共查询到20条相似文献,搜索用时 0 毫秒
1.
Thangavel Kavinkumar Heejae Yang Amarnath Thangavel Sivagurunathan Hayoung Jeong Jeong Woo Han Do-Heyoung Kim 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(32):2300963
Two essential characteristics that are required for hybrid electrocatalysts to exhibit higher oxygen and hydrogen evolution reaction (OER and HER, respectively) activity are a favorable electronic configuration and a sufficient density of active sites at the interface between the two materials within the hybrid. In the present study, a hybrid electrocatalyst is introduced with a novel architecture consisting of coral-like iron nitride (Fe2N) arrays and tungsten nitride (W2N3) nanosheets that satisfies these requirements. The resulting W2N3/Fe2N catalyst achieves high OER activity (268.5 mV at 50 mA cm−2) and HER activity (85.2 mV at 10 mA cm−2) with excellent long-term durability in an alkaline medium. In addition, density functional theory calculations reveal that the individual band centers experience an upshift in the hybrid W2N3/Fe2N structure, thus improving the OER and HER activity. The strategy adopted here thus provides a valuable guide for the fabrication of cost-effective multi-metallic crystalline hybrids for use as multifunctional electrocatalysts. 相似文献
2.
Jing Yang Donghua Guo Shulin Zhao Yue Lin Rui Yang Dongdong Xu Naien Shi Xiaoshu Zhang Lingzhi Lu Ya‐Qian Lan Jianchun Bao Min Han 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(10)
As one class of important functional materials, transition metal phosphides (TMPs) nanostructures show promising applications in catalysis and energy storage fields. Although great progress has been achieved, phase‐controlled synthesis of cobalt phosphides nanocrystals or related nanohybrids remains a challenge, and their use in overall water splitting (OWS) is not systematically studied. Herein, three kinds of cobalt phosphides nanocrystals encapsulated by P‐doped carbon (PC) and married with P‐doped graphene (PG) nanohybrids, including CoP@PC/PG, CoP‐Co2P@PC/PG, and Co2P@PC/PG, are obtained through controllable thermal conversion of presynthesized supramolecular gels that contain cobalt salt, phytic acid, and graphene oxides at proper temperature under Ar/H2 atmosphere. Among them, the mixed‐phase CoP‐Co2P@PC/PG nanohybrids manifest high electrocatalytic activity toward both hydrogen and oxygen evolution in alkaline media. Remarkably, using them as bifunctional catalysts, the fabricated CoP‐Co2P@PC/PG || CoP‐Co2P@PC/PG electrolyzer only needs a cell voltage of 1.567 V for driving OWS to reach the current density at 10 mA cm?2, superior to their pure‐phase counterparts and recently reported bifunctional catalysts based devices. Also, such a CoP‐Co2P@PC/PG || CoP‐Co2P@PC/PG device exhibits outstanding stability for OWS. This work may shed some light on optimizing TMPs nanostructures based on phase engineering, and promote their applications in OWS or other renewable energy options. 相似文献
3.
4.
Nickel Nanoparticles Encapsulated in Few‐Layer Nitrogen‐Doped Graphene Derived from Metal–Organic Frameworks as Efficient Bifunctional Electrocatalysts for Overall Water Splitting
下载免费PDF全文
![点击此处可从《Advanced materials (Deerfield Beach, Fla.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
You Xu Wenguang Tu Bowei Zhang Shengming Yin Yizhong Huang Markus Kraft Rong Xu 《Advanced materials (Deerfield Beach, Fla.)》2017,29(11)
5.
