三维百合花状的CoNi2S4作为先进的双功能电催化剂用于氢析出和氧析出反应

为简化电解水催化剂的合成过程和优化电解水操作系统, 双功能电解水催化剂的研究, 特别是在碱性条件下同时具有优异催化氢析出和氧析出反应性能的双功能电催化剂的研究尤为重要. 其中, 过渡金属硫化物, 特别是 CoNi 硫化物, 被报道有与氢化酶类似的催化活性中心, 从而具有优异的催化氢析出和催化氧析出反应性能. 虽然有关对过渡金属硫化物的研究很多, 但主要集中在具有一维纳米线和二维纳米片形貌结构的过渡金属硫化物. 不幸的是, 这些形貌结构的过渡金属硫化物在电催化过程中容易聚集和受限于电荷传输能力. 三维纳米结构的材料具有较大的比表面积以分布更多的活性位点和拥有良好的电子传输能力, 所以, 开发三维纳米结构的过渡金属硫化物材料可能是改进其催化电解水性能的一个好途径. 本文采用简单的两步水热法, 通过硫化合成的 CoNi 前体得到了长于泡沫镍上的三维百合花状的 CoNi2S4(Co-Ni2S4/Ni). 它只需要 54 mV 的过电位即可获得 10 mA cm-2的催化氢析出反应电流, 是最好的碱性催化氢析出反应电极材料之一. 它在驱动 100 mA cm-2的催化氧析出反应电流时也只需要 328 mV 的过电位. 另外, 把 CoNi2S4/Ni 分别作为阴极和阳极组装成双电极碱性水电解槽时, 它只需要 1.56 V 的电压即可获取 10 mA cm-2的催化全电解水电流并具有良好的催化全电解水稳定性.扫描电子显微镜、透射电子显微镜和 N2吸脱附曲线测试结果表明, 该三维百合花状的 CoNi2S4/Ni 的表面粗糙度高和拥有多孔特性. 多孔结构的 CoNi2S4/Ni 可提供更多可接触的催化活性位点, 也有利于催化过程中的电解质和生成的气体的扩散与传递. 交流阻抗图谱测试结果表明, CoNi2S4/Ni 具有良好的电子传输能力. 另外, 不同于前期对尖晶石结构的硫化物 AB2S4的研究结果, XPS 结果表明, CoNi2S4/Ni 中含有 Niб+和 Sб-活性物种, 表明 CoNi2S4具有与活性氢化酶类似的活 性中心. Niδ+和 Sδ-可分别作为氢氧根和质子的接收体, 协助促进吸附的水分子的分离, 从而提高材料的催化性能. 所以, Niδ+和 Sδ-活性物种的出现, 大比表面积的三维百合花状多孔结构和良好的电荷传输能力等特性集合于 CoNi2S4/Ni 上使得CoNi2S4/Ni 具有优异的催化氢析出和催化氧析出反应性能.     

水电解制氢非贵金属催化剂的研究进展

氢能作为零碳排放能源是被公认的最清洁能源之一,如何有效可持续地产氢是未来人类步入氢能经济首先要解决的问题。电解水技术基于电化学分解水的原理,利用可再生电能或太阳能驱动水分解为氢气和氧气,被认为是最有前途和可持续性的产氢途径。然而,无论是光解水还是电解水,均需要高活性、高稳定性的非贵金属氢析出和氧析出催化剂以使水电解反应经济节能。本文介绍了我们研究所近三年在水电解方面的研究进展,其中着重介绍了：（ⅰ）氢析出催化剂,包括利用低温磷化过渡金属（氢）氧化物的方法制备过渡金属磷化物,同时过渡金属硫化物、硒化物以及碳化物等均被成功合成并被应用为有效的阴极析氢催化剂;（ⅱ）氧析出催化剂,主要包括金属磷化物、硫化物、氧化物/氢氧化物等;（ⅲ）双功能催化剂,主要包括过渡金属磷化物、硒化物、硫化物等。最后,总结展望了发展水电解非贵金属催化剂所面临的挑战与未来发展方向。     

