(Co,Ni) Se2/C@FeOOH中空笼状纳米结构的自旋调控加速水氧化催化研究

氢气作为一种清洁无污染的可再生能源,可以有效地解决全球能源危机和环境污染问题.低能耗水裂解制氢是公认的未来清洁制氢的有效途径之一.水裂解反应分为阳极上发生的析氧反应(OER)和阴极上发生的析氢反应,由于阳极半反应涉及四电子过程,反应动力学缓慢,进而导致整个水分解产氢效率低下,成为规模化水裂解制氢应用的瓶颈.贵金属Ir基...     

电化学形成的PtFeNi合金与含缺陷NiFe LDHs载体之间的电荷转移实现高效水分解

氢气是一种能量密度高,可完全燃烧的清洁能源.发展绿色制氢技术对于解决全球环境污染,二氧化碳排放等环境问题具有重要意义.电化学水分解被认为是一种清洁高效的制氢手段,可自恰于可再生能源的波动性,具有效率高、响应快、氢气纯度高等优点.然而,由于电化学反应过电位大及动力学缓慢的原因,驱动电化学水分解的能量消耗巨大.因此,开发高...     

提高氧化铁光电催化分解水效率的策略进展

为了解决能源危机与环境污染问题,发展一种可再生的清洁能源至关重要.太阳能是一种取之不尽用之不竭的清洁能源,而氢气是一种良好的能源载体.利用太阳能光电催化水分解制氢,是一项有望能够解决能源与环境问题的技术,具有很大的应用前景.其中,氧化铁因为具有合适的能带位置与带隙、良好的稳定性与廉价无毒等优点,成为一种理想的光阳极材料...     

Scan rate(mV s?1)

传统化石能源的大量消耗使得能源短缺和环境污染等问题日益严峻.社会的可持续发展需要进行能源结构调整,寻求清洁、可再生的替代能源已迫在眉睫.氢能作为一种可再生能源,其热值高,燃烧产物无污染,是未来最理想的能源形式之一.水裂解制氢是公认的未来清洁制氢的一种有效途径.然而,无论是电催化或光催化水裂解反应,析氧反应都是关键的半反应.因其复杂的四电子过程导致动力学缓慢,使得析氧半反应成为水裂解反应的瓶颈.长久以来,贵金属Ir和Ru基材料是被广泛研究的高活性的析氧催化剂.然而高成本和低储量极大地限制了它们的大规模工业化应用.因此,开发高效、储量丰富的析氧催化剂,意义重大但仍充满挑战性.本文考察了一种简便而有效的合成策略,在碱性水溶液条件下,成功实现将一系列Fe基金属有机框架(MOF)前驱物原位转化为无定形Fe基双金属氢氧化物纳米结构.这些由MOF前驱物转化得到的氢氧化物纳米结构保留了前驱体纳米棒的宏观形貌,由许多超细的无定形纳米颗粒(平均粒径小于10 nm)构成,在催化反应中可以提供丰富的催化活性位,相邻的纳米颗粒之间紧密接触,有利于电子在催化活性位之间传递.以玻碳电极作为基底,通过组分优化得到的NiFe-OH-0.75催化剂样品在电催化析氧反应中仅需270 mV的过电位便可达到10 mAcm-2的电流密度, Tafel斜率为39 mVdec-1.将催化剂负载到三维泡沫镍基底上时,由于电极基底导电性提升以及传质增加,在10 mAcm-2的电流密度所需的过电位可以降低到235 mV, Tafel斜率为37 mVdec-1,并且表现出较好的稳定性.同时,本文进一步证实这些无定形氢氧化物可以用作助催化剂,与合适的光敏剂结合,实现有效的光催化水氧化反应.在KH2PO4-K2HPO4缓冲溶液(pH=9)体系中,以[Ru(2,2’-bipyridine)3]Cl2为光敏剂, Na2S2O8为电子受体,由CoFe-MIL-0.75前驱体转化所得到的CoFe-OH-0.75助催化剂表现出更优越的光催化产氧性能,产氧效率可达59.6%.本文结果可以为其他基于MOF及其相关衍生材料的制备提供新思路.     

