thin nanosheets forming three-dimensional dendritic structure to expose electrochemical active surface area and more higher oxidation states for enhanced oxygen evolution reaction.

scholarly journals Preparation and Electrocatalytic Characteristics Research of Pd/C Catalyst for Direct Ethanol Fuel Cell

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Qiao Xia Li ◽  
Ming Shuang Liu ◽  
Qun Jie Xu ◽  
Hong Min Mao
Keyword(s):  
Fuel Cell ◽  
Average Particle Size ◽  
Active Surface ◽  
Carbon Support ◽  
Catalytic Performance ◽  
Active Surface Area ◽  
Average Particle ◽  
Ethanol Fuel ◽  
Direct Ethanol Fuel Cell ◽  
Electrochemical Active Surface Area

Two kinds of carbon-support 20% Pd/C catalysts for use in direct ethanol fuel cell (DEFC) have been prepared by an impregnation reduction method using NaBH4and NaH2PO2as reductants, respectively, in this study. The catalysts were characterized by XRD and TEM. The results show that the catalysts had been completely reduced, and the catalysts are spherical and homogeneously dispersed on carbon. The electrocatalytic activity of the catalysts was investigated by electrochemical measurements. The results indicate that the catalysts had an average particle size of 3.3 nm and showed the better catalytic performance, when NaBH4was used as the reducing agent. The electrochemical active surface area of Pd/C (NaBH4) was 56.4 m2·g−1. The electrochemical activity of the Pd/C (NaBH4) was much higher than that of Pd/C (NaH2PO2).

scholarly journals Three-Dimensionally Ordered Macroporous ZnO Framework as Dual-Functional Sulfur Host for High-Efficiency Lithium–Sulfur Batteries

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2267
Author(s):  
Haisheng Han ◽  
Tong Wang ◽  
Yongguang Zhang ◽  
Arailym Nurpeissova ◽  
Zhumabay Bakenov
Keyword(s):  
High Efficiency ◽  
High Capacity ◽  
Active Surface ◽  
Active Surface Area ◽  
Shuttle Effect ◽  
Dual Functional ◽  
Lithium Sulfur Batteries ◽  
Sulfur Host ◽  
Ordered Macroporous ◽  
Lithium Sulfur

A three-dimensionally ordered macroporous ZnO (3DOM ZnO) framework was synthesized by a template method to serve as a sulfur host for lithium–sulfur batteries. The unique 3DOM structure along with an increased active surface area promotes faster and better electrolyte penetration accelerating ion/mass transfer. Moreover, ZnO as a polar metal oxide has a strong adsorption capacity for polysulfides, which makes the 3DOM ZnO framework an ideal immobilization agent and catalyst to inhibit the polysulfides shuttle effect and promote the redox reactions kinetics. As a result of the stated advantages, the S/3DOM ZnO composite delivered a high initial capacity of 1110 mAh g−1 and maintained a capacity of 991 mAh g−1 after 100 cycles at 0.2 C as a cathode in a lithium–sulfur battery. Even at a high C-rate of 3 C, the S/3DOM ZnO composite still provided a high capacity of 651 mAh g−1, as well as a high areal capacity (4.47 mAh cm−2) under high loading (5 mg cm−2).

Synthesis of Novel Pd Nanosponges for Non-Enzymatic Glucose Sensor

2020 ◽  
Vol 20 (12) ◽  
pp. 7333-7341
Author(s):  
Feng Chen ◽  
Jing-Hao Li ◽  
Yu-Chen Chi ◽  
Zhen-Hua Dan ◽  
Feng-Xiang Qin
Keyword(s):  
Glucose Sensor ◽  
High Sensitivity ◽  
Cost Effective ◽  
Active Surface ◽  
Glucose Sensing ◽  
Active Surface Area ◽  
Long Term Stability ◽  
High Uniformity ◽  
One Step ◽  
The Cost

A unique nanostructured electrocatalyst based on Palladium (Pd) nanosponge architecture is synthesized by one-step dealloying of the amorphous alloy precursor with low Pd concentration. The sponge-like nanostructure with hollow interiors enables sufficient contact between reactants andboth the interior and exterior surfaces. The results of cyclic voltammetry reveal that the as-prepared Pd nanosponge exhibits high sensitivity of 32 μA mM−1 cm−2 in a wide linear range (1–18 mM), and long-term stability toward glucose electro-oxidation. The Pd nanosponge also manifests detection limit as low as 2.0 μM (S/N = 3) and high selectivity for glucose sensing. The enhanced catalytic activity of the Pd nanosponge is attributed to the bimetallic synergistic effect and the large active surface area of the high-uniformity porous structure. The facile synthesis of the cost-effective Pd nanosponge with superior electrocatalytic performance makes it hold great potentials for biosensor and other catalysis applications.