多孔二元过渡金属纳米片阵列电极制备及电催化析氢研究

碱性电解液中,电解水析氢的H20解离过程非常缓慢,造成析氢反应较高的过电位和Tafel效率.选择具有本征高析氢活性的合金催化剂与水解离中心-过渡金属氧化物复合,并进一步优化复合物形貌结构,被证明是解决这个科学问题的重要策略.我们报道一例新颖的二元过渡金属纳米片阵列自支撑电极(MoO3_x-MoNi4@NF),多孔MoO...     

基于类石墨烯二维材料的析氢反应电催化剂的研究进展

利用可再生能源产生的电能电解水制取氢气,被认为是下一代清洁能源的最佳选择之一。然而,通过电解水可持续的产生氢气需要高活性的催化剂来使得反应有效地进行。基于类石墨烯二维材料的析氢反应电催化剂展现出巨大的潜力,因而备受关注。本文主要结合我们课题组近期在析氢反应电催化剂方面的研究,介绍了类石墨烯二维材料的析氢反应电催化剂的研究进展,主要包括过渡金属二硫族化合物、前过渡金属碳化物(MXenes)以及硼单层纳米片等。最后总结和展望了析氢反应电催化剂所面临的挑战与未来发展方向。     

三维百合花状的CoNi_2S_4作为先进的双功能电催化剂用于氢析出和氧析出反应（英文）

为简化电解水催化剂的合成过程和优化电解水操作系统,双功能电解水催化剂的研究,特别是在碱性条件下同时具有优异催化氢析出和氧析出反应性能的双功能电催化剂的研究尤为重要.其中,过渡金属硫化物,特别是CoNi硫化物,被报道有与氢化酶类似的催化活性中心,从而具有优异的催化氢析出和催化氧析出反应性能.虽然有关对过渡金属硫化物的研究很多,但主要集中在具有一维纳米线和二维纳米片形貌结构的过渡金属硫化物.不幸的是,这些形貌结构的过渡金属硫化物在电催化过程中容易聚集和受限于电荷传输能力.三维纳米结构的材料具有较大的比表面积以分布更多的活性位点和拥有良好的电子传输能力,所以,开发三维纳米结构的过渡金属硫化物材料可能是改进其催化电解水性能的一个好途径.本文采用简单的两步水热法,通过硫化合成的CoNi前体得到了长于泡沫镍上的三维百合花状的CoNi_2S_4(CoNi_2S_4/Ni).它只需要54 mV的过电位即可获得10 mA cm~(-2)的催化氢析出反应电流,是最好的碱性催化氢析出反应电极材料之一.它在驱动100 mA cm~(-2)的催化氧析出反应电流时也只需要328 mV的过电位.另外,把CoNi_2S_4/Ni分别作为阴极和阳极组装成双电极碱性水电解槽时,它只需要1.56 V的电压即可获取10 mA cm~(-2)的催化全电解水电流并具有良好的催化全电解水稳定性.扫描电子显微镜、透射电子显微镜和N_2吸脱附曲线测试结果表明,该三维百合花状的CoNi_2S_4/Ni的表面粗糙度高和拥有多孔特性.多孔结构的CoNi_2S_4/Ni可提供更多可接触的催化活性位点,也有利于催化过程中的电解质和生成的气体的扩散与传递.交流阻抗图谱测试结果表明,CoNi_2S_4/Ni具有良好的电子传输能力.另外,不同于前期对尖晶石结构的硫化物AB_2S_4的研究结果,XPS结果表明,CoNi_2S_4/Ni中含有Ni~(б+)和S~(б–)活性物种,表明CoNi_2S_4具有与活性氢化酶类似的活性中心.Ni~(δ+)和S~(δ–)可分别作为氢氧根和质子的接收体,协助促进吸附的水分子的分离,从而提高材料的催化性能.所以,Ni~(δ+)和S~(δ–)活性物种的出现,大比表面积的三维百合花状多孔结构和良好的电荷传输能力等特性集合于CoNi_2S_4/Ni上使得CoNi_2S_4/Ni具有优异的催化氢析出和催化氧析出反应性能.     

