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1.
Xiangkai Kong Changlin Zhang Sang Youp Hwang Qianwang Chen Zhenmeng Peng 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(26)
Electrochemical water oxidation is the key technology in water‐splitting reactions and rechargeable metal–air batteries, which is very attractive for renewable energy conversion and storage. Replacement of precious catalysts with cost‐effective and highly active alternatives is still a great challenge. Herein, based on theoretical predictions, holey structures are designed and fabricated on the free‐standing conventional 2D OER catalyst. By well‐controlled defects engineering, uniform tiny holes are created on the free‐standing Ni(OH)2 nanosheets via a sol–gel method, with the embedded Zn components as the template for holes production. The whole preparation process is feasible and effective to make full use of the basal plane of 2D nanomaterials, which can provide higher surface area, richer defects, more grain boundaries, and edge sites, as well as greater distorted surfaces. Meanwhile, these holes developed inside the sheet structure can supply tremendous permeable channels for ions adsorption and transportation, enable a fast interfacial charge transfer and accelerate the reaction process. The as‐prepared 2D holey Ni(OH)2 nanostructures exhibit excellent catalytic performance toward electrochemical water oxidation, with lower onset overpotentials and higher current densities compared with the pristine Ni(OH)2 catalyst, suggesting the holey defects engineering is a promising strategy for efficient water‐splitting devices and rechargeable metal–air batteries. 相似文献
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Synergism of Geometric Construction and Electronic Regulation: 3D Se‐(NiCo)Sx/(OH)x Nanosheets for Highly Efficient Overall Water Splitting
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Congling Hu Lei Zhang Zhi‐Jian Zhao Ang Li Xiaoxia Chang Jinlong Gong 《Advanced materials (Deerfield Beach, Fla.)》2018,30(12)
The exploration of highly efficient electrocatalysts for both oxygen and hydrogen generation via water splitting is receiving considerable attention in recent decades. Up till now, Pt‐based catalysts still exhibit the best hydrogen evolution reaction (HER) performance and Ir/Ru‐based oxides are identified as the benchmark for oxygen evolution reaction (OER). However, the high cost and rarity of these materials extremely hinder their large‐scale applications. This paper describes the construction of the ultrathin defect‐enriched 3D Se‐(NiCo)Sx/(OH)x nanosheets for overall water splitting through a facile Se‐induced hydrothermal treatment. Via Se‐induced fabrication, highly efficient Se‐(NiCo)Sx/(OH)x nanosheets are successfully fabricated through morphology optimization, defect engineering, and electronic structure tailoring. The as‐prepared hybrids exhibit relatively low overpotentials of 155 and 103 mV at the current density of 10 mA cm?2 for OER and HER, respectively. Moreover, an overall water‐splitting device delivers a current density of 10 mA cm?2 for ≈66 h without obvious degradation. 相似文献
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Water Splitting: Synergism of Geometric Construction and Electronic Regulation: 3D Se‐(NiCo)Sx/(OH)x Nanosheets for Highly Efficient Overall Water Splitting (Adv. Mater. 12/2018)
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Congling Hu Lei Zhang Zhi‐Jian Zhao Ang Li Xiaoxia Chang Jinlong Gong 《Advanced materials (Deerfield Beach, Fla.)》2018,30(12)
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A Cost‐Efficient Bifunctional Ultrathin Nanosheets Array for Electrochemical Overall Water Splitting
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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
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Incorporating Nitrogen‐Doped Graphene Quantum Dots and Ni3S2 Nanosheets: A Synergistic Electrocatalyst with Highly Enhanced Activity for Overall Water Splitting
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Jing‐Jing Lv Jun Zhao Hua Fang Li‐Ping Jiang Ling‐Ling Li Jing Ma Jun‐Jie Zhu 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(24)
A noble‐metal‐free electrocatalyst is fabricated via in situ formation of nanocomposite of nitrogen‐doped graphene quantum dots (NGQDs) and Ni3S2 nanosheets on the Ni foam (Ni3S2‐NGQDs/NF). The resultant Ni3S2‐NGQDs/NF can serve as an active, binder‐free, and self‐supported catalytic electrode for direct water splitting, which delivers a current density of 10 mA cm?2 at an overpotential of 216 mV for oxygen evolution reaction and 218 mV for hydrogen evolution reaction in alkaline media. This bifunctional electrocatalyst enables the construction of an alkali electrolyzer with a low cell voltage of 1.58 V versus reversible hydrogen electrode (RHE) at 10 mA cm?2. The experimental results and theoretical calculations demonstrate that the synergistic effects of the constructed active interfaces are the key factor for excellent performance. The nanocomposite of NGQDs and Ni3S2 nanosheets can be promising water splitting electrocatalyst for large‐scale hydrogen generation or other energy storage and conversion applications. 相似文献
8.
