钴钒水滑石纳米片用于电催化尿素氧化（英文）

电解水是一种常用的制氢方法,但高能耗的阳极析氧反应(OER)阻碍了其应用。尿素氧化反应(UOR)具有较低的热力学电势,是最有前景的OER替代反应之一。过渡金属基水滑石具有独特的层状结构和层间阴离子可交换等优点,被认为是性能优异的UOR催化剂,然而目前大多数研究主要聚焦于后过渡金属元素。该研究通过一步法制备了具有前/后过渡金属的CoV-LDHs纳米片。与相同方法制备的Co(OH)₂相比,CoV-LDHs纳米片具有以下优点:1)纳米片结构有利于暴露更多的活性位点。2) V的引入增强了CoV-LDHs的亲水性,提高了其本征电催化动力学。3) Co (3d⁷4s²)和V(3d³4s²)之间的d-电子补偿效应有利于促进尿素的吸附。因此,CoV-LDHs仅需要1.52V(vs.RHE)就可以达到10mA·cm^-2的电流密度,比Co(OH)₂低了70 mV,同时CoV-LDHs较低的塔菲尔斜率表明了其较快的反应动力学。此外,CoV-LDHs在连续反...     

泡沫铜支撑Ru掺杂Cu3P自支撑催化剂及其析氢性能

过渡金属磷化物(TMP)是一种用于碱性条件下析氢反应(HER)的有效催化剂, 然而其活性严重受限于水解离步。本文通过在泡沫铜(CF)上生长Cu(OH)₂纳米阵列, RuCl₃溶液浸泡和磷酸化, 制备了一种具有较大比表面积和适当Ru掺杂的Ru-Cu₃P自支撑催化剂(Ru-Cu₃P/CF)。作为一种优良的HER催化剂,在电流密度为10 mA·cm^-2时, 其过电位为95.6 mV, 比Cu₃P/CF降低149.4 mV。其决速步由Volmer向Heyrovsky机制过渡。HER性能的提高可以归因于Ru掺杂磷化铜促进水解离过程,以及Cu(OH)₂纳米阵列衍生Cu₃P纳米结构具有更高的电化学活性面积, 从而保证了更多的活性位点。本论文突出了具有空的d轨道的金属掺杂促进水解离的重要性,为高性能电解水析氢催化剂的设计提供了新思路。     

Ni2P/Cu(OH)2催化剂的制备及其全解水性能研究

通过化学处理法在泡沫铜基底表面生成Cu(OH)₂纳米线,大大增加了基底材料的表面积和导电性.采用水热法在Cu(OH)₂纳米线表面制备片状Ni-CH/Cu(OH)₂前驱体,对Ni-CH/Cu(OH)₂前驱体进行低温磷化得到多级结构Ni₂P/Cu(OH)₂催化剂.通过扫描电子显微镜(SEM)、X射线光电子能谱仪(XPS)和X射线衍射仪(XRD)对催化剂的物质结构和表面形貌进行了表征.采用线性伏安法、恒电位等技术对催化剂的电化学性能进行测试.在1.0 mol·L^-1 KOH碱性溶液中,当电流密度为10 mA·cm^-2时,Ni₂P/Cu(OH)₂的析氢反应(HER)和析氧反应(OER)过电位分别为133和333 mV,且均具有较好的稳定性.将这种多级结构Ni₂P/Cu(OH)₂催化剂分别用作阳极和阴极进行全解水电解,电流密度达到10 ...     

