The Co_3O_4 nanosheet array as support for MoS_2 as highly efficient electrocatalysts for hydrogen evolution reaction

The electrochemical hydrogen evolution reaction(HER) on a non-precious electrocatalyst in an alkaline environment is of essential importance for future renewable energy. The design of advanced electrocatalysts for HER is the most important part to reduce the cost and to enhance the efficiency of water splitting. MoS_2 is considered as one of the most promising electrocatalysts to replace the precious Pt catalyst.Herein, for the first time, we have successfully loaded MoS_2 electrocatalysts onto the Co_3O_4 nanosheet array to catalyze HER with a low onset potential of ~76 mV. The high hydrogen evolution activity of MoS_2 supported on the Co_3O_4 nanosheet array may be attributed to the increased active sites and the electronic interactions between MoS_2 and Co_3O_4.     

Air-Stable Mn doped CuCl/CuO Hybrid Triquetrous Nanoarrays as Bifunctional Electrocatalysts for Overall Water Splitting

The development of highly efficient non-precious metal catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is key for large-scale hydrogen evolution through water splitting technology. Here, we report an air-stable Cu-based nanostructure consisting of Mn doped CuCl and CuO (CuCl/CuO(Mn)-NF) as a dual functional electrocatalyst for water splitting. CuCl is identified as the main active component, together with Mn doping and the synergistic effect between CuCl and CuO are found to make responsibility for the excellent OER and HER catalytic activity and stability. The assembled electrolyzes also exhibit decent water splitting performance. This work not only provides a simple method for preparing Cu-based composite catalyst, but also demonstrates the great potential of Cu-based non-noble metal electrocatalysts for water splitting and other renewable energy conversion technologies.     

One-Step Template/Solvent-Free Pyrolysis for In Situ Immobilization of CoP Nanoparticles onto N and P Co-Doped Carbon Porous Nanosheets towards High-efficiency Electrocatalytic Hydrogen Evolution

The search for economical, active and stable electrocatalysts towards the hydrogen evolution reaction (HER) is highly imperative for the progression of water electrolysis technology and related sustainable energy conversion technologies. The delicate optimization of chemical composition and architectural configuration is paramount to design high-efficiency non-precious metal HER electrocatalysts. Herein, we report a one-step scalable template/solvent-free pyrolysis approach for in situ immobilizing uniform CoP nanoparticles onto N and P co-doped carbon porous nanosheets (denoted as CoP@N,P-CNSs hereafter). The simultaneous consideration of architectural design and nanocarbon hybridization renders the formed CoP@N,P-CNSs with plentiful well-dispersed anchored active sites, shortened pathway for mass diffusion, enhanced electric conductivity, and reinforced mechanical stability. As a consequence, the optimized CoP@N,P-CNSs exhibit an overpotential of 115 mV to afford a current density of 10 mA cm⁻², small Tafel slope of 74.2 mV dec⁻¹, high Faradaic efficiency of nearly 100 %, and superb long-term durability in an alkaline medium. Given the fabrication feasibility, mass production potential and outstanding HER performance, the CoP@N,P-CNSs may hold great promise for large-scale electrochemical water splitting. More importantly, the explored one-step template/solvent-free pyrolysis methodology offers a feasible and versatile route to fabricate carbon nanosheet-based nanocomposites for diverse energy conversation-related applications.     

General π‐Electron‐Assisted Strategy for Ir,Pt, Ru,Pd, Fe,Ni Single‐Atom Electrocatalysts with Bifunctional Active Sites for Highly Efficient Water Splitting

Both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are crucial to water splitting, but require alternative active sites. Now, a general π‐electron‐assisted strategy to anchor single‐atom sites (M=Ir, Pt, Ru, Pd, Fe, Ni) on a heterogeneous support is reported. The M atoms can simultaneously anchor on two distinct domains of the hybrid support, four‐fold N/C atoms (M@NC), and centers of Co octahedra (M@Co), which are expected to serve as bifunctional electrocatalysts towards the HER and the OER. The Ir catalyst exhibits the best water‐splitting performance, showing a low applied potential of 1.603 V to achieve 10 mA cm^?2 in 1.0 m KOH solution with cycling over 5 h. DFT calculations indicate that the Ir@Co (Ir) sites can accelerate the OER, while the Ir@NC₃ sites are responsible for the enhanced HER, clarifying the unprecedented performance of this bifunctional catalyst towards full water splitting.     