Akbar I. Inamdar Harish S. Chavan Bo Hou Chi Ho Lee Sang Uck Lee SeungNam Cha Hyungsang Kim Hyunsik Im 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(2)
To generate hydrogen, which is a clean energy carrier, a combination of electrolysis and renewable energy sources is desirable. In particular, for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in electrolysis, it is necessary to develop nonprecious, efficient, and durable catalysts. A robust nonprecious copper–iron (CuFe) bimetallic composite is reported that can be used as a highly efficient bifunctional catalyst for overall water splitting in an alkaline medium. The catalyst exhibits outstanding OER and HER activity, and very low OER and HER overpotentials (218 and 158 mV, respectively) are necessary to attain a current density of 10 mA cm?2. When used in a two‐electrode water electrolyzer system for overall water splitting, it not only achieves high durability (even at a very high current density of 100 mA cm?2) but also reduces the potential required to split water into oxygen and hydrogen at 10 mA cm?2 to 1.64 V for 100 h of continuous operation. 相似文献
9.
Yakun Tian Ming Wen Aijian Huang Qingsheng Wu Zhiguo Wang Quanjing Zhu Tao Zhou Yongqing Fu 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(20):2207569
High stability and efficiency of electrocatalysts are crucial for hydrogen evolution reaction (HER) toward water splitting in an alkaline media. Herein, a novel nano-Pt/Nb-doped Co(OH)2 (Pt/Nb Co(OH)2) nanosheet is designed and synthesized using water-bath treatment and solvothermal reduction approaches. With nano-Pt uniformly anchored onto Nb Co(OH)2 nanosheet, the synthesized Pt/Nb Co(OH)2 shows outstanding electrocatalytic performances for alkaline HER, achieving a high stability for at least 33 h, a high mass activity of 0.65 mA µg−1 Pt, and a good catalytic activity with a low overpotential of 112 mV at 10 mA cm−2. Both experimental and theoretical results prove that Nb-doping significantly optimizes the hydrogen adsorption free energy to accelerate the Heyrovsky step for HER, and boosts the adsorption of H2O, which further enhances the water activation. This study provides a new design methodology for the Nb-doped electrocatalysts in an alkaline HER field by facile and green way. 相似文献
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Ultrathin Porous NiFeV Ternary Layer Hydroxide Nanosheets as a Highly Efficient Bifunctional Electrocatalyst for Overall Water Splitting
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Khang Ngoc Dinh Penglun Zheng Zhengfei Dai Yu Zhang Raksha Dangol Yun Zheng Bing Li Yun Zong Qingyu Yan 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(8)
Herein, the hydrothermal synthesis of porous ultrathin ternary NiFeV layer double hydroxides (LDHs) nanosheets grown on Nickel foam (NF) substrate as a highly efficient electrode toward overall water splitting in alkaline media is reported. The lateral size of the nanosheets is about a few hundreds of nanometers with the thickness of ≈10 nm. Among all molar ratios investigated, the Ni0.75Fe0.125V0.125‐LDHs/NF electrode depicts the optimized performance. It displays an excellent catalytic activity with a modest overpotential of 231 mV for the oxygen evolution reaction (OER) and 125 mV for the hydrogen evolution reaction (HER) in 1.0 m KOH electrolyte. Its exceptional activity is further shown in its small Tafel slope of 39.4 and 62.0 mV dec?1 for OER and HER, respectively. More importantly, remarkable durability and stability are also observed. When used for overall water splitting, the Ni0.75Fe0.125V0.125‐LDHs/NF electrodes require a voltage of only 1.591 V to reach 10 mA cm?2 in alkaline solution. These outstanding performances are mainly attributed to the synergistic effect of the ternary metal system that boosts the intrinsic catalytic activity and active surface area. This work explores a promising way to achieve the optimal inexpensive Ni‐based hydroxide electrocatalyst for overall water splitting. 相似文献