MOF衍生的分层多孔三维N-CoPx/Ni2P大电流密度下加速析氢

氢气(H2)具有能量密度高、环境友好等优点,是一种很有前景的清洁能源载体.目前,电催化水裂解大规模制氢被认为是一种理想可行的方法.析氢反应(HER)涉及多个步骤,首先形成吸附的氢(Volmer步骤),然后是脱附步骤(Heyrovsky步骤)或两个相邻的吸附氢形成H2(Tafel步骤).与酸性介质相比,碱性介质中的HER...     

MoSe2纳米片耦合Pt纳米颗粒用于高效双功能催化甲醇辅助水电解制氢(英文)

化石燃料的大量消耗所带来的全球性挑战推动人们大力发展清洁和可持续的能源.氢能作为一种绿色、无污染的能源载体,是能源向绿色经济转换的关键,而利用可再生能源进行的电解水制氢被认为是实现绿色制氢的最佳选择.然而由于析氧反应(OER)的氧化电位(1.23 V)较高,动力学缓慢,实际水电解需要更多的能量输入.具有低氧化电位的甲醇辅助水电解(0.016 V)可以匹配可再生能源实现低能耗电解制氢,受到了广泛关注.开发高效的用于催化甲醇氧化(MOR)和析氢反应(HER)的双功能催化剂是实现这一愿景的前提.传统的Pt基催化剂容易受到阳极侧MOR过程中产生的CO中间体毒化,严重影响甲醇辅助水电解制氢的效率.为了提升Pt基催化剂的催化活性和稳定性,一种有效的策略是引入合适的功能组分来促进催化反应.例如,贵金属颗粒和亲氧化成分(如过渡金属氧化物和磷化物)之间的金属-载体相互作用可以有效提高Pt基催化剂的抗CO中毒能力.过渡金属硒化物由于其优良的金属性和亲氧性作为催化促进剂受到越来越多的关注.硒化钼(MoSe₂)具有良好的稳定性和导电性并且其2H相中的不饱和边缘具有水活化和解离活性,同时其...     

优化金属磷化物电催化析氢性能的策略

日益严重的能源危机和环境污染问题使得探索清洁的可再生能源载体及减少对传统化石燃料的过度依赖成为人们面临的一项重要任务.因此,各种可持续能源如太阳能、风能、海洋能和生物质能等得到了广泛研究并取得了一定的进展.然而,这些能源因存在间歇性和不稳定性等缺点阻碍了其实际应用.近年,氢气作为一种能源载体,以其高能量密度和无碳排放的优点引起了人们的广泛关注,被认为是缓解日益严重的污染问题的最有前途的环保能源.对比目前采用的天然气热解和煤炭气化等传统制氢策略,电催化水裂解由于催化效率高,制氢纯度高和不产生温室气体,被认为是高效、环保、可持续的制氢策略.电催化水裂解由两个独立的半反应组成,分别是析氢反应和析氧反应.析氢反应作为水裂解的一个半反应,在降低制氢成本及提高产氢催化效率方面起着关键作用.然而,目前的核心问题之一是要开发高效的析氢电催化剂,以加快反应速度.目前,铂和铂基纳米材料被认为是高效的析氢电催化剂,但是其稀缺性和高成本阻碍了大规模实际应用.金属磷化物由于具有较高的本征活性并且在不同的电解质中都具有良好的电催化析氢性能,被证明是一种优良的析氢电催化剂.此外,与普通催化剂相比,金属磷化电催化剂还具有合成简便、效率高、成本低、省时等优点.本文详细介绍了近年人们在金属磷化物用于电催化析氢研究中取得的进展.首先,介绍了电催化析氢反应机理,金属磷化物的结构及作用,并对其优缺点进行了总结;随后,综述了金属磷化物的合成方法,包括后处理、原位生成和电沉积策略,并对不同方法进行了比较和讨论.此外,从元素掺杂、界面工程、空穴工程、修饰特定载体、构建特定纳米结构、设计双或多金属磷化物和其他发展的新方法等七个方面详细总结了促进金属磷化物电催化活性的多种策略,并进行了对比和讨论.最后,归纳了金属磷化物在电催化析氢应用中存在的问题和面临的挑战,并对未来的研究发展提出了展望.     