Yiqiang Wu Xu Tao Yan Qing Han Xu Fan Yang Sha Luo Cuihua Tian Ming Liu Xihong Lu 《Advanced materials (Deerfield Beach, Fla.)》2019,31(15)
Exploring high‐efficiency, stable, and cost‐effective bifunctional electrocatalysts for overall water splitting is greatly desirable and challenging. Herein, a newly designed hybrid catalyst with Cr‐doped FeNi–P nanoparticles encapsulated into N‐doped carbon nanotubes (Cr‐doped FeNi–P/NCN) with unprecedented electrocatalytic activity is developed by a simple one‐step heating treatment. The as‐synthesized Cr‐doped FeNi–P/NCN with moderate Cr doping exhibits admirable oxygen evolution reaction and hydrogen evolution reaction activities with overpotentials of 240 and 190 mV to reach a current density of 10 mA cm?2 in 1 m KOH solution. When used in overall water splitting as a bifunctional catalyst, it needs only 1.50 V to give a current density of 10 mA cm?2, which is superior to its typically integrated Pt/C and RuO2 counterparts (1.54 V @ 10 mA cm?2). Density functional theory calculation confirms that Cr doping into a FeNi‐host can effectively alter the relative Gibbs adsorption energy and reduces the theoretical overpotential. Additionally, the synergetic effects between Cr‐doped FeNi–P nanoparticles and NCNs are regarded as significant contributors to accelerate charge transfer and promote electrocatalytic activity in hybrid catalysts. 相似文献
6.
Ik Seon Kwon Tekalign Terfa Debela In Hye Kwak Yun Chang Park Jaemin Seo Ju Yong Shim Seung Jo Yoo Jin‐Gyu Kim Jeunghee Park Hong Seok Kang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(13)
2D MoS2 nanostructures have recently attracted considerable attention because of their outstanding electrocatalytic properties. The synthesis of unique Co–Ru–MoS2 hybrid nanosheets with excellent catalytic activity toward overall water splitting in alkaline solution is reported. 1T′ phase MoS2 nanosheets are doped homogeneously with Co atoms and decorated with Ru nanoparticles. The catalytic performance of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is characterized by low overpotentials of 52 and 308 mV at 10 mA cm?2 and Tafel slopes of 55 and 50 mV decade?1 in 1.0 m KOH, respectively. Analysis of X‐ray photoelectron and absorption spectra of the catalysts show that the MoS2 well retained its metallic 1T′ phase, which guarantees good electrical conductivity during the reaction. The Gibbs free energy calculation for the reaction pathway in alkaline electrolyte confirms that the Ru nanoparticles on the Co‐doped MoS2 greatly enhance the HER activity. Water adsorption and dissociation take place favorably on the Ru, and the doped Co further catalyzes HER by making the reaction intermediates more favorable. The high OER performance is attributed to the catalytically active RuO2 nanoparticles that are produced via oxidation of Ru nanoparticles. 相似文献
7.
Iron Vacancies Induced Bifunctionality in Ultrathin Feroxyhyte Nanosheets for Overall Water Splitting
下载免费PDF全文
![点击此处可从《Advanced materials (Deerfield Beach, Fla.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bin Liu Yun Wang Hui‐Qing Peng Ruoou Yang Zheng Jiang Xingtai Zhou Chun‐Sing Lee Huijun Zhao Wenjun Zhang 《Advanced materials (Deerfield Beach, Fla.)》2018,30(36)
Exploring of new catalyst activation principle holds a key to unlock catalytic powers of cheap and earth‐abundant materials for large‐scale applications. In this regard, the vacancy defects have been proven to be effective to initiate catalytic active sites and endow high electrocatalytic activities. However, such electrocatalytically active defects reported to date have been mostly formed by anion vacancies. Herein, it is demonstrated for the first time that iron cation vacancies induce superb water splitting bifunctionality in alkaline media. A simple wet‐chemistry method is developed to grow ultrathin feroxyhyte (δ‐FeOOH) nanosheets with rich Fe vacancies on Ni foam substrate. The theoretical and experimental results confirm that, in contrast to anion vacancies, the formation of rich second neighboring Fe to Fe vacancies in δ‐FeOOH nanosheets can create catalytic active centers for both hydrogen and oxygen evolution reactions. The atomic level insight into the new catalyst activation principle based on metal vacancies is adaptable for developing other transition metal electrocatalysts, including Fe‐based ones. 相似文献
8.