具有高价氧化态的超薄二维Ni–MOF高性能电催化剂用于苯甲醇氧化反应

超薄二维金属有机框架(Two-dimensional metal-organic frameworks (2D MOFs))具有较大的比表面积和开放的催化活性中心,在电催化反应中具有潜在的应用价值.本工作报道了一种溶剂热法制备的具有开放位点的超薄2D Ni–MOF纳米片阵列及其在电催化苯甲醇氧化(Electrocatalytic benzyl-alcohol oxidation (EBO))方面的应用.作为一种高性能的EBO电催化剂,2D Ni–MOF表现出较低的过电位和优异的化学耐久性,仅需要约1.50 V的电位即可达到250 m A cm^-2,苯甲醇氧化效率达85%.2D Ni–MOF纳米片阵列相比于同样具有超薄结构的2D Ni(OH)₂纳米片阵列,反应过电势降低约35 m V(@50 m A cm^-2),具有更快的反应动力学.在同一恒电位下进行苯甲醇氧化反应时,具有更高的响应电流,并且在连续电解20000 s后,可保留25 mA cm^-2的电流密度,接近Ni(OH)₂纳米...     

金属性Ni3N纳米粒子的制备与乙二醇电氧化性能

利用小分子电催化氧化反应耦合水解制氢不仅有助于降低阳极反应过电位,提高析氢反应(HER)效率,而且产生高附加值的化学品,是提升电催化水分解性能的有效策略.其关键是开发具有高导电性和低氧化电位的非贵金属电催化剂.以Ni(OH)₂纳米片为前驱物,通过退火氮化工艺,制备了具有低氧化电位和高导电性的金属相Ni₃N纳米颗粒(Ni₃N-NPs).与Ni(OH)₂相比,Ni₃N-NPs具有较小的法拉第电阻,更低的氧化电位(1.36 V时达到10 mA·cm^-2),较小的Tafel斜率(29 mV·dec^-1),表现出更好的乙二醇(EG)电催化氧化性能.在1.36 V时,Ni₃N-NPs电催化氧化EG生成甲酸盐的法拉第效率高达91.16%.通过X射线衍射(XRD)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)对反应前后Ni₃N-NPs结构进行详细表征发现,在电催化EG氧化过程中,Ni₃     

基于磺酰基杯[4]芳烃的Co16笼簇的合成、结构及电化学性质

以氯化钴、 对叔丁基磺酰杯[4]芳烃(H₄TC4A-SO₂)和非对称性3-(1H-四唑-5-基)苯甲酸(H₂L)为原料, 通过溶剂热法合成了一个具有四面体配位笼结构的16核化合物[Co₁₆(TC4A-SO₂)₄(OH)₄(L)₈]·[(C₈H₂₀N)(C₄H₁₂N)₂(C₂H₈N)]·solvent(Co₁₆-TC4A-SO₂). 采用X射线单晶衍射、 X射线粉末衍射、 热重分析、 红外光谱方法对配合物进行了表征. 将Co₁₆-TC4A-SO₂笼簇直接负载到碳纸上(Co₁₆-TC4A-SO₂/CP)用作工作电极, 其对析氧反应(OER)展现出较好的催化性能. 在1 mol/L KOH中, Co₁₆-TC4A-SO₂/CP在343.8 mV的过电位下达到10.0 mA/cm ²电流密度, Tafel斜率为79.31 mV/dec, 并且在20.0 mA/cm ²电流密度下表现出长达48 h的催化稳定性.     

锚定在中空碳纳米笼上的Fe掺杂Co3O4用于高效电催化析氧(英文)

本研究采用[Fe(CN)₆]^3-阴离子交换2-甲基咪唑再于空气气氛下退火衍生的策略,制备了一种负载在氮掺杂中空纳米笼碳骨架上的Fe掺杂Co₃O₄电催化剂(Fe-Co₃O₄/NC),用于电催化OER。XRD和HRTEM表征证实了Fe掺人Co₃O₄的晶格中。XPS表征明确了Fe引入后Co价态升高,这是基于Co²⁺/Co³⁺和Fe³⁺的价电子构型诱导的电子由Co²⁺/Co³⁺向Fe³⁺的转移,这会促使Co位点在OER过程中衍生为CoOOH活性物种,作为真正的电催化活性中心,这也被OER稳定性测试后的HRTEM和XPS表征所证实。电化学性能测试显示,该电催化剂的OER过电位仅有275 mV且能够在100 mA/cm²的电流密度下稳定维持20 h,兼具优异的电催化活性和稳...     