增强UiO-66-NH2光催化水分解制氢性能的研究进展

氢能是一种能量密度高、储量大、可再生、零污染的新能源。光催化水分解制氢是一种绿色、清洁的能源转换技术,被认为是一种有效的制氢方法。UiO-66-NH2是一种可见光响应、稳定性良好的金属有机骨架材料,但存在可见光响应范围有限、导电性差、载流子复合率高等问题。研究者们采用金属粒子掺杂、染料敏化、金属纳米粒子负载等多种方法对UiO-66-NH2进行改性,提升UiO-66-NH2在光催化水分解制氢反应中的性能,并报道了许多研究成果。因此,本文对近年来报道的有关增强UiO-66-NH2光催化水分解制氢性能的方法进行了综述,并对后续的发展提出了建议,以期为UiO-66-NH2在光催化水分解制氢中应用研究提供参考。     

太阳能光催化制氢研究进展

随着人类社会的快速发展和传统能源的急剧消耗,能源紧缺和环境污染已经成为制约人类社会可持续发展的重要因素,构建清洁的环境友好的可再生新能源体系是当前各国高度关注的焦点和重大战略.在众多绿色环保、可持续新能源选项中,半导体光催化制氢因其可利用清洁可再生的太阳能制取高效清洁氢能,有望完全解决能源紧缺和环境污染问题,成为最有应用前景的技术之一. 本文通过概述半导体光催化制氢原理、半导体光电化学及光电稳定性、半导体光催化制氢效率,重点介绍半导体光催化剂、光生电荷分离及光催化制氢体系等方面若干新进展,并对太阳能光催化制氢技术的发展加以评述和展望.     

碳质与金属催化剂热催化裂解甲烷产氢研究进展

甲烷裂解制氢方法具有产氢纯度高和清洁无污染的特点,被认为是当前最有前景的制氢方法之一.现阶段甲烷裂解制氢的研究工作主要集中于制备活性与稳定性兼备的催化剂.我们综述了近年来甲烷裂解制氢反应中碳质催化剂和金属催化剂两大系列催化剂的研究进展,从载体、活性组分、助剂3个方法对目前催化剂裂解甲烷产氢性能的影响进行了系统分析,总结了反应机理和催化剂的失活与再生情况,在以上基础上对催化剂未来的发展趋势进行了展望.     

具有高效析氧催化性能的铁基双元金属有机框架纳米棒研究

析氧反应(OER)是电解水制氢的关键步骤,开发高效、稳定、廉价的OER电催化剂是目前该领域的研究热点.碱性电解液中的OER电催化剂成分以Mn、Fe、Co、Ni等为主,其中单一组分的Fe基化合物催化活性不高,但碱性电解液中的痕量铁杂质极易掺入Ni、Co等非Fe基材料的结构中,极大影响其OER催化性能,即现有大部分非Fe基...     

Electrosynthesis of hierarchical NiLa-layered double hydroxide electrode for efficient oxygen evolution reaction

Oxygen evolution reaction(OER) is a key process for electrochemical water splitting due to its intrinsic large overpotential. Recently, layered double hydroxides(LDHs), especially Ni Fe-LDH, have been regarded as highly performed electrocatalysts for OER in alkaline condition. Here we first present a new class of Ni La-LDH electrocatalyst synthesized by an electrochemical process for efficient water splitting. The as-prepared NiL a-LDH nanosheet arrays(NSAs) give remarkable electrochemical activity and durability under alkaline environments, with a low overpotential of 209 mV for OER to deliver a current density of 10 mA cm~(-2), surpassing most of previous reported LDHs eletrocatalysts. The presence of NiLa-LDH in this work extends the studies about LDHs-based electrocatalysts, which will benefit the development of electrochemical energy storage and conversion systems.     

Amorphous Nanocages of Cu‐Ni‐Fe Hydr(oxy)oxide Prepared by Photocorrosion For Highly Efficient Oxygen Evolution

Electrochemical water splitting requires efficient, low‐cost water oxidation catalysts to accelerate the sluggish kinetics of the water oxidation reaction. A rapid photocorrosion method is now used to synthesize the homogeneous amorphous nanocages of Cu‐Ni‐Fe hydr(oxy)oxide as a highly efficient electrocatalyst for the oxygen evolution reaction (OER). The as‐fabricated product exhibits a low overpotential of 224 mV on a glassy carbon electrode at 10 mA cm^?2 (even lower down to 181 mV when supported on Ni foam) with a Tafel slope of 44 mV dec^?1 for OER in an alkaline solution. The obtained catalyst shows an extraordinarily large mass activity of 1464.5 A g^?1 at overpotential of 300 mV, which is the highest mass activity for OER. This synthetic strategy may open a brand new pathway to prepare copper‐based ternary amorphous nanocages for greatly enhanced oxygen evolution.     