scholarly journals Exploring the effect of Ni/Cr contents on the sheet-like NiCr-oxide-decorated CNT composites as highly active and stable catalysts for urea electrooxidation

Clean Energy ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 58-66
Author(s):  
Qiuping Gan ◽  
Benzhi Wang ◽  
Judan Chen ◽  
Jianniao Tian ◽  
Tayirjan Taylor Isimjan ◽  
...  
Keyword(s):  
Surface Area ◽  
Current Density ◽  
High Efficiency ◽  
Catalytic Mechanism ◽  
Low Cost ◽  
Scale Up ◽  
Active Surface ◽  
Environmental Crisis ◽  
Active Surface Area ◽  
Defect Sites

Abstract The developing high-efficiency urea fuel cells have an irreplaceable role in solving the increasingly severe environmental crisis and energy shortages. The sluggish six-electron dynamic anodic oxidation reaction is the bottleneck of the rapid progress of urea fuel-cell technology. To tackle this challenge, we select the NiCr bimetallic system due to the unique synergic effect between the Ni and the Cr. Moreover, better conductivity is assured using carbon nanotubes (CNTs) as the support. Most importantly, we use a simple hydrothermal method in catalyst preparation for easy scale-up at a low cost. The results show that the hybrid catalysts of NiCrx-oxide-CNTs with different Ni/Cr ratios show much better catalytic performance in terms of active surface area and current density as compared to that of Ni-hydro-CNTs. The optimized NiCr2-oxide-CNTs catalyst exhibits not only the largest electrochemically active surface area (ESA, 50.7 m2 g−1) and the highest urea electrocatalytic current density (115.6 mA cm−2), but also outstanding long-term stability. The prominent performance of the NiCr2-oxide-CNTs catalyst is due to the combined effect of the improved charge transfer between Ni and Cr species, the large ESA, along with an elegant balance between the oxygen-defect sites and hydrophilicity. Moreover, we have proposed a synergistically enhanced urea catalytic mechanism.

One-step synthesis of three-dimensional Pd polyhedron networks with enhanced electrocatalytic performance

2012 ◽  
Vol 48 (32) ◽  
pp. 3881 ◽  
Author(s):  
You Xu ◽  
Rui Xu ◽  
Jianhua Cui ◽  
Yang Liu ◽  
Bin Zhang
Keyword(s):  
Three Dimensional ◽  
Electrocatalytic Performance ◽  
One Step

Flowerlike submicrometer gold particles: Size- and surface roughness-controlled synthesis and electrochemical characterization

2010 ◽  
Vol 25 (9) ◽  
pp. 1755-1760 ◽  
Author(s):  
Changsheng Shan ◽  
Dongxue Han ◽  
Jiangfeng Song ◽  
Ari Ivaska ◽  
Li Niu
Keyword(s):  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
Electrocatalytic Activity ◽  
Active Surface ◽  
Molar Ratio ◽  
Active Surface Area ◽  
Step Method ◽  
Gold Particles ◽  
X Ray ◽  
One Step

Flowerlike submicrometer gold particles were synthesized through a simple one-step method using p-diaminobenzene as a reductant in the presence of poly(sodium 4-styrenesulfonate) in aqueous solution. The particle size with diameters ranging from 267 to 725 nm could be tuned by varying the molar ratio of poly(sodium 4-styrenesulfonate) to HAuCl4, which also resulted in tunable roughness. The gold particles were confirmed by scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. Cyclic voltammetry showed that the specific surface area of the flowerlike particles was larger than that of sphere particles. The obtained flowerlike particles with higher surface area also exhibited higher electrocatalytic activity toward H2O2 and O2. The increase of electrocatalytic activity could be attributed to the increase of the active surface area.

Facile Preparation of a Surface-Enriched Pt Layer Over Pd/C as an Efficient Oxygen Reduction Catalyst With Enhanced Activity and Stability

2020 ◽  
Vol 17 (3) ◽  
Author(s):  
Narayanamoorthy Bhuvanendran ◽  
Sabarinathan Ravichandran ◽  
Qian Xu ◽  
Sivakumar Pasupathi ◽  
Huaneng Su
Keyword(s):  
Surface Layer ◽  
Oxygen Reduction ◽  
Structural Characteristics ◽  
Active Surface ◽  
Reduction Reaction ◽  
Intrinsic Activity ◽  
Active Surface Area ◽  
One Pot ◽  
Electrocatalytic Performance ◽  
Improved Stability