General π‐Electron‐Assisted Strategy for Ir,Pt, Ru,Pd, Fe,Ni Single‐Atom Electrocatalysts with Bifunctional Active Sites for Highly Efficient Water Splitting

Both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are crucial to water splitting, but require alternative active sites. Now, a general π‐electron‐assisted strategy to anchor single‐atom sites (M=Ir, Pt, Ru, Pd, Fe, Ni) on a heterogeneous support is reported. The M atoms can simultaneously anchor on two distinct domains of the hybrid support, four‐fold N/C atoms (M@NC), and centers of Co octahedra (M@Co), which are expected to serve as bifunctional electrocatalysts towards the HER and the OER. The Ir catalyst exhibits the best water‐splitting performance, showing a low applied potential of 1.603 V to achieve 10 mA cm^?2 in 1.0 m KOH solution with cycling over 5 h. DFT calculations indicate that the Ir@Co (Ir) sites can accelerate the OER, while the Ir@NC₃ sites are responsible for the enhanced HER, clarifying the unprecedented performance of this bifunctional catalyst towards full water splitting.     

A General Route to Prepare Low‐Ruthenium‐Content Bimetallic Electrocatalysts for pH‐Universal Hydrogen Evolution Reaction by Using Carbon Quantum Dots

A challenging but pressing task to design and synthesize novel, efficient, and robust pH‐universal hydrogen evolution reaction (HER) electrocatalysts for scalable and sustainable hydrogen production through electrochemical water splitting. Herein, we report a facile method to prepare an efficient and robust Ru‐M (M=Ni, Mn, Cu) bimetal nanoparticle and carbon quantum dot hybrid (RuM/CQDs) for pH‐universal HER. The RuNi/CQDs catalysts exhibit outstanding HER performance at all pH levels. The unexpected low overpotentials of 13, 58, and 18 mV shown by RuNi/CQDs allow a current density of 10 mA cm^?2 in 1 m KOH, 0.5 m H₂SO₄, and 1 m PBS, respectively, for Ru loading at 5.93 μgRu cm^?2. This performance is among the best catalytic activities reported for any platinum‐free electrocatalyst. Theoretical studies reveal that Ni doping results in a moderate weakening of the hydrogen bonding energy of nearby surface Ru atoms, which plays a critical role in improving the HER activity.     

多壳层中空镍钴双金属磷化物纳米球用于高效电催化析氧北大核心CSCD

析氧反应是金属-空气电池和电解水制氢等电化学系统中关键的反应,研究其高效稳定非贵金属电催化剂至关重要。本文以金属有机骨架化合物(MOF)作为前驱体,通过高温煅烧制备了具有多壳层中空结构的镍钴双金属磷化物(NiCo-P)。这种独特的结构有利于电解液的渗透,能够提供丰富的暴露活性位点和快速传质路径,同时,镍钴双金属具有协同作用促进电化学性能。结果表明,n(Ni)∶n(Co)=1∶10制备的NiCo-P-0.1催化剂在1.0 mol/L KOH电解液中表现出良好的催化活性和稳定性,在10 mA/cm^(2)电流密度的过电势为329 mV,具有良好的应用前景。本工作为高活性和高稳定性的电催化析氧催化剂的制备提供了一种全新途径。     

RuP2‐Based Catalysts with Platinum‐like Activity and Higher Durability for the Hydrogen Evolution Reaction at All pH Values

Highly active, stable, and cheap Pt‐free catalysts for the hydrogen evolution reaction (HER) are under increasing demand for future energy conversion systems. However, developing HER electrocatalysts with Pt‐like activity that can function at all pH values still remains as a great challenge. Herein, based on our theoretical predictions, we design and synthesize a novel N,P dual‐doped carbon‐encapsulated ruthenium diphosphide (RuP₂@NPC) nanoparticle electrocatalyst for HER. Electrochemical tests reveal that, compared with the Pt/C catalyst, RuP₂@NPC not only has Pt‐like HER activity with small overpotentials at 10 mA cm⁻² (38 mV in 0.5 m H₂SO₄, 57 mV in 1.0 m PBS and 52 mV in 1.0 m KOH), but demonstrates superior stability at all pH values, as well as 100 % Faradaic yields. Therefore, this work adds to the growing family of transition‐metal phosphides/heteroatom‐doped carbon heterostructures with advanced performance in HER.     

