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Rong Chen Sung‐Fu Hung Daojin Zhou Jiajian Gao Cangjie Yang Huabing Tao Hong Bin Yang Liping Zhang Lulu Zhang Qihua Xiong Hao Ming Chen Bin Liu 《Advanced materials (Deerfield Beach, Fla.)》2019,31(41)
NiFe‐based layered double hydroxides (LDHs) are among the most efficient oxygen evolution reaction (OER) catalysts in alkaline medium, but their long‐term OER stabilities are questionable. In this work, it is demonstrated that the layered structure makes bulk NiFe LDH intrinsically not stable in OER and the deactivation mechanism of NiFe LDH in OER is further revealed. Both operando electrochemical and structural characterizations show that the interlayer basal plane in bulk NiFe LDH contributes to the OER activity, and the slow diffusion of proton acceptors (e.g., OH?) within the NiFe LDH interlayers during OER causes dissolution of NiFe LDH and therefore decrease in OER activity with time. To improve diffusion of proton acceptors, it is proposed to delaminate NiFe LDH into atomically thin nanosheets, which is able to effectively improve OER stability of NiFe LDH especially at industrial operating conditions such as elevated operating temperatures (e.g., at 80 °C) and large current densities (e.g., at 500 mA cm?2). 相似文献
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Yanping Lin Hao Wang Chun‐Kuo Peng Liangmin Bu Chao‐Lung Chiang Kai Tian Yue Zhao Jianqing Zhao Yan‐Gu Lin Jong‐Min Lee Lijun Gao 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(38)
Developing efficient and stable non‐noble electrocatalysts for the oxygen evolution reaction (OER) remains challenging for practical applications. While nickel–iron layered double hydroxides (NiFe‐LDH) are emerging as prominent candidates with promising OER activity, their catalytic performance is still restricted by the limited active sites, poor conductivity and durability. Herein, hierarchical nickel–iron–cobalt LDH nanosheets/carbon fibers (NiFeCo‐LDH/CF) are synthesized through solvent‐thermal treatment of ZIF‐67/CF. Extended X‐ray adsorption fine structure analyses reveal that the Co substitution can stabilize the Fe local coordination environment and facilitate the π‐symmetry bonding orbital in NiFeCo‐LDH/CF, thus modifying the electronic structures. Coupling with the structural advantages, including the largely exposed active surface sites and facilitated charge transfer pathway ensured by CF, the resultant NiFeCo‐LDH/CF exhibits excellent OER activity with an overpotential of 249 mV at 10 mA cm?1 as well as robust stability over 20 h. 相似文献
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Yufang Xie Jinyan Cai Yishang Wu Yipeng Zang Xusheng Zheng Jian Ye Peixin Cui Shuwen Niu Yun Liu Junfa Zhu Xiaojing Liu Gongming Wang Yitai Qian 《Advanced materials (Deerfield Beach, Fla.)》2019,31(16)
Although it is commonly believed that the water‐dissociation‐related Volmer process is the rate‐limiting step for alkaline hydrogen evolution reaction (HER) on Pt‐based catalysts, the underlying essence, particularly on the atomic scale, still remains unclear. Herein, it is revealed that the sluggish water‐dissociation behavior probably stems from unfavorable orbital orientation and the kinetic issue is successfully resolved via N‐induced orbital tuning. Impressively, N modified Pt–Ni nanowires deliver an ultralow overpotential of 13 mV at 10 mA cm?2, which represents a new benchmark for alkaline HER catalysis. Fine‐structural characterization and density functional theory analysis illustrate that the introduced nitrogen can uniquely modulate the electron densities around the Ni sites, and further create empty dz2 orbitals with superior orientation for water adsorption and activation. More importantly, it is demonstrated that N‐induced orbital modulation can generally boost the alkaline HER activities of Pt–Co, Pt–Ni, and Pt–Cu, offering a new perspective for the design of HER catalysts and beyond. 相似文献
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Lulu Wen Xilin Zhang Jieyu Liu Xinyang Li Changchang Xing Xianjun Lyu Weiping Cai Weichao Wang Yue Li 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(35)
