深共晶溶剂中电沉积制备Co-Fe-Gd/NF电极及其析氢性能研究

为了制备出在碱性环境中具备高效能的廉价析氢电极催化剂,选择不同的沉积电位在氯化胆碱-尿素(ChCl-urea)中电沉积制备出五种Co-Fe-Gd/NF电极催化剂。通过扫描电镜(SEM)和光谱仪(EDX)对电极表面形貌、元素含量及分布情况进行表征,X射线光电子能谱(XPS)对电极表面化学性质进行表征。结合线性扫描伏安法(LSV)、电化学阻抗技术(EIS)和循环伏安法(CV)电化学测试结果,表明-1.24 V沉积电位下制备的Co-Fe-Gd/NF-3电极具备优异的析氢催化性能,在10 mA·cm^-2时的过电位仅为71 mV,最小的塔菲尔斜率(45 mV·dec^-1)与电荷转移电阻(0.28503Ω·cm^-2)表明其具备更快的析氢反应动力学过程,电化学活性表面积(ECSA)最大为390.5,为析氢过程提供更多的反应活性位点。对电极进行循环伏安耐久性测试与计时电流法(I-t)测试,结果表明Co-Fe-Gd/NF-3电极催化剂在碱性环境中稳定性良好。     

非晶Nd-Ni-B/NF稀土复合电极材料的制备及其析氢性能

本研究采用简单的一步化学沉积法制备非晶纳米Nd-Ni-B/NF稀土复合电极并研究其析氢(Hydrogen evolution reaction, HER)性能。通过各种测试方法对纳米电极材料进行物相分析和形貌表征,并探索其电催化析氢性能和稳定性。结果表明, 稀土Nd可提高电极的电催化析氢性能, 当硝酸钕浓度为3 g?L^-1时, 恒温35 ℃下施镀1 h, 制备的Nd-Ni-B/NF电极析氢性能最佳。Nd-Ni-B/NF(Nickel foam)电极在1.0 mol?L^-1KOH 溶液中, 20 mA?cm^-2电流密度下的析氢过电位仅为180 mV, Tafel斜率为117 mV?dec^-1, 析氢反应由Volmer-Heyrovsky步骤控制。此外, Nd-Ni-B/NF电极具有优越的电化学稳定性, 在持续电解12 h或2000次循环伏安测试后, 催化剂的活性没有明显衰减。     

Ag2S修饰TiO2纳米管复合电极的制备及其析氢性能研究

以硫化钠和硝酸银为原料,采用了化学浴沉积法将Ag₂S沉积在高度有序TiO₂纳米管(TNTs)上制备出Ag₂S/TNTs析氢电极。采用扫描电子显微镜(SEM)、X射线衍射分析(XRD)、X射线光电子能谱分析(XPS)对电极进行表征,结果显示Ag₂S颗粒均匀的沉积在TiO₂纳米管表面,且没有破坏纳米管原有的形态结构。在0.5 mol/L H₂SO₄条件下,通过线性扫描伏安法(LSV)、塔菲尔曲线(Tafel)、双电层电容和电化学阻抗谱(EIS)等电化学测试分析了不同Ag₂S沉积圈数所得的复合电极的析氢性能。与TNTs相比,Ag₂S/TNTs显示出更优异的析氢性能。Ag₂S沉积圈数为9圈时制备出的复合电极在10 mA/cm²电流密度时,过电位达到了288.14 mV,Tafel斜率为61.8 mV/dec,双电层电容分别为54.7 mF/cm^2...     

氯化胆碱-尿素体系中电沉积Ni-Fe-Sm析氢催化电极研究

采用恒电位电沉积技术,在氯化胆碱-尿素体系中制备Ni-Fe-Sm/Cu稀土合金电极并研究其析氢(HER)性能。通过阴极极化曲线(LSV)、循环伏安曲线(CV)等电化学测试方法及SEM等表征技术,研究沉积条件对稀土合金电极的析氢性能及其表面形貌的影响。结果表明,添加稀土元素Sm能够有效提升合金电极的析氢性能。在-1.22 V的沉积电位下,沉积20 min制备的Ni-Fe-Sm/Cu稀土合金电极析氢性能最佳。在10 mA/cm²电流密度下,稀土合金电极的析氢过电位仅115 mV,Tafel斜率最小,析氢反应受Volmer-Heyrovsky反应控制。且该条件下制备的Ni-Fe-Sm/Cu稀土合金具备最高的双电层电容,电催化活性表面积最大。通过交流阻抗法(EIS)可知,Ni-Fe-Sm/Cu合金电极具有较高电荷转移速率。此外,Ni-Fe-Sm/Cu稀土合金电极在碱性介质中具有较好的稳定性,在经过1000圈的循环侧安测试,电催化析氢性能没有明显变化。     