孔隙结构可调的Cu2O球状纳米结构及其NO2气体传感性质

报道在聚乙烯吡咯烷酮(PVP)的协助作用下,通过简单调节OH^-离子的浓度及Cu²⁺的释放速度,将Cu₂O调节为具有不同空腔特征(介孔、空心及实心)结构的纳米球.研究表明, OH^-根离子的扩散动力学是决定产物结构的关键因素.当[OH^-] > 0.05 mol·L^-1时,高的化学势使其迅速扩散到PVP胶团内部,与吸附在PVP链上的Cu²⁺反应形成Cu(OH)₂,在抗坏血酸(Vc)的还原作用下经过重结晶得到Cu₂O实心球纳米结构;当[OH^-] < 0.025 mol·L^-1时,其扩散速度下降,首先与吸附在PVP胶团外部的Cu²⁺反应形成Cu(OH)₂, Cu(OH)₂的形成阻碍了OH^-离子的向内扩散,形成具有较大空腔(~220 nm)的空心球;当0.025 mol·L^-1 < [OH^-] < 0.05 mol·L^-1时,形成较小空腔(30-60 nm)的空心球.以NH₃水为OH^-缓释源时,虽然OH^-浓度较低,但同时Cu²⁺的浓度也低,胶团外部形成的Cu(OH)₂不足以阻碍OH^-离子的向内扩散,反应过程中NH₃的释放及较低的OH^-浓度阻碍了重结晶的发生,从而形成Cu₂O介孔纳米球.对三种典型结构特征的产物进行了NO₂气体传感性质研究,结果表明, Cu₂O介孔纳米球相比空心结构和实心结构具有更为优异的响应性.结合比表面积数据,我们认为介孔纳米球疏散的结构有利于NO₂气体的扩散和O₂的吸附,从而表现出了更灵敏的气体传感性.     

硝酸异丙酯与Cl原子、 OH和NO3自由基反应的机理及动力学

采用CCSD(T)//M06-2X/6-311++G(d,p)方法, 结合传统过渡态理论, 研究了硝酸异丙酯与Cl原子、 OH及NO₃自由基的反应机理和动力学. 两个反应物单体首先形成氢键复合物, 随后X(X=Cl原子、 OH和NO₃自由基)提取硝酸异丙酯中叔碳的α-H原子或甲基的β-H原子, 室温下, 以X提取α-H原子为主. 反应的主要历程为 Cl原子(OH或NO₃自由基)提取(CH₃)₂CHONO₂的α-H原子, 生成HCl(H₂O或HNO₃)分子和(CH₃)₂CONO₂自由基, 后者分解为丙酮和NO₂. 结果表明, 在200~500 K温度范围内, 随着温度的升高, 丙酮和NO₂的产率降低; 在室温下, 硝酸异丙酯与Cl原子、 OH和NO₃自由基反应的速率常数分别为3.933×10^-11, 1.182×10^-13和7.134×10^-19 cm³·molecule^-1·s^-1. 计算所得硝酸异丙酯与OH自由基反应的动力学数据与实验结论一致.     

新型含硅表面活性剂的合成及性能研究

含有双胺基的三硅氧烷中的伯胺基与D-葡萄糖酸-δ-内酯进行酰胺化,仲胺基与低聚乙二醇甲醚缩水甘油醚、二缩水甘油醚进行烷基化,制备了新型含硅表面活性剂Me₃SiOSiMeR¹OSiMe₃ [R¹=(CH₂)₃NR²(CH₂)₂NHCO(CHOH)₄CH₂OH; R²=H, CH₂CH(OH)CH₂O(CH₂CH₂O)_xCH₃, x=1, 2, 3] (1a, 2a～2c)和(CH₂OCH₂)_y(Me₃SiOSiMeR³OSiMe₃)₂ [R³=(CH₂)₃NR⁴～(CH₂)₂NHCO(CHOH)₄CH₂OH; R⁴=CH₂CH(OH)CH₂OCH₂, y=0, 1, 2] (3a～3c).这些化合物的结构用¹H, ¹³C核磁共振仪和元素分析仪进行鉴定.研究了这些新型含硅表面活性剂的界面性能,在浓度分别为10^-4和10^-5 mol·L^-1时可以将水的表面张力降低至约21 mN·m^-1.     