Monodentate adsorption of oxygen intermediates results in a theoretical overpotential limit of ≈0.35 V for oxygen evolution reaction (OER), which causes the sluggish kinetics of the OER process. In this work, nonprecious chromium dopant is introduced into the self‐supported CoFe layered double hydroxides (LDHs) on nickel foam (Cr‐CoFe LDHs/NF) via a facile one‐step hydrothermal method, which exhibits a preeminent electrocatalytic activity toward the OER with an ultralow overpotential of 238 mV to obtain 10 mA cm?2 and a high stability after cyclic voltammetry for 5000 cycles in alkaline solution (1 m KOH). Density functional theory (DFT) calculations unveil that Cr dopants as new active sites could improve the electron‐donation ability of the resultant Cr‐CoFe LDHs due to the smaller electronegativity of Cr in comparison with Fe and Co. Therefore, the scaling relation of adsorption energy among four oxygen intermediates is broken and consequently the OER performance is further promoted. This work provides a strategy to develop efficient metal layered double hydroxide OER catalysts. 相似文献
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Water‐Plasma‐Enabled Exfoliation of Ultrathin Layered Double Hydroxide Nanosheets with Multivacancies for Water Oxidation
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Rong Liu Yanyong Wang Dongdong Liu Yuqin Zou Shuangyin Wang 《Advanced materials (Deerfield Beach, Fla.)》2017,29(30)
An earth‐abundant and highly efficient electrocatalyst is essential for oxygen evolution reaction (OER) due to its poor kinetics. Layered double hydroxide (LDH)‐based nanomaterials are considered as promising electrocatalysts for OER. However, the stacking structure of LDHs limits the exposure of the active sites. Therefore, the exfoliation is necessary to expose more active sites. In addition, the defect engineering is proved to be an efficient strategy to enhance the performance of OER electrocatalysts. For the first time, this study prepares ultrathin CoFe LDHs nanosheets with multivacancies as OER electrocatalysts by water‐plasma‐enabled exfoliation. The water plasma can destroy the electrostatic interactions between the host metal layers and the interlayer cations, resulting in the fast exfoliation. On the other hand, the etching effect of plasma can simultaneously and effectively produce multivacancies in the as‐exfoliated ultrathin LDHs nanosheets. The increased active sites and the multivacancies significantly contribute to the enhanced electrocatalytic activity for OER. Compared to pristine CoFe LDHs, the as‐exfoliated ultrathin CoFe LDHs nanosheets exhibit excellent catalytic activity for OER with a ultralow overpotential of only 232 mV at 10 mA cm?2 and possesses outstanding kinetics (the Tafel slope of 36 mV dec?1). This work provides a novel strategy to exfoliate LDHs and to produce multivacancies simultaneously as highly efficient electrocatalysts for OER. 相似文献
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Self‐Assembly of Single‐Layer CoAl‐Layered Double Hydroxide Nanosheets on 3D Graphene Network Used as Highly Efficient Electrocatalyst for Oxygen Evolution Reaction
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Jianfeng Ping Yixian Wang Qipeng Lu Bo Chen Junze Chen Ying Huang Qinglang Ma Chaoliang Tan Jian Yang Xiehong Cao Zhijuan Wang Jian Wu Yibin Ying Hua Zhang 《Advanced materials (Deerfield Beach, Fla.)》2016,28(35):7640-7645
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Xiaoyi Meng Junxing Han Liang Lu Genrui Qiu Zhong Lin Wang Chunwen Sun 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(41)
Developing nonprecious electrocatalysts with superior activity and durability for electrochemical water splitting is of great interest but challenging due to the large overpotential required above the thermodynamic standard potential of water splitting (1.23 V). Here, in situ growth of Fe2+‐doped layered double (Ni, Fe) hydroxide (NiFe(II,III)‐LDH) on nickel foam with well‐defined hexagonal morphology and high crystallinity by a redox reaction between Fe3+ and nickel foam under hydrothermal conditions is reported. Benefiting from tuning the local atomic structure by self‐doping Fe2+, the NiFe(II,III)‐LDH catalyst with higher amounts of Fe2+ exhibits high activity toward oxygen evolution reaction (OER) as well as hydrogen evolution reaction (HER) activity. Moreover, the optimized NiFe(II,III)‐LDH catalyst for OER (O‐NiFe(II,III)‐LDH) and catalyst for HER (H‐NiFe(II,III)‐LDH) show overpotentials of 140 and 113 mV, respectively, at a current density of 10 mA cm?2 in 1 m KOH aqueous electrolyte. Using the catalysts for overall water splitting in two‐electrode configuration, a low overpotential of just 1.54 V is required at a benchmark current density of 10 mA cm?2. Furthermore, it is demonstrated that electrolysis of the water device can be drived by a self‐powered system through integrating a triboelectric nanogenerator and battery, showing a promising way to realize self‐powered electrochemical systems. 相似文献
