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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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Patent
06 Mar 1984
TL;DR: In this article, a noble metal layer is provided on the surface of a semiconductor substrate through an ohmic contact layer, and the surface undergoes electrolysis by using plating liquid including the ions of the same noble metal as the noble metal.
Abstract: PURPOSE:To obtain a semiconductor device characterized by a low cost and improved reliability, by providing a noble metal layer on the surface of a semiconductor substrate through an ohmic contact layer, performing electrolysis of the surface of the noble metal layer in plating liquid including the ions of the same noble metal, reversing the polarity of a voltage, performing electric plating, thereby forming a uniform rear surface of electrode by few processes. CONSTITUTION:A noble metal layer 8 is provided on the surface of a semiconductor substrate 1 through an ohmic contact layer 7. The surface of the noble metal layer undergoes electrolysis by using plating liquid including the ions of the same noble metal as the noble metal 8. Thereafter, the polarity of a voltage is reversed, and electric plating 9 is performed. For example, the Ti-AuSb layer 7 is formed on the rear surface of a wafer. Then, the surface on the side, where an Ag bump 6 is formed, is covered. The wafer is connected to a positive electrode. A platinum plate is connected to a negative electrode. Ag is plated on the rear surface of the semiconductor substrate 1 in the aqueous solution of AgCN. Then, heat treatment is performed in an N2 atmosphere, and the Ag layer 8 is provided through the ohmic contact layer. Then, the wafer is connected to the positive electrode, and the platinum plate is connected to the negaive electrode, and the electrolysis is performed in the aqueous solution of AgCN. Thus the surface of the Ag layer 8 is cleaned. Then the polarity is immediately reversed, and the plating is performed. Thus the Ag layer 9 is obtained.

118 citations

Journal ArticleDOI
TL;DR: In this paper, stable mono and bimetallic nanoparticles have been prepared from colloids developed by a simple and reproducible method, based on a reduction-by-solvent process.

118 citations

Journal ArticleDOI
TL;DR: In this article, the authors present recent advances in the synthetic strategies for metal/metal compound hetero-interfaces within a nanostructure, and summarize the beneficial and synergistic effect of nanoscale metal and metal compound interfaces on the catalytic performances.
Abstract: The increasing demand to realize sustainable and clean energy conversion systems has prompted great efforts to develop electrocatalysts with maximum efficiency and minimum cost. Until now, noble-metal-based electrocatalysts have shown excellent catalytic performances toward fuel cell and water splitting electrode reactions, such as the oxygen reduction reaction (ORR), the oxygen evolution reaction (OER), and the hydrogen evolution reaction (HER). Despite their outstanding activities, their high cost interrupted any further progress toward practical applications. Recently, the fabrication of metal/metal compound hetero-nanostructures has emerged as a promising strategy to develop a cost-effective and high-performance electrocatalyst. The introduction of metal compounds, such as sulfides, phosphides, oxides, and carbides, appropriately modified the energy state of the metal catalyst to achieve optimum activity, thus lowering the usage of expensive noble metal species to reduce the overall cost. In this review, we present recent advances in the synthetic strategies for metal/metal compound hetero-interfaces within a nanostructure. We also summarize the beneficial and synergistic effect of nanoscale metal/metal compound hetero-interfaces on the catalytic performances. Finally, we provide perspectives on further development of hetero-structured electrocatalysts toward energy conversion applications.

117 citations

Journal ArticleDOI
TL;DR: In this paper, the authors presented a noble-metal free but more efficient COF-based photocatalytic H2 evolution system, which used a typical ketoenamine-based TpPa-1-COF as a model and integrated it with MoS2.
Abstract: Covalent Organic Frameworks (COFs) as an emerging class of crystalline and porous materials have exhibited excellent visible-light-driven H2 generation activity in more recent years. However, noble metal co-catalysts are inevitable even in all COF-based photocatalysts to realize a high hydrogen evolution rate. In this work, for the first time we present a noble-metal free but more efficient COF-based photocatalytic H2 evolution system. We chose a typical ketoenamine-based TpPa-1-COF as a model and integrated it with MoS2 to construct MoS2/TpPa-1-COF composites by in situ growth of the TpPa-1-COF in an exfoliated MoS2 dispersion solution of N,N-dimethylformamide (DMF). The results of photocatalytic H2 evolution under visible light irradiation show that the MoS2/TpPa-1-COF composite with an optimized amount of 3 wt% MoS2 loading exhibits a H2 evolution rate of 55.85 μmol h−1 (10 mg photocatalyst) without any noble metal in the catalytic system, and the apparent quantum efficiency is 0.76% at 420 nm. In comparison, this H2 evolution rate of the MoS2-3%/TpPa-1-COF composite is 32 times as high as that of the pure TpPa-1-COF (1.72 μmol h−1) and even a little better than that of the Pt/TpPa-1-COF (54.79 μmol h−1) with the same Pt loading (3 wt%). Further investigation demonstrates that MoS2 in the composite, acting as an effective non-noble-metal co-catalyst, can enormously facilitate the transfer of photogenerated electrons from the COF to MoS2 and improve the separation of photogenerated charges, leading to the excellent H2 evolution activity of the resulting composite. Considering the promising future of COF-based photocatalysts and the first report of noble-metal-free photocatalysts of COFs, this work may provide an avenue for the further design and synthesis of low-cost COF-based photocatalysts for efficient H2 evolution.

117 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023485
2022986
2021622
2020724
2019896
2018767