双功能型嵌入镍纳米颗粒的碳棱柱状微米棒电极用于电化学甲醇氧化助力的节能产氢

With the rapid development of human society, clean energy forms are imperative to sustain the normal operations of various mechanical and electrical facilities under a cozy environment. Hydrogen is considered among the most promising clean energy sources for the future. Recently, electrochemical water splitting has been considered as one of the most efficient approaches to harvest hydrogen energy, which generates only non-pollutant water on combustion. However, the sluggish anodic oxygen evolution reaction significantly restricts the efficiency of water splitting and requires a relatively high cell voltage to drive the electrolysis. Therefore, seeking a thermodynamically favorable anodic reaction to replace the sluggish oxygen evolution reaction by utilizing highly active bifunctional electrocatalysts for the anodic reaction and hydrogen evolution are crucial for achieving energy-efficient hydrogen production for industrial applications. Nevertheless, it is known that the oxygen evolution reaction can be replaced with other useful and thermodynamically favorable reactions to reduce the electrolysis voltage for realizing energy-efficient hydrogen production. Therefore, in this study, we present a bifunctional nickel nanoparticle-embedded carbon (Ni@C) prism-like microrod electrocatalyst synthesized via a two-step method involving the synthesis of a precursor metal-organic framework-74 and subsequent carbonization treatment for methanol oxidation and hydrogen evolution. The interfacial structure consisting of a nickel and carbon skeleton was realized via in situ carbonization. However, the dispersed nickel nanoparticles do not easily aggregate owing to the partition by the surrounding carbon as it would sufficiently expose the active Ni sites to the electrolytes, ensuring fast charge transfer between the catalyst and electrolytes by accelerating the electrochemical kinetics. In the anodic methanol oxidation, the products were detected as carbon dioxide and formate with faradaic efficiencies of 36.2% and 62.5%, respectively, at an applied potential of 1.55 V. Meanwhile, the Ni@C microrod catalyst demonstrated high activity and durability (2.7% current decay after 12 h of continuous operation) toward methanol oxidation, which demonstrates that methanol oxidation precedes oxidation under voltage forces. Notably, the bifunctional catalyst not only exhibits excellent performance toward methanol oxidation but also yields a low overpotential of 155 mV to drive 10 mA∙cm⁻² toward hydrogen evolution in 1.0 mol∙L⁻¹ KOH aqueous solution with 0.5 mol∙L⁻¹ methanol at room temperature, which guarantees the hydrogen production efficiency. More importantly, the constructed two-electrode electrolyzer produced a current density of 10 mA∙cm⁻² at a low cell voltage of 1.6 V, which decreased by 240 mV after replacing the oxygen evolution reaction with methanol oxidation.     

Electronic and Nano-structural Modulation of Co(OH)2 Nanosheets by Fe-Benzenedicarboxylate for Efficient Oxygen Evolution

Oxygen evolution reaction(OER) plays a key role in the electrochemical conversion and storage processes, but the sluggish kinetics of OER strongly impedes its large-scale applications. We herein reported the in situ growth of Fe-benzenedicarboxylate(Fe-BDC) on Co(OH)₂ nanoplates[Fe-BDC/ Co(OH)₂] that showed remarkably enhanced OER activity than the pristine Co(OH)₂. The incorporation of Fe species could enhance the intrinsic OER activity of Co and BDC could increase the electro-chemically active surface area(ECSA), thus resulting in dramatically enhanced OER activity. In situ Raman spectroscopy characterization disclosed that Fe-CoOOH reconstructed from Fe-BDC/Co(OH)₂ was the real active site for OER. This work highlights the significance of rational tailoring of the nanostructure and electronic structure of Co(OH)₂ and provides more opportunities for its widespread applications.     