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Hao Sun Ling Chen Yuebin Lian Wenjuan Yang Ling Lin Yufeng Chen Jiabin Xu Dan Wang Xiaoqin Yang Mark H. Rümmerli Jun Guo Jun Zhong Zhao Deng Yan Jiao Yang Peng Shizhang Qiao 《Advanced materials (Deerfield Beach, Fla.)》2020,32(52):2006784
Layered double hydroxides (LDHs) have been recognized as potent electrocatalysts for oxygen evolution reaction (OER), but are lacking in hydrogen evolution reaction (HER) activities due to the sluggish kinetics of water dissociation in alkaline medium. Herein, aiming to simultaneously bolster the HER and OER kinetics, a metal–organic framework (MOF) mediated topotactic transformation tactic is deployed to fabricate holey ternary CoFeNi LDHs on nickel foam, exposing polygonal mesopores with atomistic edge steps and lattice defects. The optimized catalyst requires only an external voltage of 1.49 V to afford the water splitting current density of 10 mA cm−2 apart from the superb electrolytic stability, far surpassing the benchmark Pt/C||RuO2 couple. More importantly, mechanistic investigations utilizing advanced spectroscopies in conjunction with density function theory (DFT) understandings unravel while the synergetic effect among under-coordinated metal centers lowers the energy barrier of water dissociation, Fe-doping enables further modulating the d-band density of states (DOS) of Co and Ni in favor of intermediates binding, thereby promoting the intrinsic HER activity. Operando Raman studies reveal negligible structural change of the LDHs during the HER process, whereas for OER the active sites can quickly turn into oxyhydroxides in the presence of lattice defects and under-coordinated metal centers. 相似文献
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Efficient Hydrogen Evolution Reaction Catalysis in Alkaline Media by All‐in‐One MoS2 with Multifunctional Active Sites
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Mohsin Ali Raza Anjum Hu Young Jeong Min Hee Lee Hyeon Suk Shin Jae Sung Lee 《Advanced materials (Deerfield Beach, Fla.)》2018,30(20)
MoS2 becomes an efficient and durable nonprecious‐metal electrocatalyst for the hydrogen evolution reaction (HER) when it contains multifunctional active sites for water splitting derived from 1T‐phase, defects, S vacancies, exposed Mo edges with expanded interlayer spacings. In contrast to previously reported MoS2‐based catalysts targeting only a single or few of these characteristics, the all‐in‐one MoS2 catalyst prepared herein features all of the above active site types. During synthesis, the intercalation of in situ generated NH3 molecules into MoS2 sheets affords ammoniated MoS2 (A‐MoS2) that predominantly comprises 1T‐MoS2 and exhibits an expanded interlayer spacing. The subsequent reduction of A‐MoS2 results in the removal of intercalated NH3 and H2S to form an all‐in‐one MoS2 with multifunctional active sites mentioned above (R‐MoS2) that exhibits electrocatalytic HER performance in alkaline media superior to those of all previously reported MoS2‐based electrocatalysts. In particular, a hybrid MoS2/nickel foam catalyst outperforms commercial Pt/C in the practically meaningful high‐current region (>25 mA cm?2), demonstrating that R‐MoS2‐based materials can potentially replace Pt catalysts in practical alkaline HER systems. 相似文献
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Wenjun He Rui Zhang Hui Liu Qiuyan Hao Ying Li Xuerong Zheng Caichi Liu Jun Zhang Huolin L. Xin 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(34):2301610