A Cost‐Efficient Bifunctional Ultrathin Nanosheets Array for Electrochemical Overall Water Splitting
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ying Zhang Qi Shao Yecan Pi Jun Guo Xiaoqing Huang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(27)
The design of cost‐efficient earth‐abundant catalysts with superior performance for the electrochemical water splitting is highly desirable. Herein, a general strategy for fabricating superior bifunctional water splitting electrodes is reported, where cost‐efficient earth‐abundant ultrathin Ni‐based nanosheets arrays are directly grown on nickel foam (NF). The newly created Ni‐based nanosheets@NF exhibit unique features of ultrathin building block, 3D hierarchical structure, and alloy effect with the optimized Ni5Fe layered double hydroxide@NF (Ni5Fe LDH@NF) exhibiting low overpotentials of 210 and 133 mV toward both oxygen evolution reaction and hydrogen evolution reaction at 10 mA cm?2 in alkaline condition, respectively. More significantly, when applying as the bifunctional overall water splitting electrocatalyst, the Ni5Fe LDH@NF shows an appealing potential of 1.59 V at 10 mA cm?2 and also superior durability at the very high current density of 50 mA cm?2. 相似文献
9.
Tirza Shmila Sanjit Mondal Shmuel Barzilai Neeta Karjule Michael Volokh Menny Shalom 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(42):2303602
Polymeric carbon nitride is a promising photoanode material for water-splitting and organic transformation-based photochemical cells. Despite achieving significant progress in performance, these materials still exhibit low photoactivity compared to inorganic photoanodic materials because of a moderate visible light response, poor charge separation, and slow oxidation kinetics. Here, the synthesis of a sodium- and boron-doped carbon nitride layer with excellent activity as a photoanode in a water-splitting photoelectrochemical cell is reported. The new synthesis consists of the direct growth of carbon nitride (CN) monomers from a hot precursor solution, enabling control over the monomer-to-dopant ratio, thus determining the final CN properties. The introduction of Na and B as dopants results in a dense CN layer with a packed morphology, better charge separation thanks to the in situ formation of an electron density gradient, and an extended visible light response up to 550 nm. The optimized photoanode exhibits state-of-the-art performance: photocurrent densities with and without a hole scavenger of about 1.5 and 0.9 mA cm−2 at 1.23 V versus reversible hydrogen electrode (RHE), and maximal external quantum efficiencies of 56% and 24%, respectively, alongside an onset potential of 0.3 V. 相似文献
10.
11.
12.
Jieqiong Shan Tao Ling Kenneth Davey Yao Zheng Shi‐Zhang Qiao 《Advanced materials (Deerfield Beach, Fla.)》2019,31(17)
The establishment of electrocatalysts with bifunctionality for efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in acidic environments is necessary for the development of proton exchange membrane (PEM) water electrolyzers for the production of clean hydrogen fuel. RuIr alloy is considered to be a promising electrocatalyst because of its favorable OER performance and potential for HER. Here, the design of a bifunctional electrocatalyst with greatly boosted water‐splitting performance from doping RuIr alloy nanocrystals with transition metals that modify electronic structure and binding strength of reaction intermediates is reported. Significantly, Co‐RuIr results in small overpotentials of 235 mV for OER and 14 mV for HER (@ 10 mA cm?2 current density) in 0.1 m HClO4 media. Therefore a cell voltage of just 1.52 V is needed for overall water splitting to produce hydrogen and oxygen. More importantly, for a series of M‐RuIr (M = Co, Ni, Fe), the catalytic activity dependence at fundamental level on the chemical/valence states is used to establish a novel composition‐activity relationship. This permits new design principles for bifunctional electrocatalysts. 相似文献
13.
Xiao Wang Zhe Li De‐Yao Wu Gu‐Rong Shen Chengqin Zou Yi Feng Hui Liu Cun‐Ku Dong Xi‐Wen Du 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(8)
Low‐cost and high‐performance catalysts are of great significance for electrochemical water splitting. Here, it is reported that a laser‐synthesized catalyst, porous Co0.75Ni0.25(OH)2 nanosheets, is highly active for catalyzing overall water splitting. The porous nanosheets exhibit low overpotentials for hydrogen evolution reaction (95 mV@10 mA cm?2) and oxygen evolution reaction (235 mV@10 mA cm?2). As both anode and cathode catalysts, the porous nanosheets achieve a current density of 10 mA cm?2 at an external voltage of 1.56 V, which is much lower than that of commercial Ir/C‐Pt/C couple (1.62 V). Experimental and theoretical investigations reveal that numerous Co3+ ions are generated on the pore wall of nanosheets, and the unique atomic structure around Co3+ ions leads to appropriate electronic structure and adsorption energy of intermediates, thus accelerating hydrogen and oxygen evolution. 相似文献
14.