用于电化学水氧化的铁、镍、钴金属及其二元金属纳米颗粒比较研究

从环境兼容角度来设计应用于氧析出反应的电催化剂是否有效、耐用和廉价对能源转化过程至关重要. 本文报告了一种快速制备低成本、原料丰富的金属催化剂制备方法。通过一步电化学沉积法在钛金属基材上制备了铁、镍、钴金属及其钴镍、钴铁二元金属纳米颗粒. 采用场发射电子显微镜 (FE-SEM), 能量散射X-射线能谱 (EDX), X-射线衍射光谱 (XRD), X-射线光电子能谱 (XPS)和电化学技术对制备的不同纳米颗粒进行了表征. 电化学结果显示,在合成的五种钛基金属纳米催化剂中, 钛基上沉积钴金属纳米颗粒(Ti/Co)电极在0.l mol·L^-1氢氧化钾溶液中氧析出反应的电催化活性最好,0.70 V(相对于银/氯化银电极)的电流密度为10.0 mA·cm^-2. 经优化后Ti/Co电极的过电位(η)很小,当电流密度为10.0 mA·cm^-2时η为0.43 V,质量活性高达105.7 A·g^-1,逆转频率(TOF)值为1.63×10^-3 s^-1, 这些与当前最好的碳载铂(Pt/C)和氧化钌(RuO₂)电催化剂的性能相当. 此外,通过计时电位技术对优化后Ti/Co电极的耐久性进行了测试, 发现该电极在碱性溶液中氧析出反应的稳定性良好. 本工作制备的钛金属基材上电化学沉积金属钴纳米颗粒具有高催化活性、高稳定性、原料来源丰富、廉价且易于大规模生产,在工业化水分解领域具有潜在的应用前景.     

双功能2D/3D杂化结构Co2P-CeO x 异质结一体化电极的构筑及电催化尿素氧化辅助制氢性能

以泡沫镍(NF)为基底, 通过多电位阶跃电沉积和低温磷化的方法, 制备双功能的多层次二维/三维(2D/3D)杂化结构的Co₂P-CeO _x 一体化电极(Co₂P-CeO _x /NF), 并用于电催化尿素氧化辅助制氢性能研究. 结果表明, 通过3D CeO _x 纳米花与2D Co₂P纳米片之间的强界面相互作用和良好的电子协同耦合作用, 使该一体化电极具有较高的导电性、 表面活性和稳定性, 强化了电催化析氢反应(HER)和尿素氧化反应(UOR)性能. 在两电极电解池体系下进行电催化制氢的同时降解尿素, 电流密度达到30 mA/cm²时, 所需要电位为1.42 V, 比全解水所需电位降低0.17 V, 经过10 h电催化尿素的降解效率达76.4%; 综合分析表明, 2D Co₂P与3D CeO _x 多层次纳米片异质界面处电子的定向转移, 引起界面区域的局部电荷重新排布; 形成的氧空位提供配位不饱和位点, 暴露更多的活性位点, 优化反应物分子在催化剂表面的吸附能, 进而促进分子活化, 使其具有较高的催化反应活性.     

石墨炔-有机共轭分子复合材料的制备及其储锂性能

发展了基于超分子化学的新方法实现了对石墨炔的原位氮掺杂,通过利用石墨炔与有机共轭分子间强的π–π作用,原位制备了石墨炔/卟吩复合材料薄膜,并用作锂离子电池的负极材料,其比容量增加到了1000 mAh∙g⁻¹,该复合材料表现出优良的倍率性能和循环稳定性,为可控制备掺氮石墨炔复合材料提供了新的思路。     

Manganese-Modulated Cobalt-Based Layered Double Hydroxide Grown on Nickel Foam with 1D–2D–3D Heterostructure for Highly Efficient Oxygen Evolution Reaction and Urea Oxidation Reaction

