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 A Superaerophobic Bimetallic Selenides Heterostructure for Efficient Industrial-Level Oxygen Evolution at Ultra-High Current Densities

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiaxin Yuan ◽  
Xiaodi Cheng ◽  
Hanqing Wang ◽  
Chaojun Lei ◽  
Sameer Pardiwala ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Active Sites ◽  
Electronic Conductivity ◽  
Three Dimensional ◽  
Active Surface ◽  
Alkaline Media ◽  
Active Surface Area ◽  
High Current ◽  
High Electronic Conductivity ◽  
Current Densities

AbstractCost-effective and stable electrocatalysts with ultra-high current densities for electrochemical oxygen evolution reaction (OER) are critical to the energy crisis and environmental pollution. Herein, we report a superaerophobic three dimensional (3D) heterostructured nanowrinkles of bimetallic selenides consisting of crystalline NiSe2 and NiFe2Se4 grown on NiFe alloy (NiSe2/NiFe2Se4@NiFe) prepared by a thermal selenization procedure. In this unique 3D heterostructure, numerous nanowrinkles of NiSe2/NiFe2Se4 hybrid with a thickness of ~ 100 nm are grown on NiFe alloy in a uniform manner. Profiting by the large active surface area and high electronic conductivity, the superaerophobic NiSe2/NiFe2Se4@NiFe heterostructure exhibits excellent electrocatalytic activity and durability towards OER in alkaline media, outputting the low potentials of 1.53 and 1.54 V to achieve ultra-high current densities of 500 and 1000 mA cm−2, respectively, which is among the most active Ni/Fe-based selenides, and even superior to the benchmark Ir/C catalyst. The in-situ derived FeOOH and NiOOH species from NiSe2/NiFe2Se4@NiFe are deemed to be efficient active sites for OER.

scholarly journals The Determination of Electrochemical Active Surface Area and Specific Capacity Revisited for the System MnOx as an Oxygen Evolution Catalyst

2020 ◽  
Vol 234 (5) ◽  
pp. 979-994 ◽  
Author(s):  
Paula Connor ◽  
Jona Schuch ◽  
Bernhard Kaiser ◽  
Wolfram Jaegermann
Keyword(s):  
Specific Capacitance ◽  
Surface Area ◽  
Oxygen Evolution ◽  
Specific Capacity ◽  
Active Surface ◽  
Capacitance Measurement ◽  
Catalyst Loading ◽  
Active Surface Area ◽  
Electrochemical Active Surface Area

AbstractIn the last decades several different catalysts for the electrochemical water splitting reaction have been designed and tested. In so-called benchmark papers they are compared with respect to their efficiency and activity. In order to relate the different catalyst to each other the definition of well-defined procedures is required. Two different methods are mainly used: Either the normalization with respect to the geometric surface area or to the catalyst loading. Most often only one of these values is available for a sample and the other one cannot be estimated easily. One approach in electrocatalysis is to determine the Helmholtz double layer capacitance (DLC) and deduce the electrochemical active surface area (ECSA). The DLC can be obtained from two different methods, either using differential capacitance measurement (DCM) or impedance spectroscopy (EIS). The second value needed for the calculation of the ECSA is the specific capacitance, which is the capacitance for a perfectly flat surface of given catalyst material. Here, we present the determination of the different capacitance values using manganese oxide as the exemplary model for the oxygen evolution reaction (OER). We determine the capacitance by DCM and EIS to calculate the ECSA using literature values for the specific capacitance. The obtained values are comparable from the two methods, but are much larger than the surface areas obtained by atomic force microscopy. Therefore, we consider the possibility of using the measured AFM area together with the Helmholtz capacitance to determine the specific capacitances for this material class. The comparison of these results with literature values illustrates the actual limits of the ECSA method, which will be discussed in this paper.

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.

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 Characterization and Electrocatalytic Properties of Titanium-Based Ru0.3Co0.7−xCexMixed Oxide Electrodes for Oxygen Evolution in Alkaline Solution

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Hongjun Wu ◽  
Qin Ruan ◽  
Li Li ◽  
Baohui Wang
Keyword(s):  
Oxygen Evolution ◽  
Electrocatalytic Activity ◽  
Strong Dependence ◽  
Sol Gel ◽  
Active Surface ◽  
Catalytic Performance ◽  
Open Circuit ◽  
Active Surface Area ◽  
Oxide Electrodes ◽  
Sol Gel Process

Ti-supported RuO2-Co3O4-CeO2(Ru0.3Co0.7−xCexoxide,0≤x≤0.7) electrodes were prepared by sol-gel process. The phase structure, surface morphology, and microstructure of the oxide layer were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Electrocatalytic activity and oxygen evolution reaction (OER) kinetics on these electrodes in 1.0 mol⋅dm−3KOH solution were studied by recording open-circuit potential, cyclic voltammetry, and polarisation curves. The results showed that the appropriate content of CeO2could reduce the grain size and increase active surface area. The electrocatalytic activity shows a strong dependence on the CeO2content in the film. Catalytic performance of mixed oxide electrodes with 40 mol % CeO2was the best, with the greatest voltammetric charge, 86.23 mC⋅cm−2, and the smallest apparent activation energy for OER at 0.60 V was 22.76 kJ⋅mol−1.

Comparison of the effects of cation and phosphorus doping in cobalt-based spinel oxides towards the oxygen evolution reaction

CrystEngComm ◽  
2021 ◽  
Author(s):  
Lili Yao ◽  
Wenxiu Yang ◽  
Yongjian Niu ◽  
Jiming Liu ◽  
Shun Zhang ◽  
...  
Keyword(s):  
Surface Area ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Oxygen Vacancies ◽  
Active Surface ◽  
Active Surface Area ◽  
Phosphorus Doping ◽  
Electrochemically Active ◽  
Spinel Oxides ◽  
Electrochemically Active Surface

Phosphorus incorporation further boosted the OER activity of cation-doped Co-based spinel oxides via remarkably tuning the oxygen vacancies, crystallinity and electrochemically active surface area on the surface.

scholarly journals Enhanced Electrocatalytic Activity of Stainless Steel Substrate by Nickel Sulfides for Efficient Hydrogen Evolution

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1274
Author(s):  
Jong-Sang Youn ◽  
Sangmin Jeong ◽  
Inhwan Oh ◽  
Sunyoung Park ◽  
Hien Duy Mai ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Hydrogen Evolution ◽  
Steel Substrate ◽  
Carbon Dioxide Emission ◽  
Active Surface ◽  
Active Surface Area ◽  
Electrochemical Charge Transfer ◽  
Zero Carbon ◽  
Electrochemical Active Surface Area

Water splitting is one of the efficient ways to produce hydrogen with zero carbon dioxide emission. Thus far, Pt has been regarded as a highly reactive catalyst for the hydrogen evolution reaction (HER); however, the high cost and rarity of Pt significantly hinder its commercial use. Herein, we successfully developed an HER catalyst composed of NiSx (x = 1 or 2) on stainless steel (NiSx/SUS) using electrodeposition and sulfurization techniques. Notably, the electrochemical active surface area(ECSA) of NiSx/SUS was improved more than two orders of magnitude, resulting in a considerable improvement in the electrochemical charge transfer and HER activity in comparison with stainless steel (SUS). The long-term HER examination by linear scan voltammetry (LSV) confirmed that NiSx/SUS was stable up to 2000 cycles.

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