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Noble metal
About: Noble metal is a research topic. Over the lifetime, 15113 publications have been published within this topic receiving 337947 citations.
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TL;DR: A robust oxygen-evolving electrocatalyst consisting of ferrous metaphosphate on self-supported conductive nickel foam that is commercially available in large scale that satisfies the criteria for large-scale commercialization of water–alkali electrolyzers is reported.
Abstract: Commercial hydrogen production by electrocatalytic water splitting will benefit from the realization of more efficient and less expensive catalysts compared with noble metal catalysts, especially for the oxygen evolution reaction, which requires a current density of 500 mA/cm 2 at an overpotential below 300 mV with long-term stability. Here we report a robust oxygen-evolving electrocatalyst consisting of ferrous metaphosphate on self-supported conductive nickel foam that is commercially available in large scale. We find that this catalyst, which may be associated with the in situ generated nickel–iron oxide/hydroxide and iron oxyhydroxide catalysts at the surface, yields current densities of 10 mA/cm 2 at an overpotential of 177 mV, 500 mA/cm 2 at only 265 mV, and 1,705 mA/cm 2 at 300 mV, with high durability in alkaline electrolyte of 1 M KOH even after 10,000 cycles, representing activity enhancement by a factor of 49 in boosting water oxidation at 300 mV relative to the state-of-the-art IrO 2 catalyst.
281 citations
TL;DR: In this article, using the zeolitic imidazolate framework (ZIF-8) as MOF template, catalytically remarkably efficient ligand-free first-row late transition-metal nanoparticles are prepared and compared.
Abstract: Non-noble metal nanoparticles are notoriously difficult to prepare and stabilize with appropriate dispersion, which in turn severely limits their catalytic functions. Here, using zeolitic imidazolate framework (ZIF-8) as MOF template, catalytically remarkably efficient ligand-free first-row late transition-metal nanoparticles are prepared and compared. Upon scrutiny of the catalytic principles in the hydrolysis of ammonia-borane, the highest total turnover frequency among these first-row late transition metals is achieved for the templated Ni nanoparticles with 85.7 molH2 molcat–1 min–1 at room temperature, which overtakes performances of previous non-noble metal nanoparticles systems, and is even better than some noble metal nanoparticles systems. Mechanistic studies especially using kinetic isotope effects show that cleavage by oxidative addition of an O–H bond in H2O is the rate-determining step in this reaction. Inspired by these mechanistic studies, an attractive and effective “on–off” control of hyd...
281 citations
TL;DR: Li et al. as mentioned in this paper used nickel phosphide (Ni2P) as a nonprecious co-catalyst to couple with metal-free g-C3N4 based on Z-scheme type of electron transportation model.
Abstract: Photocatalysts made of earth-abundant elements are highly desired for photocatalytic H2 evolution as well as bacterial inactivation without requirement of noble metal (i.e. Pt, Ag). In this study, nickel phosphide (Ni2P) was used as a nonprecious co-catalyst to couple with metal-free g-C3N4 based on Z-scheme type of electron transportation model. The exfoliation of bulk g-C3N4, the in-situ synthesis and anchoring of Ni2P nanoparticles onto the g-C3N4 nanosheets were achieved in one-step by a hydrothermal method without adding any surfactants or templates. The optimized Ni2P/g-C3N4 lamellar nanohydrids exhibited remarkably enhanced visible-light-driven photocatalytic activity for H2 evolution and bacterial inactivation without noble metal loading, and the obtained activity is approximately 22 and 10 times higher than that of pure g-C3N4, respectively. The Ni2P was proposed to effectively trap the photo-generated e− via a Z-scheme type of route, thus significantly promoting the e−-h+ separation and subsequent reduction of protons to generate H2. The bacterial inactivation was found to undergo a direct h+ oxidation process, and therefore the trapping of e− by Ni2P also facilitated h+ accumulation, leading to enhanced bacterial inactivation efficiency. This study demonstrates a proof-of-concept for constructing all-earth-abundant photocatalysts without any noble metal elements for both energy production and environmental application.
280 citations
TL;DR: It is demonstrated that the sol–gel process represents a powerful “bottom-up” strategy for creating nanostructured materials that tackles the problems of high cost, insufficient activity, and inadequate long-term durability of metal aerogels.
Abstract: ConspectusMetallic and catalytically active materials with high surface area and large porosity are a long-desired goal in both industry and academia. In this Account, we summarize the strategies for making a variety of self-supported noble metal aerogels consisting of extended metal backbone nanonetworks. We discuss their outstanding physical and chemical properties, including their three-dimensional network structure, the simple control over their composition, their large specific surface area, and their hierarchical porosity. Additionally, we show some initial results on their excellent performance as electrocatalysts combining both high catalytic activity and high durability for fuel cell reactions such as ethanol oxidation and the oxygen reduction reaction (ORR). Finally, we give some hints on the future challenges in the research area of metal aerogels. We believe that metal aerogels are a new, promising class of electrocatalysts for polymer electrolyte fuel cells (PEFCs) and will also open great op...
280 citations
TL;DR: In this article, the catalytic decomposition of nitrous oxide to nitrogen and oxygen was studied over a number of catalysts and the effects of oxygen and nitric oxide addition, metal loading, and pretreatment upon the catalyst activity were evaluated.
Abstract: The catalytic decomposition of nitrous oxide to nitrogen and oxygen was studied over a number of catalysts. Copper and cobalt exchanged ZSM-5, mordenite, zeolite beta, ZSM-11 and ferrierite are much more active than other cation-exchanged zeolites (Cu-Y, Co-Y, Co-erionite, Cu-L, Co-L, Ni-ZSM-5, Mn-ZSM-5) and metal oxides (CuO/Al2O3, and CoO/Al2O3). For noble metal catalysts, a cation exchanged ZSM-5 has higher activity than the Al2O3 supported form. Rhodium is the most active catalyst, but surprisingly Pt-ZSM-5 is one of the least active catalysts of all. Also, the effects of oxygen and nitric oxide addition, metal loading, and pretreatment upon the catalyst activity were evaluated.
280 citations