纳米二硫化钼的掺杂及催化电解水产氢的研究进展

电催化水分解制氢是可以形成闭环的生产过程, 起始原料与副产物均为水、 过程清洁无污染, 是极具希望的产氢策略. 目前制约其发展的瓶颈之一是价格昂贵的Pt基贵金属催化剂. 为推动电催化分解水制氢的普及, 亟待开发低成本非贵金属催化剂. 在众多备选非贵金属催化材料中, 纳米层状结构二硫化钼(MoS₂)因催化效果可期、 价格低而获得了广泛关注. 然而, 通常条件下易于获得的层状结构2H相MoS₂大面积的基面部分显示惰性, 仅在片层边缘处存在少量活性位点, 且导电性较差, 因而尚不能替代Pt基催化剂, 而如何增加其活性位点数量和提高其导电性成为亟待解决的问题; 另一方面, 1T相MoS₂虽然活性高、 导电性好, 但却存在制备困难及稳定性差的问题. 鉴于此, 研究者通过对纳米MoS₂进行掺杂改性实现了其活性与稳定性的有效提升. 本文对非贵金属纳米MoS₂催化剂掺杂改性的方法、 机理及其电催化水解制氢性能的相关研究进行了总结与讨论. 作为典型的非贵金属电解水析氢催化剂, MoS₂具有巨大发展潜力, 本文能够对相关非贵金属催化剂的研发提供有益的参考.     

Controlled Synthesis of Ni-Doped MoS2 Hybrid Electrode for Synergistically Enhanced Water-Splitting Process

The development of high-efficiency, low-cost, and earth-abundant electrocatalysts for overall water splitting remains a challenge. In this work, Ni-modified MoS₂ hybrid catalysts are grown on carbon cloth (Ni-Mo-S@CC) through a one-step hydrothermal treatment. The optimized Ni-Mo-S@CC catalyst shows excellent hydrogen evolution reaction (HER) activity with a low overpotential of 168 mV at a current density of 10 mA cm⁻² in 1.0 m KOH, which is lower than those of Ni-Mo-S@CC (1:1), Ni-Mo-S@CC (3:1), and pure MoS₂. Significantly, the Ni-Mo-S@CC hybrid catalyst also displays outstanding oxygen evolution reaction (OER) activity with a low overpotential of 320 mV at a current density of 10 mA cm⁻², and remarkable long-term stability for 30 h at a constant current density of 10 mA cm⁻². Experimental results and theoretical analysis based on density functional theory demonstrate that the excellent electrocatalytic performance can be attributed mainly to the remarkable conductivity, abundant active sites, and synergistic effect of the Ni-doped MoS₂. This work sheds light on a unique strategy for the design of high-performance and stable electrocatalysts for water-splitting electrolyzers.     

Engineering morphologies of cobalt oxide/phosphate-carbon nanohybrids for high-efficiency electrochemical water oxidation and reduction

Active non-noble metal catalysts plays a decisive role for water electrolysis,however,the rational design and development of cost-efficient electrocatalysts with Pt/IrO2-like activity is still a challenging task.Herein,a facile one-step electrodeposition route in deep eutectic solvents(DESs) is developed for morphology-controllable synthesis of cobalt oxide/phosphate-carbon nano hybrids on nickel foam(CoPO@C/NF).A series of CoPO@C/NF nanostructures including cubes,octahedrons,microspheres and nanoflowers are synthesized,which show promising electrocatalytic properties toward oxygen and hydrogen evolution reactions(OER/HER).Such surface self-organized microstructure with accessible active sites make a significant contribution to the enhanced electrochemical activity,and hybridizing cobalt oxide with cobalt pyrophosphates and carbon can result in enhanced OER performance through synergistic catalysis.Among all nanostructures,the obtained microspherical CoPO@C/NF-3 catalyst exhibits excellent catalytic activities for OER and HER in 1.0 M KOH,affording an anodic current density of 10 mA cm^-2 at overpotentials of 293 mV for OER and 93 mV for HER,with good long-time stability.This work offers a practical route for engineering the high-performance electrocatalysts towards efficient energy conversion and storage devices.     