Single-crystalline layered double hydroxides with rich defects and hierarchical structure by mild reduction for enhancing the oxygen evolution reaction

The oxygen evolution reaction(OER) with sluggish reaction kinetics and large overpotential is the critical reaction in water splitting that is promising for energy storage and conversion. Layered double hydroxides(LDHs), due to their unique lamellar structure and flexibility of chemical component, are very competing material candidates for OER. Herein, the morphology structure and the electronic structure of LDHs were simultaneously tuned to improve the OER catalytic activity by mild solvothermal reduction using ethylene glycol. The increased surface area, the introduction of oxygen vacancies and the construction of hierarchical structure greatly enhanced the electro-catalytic activity of LDHs for OER. The as-prepared LDHs showed a lower over-potential as low as 276 mV at a current density of 10 mA cm~(-2), and a small Tafel slope of 40.3 mV dec~(-1) accompanied with good stability. This work provides an efficient way to the design and optimization of advanced catalysts in the future.     

Electrodeposition at Highly Negative Potentials of an Iron-Cobalt Oxide Catalyst for Use in Electrochemical Water Splitting

Earth-abundant transition metal-based catalysts have been extensively investigated for their applicability in water electrolysers to enable overall water splitting to produce clean hydrogen and oxygen. In this study a Fe−Co based catalyst is electrodeposited in 30 seconds under vigorous hydrogen evolution conditions to produce a high surface area material that is active for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). This catalyst can achieve high current densities of 600 mAcm⁻² at an applied potential of 1.6 V (vs RHE) in 1 M NaOH with a Tafel slope value of 48 mV dec⁻¹ for the OER. In addition, the HER can be facilitated at current densities as high as 400 mA cm⁻² due to the large surface area of the material. The materials were found to be predominantly amorphous but did contain crystalline regions of CoFe₂O₄ which became more evident after the OER indicating interesting compositional and structural changes that occur to the catalyst after an electrocatalytic reaction. This rapid method of creating a bimetallic oxide electrode for both the HER and OER could possibly be adopted to other bimetallic oxide systems suitable for electrochemical water splitting.     

Atmospheric-Temperature Chain Reaction towards Ultrathin Non-Crystal-Phase Construction for Highly Efficient Water Splitting

Combining the self-sacrifice of a highly crystalline substance to design a multistep chain reaction towards ultrathin active-layer construction for high-performance water splitting with atmospheric-temperature conditions and an environmentally benign aqueous environment is extremely intriguing and full of challenges. Here, taking cobalt carbonate hydroxides (CCHs) as the initial crystalline material, we choose the Lewis acid metal salt of Fe(NO₃)₃ to induce an aqueous-phase chain reaction generating free CO₃²⁻ ions with subsequent instant FeCO₃ hydrolysis. The resultant ultrathin (∼5 nm) amorphous Fe-based hydroxide layer on CCH results in considerable activity in catalyzing the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), yielding 10/50 mA ⋅ cm⁻² at overpotentials of 230/266.5 mV for OER and 72.5/197.5 mV for HER. The catalysts can operate constantly in 1.0 M KOH over 48 and 45 h for the OER and HER, respectively. For bifunctional catalysis for alkaline electrolyzer assembly, a cell voltage as low as 1.53 V was necessary to yield 10 mA cm⁻² (1.7 V at 50 mA cm⁻²). This work rationally builds high-efficiency electrochemical bifunctional water-splitting catalysts and offers a trial in establishing a controllable nanolevel ultrathin lattice disorder layer through an atmospheric-temperature chemical route.     

