National Taiwan University of Science and Technology

About: National Taiwan University of Science and Technology is a education organization based out in Taipei, Taipei, Taiwan. It is known for research contribution in the topics: Fuzzy logic & Control theory. The organization has 16288 authors who have published 21577 publications receiving 426294 citations. The organization is also known as: Taiwan Tech & Taiwantech.

Composition-dependent Raman modes of Mo1−xWxS2 monolayer alloys

Abstract: Two-dimensional (2D) transition-metal dichalcogenide alloys with tunable band gaps have promising applications in nanoelectronics and optoelectronics. Characterization of structures of 2D alloys, such as composition and atom mixing, is of fundamental importance to their applications. Here, we have conducted systematic Raman spectroscopic studies on Mo1−xWxS2 monolayers (0 ≤ x ≤ 1). First-order Raman modes and second-order Raman modes have been observed in the range of 100–480 cm−1 in the 2D alloys. The out-of-plane A1′ modes and in-plane E′ modes showed one-mode and two-mode behaviors, respectively. The broadening of A1′ and E′ modes in the alloys has been observed. The disorder-related Raman peaks at ∼360 cm−1 were only observed in the 2D alloys but not in the two end materials. Modified random-element-isodisplacement (MREI) model has been adopted to successfully predict mode behaviors of A1′ and E′ modes in the monolayer alloys. Further, composition-dependent A1′ and E′ frequencies can be well fitted by the MREI model, giving composition-dependent force constants.

Fabrication and Characterization of Well-Dispersed and Highly Stable PtRu Nanoparticles on Carbon Mesoporous Material for Applications in Direct Methanol Fuel Cell

Abstract: Well-dispersed, highly stable PtRu nanoparticles of ca. 2–3 nm on carbon mesoporous materials (PtRuCMMs) were synthesized directly using SBA-15 mesoporous silica as the template, furfuryl alcohol and trimethylbenzene as the primary carbon source, and platinum and ruthenium acetylacetonates as the cofeeding metal and carbon precursors. Results obtained from X-ray diffraction and X-ray photoelectron spectroscopy show that the Pt metal in the PtRu-CMMs was present in the form of a face-centered cubic (fcc) crystalline structure and the alloyed PtRu nanoparticles were composed mainly of Ru oxides, Ru(0), and Pt(0) metals. Further studies by X-ray absorption spectroscopy confirmed that a highly alloyed state of the PtRu nanoparticles is responsible for the superior electrocatalytic performance observed for the PtRu-CMMs, as compared to typical commercial electrocatalysts. The Pt50Ru50-CMM sample was found to possess the best electrocatalytic performance and long-term durability and should appeal to direct methanol fuel cell applications as anodic electrodecatalyst.