Finding inexpensive electrodes with high activity and stability is key to realize the practical application of fuel cells. Here, we report the fabrication of three-dimensional （3D） porous nickel nanoflower （3D-PNNF...Finding inexpensive electrodes with high activity and stability is key to realize the practical application of fuel cells. Here, we report the fabrication of three-dimensional （3D） porous nickel nanoflower （3D-PNNF） electrodes via an in situ reduction method. The 3D-PNNF electrodes have a high surface area, show tight binding to the electroconductive substrate, and most importantly, have superaerophobic （bubble repellent） surfaces. Therefore, the electrocatalytic hydrazine oxidation performance of the 3D-PNNF electrodes was much higher than that of commercial Pt/C catalysts because of its ultra-weak gas-bubble adhesion and ultra-fast gas-bubble release. Furthermore, the 3D-PNNF electrodes showed ultra-high stability even under a high current density （260 mA/cm^2）, which makes it promising for practical applications. In addition, the construction of superaerophobic nanostructures could also be beneficial for other gas evolution processes （e.g., hydrogen evolution reaction）.展开更多
The increasing demand for portable electronic devices and hybrid electric vehicles stimulates the develop- ment of supercapacitors as an advanced energy storage system. Here, we demonstrate a binder-free nickel hydrox...The increasing demand for portable electronic devices and hybrid electric vehicles stimulates the develop- ment of supercapacitors as an advanced energy storage system. Here, we demonstrate a binder-free nickel hydroxide@nano- porous gold/Ni foam （Ni（OH）2@NPG/Ni foam） electrode for high-performance supercapacitors, which is prepared by a facile three-step fabrication route including electrodeposition of Au-Sn alloy on Ni foam, chemical dealloying of Sn and electrodepostion of Ni（OH）2 on NPG/Ni foam. Such Ni（OH）2@NPG/Ni foam electrode is composed of a thin layer of conformable Ni（OH）2 nanoflakes supported on three-di- mensional （3D） hierarchically porous NPG/Ni foam substrate. The resulting Ni（OH）2@NPG/Ni foam electrode can offer highways for both electron transfer and ion transport and lead to an excellent electrochemical performance with an ultrahigh specific capacitance of 3,380 F g-1 at a current density of 2 A g-1. Even when the current density was increased to 50 A g-1, it still retained a high capacitance of 1,927 F g-1. The promising performance of the Ni（OH）2@NPG/Ni foam elec- trode is mainly ascribed to the 3D hierarchical porosity and the highly conductive network on the NPG/Ni foam composite current collector, as well as the conformal electrodeposition of Ni（OH）2 active material on the NPG/Ni foam, which induces the formation of interconnected porosity both on the top surface and on the inner surface of the electrode. This in- spiring electrochemical performance would make the as-de- signed electrode material become one of the most promising candidates for future electrochemical energy storage systems.展开更多
A highly porous nickel-film electrode with satisfactory mechanical strength was prepared by a facile vertical template-assisted composite electrodeposition method using polystyrene(PS) microspheres templates, with the...A highly porous nickel-film electrode with satisfactory mechanical strength was prepared by a facile vertical template-assisted composite electrodeposition method using polystyrene(PS) microspheres templates, with the aim of improving the electrocatalytic activity for the hydrogen-evolution reaction(HER). During the composite electrodeposition process, the hydrophobic PS microspheres were highly dispersed in the electrolyte with the help of a surfactant, and then co-deposited with Ni to form the film electrode. After removing the PS templates by annealing, a porous Ni film containing large amount of uniformly dispersed pores with narrow size distribution was obtained, and then applied as the electrode for the HER in an alkaline medium. As evidenced by the electrochemical analysis, the porous Ni film electrode exhibits higher catalytic activity as compared to a dense Ni film electrode and is superior to a Ni/Ru O2/Ce O2 commercial electrode. The effect of temperature on the catalytic properties of the porous Ni film electrode was also investigated; the activation energy was calculated as 17.26 k J/mol. The enhanced activity toward the HER was attributed to the improved electrochemical surface area and mass transportation facilitated by the high porosity of the synthesized Ni film electrode.展开更多
基金This work was supported by the National Natural Science Foundation of China （Nos. 21271018 and 21125101）, the National Basic Research Program of China （No. 2011CBA00503）, the National High-tech R＆D Program of China （No. 2012AA03A609） and the Program for Changjiang Scholars and Innovative Research Team in University.