Abstract Pt-enriched surface layer formation on Vulcan carbon-supported Pd (Pt@Pd/C) was successfully prepared through a simple and one-pot formic acid reduction approach without any stabilizing agent. The electrocatalytic performance of Pt@Pd/C catalyst toward an oxygen reduction reaction (ORR) in alkaline medium was studied and also compared with standard carbon-supported Pt (Pt/C) and Pd (Pd/C) catalysts. The Pt@Pd/C exhibits higher electrochemical active surface area (74.7 m2/g) and mass activity (1.38 mA/µg) than Pt/C, Pd/C, and contending with standard reported catalysts. In durability tests, Pt@Pd/C showed negligible loss of intrinsic activity (∼10%) after 10,000 cycles which confirmed improved stability than Pt-based catalysts for ORR in KOH medium. This improved electrocatalytic performance could be attributed to their structural characteristics of the Pt-enriched surface layer on Pd/C-core and the compressive lattice strain on Pt. The present investigation demonstrates the simple preparation procedure for surface-enriched Pt on Pd/C and its improved performance for ORR, suggesting that it is a promising contender to benchmark ORR catalysts for alkaline fuel cells.

Graphene Role as Platinum Support for CO and Formic Acid Electrooxidation

2011 ◽  
Vol 1326 ◽  
Author(s):  
Shirui Guo ◽  
Huseyin Sarialtin ◽  
Shaun Alia ◽  
Hayri Engin Akin ◽  
Yushan Yan ◽  
...  
Keyword(s):  
Particle Size ◽  
Fuel Cell ◽  
Formic Acid ◽  
High Efficiency ◽  
Chemical Reduction ◽  
Pt Nanoparticles ◽  
Active Surface ◽  
Active Surface Area ◽  
Support Materials ◽  
Loading Amount

AbstractThe direct methanol fuel cell (DMFC) is a promising power source for electronic applications due to its high efficiency and compactness. To improve the efficiency, many support materials have been developed. We investigated uniform graphene nanoflake films as a support for catalytic Pt nanoparticles in direct carbon monooxide and formic acid electro-oxidation. Pt nanoparticles were deposited on the surface of graphene films with chemical reduction method. Chemical functionalization of graphene with ethylenediamine enables Pt nanoparticles mobilize on graphene uniformly. By simply changing the loading amount of Pt precursor, various particle sizes were achieved. The particle size of Pt plays prominent role in fuel cell test. The electrochemically active surface area of different sample are 6.3 (5 wt% Pt/G), 4.1 (20 wt% Pt/G), and 3.0 (50 wt% Pt/G) cm2mg-1 corresponding to the particle size 3±1nm, 10±2nm, 20±2nm respectively. The results obtained are ascribed to a uniform network made of 2-4 nm Pt monolayer nanopaticles on the surface of graphene flakes. Graphene will play significant role in developing next-generation advanced Pt based fuel cells and their relevant electrodes in the field of energy.

scholarly journals Electrocatalytic Properties of Co Nanoconical Structured Electrodes Produced by a One-Step or Two-Step Method

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 544
Author(s):  
Katarzyna Skibinska ◽  
Karolina Kolczyk-Siedlecka ◽  
Dawid Kutyla ◽  
Anna Jedraczka ◽  
Beata Leszczyńska-Madej ◽  
...  
Keyword(s):  
Bulk Material ◽  
Active Surface ◽  
Active Surface Area ◽  
Step Method ◽  
Geometrical Size ◽  
Electrocatalytic Properties ◽  
Methods Of Synthesis ◽  
Alumina Oxide ◽  
One Step ◽  
The One

One-dimensional (1D) nanostructures, such as nanotubes, nanopores, nanodots and nanocones, are characterized by better catalytic properties than bulk material due to their large active surface area and small geometrical size. These structures can be produced by several methods of synthesis including the one- and two-step methods. In the one-step method, a crystal modifier is added to the solution in order to limit the horizontal direction of structures growing during electrodeposition. In this work, NH4Cl was used as a crystal modifier. Another way of production of 1D nanocones is the electrodeposition of metal in porous anodic alumina oxide (AAO) templates, called the two-step method. In this case, the AAO template was obtained using a two-step anodization process. Nanocones obtained by the two-step method show smaller geometrical size. In this work, cobalt nanoconical structures were obtained from an electrolyte containing CoCl2 and H3BO3. The electrocatalytic properties of materials fabricated by one-step and two-step methods were measured in 1 M NaOH and compared with bulk material electrodeposited from the same electrolyte. There were several microshell structures in the case of Co deposits obtained by the one-step method. To solve this problem, different conditions of synthesis Co cones by the one-step method were applied. The electrocatalytic activity of these samples was checked as well.

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