铁掺杂二硫化钼纳米片作为高效的双功能电解水催化剂

设计和合成具有高活性、耐久性的非贵金属电解水催化剂对能量转化和储存具有重要意义。在研究中,通过硝酸铁、硫代乙酰胺与二水钼酸钠在无水乙醇中的水热反应制备了铁掺杂二硫化钼(Fe-MoS₂)的纳米材料。Fe-MoS₂具有较高的析氧反应(OER)活性,在1 mol/L KOH电解质中,当电流密度为10 mA·cm^-2时过电位为250 mV,塔菲尔斜率为219 mV·dec^-1,而且Fe-MoS₂在这些条件下可稳定超过10 h以上。同时其具有良好的析氢反应(HER)活性,在0.5 mol/L H₂SO₄电解质中,当电流密度为10 mA cm^-2时过电位为220 mV。此外,在1 mol/L KOH电解液中,Fe-MoS₂/C(阳极)//Fe-MoS₂/C(阴极)两电极体系具有良好的电解水催化活性,在10 mA cm^-2的电流密度下低电位为1.77 V。为开发...     

自组装磷化镍纳米片阵列电极的电催化析氢性能研究

可持续发展的清洁氢能源是未来能源发展的方向之一,因而发展高效廉价的析氢材料变得尤为重要。本文首次通过水热和退火的方式制备出自组装磷化镍纳米片阵列结构,并通过SEM和XRD等技术表征这种结构的形貌和组成成分。与众多关于Ni-P纳米材料集中在酸性体系下的析氢电化学研究不同,本文首次通过在碱性条件下稳态极化曲线(LSV)、Tafel极化曲线、电流-时间曲线(i-t)以及交流阻抗曲线探究了其作为电解水析氢纳米电催化电极材料的电化学性能。该材料的电极具有特殊的纳米形貌结构和性质,使其具有更低的析氢反应电位、更大的析氢反应活性和较好的稳定性,具有替代贵金属作为水解析氢材料的潜力。     

水热法制备镍负载硫磷双掺杂石墨烯电极及其电催化析氢性能研究

设计一种高活性、高稳定性的非贵金属基催化剂,对电催化析氢的应用具有重要意义.以硫酸和植酸为硫磷掺杂剂,采用水热法合成了硫磷共掺杂石墨烯(SPG);随后,采用简单的醇热法制备了直接生长在SPG上的Ni基纳米材料(Ni/SPG).制备的Ni/SPG电催化剂表现出杰出的析氢性能,其阻抗极低(0.48Ω),电化学活性表面积极好...     

不同结构镍纳米线阵列的制备及其磁性

采用直流电沉积在多孔有序氧化铝模板中制备了不同结构的有序镍纳米线阵列。采用扫描电子显微镜和透射电子显微镜对所制备的镍纳米线的形貌和结构进行了表征。研究了镍纳米线不同结构对镍纳米线阵列磁性性能的影响规律。当电沉积电压为2.5V时制备的镍纳米线为多晶结构;电沉积电压4V时,镍纳米线为沿[220]择优取向的单晶结构;电沉积电压大于5V时,择优取向由[220]转为[111]方向。磁滞回线结果表明,单晶镍纳米线阵列与多晶纳米线阵列相比具有更高的矩形度,沿[111]择优取向的单晶纳米线相比沿[220]取向的单晶镍纳米线具有更大的矩形度,表现出显著的磁各向异性。     

非晶Co-W-B/碳布复合电极材料的制备及其电解水催化性能

通过湿化学还原在碳布(CC)表面沉积非晶Co-W-B催化活性物质,制备一种自支撑Co-W-B/碳布(Co-W-B/CC)复合电极材料。电化学研究结果表明,Co-W-B/CC材料在NaOH溶液(1 mol/L)中表现出良好的电解水催化性能。制备过程中[WO₄^2-]/([WO₄^2-]+[Co²⁺])比值为50%的Co-50W-B/CC样品其催化活性最高：10 mA/cm²时的OER过电位为0.394V,OER过程的Tafel斜率为96.8 mV/dec;-10 mA/cm²时的HER过电位为0.098 V,HER过程的Tafel斜率为117.4 mV/dec。对电化学阻抗的分析结果表明,本征催化活性和电化学活性面积两者的提高,使Co-50W-B/CC样品在较低的电流密度下具有与贵金属基材料相近的催化活性。     

电化学刻蚀制备表面纳米多孔NiMoCu电解水析氢催化剂

电解水制氢是一项制取绿色氢能的重要技术,开发高催化活性的催化剂作为电极材料是当前的研究热点。电解水反应包括阴极的析氢反应和阳极的析氧反应,以Ni₇₄Mo₆Cu₂₀三元合金条带为前驱体,采用电化学脱合金技术制备了一种用于析氢反应的表面纳米多孔NiMoCu电解水析氢催化剂,并采用扫描式电子显微镜、X射线衍射仪、X射线光电子能谱仪等设备对材料的物理化学特性进行了表征。结果表明：所制备的纳米多孔NiMoCu电极材料在1mol/L KOH溶液中具有良好的析氢性能,仅需要90mV、227mV的过电位就能达到10mA/cm²、100mA/cm²的电流密度。     