Single‐Shell Carbon‐Encapsulated Iron Nanoparticles: Synthesis and High Electrocatalytic Activity for Hydrogen Evolution Reaction

Efficient hydrogen evolution reaction (HER) through effective and inexpensive electrocatalysts is a valuable approach for clean and renewable energy systems. Here, single‐shell carbon‐encapsulated iron nanoparticles (SCEINs) decorated on single‐walled carbon nanotubes (SWNTs) are introduced as a novel highly active and durable non‐noble‐metal catalyst for the HER. This catalyst exhibits catalytic properties superior to previously studied nonprecious materials and comparable to those of platinum. The SCEIN/SWNT is synthesized by a novel fast and low‐cost aerosol chemical vapor deposition method in a one‐step synthesis. In SCEINs the single carbon layer does not prevent desired access of the reactants to the vicinity of the iron nanoparticles but protects the active metallic core from oxidation. This finding opens new avenues for utilizing active transition metals such as iron in a wide range of applications.     

Ru−FeNi Alloy Heterojunctions on Lignin-derived Carbon as Bifunctional Electrocatalysts for Efficient Overall Water Splitting

Rational design of efficient, stable, and inexpensive bifunctional electrocatalysts for oxygen evolution reactions (OER) and hydrogen evolution reactions (HER) is a key challenge to realize green hydrogen production via electrolytic water splitting. Herein, Ru nanoparticles and FeNi alloy heterojunction catalyst (Ru−FeNi@NLC) encapsulated via lignin-derived carbon was prepared by self-assembly precipitation and in situ pyrolysis. The designed catalyst displays excellent performance at 10 mA cm⁻² with low overpotentials of 36 mV for HER and 198 mV for OER, and only needs 1.48 V for overall water splitting. Results and DFT calculations show the unique N-doped lignin-derived carbon layer and Ru−FeNi heterojunction contribute to optimized electronic structure for enhancing electron transfer, balanced free energy of reactants and intermediates in the sorption/desorption process, and significantly reduced reaction energy barrier for the HER and OER rate-determining steps, thus improved reaction kinetics. This work provides a new in situ pyrolysis doping strategy based on renewable biomass for the construction of highly active, stable and cost-effective catalysts.     

Ir Nanoparticles Anchored on Metal-Organic Frameworks for Efficient Overall Water Splitting under pH-Universal Conditions

The construction of high-activity and low-cost electrocatalysts is critical for efficient hydrogen production by water electrolysis. Herein, we developed an advanced electrocatalyst by anchoring well-dispersed Ir nanoparticles on nickel metal-organic framework (MOF) Ni-NDC (NDC: 2,6-naphthalenedicarboxylic) nanosheets. Benefiting from the strong synergy between Ir and MOF through interfacial Ni−O−Ir bonds, the synthesized Ir@Ni-NDC showed exceptional electrocatalytic performance for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and overall water splitting in a wide pH range, superior to commercial benchmarks and most reported electrocatalysts. Theoretical calculations revealed that the charge redistribution of Ni−O−Ir bridge induced the optimization of H₂O, OH* and H* adsorption, thus leading to the accelerated electrochemical kinetics for HER and OER. This work provides a new clue to exploit bifunctional electrocatalysts for pH-universal overall water splitting.     

A General Route to Prepare Low-Ruthenium-Content Bimetallic Electrocatalysts for pH-Universal Hydrogen Evolution Reaction by Using Carbon Quantum Dots

A challenging but pressing task to design and synthesize novel, efficient, and robust pH-universal hydrogen evolution reaction (HER) electrocatalysts for scalable and sustainable hydrogen production through electrochemical water splitting. Herein, we report a facile method to prepare an efficient and robust Ru-M (M=Ni, Mn, Cu) bimetal nanoparticle and carbon quantum dot hybrid (RuM/CQDs) for pH-universal HER. The RuNi/CQDs catalysts exhibit outstanding HER performance at all pH levels. The unexpected low overpotentials of 13, 58, and 18 mV shown by RuNi/CQDs allow a current density of 10 mA cm⁻² in 1 m KOH, 0.5 m H₂SO₄, and 1 m PBS, respectively, for Ru loading at 5.93 μgRu cm⁻². This performance is among the best catalytic activities reported for any platinum-free electrocatalyst. Theoretical studies reveal that Ni doping results in a moderate weakening of the hydrogen bonding energy of nearby surface Ru atoms, which plays a critical role in improving the HER activity.     