Nitrogen‐Doped Porous Carbon Nanosheets Templated from g‐C3N4 as Metal‐Free Electrocatalysts for Efficient Oxygen Reduction Reaction
下载免费PDF全文
![点击此处可从《Advanced materials (Deerfield Beach, Fla.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Huijun Yu Lu Shang Tong Bian Run Shi Geoffrey I. N. Waterhouse Yufei Zhao Chao Zhou Li‐Zhu Wu Chen‐Ho Tung Tierui Zhang 《Advanced materials (Deerfield Beach, Fla.)》2016,28(25):5080-5086
15.
Significant Enhancement of Water Splitting Activity of N‐Carbon Electrocatalyst by Trace Level Co Doping
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bita Bayatsarmadi Yao Zheng Youhong Tang Mietek Jaroniec Shi‐Zhang Qiao 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(27):3703-3711
Replacement of precious metal electrocatalysts with highly active and cost efficient alternatives for complete water splitting at low voltage has attracted a growing attention in recent years. Here, this study reports a carbon‐based composite co‐doped with nitrogen and trace amount of metallic cobalt (1 at%) as a bifunctional electrocatalyst for water splitting at low overpotential and high current density. An excellent electrochemical activity of the newly developed electrocatalyst originates from its graphitic nanostructure and highly active Co‐Nx sites. In the case of carefully optimized sample of this electrocatalyst, 10 mA cm?2 current density can be achieved for two half reactions in alkaline solutions—hydrogen evolution reaction and oxygen evolution reaction—at low overpotentials of 220 and 350 mV, respectively, which are smaller than those previously reported for nonprecious metal and metal‐free counterparts. Based on the spectroscopic and electrochemical investigations, the newly identified Co‐Nx sites in the carbon framework are responsible for high electrocatalytic activity of the Co,N‐doped carbon. This study indicates that a trace level of the introduced Co into N‐doped carbon can significantly enhance its electrocatalytic activity toward water splitting. 相似文献
16.
Feroxyhyte Nanosheets: Iron Vacancies Induced Bifunctionality in Ultrathin Feroxyhyte Nanosheets for Overall Water Splitting (Adv. Mater. 36/2018)
下载免费PDF全文
![点击此处可从《Advanced materials (Deerfield Beach, Fla.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bin Liu Yun Wang Hui‐Qing Peng Ruoou Yang Zheng Jiang Xingtai Zhou Chun‐Sing Lee Huijun Zhao Wenjun Zhang 《Advanced materials (Deerfield Beach, Fla.)》2018,30(36)
17.
Jian Zhang Renjie Cui Chencheng Gao Linyi Bian Yong Pu Xinbao Zhu Xing'ao Li Wei Huang 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(47)
Atom‐scale modulation of electronic regulation in nonprecious‐based electrocatalysts is promising for efficient catalytic activities. Here, hierarchically hollow VOOH nanostructures are rationally constructed by partial iron substitution and systematically investigated for electrocatalytic water splitting. Benefiting from the hierarchically stable scaffold configuration, highly electrochemically active surface area, the synergistic effect of the active metal atoms, and optimal adsorption energies, the 3% Fe (mole ratio) substituted electrocatalyst (VOOH‐3Fe) exhibits a low overpotential of 90 and 195 mV at 10 mA cm?2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media, respectively, superior than the other samples with a different substituted ratio. To the best of current knowledge, 195 mV overpotential at 10 mA cm?2 is the best value reported for V or Fe (oxy)hydroxide‐based OER catalysts. Moreover, the electrolytic cell employing the VOOH‐3Fe electrode as both the cathode and anode exhibits a cell voltage of 0.30 V at 10 mA cm?2 with a remarkable stability over 60 h. This work heralds a new pathway to design efficient bifunctional catalysts toward overall water splitting. 相似文献
18.