酸刻蚀泡沫镍增强磷化镍的析氢催化性能

氢能作为一种资源丰富、高能、无污染的"绿色能源",被认为是后石油时代解决能源和环境危机的理想能源之一。选择三维结构的泡沫镍(NF)为基底,采用0.3%(质量分数)氢氟酸(HF)对NF表面进行化学刻蚀,"开凿"形成比表面积高、电解液和析出气体易扩散的开放结构,联用固相还原法进行原位磷化,获得一体化Ni_2P/E-NF催化电极。实验结果表明,形成的一体化Ni_2P-NF催化电极避免了使用粘结剂,电极表面结构粗糙度是未刻蚀NF的2.8倍,暴露的活性位点多,在碱性条件下显示出较高的析氢反应(HER)活性,其起始析氢过电位约27mV,在电流密度达到10mA/cm~2时,析氢过电位也只有约63mV,经过4 000圈循环伏安扫描依然保持良好的稳定性。     

氮掺杂石墨烯的简易制备及其超级电容性能

采用简易溶剂热法成功制备出了氮掺杂石墨烯(N-GNSs), 结构表征显示其形貌良好。X射线光电子能谱(XPS)结果表明在溶剂热过程中, 氧化石墨烯表面的大部分含氧功能团已被成功除去, 而且二甲基甲酰胺中的氮原子通过吡咯氮和石墨氮的形式成功掺杂到石墨烯结构中。作为电极活性材料, N-GNSs展现出优异的电容特性, 在2 mol/L KOH电解液中电流密度为0.5 A/g时比电容可达181.3 F/g。此外, N-GNSs还展示出良好的循环稳定性, 2000次连续循环后容量仍保持为初始数值的92.5%。因此, 氮掺杂石墨烯是一种潜在的超级电容器电极材料。     

稀土铈对镍-钴-磷合金电极的析氢催化性能的影响

采用自行研制的复合配合剂,用化学沉积法在酸性体系中制备了Ni-Co-P和Ni-Co-P稀土合金电极.研究了稀土元素铈对Ni-Co-P合金电极的析氢电催化活性和电化学稳定性的影响.通过电化学方法测定合金电极在7 mol/L KOH溶液中的阴极极化曲线、Tafel曲线和电化学稳定性曲线,结果表明,与Ni-Co-P合金电极相比,Ni-Co-P(RE)合金电极的析氢电位正移约90 mV,Ni-Co-P(RE)合金电极具有较优的析氢电催化活性和电化学稳定性.此外,还通过X射线衍射、扫描电镜和合金镀层成分分析,结果表明,稀土元素铈的加入使非晶态Ni-Co-P合金镀层晶粒细化,但稀土元素铈不与合金共沉积,只是起到改变镀层组织结构的作用.     

氢卤酸诱导石墨烯气凝胶组装体的制备

以氧化石墨为前驱体,氢卤酸为诱导还原剂,采用化学还原法在温和条件下制备石墨烯气凝胶组装体。利用扫描电镜、X射线衍射、拉曼光谱、X射线光电子能谱及热重等分析手段对石墨烯气凝胶组装体的结构及性质进行表征,以研究氢卤酸的种类及浓度对石墨烯气凝胶的形成、结构及性质的影响。结果表明:相比于HBr和HCl,利用H+与I-的协同作用,HI能够有效的诱导石墨烯气凝胶组装体形成。相对于氧化石墨,所制备的石墨烯气凝胶的热稳定性和导电能力均得到了显著的提高。将石墨烯气凝胶作为超级电容器电极材料,表现出优异的电化学性能。     

基于简易微波方法制备高性能MoS2/石墨烯纳米复合材料用于高效析氢反应（英文）

用于析氢反应(HER)的低成本、高效能催化剂对于推进基于清洁氢气的能源工业非常重要.二维二硫化钼(MoS2)具有显著的催化性能,因而已被人们广泛深入研究.然而,大多数现有的合成方法耗时、复杂且效率较低.本文通过超快(60秒)微波引发的方法生产MoS2/石墨烯催化剂.石墨烯的高比表面积和导电性为MoS2纳米片的生长提供了有利的导电网络和快速电荷转移动力.文中制备的MoS2/石墨烯纳米复合材料在酸性介质中对HER表现出优异的电催化活性,具有62 mV的低起始电位,高阴极电流和43.3mV/dec的Tafel斜率.除了优异的催化活性外, MoS2/石墨烯还具有较长的循环稳定性,在250 mV的过电位下阴极电流密度高达1000 mA cm^-2.此外, MoS2/石墨烯催化剂在30–120°C范围内具有出色的HER活性和36.51 kJ mol^-1的低活化能,提供了潜在的大批量生产和制备的机会.     

