نتایج جستجو برای: precious metal
تعداد نتایج: 201716 فیلتر نتایج به سال:
Carbon materials doped with transition metal and nitrogen are highly active, non-precious metal catalysts for the electrochemical conversion of molecular oxygen in fuel cells, metal air batteries, and electrolytic processes. However, accurate measurement of their intrinsic turn-over frequency and active-site density based on metal centres in bulk and surface has remained difficult to date, whic...
Catalytic oxidation of carbon monoxide (CO) is of great importance in many different fields of industry. Until now it still remains challenging to use non-noble metal based catalysts to oxidize CO at low temperature. Herein, we report a new class of nanoporous, uniform, and transition metal-doped cerium (IV) oxide (ceria, CeO2) microsphere for CO oxidation catalysis. The porous and uniform micr...
The dehydrogenation of unactivated alkanes is an important transformation both in industrial and biological systems. Recent efforts towards this reaction have revolved around high temperature, organometallic C-H activation by noble metal catalysts that produce alkenes and hydrogen gas as the sole products. Conversely, natural desaturase systems proceed through stepwise hydrogen atom transfer at...
Developing efficient and economical noble-metal free catalysts for oxygen reduction reaction (ORR) is one of the essential factors for the industrialization of fuel cells. Recent studies on transition metal ORR catalysts have become the priority to practical low-temperature fuel cells. Herein, we proposed a novel in situ design, Fe2N nanoparticles (NPs) in an N doped porous carbon matrix (Fe2N@...
This reaction is connected to high overpotentials, which are in Zn electrowinning about 800 mV, or 20–25% of the total cell voltage, and with that an equal amount of the total electrical energy1. Many attempts have been made to reduce the overpotential by introducing better catalysts. The main anode systems are nowadays all lead based1, which offer the best cost:value ratio for most of the indu...
Metal nanocrystals offer new concepts for the design of nanodevices with a range of potential applications. Currently the formation of metal nanocrystals cannot be controlled at the level of individual atoms. Here we describe a new general method for the fabrication of multi-heteroatom-doped graphitic matrices decorated with very small, ångström-sized, three-dimensional (3D)-metal crystals of d...
Hydrogen evolution reaction is catalysed efficiently with precious metals, such as platinum; however, transition metal dichalcogenides have recently emerged as a promising class of materials for electrocatalysis, but these materials still have low activity and durability when compared with precious metals. Here we report a simple one-step scalable approach, where MoOx/MoS2 core-shell nanowires ...
This paper focuses on a new polyaniline-derived non-precious cathode catalyst with high oxygen-reduction activity, verified in electrochemical and fuel cell testing. The rotating disk (RDE) onset and half-wave potential (E1⁄2) of oxygen reduction were measured at 0.90 V and 0.77 V, respectively. Rotating ring-disk electrode (RRDE) study revealed very good selectivity in the fourelectron reducti...
Oxygen reduction reaction (ORR) is an electrochemical in which dissolved oxygen electrolyte reduced to OH?/H2O when receiving electrons. This plays a crucial role shaping the efficiency of both metal–air batteries and fuel cells, precious metals are dominant catalysts carrying out ORR their cathodes. However, how manipulate electronic structure as active sites further promote performance maximi...
A unique hydrothermal selective hydrogenation process is carried out effectively in a simple and friendly way without adding any precious metal catalysts and hydrogen gas from outside. The self-assembly of the hydrogenated product 3-(4-(pyridin-4-yl)piperidin-1-yl) benzoate (PYPDB) with the zinc ion produces a highly stable photoactive complex Zn(PYPDB)2 displaying interesting long range electr...
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