In situ electrochemical dehydrogenation of ultrathin Co(OH)2 nanosheets for enhanced hydrogen evolution

Transition metal hydroxides/oxyhydroxides have recently emerged as highly active electrocatalysts for oxygen evolution reaction in alkaline water electrolysis, while have not yet been widely investigated for hydrogen evolution electrocatalysts owing to their unfavorable H*-adsorption, making it difficult to construct an overall-water-splitting cell for hydrogen production. In this work, we proposed a straightforward and effective approach to develop an efficient in-plane heterostructured CoOOH/Co(OH)₂ catalyst via in-situ electrochemical dehydrogenation method, in which the dehydrogenated –CoOOH and Co(OH)₂ at the surface synergistically boost the hydrogen evolution reaction (HER) kinetics in base as confirmed by high-resolution transmission electron microscope, synchrotron X-ray absorption spectroscopy, and electron energy loss spectroscopy. Due to the in-situ dehydrogenation of ultrathin Co(OH)₂ nanosheets, the catalytic activity of the CoOOH/Co(OH)₂ heterostructures is progressively improved, which exhibit outstanding hydrogen-evolving activity in base requiring a low overpotential of 132 mV to afford 10 mA/cm² with very fast reaction kinetics after 60 h dehydrogenation. The gradually improved catalytic performance for the CoOOH/Co(OH)₂ is probably due to the enhanced H*-adsorption induced by the synergistic effect of heterostructures and better conductivity of CoOOH relative to electrically insulating Co(OH)₂. This work will open the opportunity for a new family of transition metal hydroxides/oxyhydroxides as active HER catalysts, and also highlight the importance of using in situ techniques to construct precious metal-free efficient catalysts for alkaline hydrogen evolution.     

Multifunctional Active‐Center‐Transferable Platinum/Lithium Cobalt Oxide Heterostructured Electrocatalysts towards Superior Water Splitting

Designing cost‐effective and efficient electrocatalysts plays a pivotal role in advancing the development of electrochemical water splitting for hydrogen generation. Herein, multifunctional active‐center‐transferable heterostructured electrocatalysts, platinum/lithium cobalt oxide (Pt/LiCoO₂) composites with Pt nanoparticles (Pt NPs) anchored on LiCoO₂ nanosheets, are designed towards highly efficient water splitting. In this electrocatalyst system, the active center can be alternatively switched between Pt species and LiCoO₂ for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Specifically, Pt species are the active centers and LiCoO₂ acts as the co‐catalyst for HER, whereas the active center transfers to LiCoO₂ and Pt turns into the co‐catalyst for OER. The unique architecture of Pt/LiCoO₂ heterostructure provides abundant interfaces with favorable electronic structure and coordination environment towards optimal adsorption behavior of reaction intermediates. The 30 % Pt/LiCoO₂ heterostructured electrocatalyst delivers low overpotentials of 61 and 285 mV to achieve 10 mA cm^?2 for HER and OER in alkaline medium, respectively.     

Coupling Mo2C with Nitrogen‐Rich Nanocarbon Leads to Efficient Hydrogen‐Evolution Electrocatalytic Sites

In our efforts to obtain electrocatalysts with improved activity for water splitting, meticulous design and synthesis of the active sites of the electrocatalysts and deciphering how exactly they catalyze the reaction are vitally necessary. Herein, we report a one‐step facile synthesis of a novel precious‐metal‐free hydrogen‐evolution nanoelectrocatalyst, dubbed Mo₂C@NC that is composed of ultrasmall molybdenum carbide (Mo₂C) nanoparticles embedded within nitrogen‐rich carbon (NC) nanolayers. The Mo₂C@NC hybrid nanoelectrocatalyst shows remarkable catalytic activity, has great durability, and gives about 100 % Faradaic yield toward the hydrogen‐evolution reaction (HER) over a wide pH range (pH 0–14). Theoretical calculations show that the Mo₂C and N dopants in the material synergistically co‐activate adjacent C atoms on the carbon nanolayers, creating superactive nonmetallic catalytic sites for HER that are more active than those in the constituents.     