脱合金化制备纳米多孔Ni-Fe合金及其电催化性能

采用真空熔炼与固溶相结合的方法获得原子分数为Ni_30-xFe_xMn₇₀(x=0,10,20)的前驱体合金,通过脱合金化方法制备纳米多孔Ni及Ni-Fe合金,采用X射线衍射(XRD)、扫描电子显微镜(SEM)分析合金相组成和微观结构,运用线性扫描伏安法、交流阻抗、方波电位法及计时电位法研究电极的析氢电催化性能。结果表明:加入Fe获得了片状结构的纳米多孔Ni-Fe合金,提高了纳米多孔Ni的表面积,且Fe与Ni产生协同效应,能够有效提高合金的析氢电催化活性。当Fe含量为10%(原子分数)时,脱合金化得到的纳米多孔Ni-Fe合金表面积最大,析氢电催化性能最好,在0.1A/cm^2电流密度下,析氢过电位仅56mV,经10h连续电解,表现出良好的电催化活性和电化学稳定性。     

Graphene/TiO<Subscript>2</Subscript> hydrogel: a potential catalyst to hydrogen evolution reaction

In this study, graphene was synthesized from graphite. Graphite was oxidized via modified Hummer’s method and sonicated to form graphene oxide (GO). Infrared spectroscopy revealed the successful oxidation of graphite by the emergence of oxygen functionalities. The spectrum of GO showed peaks at 3270, 1629, 1227 and 1096 cm^?1, indicating O–H, C=O, C–OH and C–O–C functional groups, respectively. Graphene hydrogels were prepared by the addition of L-ascorbic acid to GO suspensions and subsequent heating at 90^°C. Composite hydrogels of graphene and titanium (IV) oxide (TiO₂) were synthesized with various TiO₂ to GO mass ratios. Composites were applied to photocatalytic hydrogen evolution reaction (HER) and the hydrogen gas produced was analysed by gas chromatography with thermal conductivity detector. Highest HER yield was 66.00% H₂.     

Synthesis of BaWO4/NRGO‒g-C3N4 nanocomposites with excellent multifunctional catalytic performance via microwave approach

Novel barium tungstate/nitrogen-doped reduced graphene oxide?graphitic carbon nitride (BaWO₄/NRGO?g-C₃N₄) nanocomposite has been synthesized by a simple one-pot microwave technique. The synthesized nanocomposites are well characterized by diffraction, microscopic and spectroscopic techniques to study its crystal structure, elemental composition, morphological features and optical properties. The material prepared is tested for its performance as an electrocatalyst, photocatalyst and reduction catalyst. The nanocomposite catalyzed the photodegradation of methylene blue (MB) dye in 120 min, reduction of 4-nitro phenol (4-NP) to 4-amino phenol (4-AP) in 60 s, showed an impressive Tafel slope of 62 mV/dec for hydrogen evolution reaction (HER). The observed results suggest that the nanocomposite acts as an efficient multifunctional catalyst. The reported approach provides fundamental insights which can be extended to other metal tungstate-based ternary composites for applications in the field of clean energy and environment in the future.     

Synthesis of BaWO<Subscript>4</Subscript>/NRGO–g-C<Subscript>3</Subscript>N<Subscript>4</Subscript> nanocomposites with excellent multifunctional catalytic performance via microwave approach

Novel barium tungstate/nitrogen-doped reduced graphene oxide-graphitic carbon nitride (BaWO₄/NRGO-g-C₃N₄) nanocomposite has been synthesized by a simple one-pot microwave technique. The synthesized nanocomposites are well characterized by diffraction, microscopic and spectroscopic techniques to study its crystal structure, elemental composition, morphological features and optical properties. The material prepared is tested for its performance as an electrocatalyst, photocatalyst and reduction catalyst. The nanocomposite catalyzed the photodegradation of methylene blue (MB) dye in 120 min, reduction of 4-nitro phenol (4-NP) to 4-amino phenol (4-AP) in 60 s, showed an impressive Tafel slope of 62 mV/dec for hydrogen evolution reaction (HER). The observed results suggest that the nanocomposite acts as an efficient multifunctional catalyst. The reported approach provides fundamental insights which can be extended to other metal tungstate-based ternary composites for applications in the field of clean energy and environment in the future.     

