scholarly journals Ultrathin Co–Fe hydroxide nanosheet arrays for improved oxygen evolution during water splitting

RSC Advances ◽  
2017 ◽  
Vol 7 (37) ◽  
pp. 22818-22824 ◽  
Author(s):  
Tingting Zhou ◽  
Zhen Cao ◽  
Heng Wang ◽  
Zhen Gao ◽  
Long Li ◽  
...  
Keyword(s):  
Surface Area ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Active Sites ◽  
Three Dimensional ◽  
Fe Doping ◽  
Nanosheet Arrays ◽  
Fe Hydroxide

The Fe-doping of hierarchical Co hydroxide nanosheet arrays (CoyFe1−y(OH)x NSAs) integrated on a three-dimensional electrode is shown to contribute to both increasing the available surface area and number of active sites.

scholarly journals 3D-printed NiFe-layered double hydroxide pyramid electrodes for enhanced electrocatalytic oxygen evolution reaction

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Jinhyuck Ahn ◽  
Yoo Sei Park ◽  
Sanghyeon Lee ◽  
Juchan Yang ◽  
Jaeyeon Pyo ◽  
...  
Keyword(s):  
Surface Area ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Layered Double Hydroxide ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Step Method ◽  
Highly Active ◽  
3D Printed ◽  
Double Hydroxide

AbstractElectrochemical water splitting has been considered one of the most promising methods of hydrogen production, which does not cause environmental pollution or greenhouse gas emissions. Oxygen evolution reaction (OER) is a significant step for highly efficient water splitting because OER involves the four electron transfer, overcoming the associated energy barrier that demands a potential greater than that required by hydrogen evolution reaction. Therefore, an OER electrocatalyst with large surface area and high conductivity is needed to increase the OER activity. In this work, we demonstrated an effective strategy to produce a highly active three-dimensional (3D)-printed NiFe-layered double hydroxide (LDH) pyramid electrode for OER using a three-step method, which involves direct-ink-writing of a graphene pyramid array and electrodeposition of a copper conducive layer and NiFe-LDH electrocatalyst layer on printed pyramids. The 3D pyramid structures with NiFe-LDH electrocatalyst layers increased the surface area and the active sites of the electrode and improved the OER activity. The overpotential (η) and exchange current density (i0) of the NiFe-LDH pyramid electrode were further improved compared to that of the NiFe-LDH deposited Cu (NiFe-LDH/Cu) foil electrode with the same base area. The 3D-printed NiFe-LDH electrode also exhibited excellent durability without potential decay for 60 h. Our 3D printing strategy provides an effective approach for the fabrication of highly active, stable, and low-cost OER electrocatalyst electrodes.

High Surface Area NiCoP Nanostructure as Efficient Water Splitting Electrocatalyst for the Oxygen Evolution Reaction

2021 ◽  
pp. 111312
Author(s):  
Sisir Maity ◽  
Dheeraj Kumar Singh ◽  
Divya Bhutani ◽  
Suchitra Prasad ◽  
Umesh V. Waghmare ◽  
...  
Keyword(s):  
Surface Area ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
High Surface ◽  
High Surface Area

Cathodic Corrosion Activated Fe-based Nanoglass as Highly-Active and -Stable Oxygen Evolution Catalyst for Water Splitting

2021 ◽  
Author(s):  
Kaiyao Wu ◽  
Fei Chu ◽  
Yuying Meng ◽  
Kaveh Edalati ◽  
Qingsheng Gao ◽  
...  
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Amorphous Alloys ◽  
Precious Metal ◽  
Active Sites ◽  
Metal Free ◽  
Highly Active ◽  
Stable Oxygen ◽  
Surface Active

Transition metal-based amorphous alloys have attracted increasing attention as precious-metal-free electrocatalysts for oxygen evolution reaction (OER) of water splitting due to their high macro-conductivity and abundant surface active sites. However,...

Three-dimensional graphene encapsulated hollow CoSe2-SnSe2 nanoboxes for high performance asymmetric supercapacitors

2022 ◽  
Author(s):  
Kainan Li ◽  
Ke Zheng ◽  
Zhifang Zhang ◽  
Kuan Li ◽  
Ziyao Bian ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Specific Capacity ◽  
Three Dimensional ◽  
Hollow Structure ◽  
Large Specific Surface Area ◽  
Composite Aerogel

Abstract Construction of metal selenides with a large specific surface area and a hollow structure is one of the effective methods to improve the electrochemical performance of supercapacitors. However, the nano-material easily agglomerates due to the lack of support, resulting in the loss of electrochemical performance. Herein, we successfully design a three-dimensional graphene (3DG) encapsulation-protected hollow nanoboxes (CoSe2-SnSe2) composite aerogel (3DG/CoSe2-SnSe2) via a co-precipitation method coupled with self-assembly route, followed by a high temperature selenidation strategy. The obtained aerogel possesses porous 3DG conductive network, large specific surface area and plenty of reactive active sites. It could be used as a flexible and binder-free electrode after a facile mechanical compression process, which provided a high specific capacitance of 460 F g-1 at 0.5 A g-1, good rate capability of 212.7 F g-1 at 10 A g-1, and excellent cycle stability due to the fast electron/ion transfer and electrolyte diffusion. With the as-prepared 3DG/CoSe2-SnSe2 as positive electrodes and the AC (activated carbon) as negative electrodes, an asymmetric supercapacitor (3DG/CoSe2-SnSe2//AC) was fabricated, which delivered a high specific capacity of 38 F g-1 at 1A g-1 and an energy density of 11.89 W h kg-1 at 749.9 W kg-1, as well as a capacitance retention of 91.1% after 3000 cycles. This work provides a new method for preparing electrode material.