高活性的碱性析氢电催化剂:氮掺杂类石墨烯包覆的钴-钌纳米合金

<正>氢被认为是环境友好的清洁能源,电催化分解水可以制备高纯氢气,据分析在碱性介质中电解水是最有可能实现产业化制氢的技术~(1–3)。一直以来贵金属都是该领域活性最高的催化剂,然而昂贵的价格和稀缺性限制了它们的广泛使用。近年来,科研人员持续探索致力于将过渡金属发展成高活性碱性析氢电催化剂以降低成本,然而很多催化剂的活性与贵金属相比仍然还有很大的差距。将少量的贵金属与过渡金属合金化是提高过     

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.     

水电解析氢低贵/非贵金属催化剂的研究进展

氢气作为能量载体的氢能技术由于其清洁性、高能量密度等优势已获得越来越多的青睐与关注. 其中,可持续的产氢技术是未来氢能经济发展的必要先决条件. 通过可再生资源电力驱动的电解水技术是支持氢能经济可持续发展的重要途径,高活性、低成本的析氢催化剂的开发利用是提高水电解技术效率并降低其成本的关键因素. 本文主要介绍了近年来包括低铂催化剂和金属硫化物、金属磷化物、金属硒化物等非铂过渡金属催化剂在析氢方面的研究进展,详细讨论了析氢反应的催化性能、合成方法以及结构?鄄催化性能的关系,最后总结展望了水电解低铂及非铂过渡金属催化剂在未来发展过程中所面临的机遇与挑战.     

电沉积NiCu合金锚定Co2P纳米线调控电子结构增强的析氢反应

发展高效稳定的析氢反应(HER)是实现电解水技术广泛应用于工业的关键.本文以泡沫镍(NF)为基材,通过水热-热解-电沉积法合成了具有三维高分散非均相的HER催化剂CuAl@Co₂P/NF.研究发现,晶面与非晶面异质结的形成增加了该催化剂自身的活性位点,各元素之间的协同作用使体系内Co原子核外电子重新排布,降低了对吸附H~*的吸附能力,加快了析氢反应过程中的反应动力学.该催化剂在碱性和酸性介质中均表现出良好的HER活性和稳定性,电流密度为10 mA/cm²时的过电势分别为83和27 mV,尤其在碱性环境下连续工作72 h后的电位基本保持不变.     

原位生长Pd/Ni(OH)2/NF复合催化剂及其析氢性能

采用水热合成法在泡沫镍上原位构建了低贵金属含量的钯/氢氧化镍纳米复合催化剂（Pd/Ni（OH）₂/NF）。通过扫描电镜,能谱仪,X射线衍射仪和X射线光电子谱仪等分析技术表征了催化剂的形貌和微观结构;运用线性扫描伏安法,电化学阻抗谱和计时电流法等手段研究了催化剂的催化析氢性能。实验结果显示复合催化剂具有特殊的微观构型,超薄的Ni（OH）₂薄片生长在泡沫镍表面,纳米尺寸的钯均匀地镶嵌在氢氧化镍薄片中。催化剂表面的氢氧化镍有利于促进水的解离,加快氢中间体的形成;均匀分散的钯极易吸附解离的氢中间体,快速地复合成氢气分子。我们发现复合催化剂能协同加快析氢反应过程,极大地降低析氢过电位,提高了析氢活性。此外,复合催化剂原位生长在泡沫镍上,有效地提高了催化电极的稳定性。     