Hydrogen production by energy-efficient water electrolysis is a green avenue for the development of contemporary society. However, the oxygen evolution reaction (OER) and the urea oxidation reaction (UOR) occurring at the anode are impeded by the sluggish reaction kinetics during the water-splitting process. Consequently, it is promising to develop bifunctional anodic electrocatalysts consisting of nonprecious metals. Herein, a bifunctional CoMn layered double hydroxide (LDH) was grown on nickel foam (NF) with a 1D–2D–3D hierarchical structure for efficient OER and UOR performance in alkaline solution. Owing to the significant synergistic effect of Mn doping and heterostructure engineering, the obtained Co₁Mn₁ LDH/NF exhibits satisfactory OER activity with a low potential of 1.515 V to attain 10 mA cm⁻². Besides, the potential of the Co₁Mn₁ LDH/NF catalyst for UOR at the same current density is only 1.326 V, which is much lower than those of its counterparts and most reported electrocatalysts. An urea electrolytic cell with a Co₁Mn₁ LDH/NF anode and a Pt–C/NF cathode was established, and a low cell voltage of 1.354 V at 10 mA cm⁻² was acquired. The optimized strategy may result in promising candidates for developing a new generation of bifunctional electrocatalysts for clean energy production.     

Interface‐Engineered Ni(OH)2/β‐like FeOOH Electrocatalysts for Highly Efficient and Stable Oxygen Evolution Reaction

Iron‐based (oxy)hydroxides are especially attractive electrocatalysts for the oxygen evolution reaction (OER) owing to their earth abundance, low cost, and nontoxicity. However, poor OER kinetics on the surface restricts the performance of the FeOOH electrocatalyst. Herein, a highly efficient and stable Ni(OH)₂/β‐like FeOOH electrocatalyst is obtained by facile electroactivation treatment. The activated Ni(OH)₂/β‐like FeOOH sample indicates an overpotential of 300 mV at 10 mA cm⁻² for the OER, and no clear current decay after 50 h of testing; this is comparable to the most efficient nickel‐ and cobalt‐based electrocatalysts on planar substrates. Furthermore, studies suggest that β‐like FeOOH plays a key role in remarkably enhancing the performance during the electroactivation process owing to its metastable tunnel structure with a lower barrier for interface diffusion of Ni²⁺ ions between the bilayer electrocatalyst. This study develops a new strategy to explore efficient and low‐cost electrocatalysts and deepens understanding of bilayer electrocatalysts for the OER.     

纳米颗粒结合ZIF-67衍生的PtCo-NC催化剂用于醇类燃料电氧化

Alcohols fuel electro-oxidation is significant to the development of direct alcohols fuel cells, that are considered as a promising power source for portable electronic devices. Currently, the catalyst was restricted by the serious poisoning effect and high cost of noble metals. Developing low-cost Pt alloy with high performance and anti-CO poisoning ability was highly desired. In this work, PtCo-NC catalyst was synthesized by combining Pt nanoparticles with ZIF-67 after annealing in the tube furnace and the in situ generated N-doped carbon from ZIF-67 was functionalized to support the PtCo alloy nanoparticle. The structure and morphology were probed by X-ray diffraction, scanning electron microscope and transmission electron microscope, and the electrochemical performance was evaluated for alcohols of methanol and ethanol oxidation in the acid electrolyte. Compared with the reference sample of Pt/C, several times performance enhancement for alcohols fuel oxidation was found on PtCo-NC catalyst as well as the good catalytic stability. Specifically, the peak current density of PtCo-NC was 79.61 mA∙cm⁻² for methanol oxidation, about 2.2 times higher than that of the Pt/C electrode (36.97 mA∙cm⁻²) and 2.5 times higher than that of the commercial Pt/C electrode (31.23 mA∙cm⁻²); it was 62.69 mA∙cm^–2 for ethanol oxidation, about 1.65 times higher than that of Pt/C catalyst (37.99 mA∙cm⁻²) and commercial Pt/C electrode (37.77 mA∙cm⁻²). These catalytic performances were also much higher than some analogous catalysts developed for alcohols fuel oxidation. A much higher anti-CO poisoning ability was demonstrated by the CO stripping voltammetry experiment, in which the CO_ad oxidation peak potential for PtCo-NC was 0.46 V, ca. 110 mV negative shift compared with Pt/C catalyst at 0.57 V. A strong electronic effect was indicated by the peak position shifting to the lower binding energy direction by 0.3 eV on PtCo-NC compared with Pt/C reference catalyst. According to the d-band center theory, the electron-enriched state of Pt will decrease the interaction strength of poisoning intermediates adsorbed on its surface; Moreover, according to the bifunctional catalytic mechanism, the presence of Co can form the adsorbed oxygen-containing species (―OH) more easily than Pt at low potentials, and this oxygen-species were helpful in the oxidation of CO_ad at neighboring Pt sites. The high catalytic performance for alcohols fuel oxidation could be due to the largely improved anti-CO poisoning ability and the synergistic effect between the in situ formed PtCo nanoparticles and the N-doped carbon support.     