钴-镍双金属磷化物中空纳米笼用于高效电解水

制备一种低成本、高效、稳定耐用的双功能电催化剂对于电催化水分解至关重要.本文采用自模板策略和原位磷化工艺相结合的方法构建了一种具有中空结构的钴镍双金属磷化物纳米笼(CoNiP_(x)).由于其独特的中空结构和钴镍双金属之间的协同效应,合成的CoNiP_(x)中空纳米笼催化剂在全pH值范围的电解质中对析氢反应均表现出优异...     

NiCoMo层状双氢氧化物纳米催化剂的制备及其电催化析氧性能研究

以泡沫镍(NF)为基底,通过一步水热法制备不同镍钴比的层状双氢氧化物(NiCoMo-LDH/NF)纳米催化剂,并借助X射线衍射和扫描电镜对催化剂的物相和形貌进行表征分析,研究催化剂元素组分调控对其电催化性能的影响。通过元素组分的调控,改变催化剂的显微结构,当Ni∶Co=1∶2(摩尔比,下同)时,Ni₁Co₂Mo-LDH/NF催化剂密集的纳米片结构,有利于活性位点的暴露和中间体吸脱附,以及电荷的快速传输,进而促使析氧反应的进行。电化学测试表明,在1mol/L KOH溶液中,电流密度达到10mA/cm²时,Ni∶Co=1∶2的纳米材料过电势仅为266mV,塔菲尔斜率为82.45mV/dec。此外,经12h的时间-电流稳定性测试后,材料的催化性能和形貌未有明显改变。可见,当Ni∶Co=1∶2时,材料表现出优异的催化活性和稳定性。     

耐蚀镍基催化剂的制备及电解海水性能的研究

开发抑制析氯的竞争反应和氯离子腐蚀的高效电解海水催化剂是至关重要的。通过两步法(激光扫描法+浸泡置换法)在泡沫镍上快速制备了一种高活性且耐蚀的NiFe-LDH@MnO₂/NF电解海水催化剂。该催化剂中NiFe-LDH提高了催化反应的活性,MnO₂层防止催化剂被氯侵蚀,二者的协同作用使催化剂在碱性盐水介质中表现出优异的析氧性能。所制备的NiFe-LDH@MnO₂/NF催化剂在10 mA/cm²的电流密度下,过电位仅为270 mV,在100 mA/cm²的大电流密度下过电位为360 mV,且在10 mA/cm²的电流密度下可稳定催化析氧100 h,为工业电解海水制氢催化剂的制备提供理论指导。     

Ternary NiCoP nanosheet arrays: An excellent bifunctional catalyst for alkaline overall water splitting

Exploring bifunctional catalysts for the hydrogen and oxygen evolution reactions (HER and OER) with high efficiency,low cost,and easy integration is extremely crucial for future renewable energy systems.Herein,ternary NiCoP nanosheet arrays (NSAs) were fabricated on 3D Ni foam by a facile hydrothermal method followed by phosphorization.These arrays serve as bifunctional alkaline catalysts,exhibiting excellent electrocatalytic performance and good working stability for both the HER and OER.The overpotentials of the NiCoP NSA electrode required to drive a current density of 50 mA/cm2 for the HER and OER are as low as 133 and 308 mV,respectively,which is ascribed to excellent intrinsic electrocatalytic activity,fast electron transport,and a unique superaerophobic structure.When NiCoP was integrated as both anodic and cathodic material,the electrolyzer required a potential as low as ～1.77 V to drive a current density of 50 mA/cm2 for overall water splitting,which is much smaller than a reported electrolyzer using the same kind of phosphide-based material and is even better than the combination of Pt/C and Ir/C,the best known noble metal-based electrodes.Combining satisfactory working stability and high activity,this NiCoP electrode paves the way for exploring overall water splitting catalysts.     