文摘Finding inexpensive electrodes with high activity and stability is key to realize the practical application of fuel cells. Here, we report the fabrication of three-dimensional （3D） porous nickel nanoflower （3D-PNNF） electrodes via an in situ reduction method. The 3D-PNNF electrodes have a high surface area, show tight binding to the electroconductive substrate, and most importantly, have superaerophobic （bubble repellent） surfaces. Therefore, the electrocatalytic hydrazine oxidation performance of the 3D-PNNF electrodes was much higher than that of commercial Pt/C catalysts because of its ultra-weak gas-bubble adhesion and ultra-fast gas-bubble release. Furthermore, the 3D-PNNF electrodes showed ultra-high stability even under a high current density （260 mA/cm^2）, which makes it promising for practical applications. In addition, the construction of superaerophobic nanostructures could also be beneficial for other gas evolution processes （e.g., hydrogen evolution reaction）.
基金financially supported by the National Natural Science Foundation of China (21673051,51604086)the Guangdong Science and Technology Department (2016A010104015)+4 种基金the Pearl River Scholar Funded Scheme of Guangdong Province Universities and Colleges (2015)the Science and Technology Program of Guangzhou (201604030037)the 'One-hundred Talents plan' (220418056)the 'One-hundred Young Talents plan' (220413126)the Youth Foundation (252151038) of Guangdong University of Technology
文摘The increasing demand for portable electronic devices and hybrid electric vehicles stimulates the develop- ment of supercapacitors as an advanced energy storage system. Here, we demonstrate a binder-free nickel hydroxide@nano- porous gold/Ni foam （Ni（OH）2@NPG/Ni foam） electrode for high-performance supercapacitors, which is prepared by a facile three-step fabrication route including electrodeposition of Au-Sn alloy on Ni foam, chemical dealloying of Sn and electrodepostion of Ni（OH）2 on NPG/Ni foam. Such Ni（OH）2@NPG/Ni foam electrode is composed of a thin layer of conformable Ni（OH）2 nanoflakes supported on three-di- mensional （3D） hierarchically porous NPG/Ni foam substrate. The resulting Ni（OH）2@NPG/Ni foam electrode can offer highways for both electron transfer and ion transport and lead to an excellent electrochemical performance with an ultrahigh specific capacitance of 3,380 F g-1 at a current density of 2 A g-1. Even when the current density was increased to 50 A g-1, it still retained a high capacitance of 1,927 F g-1. The promising performance of the Ni（OH）2@NPG/Ni foam elec- trode is mainly ascribed to the 3D hierarchical porosity and the highly conductive network on the NPG/Ni foam composite current collector, as well as the conformal electrodeposition of Ni（OH）2 active material on the NPG/Ni foam, which induces the formation of interconnected porosity both on the top surface and on the inner surface of the electrode. This in- spiring electrochemical performance would make the as-de- signed electrode material become one of the most promising candidates for future electrochemical energy storage systems.
基金supported by the National Natural Science Foundation of China(51125007)the National Key Technology R&D Program of China(2009BAE87B00)
文摘A highly porous nickel-film electrode with satisfactory mechanical strength was prepared by a facile vertical template-assisted composite electrodeposition method using polystyrene(PS) microspheres templates, with the aim of improving the electrocatalytic activity for the hydrogen-evolution reaction(HER). During the composite electrodeposition process, the hydrophobic PS microspheres were highly dispersed in the electrolyte with the help of a surfactant, and then co-deposited with Ni to form the film electrode. After removing the PS templates by annealing, a porous Ni film containing large amount of uniformly dispersed pores with narrow size distribution was obtained, and then applied as the electrode for the HER in an alkaline medium. As evidenced by the electrochemical analysis, the porous Ni film electrode exhibits higher catalytic activity as compared to a dense Ni film electrode and is superior to a Ni/Ru O2/Ce O2 commercial electrode. The effect of temperature on the catalytic properties of the porous Ni film electrode was also investigated; the activation energy was calculated as 17.26 k J/mol. The enhanced activity toward the HER was attributed to the improved electrochemical surface area and mass transportation facilitated by the high porosity of the synthesized Ni film electrode.
