Pt单层修饰Pd/C氧还原催化剂

分别利用液相热解法和浸渍还原法制备了碳载钯纳米催化剂（Pd/C）,并研究了其对氧还原反应的电催化活性。与浸渍还原法相比,液相热解法得到的Pd/C催化剂虽然粒径较大,但表现出较好的氧还原反应（ORR）活性和稳定性.在所制备的Pd/C催化剂基础上,通过置换欠电势沉积的Cu原子单层,获得了Pt单层修饰的Pd/C催化剂,其ORR活性较Pd/C催化剂有显著提高,且与纯Pt/C催化剂接近,而其耐久性则较纯Pt/C催化剂有显著提升,显示出Pt单层催化剂的潜在优势.     

掺氮介孔炭作为双功能材料用于氧还原与超级电容器

以壳聚糖为含氮碳源,正硅酸乙酯为软模板,硝酸镍为催化剂,通过简单的低温水热法及后续炭化,成功合成出掺氮介孔炭材料（NMC-1）.NMC-1含有多孔结构以及氮氧等杂原子,能提高其电催化性能、双电层电容与赝电容.由于NMC-1在碱液中表现出显著的催化氧还原反应活性和具有较高的超级电容器比电容（在0.2A/g时为252F/g）及好的循环稳定性,因此,它有可能作为一种可再生、环保的双功能材料同时应用于燃料电池与超级电容器领域.     

Accelerating the oxygen reduction reaction via a bioinspired carbon‐supported zinc electrocatalyst

Oxygen utilization in electrochemical energy generation systems requires to overcome the slow kinetics of oxygen reduction reaction (ORR). Herein, we have outstretched an efficient strategy in order for developing a bioinspired Zn (N₄)/sulfur/graphitic carbon composite (Zn‐S‐Gc) with an effective performance for the ORR at low temperature. The catalyst composite was created by attaching the Zn (N₄) centers in the form of zinc phthalocyanine on the sulfur‐linked graphitic carbon surface. The most positive ORR onset potential of about 1.00 V versus a reversible hydrogen electrode (RHE) was obtained due to the unique structure of a new catalyst in KOH solution (pH = 13) at low temperature (T = 298 K). The catalyst was evaluated using the rotating‐disk electrode method in the potential range of ?0.02–1.18 V versus RHE. The number of transferred electrons as one of the most important parameters (n > 3.70) is almost constant in a wide range of low overpotentials (0.1–0.6 V), which indicates a more efficient four‐electron pathway from O₂ to H₂O on the catalyst surface. The estimated Tafel slope in an appropriate range is about ≈ ?133.3 mV/dec at a low current density and E_1/2 of the electrocatalyst displays a negative shift of only 11 mV after 10,000 cycles. The mean size of the catalyst centers is on the nanoscale (<50 nm).     

Fe/N/C氧还原催化剂的热稳定性及活性位结构

研制高活性的Fe/N/C氧还原催化剂对于降低燃料电池成本、实现商业化应用有重要意义. 为了实现Fe/N/C催化剂的理性设计,需要深入研究其活性位结构. 本文我们发展一种研究活性位结构的新策略,即以预先合成好的聚间苯二胺基Fe/N/C催化剂(PmPDA-FeNx/C)为起始物,对其在1000~1500 ^oC高温下再次进行热处理并使其失活,通过关联催化剂热处理前后的结构变化与氧还原催化性能来揭示活性位结构. 实验结果表明,随着热处理温度升高,活性中心结构被破坏,铁原子析出团聚并形成纳米颗粒,氮元素挥发损失,导致催化剂失活. XPS分析显示,低结合能含氮物种的含量与催化剂的ORR活性呈良好的正相关性,表明活性中心很可能是由吡啶N和Fe-N物种构成的.     