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Wenjun He Rui Zhang Da Cao Ying Li Jun Zhang Qiuyan Hao Hui Liu Jianling Zhao Huolin L. Xin 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(2):2205719
Exploiting active and stable non-precious metal electrocatalysts for alkaline hydrogen evolution reaction (HER) at large current density plays a key role in realizing large-scale industrial hydrogen generation. Herein, a self-supported microporous Ni(OH)x/Ni3S2 heterostructure electrocatalyst on nickel foam (Ni(OH)x/Ni3S2/NF) that possesses super-hydrophilic property through an electrochemical process is rationally designed and fabricated. Benefiting from the super-hydrophilic property, microporous feature, and self-supported structure, the electrocatalyst exhibits an exceptional HER performance at large current density in 1.0 M KOH, only requiring low overpotential of 126, 193, and 238 mV to reach a current density of 100, 500, and 1000 mA cm−2, respectively, and displaying a long-term durability up to 1000 h, which is among the state-of-the-art non-precious metal electrocatalysts. Combining hard X-rays absorption spectroscopy and first-principles calculation, it also reveals that the strong electronic coupling at the interface of the heterostructure facilitates the dissociation of H2O molecular, accelerating the HER kinetics in alkaline electrolyte. This work sheds a light on developing advanced non-precious metal electrocatalysts for industrial hydrogen production by means of constructing a super-hydrophilic microporous heterostructure. 相似文献
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Substrate‐Friendly Growth of Large‐Sized Ni(OH)2 Nanosheets for Flexible Electrochromic Films
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Liangliang Zhu Wei Li Ong Xin Lu Kaiyang Zeng Hong Jin Fan Ghim Wei Ho 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(23)
Large‐area, 2D, anisotropic, direct growth of nanostructures is considered an effective and straightforward way to readily fulfill transparent, flexible technology requirements. In addition, formation of thin hybrid structures by combining with another 2D material brings about dimensional advantages, such as intimate heterostructure functionalities, large specific area, and optical transparency. Here, we demonstrate 2D planar growth of thin Ni(OH)2 nanosheets on arbitrary rigid and soft supports, by exploiting the growth strategies of oriented attachment induced by interfacial chemistry and the intrinsic driving force of layered structure constitution. Moreover, large‐scale 2D heterohybrids have successfully been prepared by direct conformal growth of Ni(OH)2 nanosheets overlying MoO3 nanobelts. Unlike the exfoliation and transfer of 2D materials technique, this approach minimizes multiple process contamination and physical‐handling structural defects. Accordingly, proof‐of‐concept flexible electrochromism is demonstrated in view of its prerequisite to the access of a large homogeneous material coating. The as‐synthesized 2D layered structure affirms its optical and electrochemical superiority through the display of wide optical modulation, high coloration efficiency, good cyclic stability, and flexibility. 相似文献
15.