Carbon Nanosheets: Nitrogen‐Doped Porous Carbon Nanosheets Templated from g‐C3N4 as Metal‐Free Electrocatalysts for Efficient Oxygen Reduction Reaction (Adv. Mater. 25/2016)
下载免费PDF全文
![点击此处可从《Advanced materials (Deerfield Beach, Fla.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Huijun Yu Lu Shang Tong Bian Run Shi Geoffrey I. N. Waterhouse Yufei Zhao Chao Zhou Li‐Zhu Wu Chen‐Ho Tung Tierui Zhang 《Advanced materials (Deerfield Beach, Fla.)》2016,28(25):5140-5140
19.
Biao Gao Xingxing Li Xiaolin Guo Xuming Zhang Xiang Peng Lei Wang Jijiang Fu Paul K. Chu Kaifu Huo 《Advanced Materials Interfaces》2015,2(13)
Flexible 3D nanoarchitectures have received tremendous interest recently because of their potential applications in flexible/wearable energy storage devices. Herein, 3D intertwined nitrogen‐doped carbon encapsulated mesoporous vanadium nitride nanowires (MVN@NC NWs) are investigated as thin, lightweight, and self‐supported electrodes for flexible supercapacitors (SCs). The MVN NWs have abundant active sites accessible to charge storage, and the N‐doped carbon shell suppresses electrochemical dissolution of the inner MVN NWs in an alkaline electrolyte, leading to excellent capacitive properties. The flexible MVN@NC NWs film electrode delivers a high areal capacitance of 282 mF cm−2 and exhibits excellent long‐term stability with 91.8% capacitance retention after 12 000 cycles in a KOH electrolyte. All‐solid‐state flexible SCs assembled by sandwiching two flexible MVN@NC NWs film electrodes with alkaline poly(vinyl alcohol) (PVA), sodium polyacrylate, and KOH gel electrolyte boast a high volumetric capacitance of 10.9 F cm−3, an energy density of 0.97 mWh cm−3, and a power density of 2.72 W cm−3 at a current density of 0.051 A cm−3 based on the entire cell. By virtue of the excellent mechanical flexibility, high capacitance, and large energy/power density, the self‐supported MVN@NC NWs paper‐like electrodes have large potential applications in portable and wearable flexible electronics. 相似文献
20.
Huanyun Liao Xingzhong Guo Yang Hou Hao Liang Zheng Zhou Hui Yang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(10)
Designing elaborate nanostructures and engineering defects have been promising approaches to fabricate cost‐efficient electrocatalysts toward overall water splitting. In this work, a controllable Prussian‐blue‐analogue‐sacrificed strategy followed by an annealing process to harvest defect‐rich Ni‐Fe‐doped K0.23MnO2 cubic nanoflowers (Ni‐Fe‐K0.23MnO2 CNFs‐300) as highly active bifunctional catalysts for oxygen and hydrogen evolution reactions (OER and HER) is reported. Benefiting from many merits, including unique morphology, abundant defects, and doping effect, Ni‐Fe‐K0.23MnO2 CNFs‐300 shows the best electrocatalytic performances among currently reported Mn oxide‐based electrocatalysts. This catalyst affords low overpotentials of 270 (320) mV at 10 (100) mA cm?2 for OER with a small Tafel slope of 42.3 mV dec?1, while requiring overpotentials of 116 and 243 mV to attain 10 and 100 mA cm?2 for HER respectively. Moreover, Ni‐Fe‐K0.23MnO2 CNFs‐300 applied to overall water splitting exhibits a low cell voltage of 1.62 V at 10 mA cm?2 and excellent durability, even superior to the Pt/C||IrO2 cell at large current density. Density functional theory calculations further confirm that doping Ni and Fe into the crystal lattice of δ‐MnO2 can not only reinforce the conductivity but also reduces the adsorption free‐energy barriers on the active sites during OER and HER. 相似文献