Ru-Ni/C催化剂在碱性介质中的析氢性能研究

氢气的高效生产和利用对构建清洁低碳的能源体系至关重要, 碱性电解水制氢是目前我国应用最多的制氢技术,但也存在能耗较高的难题。因此迫切需要寻找低成本、高性能的电催化剂用于析氢反应（HER）提高水分解效率。本工作采用沉积沉淀法合成了双金属负载型Ru-Ni/C催化剂,用透射电子显微镜（TEM）和X射线衍射（XRD）对催化剂的形貌和结构进行了表征。用线性扫描伏安法（LSV）、电化学阻抗谱（EIS）等测试了HER性能。结果显示炭载体上RuNi双金属均匀分散,在电流密度为10 mA?cm-2时过电位仅为34.4 mV且稳定性良好,Tafel斜率仅为60.33 mV?dec-1,比商用Pt/C还小。表明Ru-Ni/C催化剂展现出了优异的HER电催化活性和稳定性,RuNi双金属之间的协同效应很大程度上促进了催化剂的催化性能,该研究为发展高效的碱性电解水制氢阴极催化剂提供了新思路。     

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.     

The Hydrogen Evolution Reaction in Alkaline Solution: From Theory,Single Crystal Models,to Practical Electrocatalysts

The hydrogen evolution reaction (HER) is a fundamental process in electrocatalysis and plays an important role in energy conversion for the development of hydrogen‐based energy sources. However, the considerably slow rate of the HER in alkaline conditions has hindered advances in water splitting techniques for high‐purity hydrogen production. Differing from well documented acidic HER, the mechanistic aspects of alkaline HER are yet to be settled. A critical appraisal of alkaline HER electrocatalysis is presented, with a special emphasis on the connection between fundamental surface electrochemistry on single‐crystal models and the derived molecular design principle for real‐world electrocatalysts. By presenting some typical examples across theoretical calculations, surface characterization, and electrochemical experiments, we try to address some key ongoing debates to deliver a better understanding of alkaline HER at the atomic level.     

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.     

Heteroatom‐doped MoSe2 Nanosheets with Enhanced Hydrogen Evolution Kinetics for Alkaline Water Splitting

Electrochemical water splitting for hydrogen generation is a vital part for the prospect of future energy systems, however, the practical utilization relies on the development of highly active and earth‐abundant catalysts to boost the energy conversion efficiency as well as reduce the cost. Molybdenum diselenide (MoSe₂) is a promising nonprecious metal‐based electrocatalyst for hydrogen evolution reaction (HER) in acidic media, but it exhibits inferior alkaline HER kinetics in great part due to the sluggish water adsorption/dissociation process. Herein, the alkaline HER kinetics of MoSe₂ is substantially accelerated by heteroatom doping with transition metal ions. Specifically, the Ni‐doped MoSe₂ nanosheets exhibit the most impressive catalytic activity in terms of lower overpotential and larger exchange current density. The density functional theory (DFT) calculation results reveal that Ni/Co doping plays a key role in facilitating water adsorption as well as optimizing hydrogen adsorption. The present work paves a new way to the development of low‐cost and efficient electrocatalysts towards alkaline HER.     

Earth-Abundant Transition-Metal-Based Bifunctional Electrocatalysts for Overall Water Splitting in Alkaline Media

The depletion of fossil fuels has accelerated the search for clean, sustainable, scalable, and environmentally friendly alternative energy sources. Hydrogen is a potential energy carrier because of its advantageous properties, and the electrolysis of water is considered as an efficient method for its industrial production. However, the high-energy conversion efficiency of electrochemical water splitting requires cost-effective and highly active electrocatalysts. Therefore, researchers have aimed to develop high-performance electrode materials based on non-precious and abundant transition metals for conversion devices. Moreover, to further reduce the cost and complexity in real-world applications, bifunctional catalysts that can be simultaneously active on both the anodic (i.e., oxygen evolution reaction, OER) and cathodic (i.e., hydrogen evolution reaction, HER) sides are economically and technically desirable. This Minireview focuses on the recent progress in transition-metal-based materials as bifunctional electrocatalysts, including several promising strategies to promote electrocatalytic activities for overall water splitting in alkaline media, such as chemical doping, defect (vacancy) engineering, phase engineering, facet engineering, and structure engineering. Finally, the potential for further developments in rational electrode materials design is also discussed.     