石墨烯衍生物负载的纳米催化剂用于氧还原反应

综述了用于燃料电池中氧还原反应(ORR)的石墨烯衍生物负载的各种纳米催化剂的最新进展。介绍了用于表征石墨烯基电催化剂的常规电化学技术以及石墨烯基电催化剂最新的研究进展。负载于还原氧化石墨烯(RGO)上的Pt催化剂的电化学活性和稳定性均得到显著提高。其它贵金属催化剂,如Pd, Au和Ag也表现出较高的催化活性。当以RGO或少层石墨烯为载体时, Pd催化剂的稳定性提高。讨论了氧化石墨烯负载Au或Ag催化剂的合成方法。另外,以N4螯合络合物形式存在的非贵过渡金属可降低氧的电化学性能。 Fe和Co是可替代的廉价ORR催化剂。在大多数情况下,这些催化剂稳定性和耐受性的问题均可得到解决,但其整体性能还很难超越Pt/C催化剂。     

石墨化氮化碳负载Cu纳米颗粒用作高效氧还原电催化剂

高活性低成本氧还原反应(ORR)电催化剂是燃料电池和金属/空气电池等可再生能源技术的关键组成部分.在离子液体[(C16mim)2CuCl4]和质子化的石墨化氮化碳(g-CN)的存在下,采用简易的水热反应制备了Cu/g-CN电催化剂用于ORR.与纯的g-CN相比,所制Cu/g-CN表现出高的ORR催化活性:起始电势正移99 mV,为2倍动力学电流密度.另外,Cu/g-CN还表现出比商用Pt/C(HiSPECTM 3000,20%)催化剂更好的稳定性和甲醇容忍性.因此,该催化剂作为廉价的高效ORR电催化剂有望应用于燃料电池中.     

溶剂热法制备磷掺杂碳纳米管作为氧气还原和氧气析出反应双功能电催化剂的研究

对氧气还原(ORR)和氧气析出(OER)反应都具有催化活性的双功能催化剂在金属-空气电池中起着关键作用.本文通过溶剂热反应,一步原位合成了磷掺杂碳纳米管(P-CNT).旋转环盘电极测试表明磷掺杂能够明显提高碳纳米管的催化活性,P-CNT在碱性电解质中对ORR和OER都具有优异的催化活性.P-CNT对ORR的催化还原为近4电子反应,可与商业催化剂Pt/C(20 wt%)相比;而其对OER的催化活性则高于Pt/C(20 wt%).此外,P-CNT的长期稳定性优于Pt/C(20 wt%).P-CNT对ORR和OER的高催化活性和稳定性主要归因于磷对碳的掺杂以及磷与碳间强的化学键合.     

以细菌纤维素为前驱体简便制备氮掺杂碳纤维气凝胶作为高效氧还原催化剂

数十年来,碳气凝胶因其在催化剂载体、电容器和锂电池电极材料以及吸附剂等领域的潜在应用而备受关注.然而,传统碳气凝胶的制备往往使用昂贵且有毒的前驱体,其方法也较为复杂,不利于大规模生产及应用.本文介绍了一种以细菌纤维素为前驱体制备氮掺杂碳纤维气凝胶的方法.该方法廉价高效,简单易行且对环境无害.所制气凝胶具有密度低、孔隙度高、比表面积大以及导电性良好等优点.它继承了细菌纤维素生物质优异的三维交联多孔结构的特点,可直接用作氧还原催化剂,表现出优异的催化性能,预示着其广泛的应用前景.这在该领域的应用报道尚属首次.     

硼、氮掺杂的二硫化钼用于氧还原电催化研究

对于碱性燃料电池的阴极反应,开发具有优异催化性能的新型催化剂至关重要.本工作采用一种简单的热解方法合成了硼、氮掺杂的二硫化钼(B,N-MoS2)材料并将其应用于氧还原(ORR)电催化分析.通过循环伏安法(CV)与线性扫描伏安法(LSV)等电化学分析方法,采用旋转盘电极(RDE)与旋转环盘电极(RRDE)等技术测试了该材...     

MOF/CC-derivatives with trace amount of cobalt oxides as efficient electrocatalysts for oxygen reduction reaction

Two MOF/CC-derivatives with trace amount of cobalt oxides exhibit excellent electrocatalytic activity for oxygen reduction reaction.     

