乙醇在铂和钯电极上的电化学氧化比较

用循环伏安和计时电量法研究了乙醇在Pt和Pd电极上的电化学氧化活性。用不同扫描速度下的循环伏安研究得出乙醇在Pt和Pd电极上的电化学氧化都是扩散控制的不可逆反应。用计时电量法研究乙醇在Pt和Pd电极上的电化学氧化时,发现不同电位下失电子数是不同的,在Pt电极上在–0.30 V有最大值,在Pd电极上在–0.35 V有最大值,这个结果说明乙醇在Pd电极上比在Pt电极上更容易被电化学氧化。

碱性溶液中醇在Pd电极上失去电子数研究

用循环伏安法研究了碱性条件下甲醇、乙醇和异丙醇在Pd电极上氧化失去电子能力。甲醇和乙醇氧化是失去6个和4个电子。异丙醇容易失去2个电子氧化为丙酮,丙酮会进一步氧化,但氧化程度很低。乙醇和异丙醇在低于-0.4 V范围内失去电子数比不上甲醇,但在-0.9到-0.4 V的积分电量是甲醇的19.1和41.2倍。说明了乙醇和异丙醇在Pd电极上比甲醇更容易电化学氧化,特别是异丙醇,比乙醇更容易氧化。

Carbon dioxide-expanded ethanol-assisted synthesis of carbon-based metal composites and their catalytic and electrochemical performance in lithium-ion batteries

Highly dispersed metals,metal oxides and their composites on substrates have received considerable interest in catalysis and lithium-ion batteries,because of their superior properties compared with their single-component counterparts.In this review,we introduce the properties of supercritical carbon dioxide（scCO2） expanded ethanol,such as low viscosity,near-zero surface tension and high diffusivity.We discuss the deposition procedure and formation mechanism of carbon-based composites in scCO2-expanded ethanol.This method has been used to fabricate several carbon-based composites,such as metal and metal oxide composites deposited on zero-dimensional colloidal carbon,one-dimensional carbon nanotubes,two-dimensional graphene,and three-dimensional hierarchical porous carbon.These materials and their performance as anodic materials for lithium-ion batteries will also be reviewed.

Electrooxidation of methanol and ethanol on carbon electrodeposited Ni–MgO nanocomposite

Ni–MgO nano‐composites were prepared on carbon anodes by electrodeposition from a nickel Watts bath in the presence of fine MgO reinforcement particles. Their performance as electrocata‐lysts for the oxidation of methanol and ethanol in alkaline medium was investigated and compared with that of carbon coated pure Ni （Ni/C）. The chemical composition, phase structure, and surface morphology of the deposited nano‐composites were studied by energy dispersive X‐ray spectros‐copy, X‐ray diffractometry, and scanning electron microscopy, respectively. Different electrochemi‐cal techniques were used to estimate the catalytic activity of the prepared electrocatalyst anodes, including cyclic voltammetry （CV）, chronoamperometry, and electrochemical impedance spectros‐copy （EIS）. The Ni/C electrocatalyst alone exhibited remarkably low catalytic activity and poor stability toward the electrooxidation process. The inclusion of MgO significantly promoted the cata‐lytic activity of the Ni catalyst for the alcohol electrooxidation and enhanced its poisoning re‐sistance. The EIS results confirmed those of CV and revealed a lower charge transfer resistance and enhanced roughness for the Ni–MgO/C nano‐composite electrodes compared with those of Ni/C.

Surface-structure tailoring of ultrafine PtCu nanowires for enhanced electrooxidation of alcohols

Surface tailoring of Pt-based nanocatalysts is an effective pathway to promote their electrocatalytic performance and multifunctionality.Here,we report two kinds of one-dimensional(1D)ultrafine PtCu nanowires(smooth surface&rugged surface)synthesized via a wet chemical method and their distinct catalytic performances in electro-oxidation of alcohols.The alloyed PtCu nanowires having rough surfaces with atomic steps exhibit superior catalytic activity toward multiple electrochemical reactions compared with the smooth counterpart.Density functional theory simulations show the excellent reactivity of rugged PtCu na-nowires and attribute it to the surface synergetic Pt-Cu site which accounts for the promotion of water dissociation and the dehydrogenation of the carboxyl intermediate.The current study provides an insight into reasonable design of alloy nanocatalysts in energy-related electrocatalytic systems.