A highly efficient Fe-doped Ni3S2 electrocatalyst for overall water splitting

The development of efficient and stable electrocatalysts with earth-abundant elements for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in the same electrolyte is incontrovertibly vital in water electrolysis. However, their large-scale fabrication remains a great challenge. Here, we report a self-supported electrocatalyst in the form of Fe-doped Ni₃S₂ nanoparticles in-situ grown on three-dimensional (3D) conductive Fe−Ni alloy foam (Fe−Ni₃S₂/AF) by surface-assisted chemical vapor transport (SACVT) method. Homogeneous growth environment and scalability of SACVT method allow Fe−Ni₃S₂ nanoparticles uniformly growing on AF in large-scale. Fe−Ni₃S₂/AF exhibits high activity and durability when act as HER catalyst and OER precatalyst in alkaline media. The HER and OER overpotential at 10 mA/cm² is considerably small, only 75 and 267 mV, respectively. Moreover, the electrolyzer assembled by Fe−Ni₃S₂/AF for overall water splitting exhibits a low cell voltage and high durability in long-term test. Based on experiments and theoretical calculation, the significantly enhanced activity could be originated from the incorporation of Fe, which contributed to increase the electrochemical active surface area, enhance electrical conductivity, optimize the hydrogen and H₂O adsorption energy of Ni₃S₂ (101) surface in HER, and form active bimetallic Ni−Fe(oxy)hydroxide in OER. The excellent durability of self-supported Fe−Ni₃S₂/AF could be benefited from the in-situ growth of Fe−Ni₃S₂ nanoparticles on 3D AF, which could ensure closely mechanical adhesion between active materials and substrate, promote charge transport and increase surface area. This work provides a facile method for large-scale synthesis of electrocatalysts with high activity and long-term durability for efficient water electrolysis in alkaline media.

     

Self-supporting amorphous nanoporous NiFeCoP electrocatalyst for efficient overall water splitting

The design of cost-effective and earth-abundant bifunctional electrocatalysts for highly efficient oxy-gen evolution reaction(OER)and hydrogen evolution reaction(HER)is important for water splitting as an advanced renewable energy transformation system.In this work,the self-supporting amorphous NiFeCoP catalyst with nanoporous structure via a facile electrochemical dealloying method is reported.Benefiting from the bicontinuous nanostructure,disordered atomic arrangement,abundant active sites and synergic effect of various transition metals,the as-prepared nanoporous NiFeCoP(np-NiFeCoP)cat-alyst exhibits good electrocatalytic activity,which achieves the current densities of 10 mA cm-2 at low overpotentials of 244 mV and 105 mV for OER and HER in 1.0 M KOH,respectively.In addition,the bifunc-tional electrocatalyst also shows outstanding and durable electrocatalytic activity in water splitting with a small voltage of 1.62 V to drive a current density of 10 mA cm-2 in a two-electrode electrolyzer system.The present work would provide a feasible strategy to explore the efficient and low-cost bifunctional electrocatalysts toward overall water splitting.     

Hierarchical NiMoP2-Ni2P with amorphous interface as superior bifunctional electrocatalysts for overall water splitting

Producing highly efficient bifunctional catalyst for the generation of hydrogen and oxygen through overall water splitting is an emerging direction in electrocatalysis,Herein,a dandelion-like hierarchi-cal NiMoP2-Ni2P(nanowire/nanoparticle)heterostructure was synthesized for efficient electrochemical water splitting.The NiMoP2-Ni2P heterostructures grown on carbon cloth as a freestanding integrated electrode exhibited excellent oxygen evolution reaction(OER)activity and hydrogen evolution reaction(HER)activities with low overpotentials(258 mV and 53 mV to reach 10 mA cm-2 for the OER and HER,respectively),and small Tafel slope(45 mV dec-1 and 58 mV dec-1 for the OER and HER,respectively).Moreover,the NiMoP2-Ni2 P heterostructure can act as both anode and cathode catalysts for overall water splitting with low overall potential of 1.48 V at 10 mA cm-2.Density functional theory(DFT)combined with structural probes suggests that the amorphous heterogeneous interfaces play an essential role in enhanced catalytic performance.     

Metal-organic framework derived CoSe2 nanoparticles anchored on carbon fibers as bifunctional electrocatalysts for efficient overall water splitting

The development of efficient,low-cost,stable,non-noble-metal electrocatalysts for water splitting,particularly those that can catalyze both the hydrogen evolution reaction (HER) at the cathode and oxygen evolution reaction (OER) at the anode,is a challenge.We have developed a facile method for synthesizing CoSe2 nanoparticles uniformly anchored on carbon fiber paper (CoSe2/CF) via pyrolysis and selenization of in situ grown zeolitic imidazolate framework-67 (ZIF-67).CoSe2/CF shows high and stable catalytic activity in both the HER and OER in alkaline solution.At a low cell potential,i.e.,1.63 V,a water electrolyzer equipped with two CoSe2/CF electrodes gave a water-splitting current of 10 mA.cm-2.At a current of 20 mA.cm-2,it can operate without degradation for 30 h.This study not only offers a cost-effective solution for water splitting but also provides a new strategy for developing various catalytic nanostructures by changing the metal-organic framework precursors.     

Ni-NiO/N-C的制备及其电解水析氢性能

电催化分解水制氢(HER)被认为是最具应用前景的能量转换方式之一,可同时获得高纯度氢气并实现能量储存与转化,其关键在于低廉、高效且高稳定HER电催化剂的设计与开发.采用一步水热法得到羟基氧化镍/聚苯胺(NiOOH/PANI)催化剂前驱体,经800℃热解后制备出Ni-NiO/N-C负载型电催化剂,并考察其HER性能.采用...