Minki Baek Guan‐Woo Kim Taiho Park Kijung Yong 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(49)
Complementary water splitting electrocatalysts used simultaneously in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) can simplify water splitting systems. Herein, earth‐abundant NiMoFe (NMF) and phosphorized NiMoFeP (NMFP) are synthesized as complementary overall water splitting (OWS) catalysts. First, NMF is tested as both the HER and OER promoter, which exhibits low overpotentials of 68 (HER) and 337 mV (OER). A quaternary NMFP is then prepared by simple phosphorization of NMF, which shows a much lower OER overpotential of 286 mV. The enhanced OER activity is attributed to the unique surface/core structure of NMFP. The surface phosphate acts as a proton transport mediator and expedites the rate‐determining step. With the application of OER potential, the NMFP surface is composed of Ni(OH)2 and FeOOH, active sites for OER, but the inner core consists of Ni, Mo, and Fe metals, serving as a conductive electron pathway. OWS with NMF‐NMFP requires an applied voltage of 1.452 V to generate 10 mA cm?2, which is one of the lowest values among OWS results with transition‐metal‐based electrocatalysts. Furthermore, the catalysts are combined with tandem perovskite solar cells for photovoltaic (PV)‐electrolysis, producing a high solar‐to‐hydrogen (STH) conversion efficiency of 12.3%. 相似文献
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本工作采用缓冲溶液法制备Mn掺杂Ni(OH)2(Ni1-xMnx(OH)2, x=0.1, 0.2, 0.3, 0.4), X射线衍射测试表明样品主要是β相, 有少量Mn3O4杂相; 循环伏安测试表明, x=0.2的材料还原峰积分面积最大、还原分支的峰电流最高; 恒流充放电测试表明, 在100 mA/g电流密度下, Ni0.8Mn0.2(OH)2放电比容量最高, 其第20次循环放电比容量为271.8 mAh/g, 同等条件测试的商用β-Ni(OH)2放电比容量为253.6 mAh/g; 在300、500 mA/g电流密度下, Ni0.8Mn0.2(OH)2放电比容量仍保持最高, 分别为294.7、291.5 mAh/g, 而且Mn掺杂Ni(OH)2的循环稳定性也优于商用β-Ni(OH)2。Mn掺杂可改善镍电极的循环稳定性、降低镍电极成本, 具有广阔的应用前景。 相似文献
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Feroxyhyte Nanosheets: Iron Vacancies Induced Bifunctionality in Ultrathin Feroxyhyte Nanosheets for Overall Water Splitting (Adv. Mater. 36/2018)
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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)
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In the near future, sustainable energy conversion and storage will largely depend on the electrochemical splitting of water into hydrogen and oxygen. Perceiving this, countless research works focussing on the fundamentals of electrocatalysis of water splitting and on performance improvements are being reported everyday around the globe. Electrocatalysts of high activity, selectivity, and stability are anticipated as they directly determine energy‐ and cost efficiency of water electrolyzers. Amorphous electrocatalysts with several advantages over crystalline counterparts are found to perform better in electrocatalytic water splitting. There are plenty of studies witnessing performance enhancements in electrocatalysis of water splitting while employing amorphous materials as catalysts. The harmony between the flexibility of amorphous electrocatalysts and electrocatalysis of water splitting (both the oxygen evolution reaction [OER] and the hydrogen evolution reaction [HER]) is one of the untold and unsummarized stories in the field of electrocatalytic water splitting. This Review is devoted to comprehensively discussing the upsurge of amorphous electrocatalysts in electrochemical water splitting. In addition to that, the basics of electrocatalysis of water splitting are also elaborately introduced and the characteristics of a good electrocatalyst for OER and HER are discussed. 相似文献
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Oxidative Intercalation for Monometallic Ni2+‐Ni3+ Layered Double Hydroxide and Enhanced Capacitance in Exfoliated Nanosheets
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Feng Gu Xing Cheng Shufen Wang Xu Wang Pooi See Lee 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(17):2044-2050
Monometallic Ni2+‐Ni3+ layered double hydroxide (LDH) is prepared using a simple oxidative intercalation process and may be further exfoliated into positively charged Ni(OH)2 unilamellar sheets. The superior capacitive behavior of the unilamellar sheets stranded in carbon nanotubes (CNTs) networks is achieved because of the complete interfacial charge storage arising from the confined Faradaic reactions at the interfacial region. 3D nanosheet/CNT composites are prepared using an in situ electrostatic assembly of positive charged sheets with CNTs bearing negative charges. The restacking of active nanosheets during electrochemical cycling is effectively prohibited. Consequently, the outstanding specific capacitance and remarkable rate capability of the nanosheet/CNT hybrid electrodes are demonstrated, making them promising candidates for high performance supercapacitors, combining high‐energy storage densities with high levels of power delivery. 相似文献