简易电沉积法制备CoFe-P催化剂用于高效析氧反应

开发低成本、高活性且稳定的非贵金属催化剂是实现大规模电解水制氢的关键所在。在此,我们通过简便、合理的电沉积法在泡沫镍(NF)上构建了一种具备超薄二维纳米片形貌的高度非晶相Co1Fe1-P薄膜用于高效催化析氧反应(OER)。在1.0mol·L^-1 KOH溶液中,所制备的Co1Fe1-P/NF催化剂在电流密度为10和100 mA·cm^-2处的过电位分别为274.4和329.5 mV,Tafel斜率仅为 45.3 mV·dec^-1,可以媲美商业 RuO₂催化剂。此外,Co1Fe1-P/NF 催化剂在 10 mA·cm^-2的 100 h 计时电压法测试和1 000次循环伏安法测试中均表现出卓越的催化稳定性。Co1Fe1-P/NF催化剂优秀的催化活性归因于其独特的形貌、高度非晶相结构提供的低能垒、优化的电子结构以及钴磷化物和铁磷化物的强协同效应。     

红毛丹状磷化钴@钼钴氧空心微米小球用于碱性电催化析氢（英文）

氢气因其能量密度高、零排放和可再生的特点被广泛认为是最有前景的能源.电解水是一种产生高纯氢气的有效途径.目前,高性能的促进水电解的催化剂主要是贵金属材料,例如贵金属铂.然而,高成本大大阻碍了贵金属材料在电催化水分解中的广泛应用.因此,我们致力于研究具有高活性的非贵金属催化剂.因为电催化水分解析氢反应更容易发生在质子浓度高的条件下,所以研究碱性条件下催化析氢比研究酸性条件下催化析氢更具挑战性.在工业应用中,酸性电解质溶液对仪器设备的腐蚀性比碱性溶液更大,因此研究应用在碱性溶液中的析氢催化剂更有发展前景.过渡金属磷化物被广泛地研究作为高性能析氢电催化剂,然而过渡金属磷化物作为析氢催化剂的稳定性通常不是很好.我们通过钼元素的引入,提高过渡金属磷化物作为析氢催化剂的稳定性.电化学催化效率同样受到材料形貌和导电性的影响.大的比表面积有利于暴露更多的活性位点,使活性位点与电解质溶液的接触更加充分,有利于催化剂和溶液之间的传质.据报道,金属磷化物具有良好的导电性是由于磷化物中存在金属-金属键.所以合成具有大比表面积形貌的过渡金属磷化物材料能够满足析氢电催化剂对比表面积和导电性的两个需求.界面效应是调节催化剂性能的一个有效方法.析氢催化剂常常存在吸附质子能力过强或过弱、稳定性不好等问题.这些问题可以通过界面效应来解决.本文通过形成磷化估和钼钴氧的界面来调节改善磷化钴表面原来的电子密度,以达到理想的氢吸附自由能;同时此界面效应还能起到稳定催化剂性能的作用.本文首先采用水热法合成了红毛丹状钼钴氧空心微米小球前驱体.在钼酸根离子的引导下,利用奥斯特瓦尔德熟化原理一步实现了红毛丹状空心结构.前驱体再以次亚磷酸钠为磷源进行气相磷化,得到产物红毛丹状磷化钴@钼钴氧空心微米小球.通过扫描电镜和透射电镜对其红毛丹状空心结构进行了表征.利用X射线衍射和X射线光电子能谱等手段表征了材料的物相组成和价态分布.电化学测试均使用电化学工作站完成.该材料在碱性电解质溶液中展现了极好的电化学催化析氢性能,在电流密度为10 mA cm^-2时对应的析氢过电位仅为62 mV.在1 MKOH溶液中10 mA cm^-2电流密度下测试55 h,过电位仅增大约17 mV,显示了非常强的碱性析氢稳定性.得益于磷化钴和钼钴氧之间的界面效应,以及特殊的三维空心结构,红毛丹状磷化钴@钼钴氧空心微米小球表现出优异的析氢催化性能和稳定性.