Single-atom rhodium anchored on S-doped black phosphorene as a promising bifunctional electrocatalyst for overall water splitting

Superior bifunctional electrocatalysts with ultra-high stability and excellent efficiency are crucial to boost the oxygen evolution reaction (OER) and the hydrogen evolution reduction (HER) in the overall water splitting (OWS) for the sustainable production of clean fuels. Herein, comprehensive density functional theory (DFT) computations were performed to explore the potential of several single transition metal (TM) atoms anchored on various S-doped black phosphorenes (TM/S_nx-BP) for bifunctional OWS electrocatalysis. The results revealed that these candidates display good stability, excellent electrical conductivity, and diverse spin moments. Furthermore, the Rh/S₁₂-BP catalyst was identified as an eligible bifunctional catalyst for OWS process due to the low overpotentials for OER (0.43 V) and HER (0.02 V), in which Rh and its adjacent P atoms were identified as the active sites. Based on the computed Gibbs free energies of OH*, O*, OOH* and H*, the corresponding volcano plots for OER and HER were established. Interestingly, the spin moments and the charge distribution of the active sites determine the catalytic trends of OER and HER. Our findings not only propose a promising bifunctional catalyst for OWS, but also widen the potential application of BP in electrocatalysis.     

Electrochemically exfoliated Ni-doped MoS2 nanosheets for highly efficient hydrogen evolution and Zn-H2O battery

Thanks to tunable physical and chemical properties, two-dimensional (2D) materials have received intensive interest, endowing their excellent electrocatalytic performances for applications in energy conversion. However, their catalytic activities are largely determined by poor adsorption energy and limited active edge sites. Herein, a one-step electrochemical exfoliation strategy was developed to fabricate 2D Ni-doped MoS₂ nanosheets (Ni-EX-MoS₂) with a lateral size of ～500 nm and thickness of ～3.5 nm. Profiting from high electrical conductivity and abundant exposing active sites, Ni-EX-MoS₂ catalyst displayed an admirable performance for electrochemical hydrogen evolution reaction (HER) with a low overpotential of 145 mV at 10 mA/cm² as well as a small Tafel slope of 89 mV/dec in alkaline media, which are superior to those of the most reported MoS₂-based electrocatalysts. The formed Ni species with tuning electronic structure played a crucial role as primary active center of Ni-EX-MoS₂, as well as the forming stable 1T/2H phase MoS₂ interface demonstrated a synergistic effect on electrocatalytic HER performance. Further, Ni-EX-MoS₂ was employed as a cathode electrode for alkaline Zn-H₂O battery, which displayed a high power density of 3.3 mW/cm² with excellent stability. This work will provide a simple and effective guideline for design of electrochemically exfoliated transition metal-doped MoS₂ nanosheets to inspire their practical applications in energy catalytic and storage.     

Dual modulation of morphology and electronic structures of VN@C electrocatalyst by W doping for boosting hydrogen evolution reaction

Developing high-efficiency and robust durability electrocatalyst for hydrogen evolution reaction (HER) in water electrolysis functions as a crucial role for the construction of green hydrogen economy, herein, ultrafine W-doped vanadium nitride nanoparticles anchored on N-doped graphitic carbon framework (WVN@NGC) are synthesized through a one-step simple pyrolysis protocol. Owing to the enlarged catalytically active sites, enhanced electrical conductivity and optimized electronic structure, the resultant VN/WN@NGC delivered the prominent HER performance with overpotentials of 143 mV and 158 mV at 10 mA/cm² in acid and alkaline media, respectively, accompanied by the long-term stability for at least 50 h. This work highlights a novel strategy for a metal-triggered modulation of nitride-based HER electrocatalyst for sustainable energy conversion device.