本研究之主要目的在於探討不同碳材(包括：活性碳、碳纖維與奈米碳管)以及奈米碳管經過鉑金屬顆粒負載和酸洗處理之後材料結構與儲氫性能之關聯性。鉑金屬顆粒在奈米碳管上的負載是使用H2PtCl6之前驅物於超臨界二氧化碳流體中以化學還原的方法施行。
不同的碳材以及經各種改質處理後的碳管以掃描式電子顯微鏡(SEM)、高解析穿透式電子顯微鏡(HRTEM)、X 光繞射分析儀(XRD)、能量散佈偵測儀(EDS)以及拉曼光譜儀(Raman spectra)分別鑑定碳材之結構特徵。各種奈米碳材儲氫量以高壓熱重微天平(HPTGA)，在室溫(300 k)高壓(1000 psi, 6.89 Mpa)的氫氣中加以量測，進而評估碳材之吸氫效能。
根據TEM和拉曼光譜分析，於硫酸和硝酸混酸水溶液(4:1, v/v 96% H2SO4/70% HNO3)以及硫酸和過氧化氫(4:1, v/v 96% H2SO4/30% H2O2)，加入0.02M之二價硫酸鐵(Fenton’s solution)中進行酸蝕可使碳管封閉端的開口並於管壁製造適量缺陷，藉而改善氣體流通性與增加表面吸附位置。相對於原材儲氫量0.52 wt%，經兩種氧化劑酸洗後之儲氫量分別為0.70 wt%和1.06 wt%。
室溫氫吸附等溫線顯示，鉑/碳管複合材之儲氫量由碳管原材之0.30 wt%，大幅提昇至1.42 wt%，約為碳管原材儲氫量的四倍。儲氫量之提昇可歸功於鉑金屬所引發的氫移轉(spillover)效應。經過酸洗處理之碳管，其表面缺陷增加提供氫吸附位置，亦有助儲存更多氫氣。以酸洗後披覆鉑金屬之奈米碳管，其室溫儲氫量可高達2.70 wt%。

The main purpose of this study is to explore the relationshio between the hydrogen storage properties and the material structure of different caron materals (including:activated carbon(AC), vapor growth carbon fiber(VGCF) and multi-walled cabon nanotubes(CNT, CNT(b)) and the carbon nanotube after nano Pt particles deposited and acidic treatement. The nano-sized Pt particles were deposited onto the surface of MWCNT through the rfduction of H2PtCl6 precusors in supercritical carbon dioxide fluid (sc-CO2).
The structural features of different carbon materials and modified carbon nanotubes with a variety of treatement were identified by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), energy dispersive sensors (EDS) and Raman spectra. The hydrogen storage capacity of various carbon material were measured by high thermal gravimetric microbalance (HPTGA) at room temperature (300K) and high pressure (1000 psi, 6.89 Mpa) to evaluate the performance of materials.
According to TEM and Raman spectra, the end of CNT(b) was opened in aqueous solution of H2SO4/HNO3 mixture and Fenton’d solution ( H2SO4/H2O2, adding 0.02M FeSO4). The amount of defects were generated to facilitate hydrogen adsorbed . Thy hydrogen storage capacity of pristine CNT(b) is 0.52 wt%, and after two mixed acidic treatement, the hydrogen storage capacity are 0.70 wt% and 1.06 wt% respectively.
The diffusive dense property of CO2 played an important role in suppression of the growth of platinum, and resulted in better dispersion than it deposited in conventional process. The highest hydrogen storage capacity of platinum/CNT composite was 1.42 wt%, which was 4~5 times than that of pristine CNT (0.30 wt%). The promotion could be attributed to the spillover mechanism. Therefore, the presence of suitable amount and morphology of Pt could improve the hydrogen storaged capacity.The experimental results revealed that the hydrogen storage of CNTs was affected by the metal loaded and physical surface structure. In the best case, 2.70 wt% of hydrogen was stored in Pt/etched CNT(b) composites.

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