Single-atom Fe Embedded Co3S4 for Efficient Electrocatalytic Oxygen Evolution Reaction

Constructing atomically dispersed active sites with densely exposed and dispersed double metal-S_x catalytic sites for favorable OER catalytic activity remains rare and challenging. Herein, we design and construct a Fe₁S_x@Co₃S₄ electrocatalyst with Fe single atoms epitaxially confined in Co₃S₄ nanosheets for catalyzing the sluggish alkaline oxygen evolution reaction(OER). Consequently, in ultralow concentration alkaline solutions(0.1 mol/L KOH), such a catalyst is highly active and robust for OER with low overpotentials of 300 and 333 mV at current densities of 10 and 30 mA/cm², respectively, accompanying long-term stability without significant degradation even for 350 h. In addition, Fe₁S_x@Co₃S₄ shows a turnover frequency(TOF) value of 0.18 s⁻¹, nearly three times that of Co₃S₄(0.07 s⁻¹), suggesting the higher atomic utilization of Fe single atoms. Mössbauer and in-situ Raman spectra confirm that the OER activity of Fe₁S_x@Co₃S₄ origins from a thin catalytic layer of Co(Fe)OOH that interacts with trace-level Fe species in the electrolyte, creating dynamically stable active sites. Combined with experimental characterizations, it suggests that the most active S-coordinated dual-metal site configurations are 2S-bridged (Fe-Co)S₄, in which Co-S and Fe-S moieties are shared with two S atoms, which can strongly regulate the adsorption energy of reaction intermediates, accelerating the OER reaction kinetics.     

MoP-NC纳米球负载Pt纳米粒子用于高效甲醇电解

实现绿色甲醇电解制氢需要高效的双功能催化剂。本文采用热处理结合乙二醇还原法成功制备了MoP-NC纳米球负载的超细Pt纳米粒子(平均粒径为2.53 nm)复合催化剂(Pt/MoP-NC)用于高效甲醇电解制氢。MoP-NC纳米球不仅能提高Pt纳米粒子的分散性并且增强Pt的抗中毒能力。电化学测试表明Pt/MoP-NC催化剂在酸性甲醇氧化反应(MOR)和析氢反应(HER)中具有较高的催化性能;其中,MOR的正向扫描峰值电流密度为90.7 mA∙cm⁻²,是商业Pt/C催化剂的3.2倍,在10 mA∙cm⁻²的电流密度下,HER的过电位低至30 mV,与商业Pt/C接近。由Pt/MoP-NC||Pt/MoP-NC组装的两电极电解槽驱动10 mA∙cm⁻²的电流密度仅需要0.67 V的电压,比相同条件下电解水的电压低1.02 V,大大降低了能量输入。Pt/MoP-NC的高催化性能主要来源于Pt活性中心与相邻层状多孔球形结构的MoP-NC载体之间电子效应及配体效应引起的抗一氧化碳中毒能力的提升和含氧物种的容易生成。