热解二氧化钛/聚苯胺制备高效非贵金属氧还原电催化剂

为了克服传统Pt系催化剂价格昂贵、稳定性差的缺点,采用热解新型Ti O2/聚苯胺(PANI)复合物的方法合成了Ti O2/C催化剂.用扫描电子显微镜、X射线光电子能谱、X射线衍射、傅里叶变换红外光谱、拉曼光谱、透射电子显微镜、循环伏安法和线性扫描伏安法等方法研究了热处理和PANI复合比例对复合物的形貌、成键、晶相组成及氧还原性能的影响.结果表明,PANI与Ti O2间存在相互作用,可以抑制Ti O2的团聚和锐钛矿向金红石的转变.热处理制得Ti O2/C的氧还原活性随着PANI载体含量增加先升高后降低,PANI和Ti O2质量比为35/100时,催化剂的氧还原活性最高.同时,循环伏安和时间-电流曲线测试表明,已制备的复合材料在催化氧还原反应进行时具有较好的稳定性.     

碳基无金属氧还原电催化剂研究的新进展

以替代铂为目标的高性能廉价氧还原电催化剂的研究为当今科学前沿. 近年来人们发现, 掺杂的碳基纳米结构具有催化活性高、稳定性好、资源丰富、抗CO和抗甲醇能力强等优点, 是一种新型无金属氧还原电催化剂, 具有替代铂基催化剂的潜力. 本文结合作者课题组的最新研究成果, 简要综述了碳基无金属氧还原电催化剂研究的主要进展, 重点关注了富电子氮和缺电子硼单/共掺杂的碳纳米结构的氧还原催化性能及其与电子结构的关系, 展望了碳基无金属氧还原催化剂的发展策略与前景.     

应用于氧还原反应的石墨烯-无定形碳核壳结构复合材料载铂催化剂(英文)

采用氯化法制备石墨烯-无定型碳复合材料(GNS@a-C),并用作质子交换膜燃料电池(PEMFC)氧还原反应Pt催化剂的载体.结果显示,所制Pt/GNS@a-C催化剂与传统商业催化剂Pt/C相比,有较好的活性和较高的稳定性:质量活性(0.121 A/mg)几乎是Pt/C(0.064 A/mg)的两倍.更重要的是,该新型催化剂加速4000圈后其电化学活性面积保留了最初的51%,与Pt/C的33%相比,前者有更好的电化学稳定性,显示它在PEMFC中将具有较好的应用潜力.     

Effect of doping order on metal-free heteroatoms dual-doped carbon as oxygen reduction electrocatalyst

Metal-free heteroatoms dual-doped carbon has been recognized as one of the most promising Pt/C-substitutes for oxygen reduction reaction(ORR).Herein,we optimize the preparation process by doping order of metal-free heteroatoms to obtain the best electrocatalytic performance through three types of dual-doped carbon,including XC-N(first X doping then N doping),NC-X(first N doping then X doping) and NXC(N and X doping)(X=P,S and F).XC-N has more defect than the other two indicated by Raman spectra.X-ray photoelectron spectrom(XPS) measurements indicate that N and X have been dual-doped into the carbon matrix with different doping contents and modes,Electrocatalytic results,including the potential of ORR peak(E_p),the half-wave potential,the diffusion-limiting current density mainly follows the order of XC-NNC-X NXC,Furthermore,the synergistic effect of second atom doping are also compared with the single doped carbon(NC,PC,SC and FC).The differences in electronegativity and atomic radius of these metal-free heteroatoms can affect the defect degree,the doping content and mode of hete roatoms on carbon matrix,induce polarization effect and space effect to affect O_2 adsorption and product desorption,ultimately to the ORR electrocatalytic performance.     

