Electrodeposition of platinum nanoclusters on type I collagen modified electrode and its electrocatalytic activity for methanol oxidation

We firstly reported a novel polymer matrix fabricated by type I collagen and polymers, and this matrix can be used as nanoreactors for electrodepositing platinum nanoclusters (PNCs). The type I collagen film has a significant effect on the growth of PNCs. The size of the platinum nanoparticles could be readily tuned by adjusting deposition time, potential and the concentration of electrolyte, which have been verified by field-emitted scanning electron microscopy (FE-SEM). Furthermore, cyclic voltammetry (CV) has demonstrated that the as-prepared PNCs can catalyze methanol directly with higher activity than that prepared on PSS/PDDA film, and with better tolerance to poisoning than the commercial E-TEK catalyst. The collagen-polymer matrix can be used as a general reactor to electrodeposit other metal nanostructures.     

Electrodeposited silver nanodendrites electrode with strongly enhanced electrocatalytic activity

Highly uniform dendritic silver nanostructures as a new electrode material, have been synthesized by electrodeposition on the glassy carbon (GC) electrode with assistance of polyethylene glycol 400 (PEG-400) as a soft template, to achieve a superior electrocatalyst with enhanced detection sensitivity in electroanalysis compared to conventional bulk Ag electrodes. The effects of the growth conditions such as concentrations of the reagents and applied potentials on the morphology and structure of as-prepared tree-like nanostructures have also been investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). In the silver nanodendrites (AgNDs), the diameter of the trunk is around 100-200 nm with length up to 10-40 μm, and the length of its branches can reach 10 μm. In addition, the electrocatalytic behavior of this modified electrode was exploited as a sensitive detection system for the reduction of RDX high explosive, hydrogen peroxide and hexacyanoferrate (HCF) by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Also, the obtained results were compared to multiwalled carbon nanotubes (MWCNTs) and bulk silver electrodes. These studies show that the nanodendritic silvers significantly increase the electron-transfer rate of the electrochemical reactions by as much as 1-2 orders of magnitude.     

A review on non-noble metal based electrocatalysis for the oxygen evolution reaction

In order to find a clean, efficient and sustainable new energy source that can replace fossil fuels, hydrogen energy is considered to be the most ideal choice. Electrocatalytic oxygen evolution plays a vital role in the development of hydrogen energy, promotes the research of new electrocatalysts, and is dedicated to find materials with high electrocatalytic efficiency. This article discusses in detail the major developments in OER electrocatalysts, including recently reported metal and non-metal based materials. Metal-based catalysts, although having the advantages of high catalytic activity, have disadvantages such as poor stability and low selectivity, which hinder the further application of such materials. Non-metallic based materials avoid such disadvantages and exhibit very substantial performance in overall water decomposition. This review provides useful knowledge of a well-designed OER electrocatalyst and a possible strategy for OER/HER dual-function catalytic performance for future development.     

碳化钨在对硝基苯酚电还原过程中的电催化行为

以碳化钨(WC)粉末为电催化材料制成了碳化钨粉末微电极(WC-PME). 采用循环伏安和线性扫描等方法研究了酸性溶液中对硝基苯酚(PNP)在WC-PME上的电还原行为. 研究表明, 在相同测试条件下, PNP在WC-PME上电还原的电位比Cu-Hg微电极正得多；WC-PME对氢具有较强的吸附能力, 有利于有机物的电还原反应. PNP在WC-PME上和Pt微电极上的还原电位相近, 但在WC-PME上的峰电流比在Pt微电极上高5倍多, 这主要与WC粉末的结构形貌有关.     

Ru Nanoparticles Supported on Co-Embedded N-Doped Carbon Nanotubes as Efficient Electrocatalysts for Hydrogen Evolution in Basic Media

A challenging but urgent task is to construct efficient and robust hydrogen evolution reaction(HER) electrocatalysts for practically feasible and sustainable hydrogen production through alkaline water electrolysis. Herein we report a simple and mild pyrolysis method to synthesize the efficient Ru nanoparticles(NPs) supported on Co-embedded N-doped carbon nanotubes(Ru/Co-NCNTs) catalyst for HER in basic media. The Ru/Co-NCNTs display remarkable performance with a low overpotential of only 35 mV at 10 mA/cm², a small Tafel slope(36 mV/dec), and a high mass activity in 1 mol/L KOH, which is superior to commercial 20% Pt/C catalyst. This excellent performance is benefited from the enhanced conductivity of N-doped carbon nanotubes(NCNTs) and high intrinsic activity triggered by synergistic coupling between Ru NPs and Co-embedded N-doped carbon nanotubes(Co-NCNTs).     

Untersuchungen über die selektive Katalyse der Elektrodenreaktionen im Aasserstoff-Brom-Speichersystem

Summary Considerable rates are obtained for the hydrogen electrode reactions using WC-gas-diffusion electrodes which are not impaired by active Br₂ in the solution. Tafel-lines withb-values of appr. 30 mV for both, anodic and cathodic current density potential curves, can be attributed to the Tafel-reaction as the rate controlling step. High reversibility (very low polarization) of the Br₂/2 Br^– redox couple is observed at activated carbon plastic composite material. The presence of H₂ does not influence the electrode behavior. The use of both substrates in the H₂/Br₂ storage system provides definite advantages of the conceptual design and operation due to their electrocatalytic selectivity.