Synthesis and Optimization of Zeolitic Imidazolate Frameworks for the Oxygen Evolution Reaction

Metal–organic frameworks/zeolitic imidazolate frameworks (MOFs/ZIFs) and their post-synthesis modified nanostructures, such as oxides, hydroxides, and carbons have generated significant interest for electrocatalytic reactions. In this work, a high and durable oxygen evolution reaction (OER) performance directly from bimetallic Zn_100−xCo_x-ZIF samples is reported, without carrying out high-temperature calcination and/or carbonization. ZIFs can be reproducibly and readily synthesized in large scale at ambient conditions. The bimetallic ZIFs show a systematic and gradually improved OER activity with increasing cobalt concentration. A further increase in OER activity is evidenced in ZIF-67 polyhedrons with controlled particle size of <200 nm among samples of different sizes between 50 nm and 2 μm. Building on this, a significantly enhanced, >50 %, OER activity is obtained with ZIF-67/carbon black, which shows a low overpotential of approximately 320 mV in 1.0 m KOH electrolyte. Such activity is comparable to or better than numerous MOF/ZIF-derived electrocatalysts. The optimized ZIF-67 sample also exhibits increased activity and durability over 24 h, which is attributed to an in situ developed active cobalt oxide/oxyhydroxide related nanophase.     

Preparation of Quaternary FeCoMoCu Metal Oxides for Oxygen Evolution Reaction

Molybdenum doping is an effective way to improve the oxygen evolution reaction(OER) properties of catalysts, which can efficiently improve the electronic conductivity, mass transport process, and intrinsic activity of transition metal oxides or hydroxides, especially for those multi-component oxides with more abundant active sites. Herein, we have prepared a quaternary FeCoMoCu metal oxide on Cu foam(FeCoMoCuO_x@Cu) as an efficient OER catalyst. As expected, FeCoMoCuO_x@Cu could exhibit a low overpotential(252 mV at the current density of 10 mA/cm²) and exceptional stability(10000 cycles of CV scans or constant electrolysis for 48 h).     

Toward Understanding the Formation Mechanism and OER Catalytic Mechanism of Hydroxides by In Situ and Operando Techniques

Developing efficient and affordable electrocatalysts for the sluggish oxygen evolution reaction (OER) remains a significant barrier that needs to be overcome for the practical applications of hydrogen production via water electrolysis, transforming CO₂ to value-added chemicals, and metal-air batteries. Recently, hydroxides have shown promise as electrocatalysts for OER. In situ or operando techniques are particularly indispensable for monitoring the key intermediates together with understanding the reaction process, which is extremely important for revealing the formation/OER catalytic mechanism of hydroxides and preparing cost-effective electrocatalysts for OER. However, there is a lack of comprehensive discussion on the current status and challenges of studying these mechanisms using in situ or operando techniques, which hinders our ability to identify and address the obstacles present in this field. This review offers an overview of in situ or operando techniques, outlining their capabilities, advantages, and disadvantages. Recent findings related to the formation mechanism and OER catalytic mechanism of hydroxides revealed by in situ or operando techniques are also discussed in detail. Additionally, some current challenges in this field are concluded and appropriate solution strategies are provided.     

Phytic Acid-Based FeCo Bimetallic Metal-Organic Gels for Electrocatalytic Oxygen Evolution Reaction

Electrocatalysts have been developed to improve the efficiency of gas release for oxygen evolution reaction (OER), and finding a simple and efficient method for efficient electrocatalysts has inspired research enthusiasm. Herein, we report bimetallic metal-organic gels derived from phytic acid (PA) and mixed transition metal ions to explore their performance in electrocatalytic oxygen evolution reaction. PA is a natural phosphorus-rich organic compound, which can be obtained from plant seeds and grains. PA reacts with bimetallic ions (Fe³⁺ and Co²⁺) in a facile one-pot synthesis under mild conditions to form PA-FeCo bimetallic gels, and the corresponding aerogels are further partially reduced with NaBH₄ to improve the electrocatalytic activity. Mixed valence states of Fe(II)/Fe(III) and Co(III)/Co(II) are present in the materials. Excellent OER performance in terms of overpotential (257 mV at 20 mA cm⁻²) and Tafel slope (36 mV dec⁻¹) is achieved in an alkaline electrolyte. This reduction method is superior to the pyrolysis method by well maintaining the gel morphology structure. This strategy is conducive to the further improvement of the performance of metal-organic electrocatalysts, and provides guidance for the subsequent application of metal-organic gel electrocatalysts.