Electrochemically exfoliating graphite into N-doped graphene and its use as a high efficient electrocatalyst for oxygen reduction reaction

N-doped graphene has been extensively explored because of their intriguing properties. However, most of the conventional heat-processed N-doped graphene (HNG) suffer from the poor hydrophilic property and low electric conductivity when using electrode materials. Herein, we present a facile solution-processed strategy to fabricate N-doped graphene through electrochemical exfoliation of graphite in inorganic electrolyte solution. The resulting electrochemically exfoliated N-doped graphene (ENG) has high level of nitrogen (7.9 at.%) and oxygen (16.5 at.%), moreover, excellent electric conductivity (19 s cm^?1). As a binder-free electrode material for oxygen reduction reaction (ORR), ENG exhibits much better electroactivity than HNG and electrochemically exfoliated graphene (EG), moreover, much better methanol tolerance and long-term durability than that commercial Pt/C catalyst. The results provide new sights into scalable production of noble metal-free catalyst towards ORR.     

Oxygen-deficient titania as alternative support for Pt catalysts for the oxygen reduction reaction

Insufficient electrochemical stability is a major challenge for carbon materials in oxygen reduction reaction （ORR） due to carbon corrosion and insufficient metal-support interactions. In this work, titania is explored as an alternative support for Pt catalysts. Oxygen deficient titania samples including TiO2-x and TiO2_xNy were obtained by thermal treatment of anatase TiO2 under flowing H2 and NH3, respectively. Pt nanoparticles were deposited on the titania by a modified ethylene glycol method. The samples were characterized by N2-physisorption, X-ray diffraction and X-ray photoelectron spectroscopy. The ORR activity and long-term stability of supported Pt catalysts were evaluated using linear sweep voltammetry and chronoamperometry in 0.1 mol/L HC104. Pt/TiO2_x and Pt/TiO2_xNy showed higher ORR activities than Pt/TiO2 as indicated by higher onset potentials. Oxygen deficiency in TiO2-x and TiO2-xNy contributed to the high ORR activity due to enhanced charge transfer, as disclosed by electrochemical impedance spectroscopy studies. Electrochemical stability studies revealed that Pt/TiOE_x exhibited a higher stability with a lower current decay rate than commercial Pt/C, which can be attributed to the stable oxide support and strong interaction between Pt nanoparticles and the oxygen-deficient TiO2-x support.     

Microwave-assisted synthesis of sulfur-doped graphene supported PdW nanoparticles as a high performance electrocatalyst for the oxygen reduction reaction

Sulfur-doped graphene (SG) is synthesized by a simple microwave irradiation method and PdW nanoparticles are grown in situ on SG. The electrocatalyst shows excellent activity for the oxygen reduction reaction (ORR) in alkaline solution and the reaction kinetics investigation shows that PdW-SG follows a four-electron transfer process in ORR, which is much better than Pd-SG or Pd-G. The improved catalytic performance may result from the changes in the electronic structure when Pd alloys with W as well as the strong interactions between the PdW nanoparticles and SG.     

Bio‐inspired iron/sulfur/graphene nanocomposite and its use in the catalysis of the oxygen reduction reaction at room temperature in alkaline media on a glassy carbon electrode

This work demonstrates the performance of a bio‐inspired iron/sulfur/graphene nanocomposite as a non‐platinum electrocatalyst for the oxygen reduction reaction (ORR) in an alkaline medium. The catalyst shows the most positive ORR onset potential (1.1 V vs. RHE) according to its unique structure in the alkaline medium (KOH solution, pH = 13) at low temperature (T = 298 K). The catalyst is evaluated by the rotating‐disk electrode (RDE) method under various rotating speeds (0–2,000 rpm) in the potential range ?0.02–1.18 V vs. a rechargeable hydrogen electrode (RHE). The number of transferred electrons, as one of the most important parameters, is almost constant over a wide range of potentials (0.1–0.8 V), which indicates a more efficient four‐electron pathway from O₂ to H₂O on the FePc‐S‐Gr surface. The mean size of catalyst centers are in the nanoscale (<10 nm). The estimated Tafel slope in the appropriate range is about ?110 mV per decade at low current density, and E_1/2 of FePc‐S‐Gr displays a negative shift of only 7.1 mV after 10,000 cycles.