     

PEMFC催化剂的研究：自制Pt/C电催化剂的性质

研究了一种用于质子交换膜燃料电池(PEMFC)的自制Pt/C电催化剂(标记为THYT-1)的物理化学和电化学性质.将THYT-1电催化剂与E-TEK公司的同类电催化剂的组成、形态及电催化性能进行了比较.单电池测试结果显示, THYT-1的电催化性能优于E-TEK电催化剂. CV测试结果表明CO在这两种电催化剂上的电氧化性能相近；TEM分析表明两种催化剂上Pt晶粒在炭载体上呈均匀分布，平均粒径均为2～3 nm； XPS和XRD测试结果表明两种催化剂中Pt主要以金属态存在.这些数据表明THYT-1催化剂的物理化学性质与E-TEK公司的相类似.     

Studies on State and Structure of Noble Metals in Electrocatalyst Made by Coprecipitation Method

The electrocatalysts of Pt/C,PtRu/C and Ru/C were prepared by the impregnation method.The facet characterization.The dispersion and the particle size for the catalysts were determined by means of X-ray diffraction and transmission electron microscopy,X-ray photoelectron spectroscopy was also used to analyze the state and the valency of the noble metals.The results show that the particle size was in nanometer range and the binary metals have come into being an alloy.The platinum in the catalysts existed in zero valency.The valency of the ruthenium on the surface is different from that in the body,while the ruthenium on the surface existed in oxide-form.PtRu/C and Pt/C are of good activity of the electrooxidation of hydrogen except Ru/C.PtRu/C is more tolerant of CO than Pt/C,and CO is only adsorbed on Pt.     

基于金属有机框架衍生的Fe-N-C纳米复合材料作为高效的氧还原催化剂

Environmentally friendly and renewable energy technologies, such as fuel cells and metal-air batteries, hold great promise for solving current energy and environmental challenges. The oxygen reduction reaction (ORR) plays a pivotal role in this top-drawer question. However, the sluggish kinetics of the ORR and prohibitive costs limit the global scalability of such devices. Traditionally, platinum-based electrocatalysts exhibit the best performance for ORRs in both acid and alkaline electrolytes. However, to significantly reduce the cost and realize sustainable development, utilization of Pt must be replaced or significantly reduced in the ORR cathode for fuel cell applications. Therefore, developing earth-abundant and high-performance non-precious metal catalysts (NPMCs) for ORR is of critical importance for the commercialization of fuel cells. In comparison to traditional catalysts, metal-organic frameworks (MOFs) are ideal precursors that integrate metal, nitrogen, and carbon functionalities together into one ordered 3D crystal structure. MOFs, assembled by secondary building of units comprised of metals and organic linkers with strong bonding, have received significant research attention because they possess permanent porosity, a three-dimensional (3D) structure, and can be prepared using a diversity of metals and organic linkers. High surface area, and microporous carbon materials can be easily obtained by carbonization of MOFs at high temperatures. In particular, MOF-derived carbon nanocomposites, which were prepared from transition metals, and have the form M-N-C (M = Fe or Co), have demonstrated remarkably improved catalytic activity and stability. Herein, we report an NPMC material consisting of Fe₃C nanoparticles encapsulated in mesoporous N-doped carbon (Fe-N-C), synthesized by a simple strategy involving physical mixing of MIL-100(Fe) with glucose and urea, and subsequent pyrolysis under inert atmosphere. The strong interaction between metal atoms and nitrogen atoms is beneficial in generating more active sites, and sites with a higher intrinsic catalytic activity, via carbonization. The as-obtained catalysts exhibit remarkable ORR activity in alkaline media, with the best catalyst (Fe-N-C-900, which is synthesized at 900 ℃) featuring a more positive onset potential (0.96 V vs the reversible hydrogen electrode (RHE)), a more positive half-wave potential (0.83 V vs RHE), a much higher diffusion limiting current density (6.28 mA·cm^-2) and a larger electron-transfer number (n), even at low overpotentials, compared with other contrast materials. Fe-N-C-900's excellent catalytic activity and stability in ORR are due to its large BET surface area, its large total pore volume, its nitrogen dopants, its active Fe₃C nanoparticles and the cooperative effects among its reactive functionalities.     

磷化镍/氮硫双掺杂石墨烯复合材料的制备及电催化析氢性能

采用水热法合成了具有高活性的磷化镍纳米晶(Ni₂P), 并合成了氮、 硫共掺杂石墨烯负载磷化镍纳米催化剂(Ni₂P/NSRGO). 对该催化剂的结构和形貌进行了表征, 并研究其电催化析氢性能. 电化学测试结果表明, Ni₂P/NSRGO复合电催化剂的析氢性能优于Ni₂P/RGO催化剂, 具有较小的Tafel斜率(35 mV/dec)、 较低的过电位(η₁₀=140 mV)和良好的稳定性.