氧化石墨烯还原制备石墨烯的方法研究

以天然鳞片石墨为原料,对Hummers法制备的氧化石墨烯,分别采用氢碘酸、葡萄糖、乙二胺、氢氧化钠进行化学还原,同时对比用快速热处理制备石墨烯。利用傅立叶红外光谱（FT—IR）、拉曼光谱（Raman）、扫描电子显微镜（SEM）对所得产物进行了比较分析。结果表明：对Hummers法制备的氧化石墨烯还原,葡萄糖的还原效果比较好;通过热处理可有效地将氧化石墨烯的含氧官能团还原,是一种高效、可行的方法。     

Polyaniline Derived N‐Doped Carbon‐Coated Cobalt Phosphide Nanoparticles Deposited on N‐Doped Graphene as an Efficient Electrocatalyst for Hydrogen Evolution Reaction

The development of highly efficient and durable non‐noble metal electrocatalysts for the hydrogen evolution reaction (HER) is significant for clean and renewable energy research. This work reports the synthesis of N‐doped graphene nanosheets supported N‐doped carbon coated cobalt phosphide (CoP) nanoparticles via a pyrolysis and a subsequent phosphating process by using polyaniline. The obtained electrocatalyst exhibits excellent electrochemical activity for HER with a small overpotential of ?135 mV at 10 mA cm^?2 and a low Tafel slope of 59.3 mV dec^?1 in 0.5 m H₂SO₄. Additionally, the encapsulation of N‐doped carbon shell prevents CoP nanoparticles from corrosion, exhibiting good stability after 14 h operation. Moreover, the as‐prepared electrocatalyst also shows outstanding activity and stability in basic and neutral electrolytes.     

Co-Mn掺杂碳气凝胶的制备与性能

为探究不同碳化温度对Co-Mn掺杂碳气凝胶（Co-Mn/CA）电催化析氢性能的影响,以资源丰富且可再生的木质纤维素为碳源、四水乙酸钴为钴源、四水乙酸锰为Mn源,通过水热法制备出Co-Mn/CA。研究发现,纤维素气凝胶碳化后表面形貌发生改变,由片层结构转变为多孔结构,使其活性位点数量增多,电催化析氢活性增加。通过XRD和N₂吸-脱附对其结构进行了表征处理分析,结果表明,经碳化处理后的CA产物以无定型碳为主,经900℃碳化处理后的CA（CA-900）比表面积和总孔隙体积均为最大,分别为958 m2g-1和0.33 cm3·g-1。电化学性能测试表明,Co-Mn/CA-900表现出最好的电催化析氢反应（HER）催化活性,在1 mol/L KOH电解液中、50 mA·cm-2的电流密度下,具有175 mV的过电势,经过10 h的计时电位测试,压降仅为7%,表现出较好的电催化析氢稳定性。      

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.     

Sponge-like nickel phosphide–carbon nanotube hybrid electrodes for efficient hydrogen evolution over a wide pH range

Cost-effective hydrogen production via electrolysis of water requires efficient and durable earth-abundant catalysts for the hydrogen evolution reaction (HER) over a wide pH range.Herein,we report sponge-like nickel phosphidecarbon nanotube (NixP/CNT) hybrid electrodes that were prepared by facile cyclic voltammetric deposition of amorphous NixP catalysts onto the threedimensional (3D) porous CNT support.These compounds exhibit superior catalytic activity for sustained hydrogen evolution in acidic,neutral,and basic media.In particular,the NixP/CNT electrodes generate cathodic currents of 10 and 100 mA.cm-2 at overpotentials of 105 and 226 mV,respectively,in a 1 M phosphate buffer solution (pH =6.5) with a Tafel slope of 100 mV·dec-1;the currents were stable for over 110 h without obvious decay.Our results suggest that the 3D porous CNT electrode supports could serve as a general platform for earth-abundant HER catalysts for the development of highly efficient electrodes for hydrogen production.     

氧化还原法制备石墨烯及其表征

采用改进的Hummers法氧化处理石墨粉制得氧化石墨,利用超声波作用将氧化石墨剥离,得到均匀分散的氧化石墨烯胶状悬浮液,然后在水合肼的还原作用下得到石墨烯。采用SEM、XRD以及Raman光谱对样品进行了形貌、结构以及谱学的表征分析。考察了还原过程中温度对还原效果的影响,以及中性条件下、碱性条件下水合肼用量对还原效果的影响。