Noble metal

About: Noble metal is a research topic. Over the lifetime, 15113 publications have been published within this topic receiving 337947 citations.

Platinum Monolayer on Nonnoble Metal−Noble Metal Core−Shell Nanoparticle Electrocatalysts for O2 Reduction

Abstract: We synthesized a new class of O2 electrocatalysts with a high activity and very low noble metal content. They consist of Pt monolayers deposited on the surfaces of carbon-supported nonnoble metal−noble metal core−shell nanoparticles. These core−shell nanoparticles were formed by segregating the atoms of the noble metal on to the nanoparticles' surfaces at elevated temperatures. A Pt monolayer was deposited by galvanic displacement of a Cu monolayer deposited at underpotentials. The mass activity of all the three Pt monolayer electrocatalysts investigated, viz., Pt/Au/Ni, Pt/Pd/Co, and Pt/Pt/Co, is more than order of magnitude higher than that of a state-of-the-art commercial Pt/C electrocatalyst. Geometric effects in the Pt monolayer and the effects of PtOH coverage, revealed by electrochemical data, X-ray diffraction, and X-ray absorption spectroscopy data, appear to be the source of the enhanced catalytic activity. Our results demonstrated that high-activity electrocatalysts can be devised that contain ...

Catalyst design for dry reforming of methane: Analysis review

Abstract: The performance of catalysts used for the dry reforming of methane can strongly depend on the selection of active metals, supports and promoters. This work studies their effects on the activity and stability of selected catalysts. Designing an economically viable catalyst that maintains high catalytic activity and stability can be achieved by exploiting the synergic effects of combining noble and/or non-noble metals to form highly active and stable bi- and tri-metallic catalysts. Perovskite type catalysts can also constitute a potent and cost effective substituent. Metal oxide supports with surface Lewis base sites are able to reduce carbon formation and yield a greater stability to the catalyst, while noble metal promoters have proven to increase both catalyst activity and stability. Moreover, a successful metal-support-promoter combination should lead to higher metal-support interacrtion, lower reduction temperature and enhancement of the anti-coking and anti-amalgamation properties of the catalyst. However, the effect of each parameter on the overall performance of the catalyst is usually complex, and the catalyst designer is often faced with a tradeoff between activity, stability and ease of activation. Based on the review carried out on various studies, it is concluded that a catalyst design must take into consideration not only the separate effects of the active metal, support and promoter, but should also include the combined and mutual interactions of these components.

Molecular metal–N x centres in porous carbon for electrocatalytic hydrogen evolution

Abstract: Replacement of precious platinum with efficient and low-cost catalysts for electrocatalytic hydrogen evolution at low overpotentials holds tremendous promise for clean energy devices. Here we report a novel type of robust cobalt–nitrogen/carbon catalyst for the hydrogen evolution reaction (HER) that is prepared by the pyrolysis of cobalt–N4 macrocycles or cobalt/o-phenylenediamine composites and using silica colloids as a hard template. We identify the well-dispersed molecular CoNx sites on the carbon support as the active sites responsible for the HER. The CoNx/C catalyst exhibits extremely high turnover frequencies per cobalt site in acids, for example, 0.39 and 6.5 s−1 at an overpotential of 100 and 200 mV, respectively, which are higher than those reported for other scalable non-precious metal HER catalysts. Our results suggest the great promise of developing new families of non-precious metal HER catalysts based on the controlled conversion of homogeneous metal complexes into solid-state carbon catalysts via economically scalable protocols. Hydrogen evolution from water promises a future clean energy source, however the cost of noble metal catalysts, which are necessary for high efficiency, are very expensive. Here, the authors fabricate a porous cobalt–nitrogen/carbon catalyst which can deliver high activity and stability but at reduced cost.