N+-ion irradiation engineering towards the efficient oxygen evolution reaction on NiO nanosheet arrays

2019 ◽  
Vol 7 (9) ◽  
pp. 4729-4733 ◽  
Author(s):  
Baorui Xia ◽  
Tongtong Wang ◽  
Xingdong Jiang ◽  
Jun Li ◽  
Tongming Zhang ◽  
...  
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Ion Irradiation ◽  
Nanosheet Arrays ◽  
New Generation

The oxygen evolution reaction (OER) is an essential process in water splitting, which is highly relevant to the new generation of energy exploration approaches. N+ ions irradiation is an effective method for improving the OER electrocatalytic capacity of NiO.

Nanoporous NiAl-LDH nanosheet arrays with optimized Ni active sites for efficient electrocatalytic alkaline water splitting

2020 ◽  
Vol 4 (6) ◽  
pp. 2850-2858 ◽  
Author(s):  
Liangliang Feng ◽  
Yingying Du ◽  
Jianfeng Huang ◽  
Liyun Cao ◽  
Li Feng ◽  
...  
Keyword(s):  
Water Splitting ◽  
Active Sites ◽  
Alkaline Water ◽  
Nanosheet Array ◽  
Nanosheet Arrays

A novel nanoporous NiAl-LDH nanosheet array with optimized Ni active sites is prepared for efficient electrocatalytic alkaline water splitting.

scholarly journals Study of oxygen evolution reaction on thermally prepared xPtOy-(100-x)IrO2 electrodes

2020 ◽  
Vol 10 (4) ◽  
pp. 347-360
Author(s):  
Ollo Kambiré ◽  
Lemeyonouin A. G. Pohan ◽  
Konan H. Kondro ◽  
Lassiné Ouattara
Keyword(s):  
Surface Area ◽  
Oxygen Evolution ◽  
Photoelectron Spectroscopy ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Platinum Oxide ◽  
Basic Medium ◽  
X Ray ◽  
Tafel Slopes ◽  
Ohmic Drop

The mixed coupled xPtOy-(100-x)IrO2 electrodes (x = 0, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100) were thermally prepared at 450 °C on titanium supports. The prepared electrodes were firstly physically characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Afterwards, electrochemical characteri­zations were performed by voltammetric (cyclic and linear) methods in different electrolyte media (KOH and HClO4). It is shown that the prepared electrodes are composed by both PtOy (platinum and platinum oxide) and IrO2 (iridium dioxide). For xPtOy-(100-x)IrO2 electrodes having higher content of IrO2, more surface cracks and pores are formed, defining a higher surface area with more active sites. Higher surface area due to presence of both PtOy and IrO2, is for xPtOy-(100-x)IrO2 electrodes in 1 M KOH solution confirmed by cyclic voltammetry at potentials of the oxide layer region. For all prepared electrodes, voltammetric charges were found higher than for PtOy, while the highest voltammetric charge is observed for the mixed 40PtOy-60IrO2 (x = 40) electrode. The Tafel slopes for oxygen evolution reaction (OER) in either basic (0.1 M KOH) or acid (0.1 M HClO4) media were determined from measured linear voltammograms corrected for the ohmic drop. The values of Tafel slopes for OER at PtOy, 90PtOy-10IrO2 and IrO2 in basic medium are 122, 55 and 40 mV dec-1, respectively. For other mixed electrodes, Tafel slopes of 40 mV dec-1 were obtained. Although proceeding by different OER mechanism, similar values of Tafel slopes were obtained in acid medium, i.e., Tafel slopes of 120, 60 and 39 mV dec-1 were obtained for PtOy, 90PtOy-10IrO2 and IrO2, and 40 mV dec-1 for other mixed electrodes. The analysis of Tafel slope values showed that OER is more rapid on coupled mixed electrodes than on pure PtOy. For mixed xPtOy-(100-x)IrO2 electrodes, OER is more rapid when the molar percent of PtOy meets the following condition: 0 ˂ x ≤ 80. This study also showed that the mixed coupled electrodes are more electro­cata­lytically active for OER than either PtOy or IrO2 in these two media. 

scholarly journals Conformation-modulated three-dimensional electrocatalysts for high-performance fuel cell electrodes

2021 ◽  
Vol 7 (30) ◽  
pp. eabe9083
Author(s):  
Jong Min Kim ◽  
Ahrae Jo ◽  
Kyung Ah Lee ◽  
Hyeuk Jin Han ◽  
Ye Ji Kim ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Fuel Cells ◽  
Surface Area ◽  
Active Sites ◽  
High Performance ◽  
Polymer Electrolyte Membrane ◽  
Three Dimensional ◽  
Building Blocks ◽  
High Mass ◽  
Transfer Resistance

Unsupported Pt electrocatalysts demonstrate excellent electrochemical stability when used in polymer electrolyte membrane fuel cells; however, their extreme thinness and low porosity result in insufficient surface area and high mass transfer resistance. Here, we introduce three-dimensionally (3D) customized, multiscale Pt nanoarchitectures (PtNAs) composed of dense and narrow (for sufficient active sites) and sparse (for improved mass transfer) nanoscale building blocks. The 3D-multiscale PtNA fabricated by ultrahigh-resolution nanotransfer printing exhibited excellent performance (45% enhanced maximum power density) and high durability (only 5% loss of surface area for 5000 cycles) compared to commercial Pt/C. We also theoretically elucidate the relationship between the 3D structures and cell performance using computational fluid dynamics. We expect that the structure-controlled 3D electrocatalysts will introduce a new pathway to design and fabricate high-performance electrocatalysts for fuel cells, as well as various electrochemical devices that require the precision engineering of reaction surfaces and mass transfer.

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