Browsing by Author "Wu, Szu-Chen"

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A Strategy to Synthesize Ultrahigh-N-Doped Hierarchical Carbons via Induced beta-Sheet from Silk Fibroin by In Situ Electrogelation/Electropolymerization
(2020-04-27)
Liu, Ta-Chung
;
Li, Tsung-Yu
;
Hung, Pei-Sung
;
Liang, Chun-Wei
;
Wu, Szu-Chen
Silk fibroin (SF) is recognized for its rich nitrogen content and has been explored for its promising potential in energy storage because of its hexagonal pseudographitic structure from the direct transformation of the unique secondary protein beta-sheet peptides of carbonized SF. In this work, we proposed a novel strategy that combined with in situ electrophoresis and electrogelation of SF as well as the electropolymerization of 3,4-ethylenedioxythiophene (EDOT) for producing high-level nitrogen-doped (N-doped) carbons. A high beta-sheet content of SF can be synthesized in a three-dimensional (3D) inverse opaline skeleton via double-network microstructure (physical beta-sheet cross-linking and chemical PEDOT cross-linking) induced by the hydrophobic EDOTs. This synergistic effect regulating SF distribution and balancing the intra/intermoleeular hydrogen bonding among SF results in boosting beta-sheet contents. Herein, this 3D SF/PEDOT composite inverse opal (SPIO) exhibits a much ultrahigh-coneentrated beta-sheets (46.4%) compared to pure electrogelated SFIO with 16.4% of beta-sheets. After subsequent pyrolysis, a high-level (14.7%) N-doped pseudographitic carbon inverse opal is realized. For evaluation as a pseudocapacitor, this high-level N-doped pseudographitic carbon inverse opal shows a capacitance of 342 F g(-1) at 0.5 A g(-1) and a commendable energy density of 31.7 Wh kg(-1) at an ultrahigh power density of 25009 W kg(-1) (at 50 A g(-1)). After galvanostatic charging/discharging at 15 A g(-1) for 10000 cycles, the sample maintains an impressive capacitance retention of 89.8%.
Multi-Metals CaMgAl Metal-Organic Framework as CaO-based Sorbent to Achieve Highly CO2 Capture Capacity and Cyclic Performance
(2020-05-01)
Wu, Szu-Chen
;
Chang, Po-Hsueh
;
Lin, Chieh-Yen
;
Peng, Cheng-Hsiung
;
材料科學與工程學系
In this study, Ca-based multi-metals metal-organic framework (CaMgAl-MOF) has been designed as precursor material for carbon dioxide (CO2) capture to enhance the CO2 capture capacity and stability during multiple carbonation-calcination cycles. The CaMgAl-MOFs were constructed from self-assembly of metal ions and organic ligands through hydrothermal process to make metal ions uniformly distributed through the whole structure. Upon heat treatment at 600 degrees C, the Ca-based multi-metals CaMgAl-MOF would gradually transform to CaO and MgO nanoparticles along with the amorphous aluminum oxide distributed in the CaO matrix. XRD, Fourier transform infrared (FTIR), and SEM were used to identify the structure and characterize the morphology. The CO2 capture capacity and multiple carbonation-calcination cyclic tests of calcined Ca-based metal-organic framework (MOF) (attached with O and indicated as Ca-MOF-O) were performed by thermal gravimetric analysis (TGA). The single metal component calcined Ca-MOF sorbent have the highest CO2 capture capacity up to 72 wt.%, but a lower stability of 61% due to severe particle aggregation. In contrast, a higher Ca-rich MOF oxide sorbent with tailoring the Mg/Al ratios, Ca0.97Mg0.025Al0.005-MOF-O, showed the best performance, not only having the high stability of similar to 97%, but also maintaining the highest capacity of 71 wt.%. The concept of using Ca-based MOF materials combined with mixed-metal ions for CO2 capture showed a potential route for achieving efficient multiple carbonation-calcination CO2 cycles.