運用奈米粒子作為非勻相反應的觸媒在能源應用領域中是一個具有發展潛力的主題。透過開發有效的觸媒，降低反應的活化能與反應所需溫度，進而提升催化活性以及反應上的操作穩定性。本研究以氣相蒸發誘導自組裝法合成氣溶膠奈米粒子作為觸媒並應用於催化甲烷蒸氣重組反應。
首先，我們透過氣溶膠法成功製備了鎳鋁奈米粒子團簇(Ni-Al2O3 NPCs)和鎳鈰鋁奈米粒子團簇(Ni-CeO2-Al2O3 NPCs)，接著由X光繞射(XRD)、比表面積分析(SBET)、脈衝式化學吸附(Smsa)和程序升溫脫附(TPD)所組成的材料分析平台來研究氣溶膠粒子的材料性質。
材料分析結果指出複合式奈米結構中有超細小的鎳晶體(小於7 nm)，且具有可控的化學組成及奈米粒子團簇尺寸。添加氧化鋁增加了Ni-Al2O3 NPCs和Ni-CeO2-Al2O3 NPCs的比表面積和活性金屬表面積。氧化鋁能夠增加複合式奈米結構的表面積，同時，成功地抑制催化過程中鎳金屬的燒結效應。與二氧化鈰的混摻則顯著地提高了鎳觸媒的催化活性與穩定性，更進一步降低催化反應所需的起始反應溫度至377 °C。與文獻的結果相比，達成卓越的高催化活性：低起始反應溫度(400 °C)、高催化活性、高氫氣產率(H2 = 110 %)以及8小時反應的操作穩定性。
研究成果展示出一套氣相合成方法來製備可調控組成的複合式奈米粒子，以氧化鋁奈米粒子團簇作為載體來製備氣溶膠奈米觸媒，並在低溫操作條件下達成非常高的轉換頻率(turnover frequency = 0.8 s-1 at 500 °C)。本研究展示了Ni-Ce-Al-O在協同催化上的機制理解，更進一步地增強甲烷相關能源的應用前景。

Nanocatalysts for heterogeneous reactions is a promising subject in energy application. With the development of effective catalyst, the activation energy and the required reaction temperature can be lowered, thereby improving the catalytic performance and the operational stability of the reaction.
A gas-phase evaporation-induced self-assembly (EISA) method was developed to synthesize Ni-only and Ni-CeO2 nanoparticles decorated on Al2O3 nanoparticle clusters (Ni-Al2O3 NPC and Ni-CeO2-Al2O3 NPC) as the hybrid catalysts of steam reforming of methane (SRM). A material characterization platform consisting of X-ray diffraction (XRD), specific surface area (SBET), pulse chemisorption (Smsa) and temperature-programed desorption (TPD) was employed to study material properties of the synthesized hybrid nanostructures. The results show that ultrafine Ni crystallites (< 7 nm) were created in the hybrid nanostructure with tunable chemical composition and cluster size. Addition of aluminum oxide increases the specific surface area and active metal surface area of the Ni-Ce-Al-NP. The presence of Al2O3 nanoparticle clusters increases surface area of the hybrid nanostructure and successfully suppressed the sintering effect during the catalysis. Hybridization with CeO2 significantly improved catalytic activity and stability of Ni catalyst and further reduced the required starting temperature of the reaction by 377 C. A superior high catalytic performance achieved in comparison to the results reported in the literatures: low starting temperature (400 ˚C), high activity (turnover frequency = 2.0 s-1 at 700 °C), high H2 yield (H2 = 110 %), and operation stability over 8-h reaction. The work demonstrated a facile route for controlled gas-phase synthesis of hybrid nanocatalysts using Al2O3 NPC as the support matrix in gas phase to achieve a very high turnover frequency at low temperature operation (0.8 s-1 at 500 °C) toward SRM. The mechanistic understanding of synergistic catalysis of steam reforming of methane developed in this study shown promise for a further enhancement of methane-based energy applications.

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