Bimetallic layered double hydroxides (LDHs) are promising catalysts for anodic oxygen evolution reaction (OER) in alkaline media. Despite good stability, NiCo LDH displays an unsatisfactory OER activity relative to the most robust NiFe LDH and CoFe LDH. Herein, a novel NiCo LDH electrocatalyst modified with single-atom silver grown on carbon cloth (AgSA-NiCo LDH/CC) that exhibits exceptional OER activity and stability in 1.0 m KOH is reported. The AgSA-NiCo LDH/CC catalyst only requires a low overpotential of 192 mV to reach a current density of 10 mA cm−2, obviously boosting the OER activity of NiCo LDH/CC (410 mV@10 mA cm−2). Inspiringly, AgSA-NiCo LDH/CC can maintain its high activity for up to 500 h at a large current density of 100 mA cm−2, exceeding most single-atom OER catalysts. In situ Raman spectroscopy studies uncover that the in situ formed NiCoOOH during OER is the real active species. Hard X-ray absorption spectrum (XAS) and density functional theory (DFT) calculations validate that single-atom Ag occupying Ni site increases the chemical valence of Ni elements, and then weakens the adsorption of oxygen-contained intermediates on Ni sites, fundamentally accounting for the enhanced OER performance. 相似文献
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Liquid‐Phase Exfoliated Indium–Selenide Flakes and Their Application in Hydrogen Evolution Reaction
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Single‐ and few‐layered InSe flakes are produced by the liquid‐phase exfoliation of β‐InSe single crystals in 2‐propanol, obtaining stable dispersions with a concentration as high as 0.11 g L−1. Ultracentrifugation is used to tune the morphology, i.e., the lateral size and thickness of the as‐produced InSe flakes. It is demonstrated that the obtained InSe flakes have maximum lateral sizes ranging from 30 nm to a few micrometers, and thicknesses ranging from 1 to 20 nm, with a maximum population centered at ≈5 nm, corresponding to 4 Se–In–In–Se quaternary layers. It is also shown that no formation of further InSe‐based compounds (such as In2Se3) or oxides occurs during the exfoliation process. The potential of these exfoliated‐InSe few‐layer flakes as a catalyst for the hydrogen evolution reaction (HER) is tested in hybrid single‐walled carbon nanotubes/InSe heterostructures. The dependence of the InSe flakes' morphologies, i.e., surface area and thickness, on the HER performances is highlighted, achieving the best efficiencies with small flakes offering predominant edge effects. The theoretical model unveils the origin of the catalytic efficiency of InSe flakes, and correlates the catalytic activity to the Se vacancies at the edge of the flakes. 相似文献
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In Situ Transformation of MOFs into Layered Double Hydroxide Embedded Metal Sulfides for Improved Electrocatalytic and Supercapacitive Performance
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Gamze Yilmaz Kah Meng Yam Chun Zhang Hong Jin Fan Ghim Wei Ho 《Advanced materials (Deerfield Beach, Fla.)》2017,29(26)
Direct adoption of metal‐organic frameworks (MOFs) as electrode materials shows impoverished electrochemical performance owing to low electrical conductivity and poor chemical stability. In this study, we demonstrate self‐templated pseudomorphic transformation of MOF into surface chemistry rich hollow framework that delivers highly reactive, durable, and universal electrochemically active energy conversion and storage functionalities. In situ pseudomorphic transformation of MOF‐derived hollow rhombic dodecahedron template and sulfurization of nickel cobalt layered double hydroxides (NiCo‐LDHs) lead to the construction of interlayered metal sulfides (NiCo‐LDH/Co9S8) system. The embedment of metal sulfide species (Co9S8) at the LDH intergalleries offers optimal interfacing of the hybrid constituent elements and materials stability. The hybrid NiCo‐LDH/Co9S8 system collectively presents an ideal porous structure, rich redox chemistry, and high electrical conductivity matrix. This leads to a significant enhancement in its complementary electrocatalytic hydrogen evolution and supercapacitive energy storage properties. This work establishes the potential of MOF derived scaffold for designing of novel class hybrid inorganic–organic functional materials for electrochemical applications and beyond. 相似文献
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Transition‐Metal‐Based Electrocatalysts as Cocatalysts for Photoelectrochemical Water Splitting: A Mini Review
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Converting solar energy into hydrogen via photoelectrochemical (PEC) water splitting is one of the most promising approaches for a sustainable energy supply. Highly active, cost‐effective, and robust photoelectrodes are undoubtedly crucial for the PEC technology. To achieve this goal, transition‐metal‐based electrocatalysts have been widely used as cocatalysts to improve the performance of PEC cells for water splitting. Herein, this Review summarizes the recent progresses of the design, synthesis, and application of transition‐metal‐based electrocatalysts as cocatalysts for PEC water splitting. Mo, Ni, Co‐based electrocatalysts for the hydrogen evolution reaction (HER) and Co, Ni, Fe‐based electrocatalysts for the oxygen evolution reaction (OER) are emphasized as cocatalysts for efficient PEC HER and OER, respectively. Particularly, some most efficient and robust photoelectrode systems with record photocurrent density or durability for the half reactions of HER and OER are highlighted and discussed. In addition, the self‐biased PEC devices with high solar‐to‐hydrogen efficiency based on earth‐abundant materials are also addressed. Finally, this Review is concluded with a summary and remarks on some challenges and opportunities for the further development of transition‐metal‐based electrocatalysts as cocatalysts for PEC water splitting. 相似文献
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Bo‐Quan Li Chang‐Xin Zhao Jia‐Ning Liu Qiang Zhang 《Advanced materials (Deerfield Beach, Fla.)》2019,31(35)
Hydrogen peroxide (H2O2) is a green oxidizer widely involved in a vast number of chemical reactions. Electrochemical reduction of oxygen to H2O2 constitutes an environmentally friendly synthetic route. However, the oxygen reduction reaction (ORR) is kinetically sluggish and undesired water serves as the main product on most electrocatalysts. Therefore, electrocatalysts with high reactivity and selectivity are highly required for H2O2 electrosynthesis. In this work, a synergistic strategy is proposed for the preparation of H2O2 electrocatalysts with high ORR reactivity and high H2O2 selectivity. A Co?Nx?C site and oxygen functional group comodified carbon‐based electrocatalyst (named as Co–POC–O) is synthesized. The Co–POC–O electrocatalyst exhibits excellent catalytic performance for H2O2 electrosynthesis in O2‐saturated 0.10 m KOH with a high selectivity over 80% as well as very high reactivity with an ORR potential at 1 mA cm?2 of 0.79 V versus the reversible hydrogen electrode (RHE). Further mechanism study identifies that the Co?Nx?C sites and oxygen functional groups contribute to the reactivity and selectivity for H2O2 electrogeneration, respectively. This work affords not only an emerging strategy to design H2O2 electrosynthesis catalysts with remarkable performance, but also the principles of rational combination of multiple active sites for green and sustainable synthesis of chemicals through electrochemical processes. 相似文献
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Chenlong Dong Xilin Zhang Jie Xu Rui Si Jun Sheng Jun Luo Shaoning Zhang Wujie Dong Guobao Li Weichao Wang Fuqiang Huang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(5)
Exploring the origin of transition metal (TM) lattice‐doped layered double hydroxides (LDHs) toward the oxygen evolution reaction (OER) plays a crucial role in engineering efficient electrocatalysts. Without understanding the physics behind the TM‐induced catalytic enhancements, it would be challenging to design the next generation of electrocatalysts. Herein, single Ru atoms are introduced into a CoCr LDHs lattice to improve activity. In 0.1 m KOH, CoCrRu LDHs require only 290 mV overpotential to drive to 10 mA cm?2 and show a Tafel slope of 56.12 mV dec?1. Electronic structure analyses based on density functional theory confirm that promoted OER activity originates from synergetic charge transfer among Ru, Cr, and Co elements. Specifically, Ru dopants can downshift d states of Co and enhance electron donation of Cr to oxygenates, which essentially breaks the scaling relation and achieves higher activity. This work provides insights into how single atomic Ru dopant tunes the electronic structures of its neighbor's active site Co and thus increases OER activities. 相似文献