| 摘要: | 隨著全球淨零碳排目標推動，氫能因具高能量密度與零碳燃燒特性，被視為再生能源體系中重要的潔淨能源載體。目前綠氫生產技術以水電解法最具潛力，具備高純度、無碳排與過程無污染等優勢。考量全球海水資源占比達97%，若能發展高效、耐腐蝕且穩定的鹼性或海水電解產氫技術，不僅能解決淡水資源耗用問題，亦有助於降低綠氫製備成本，加速實現大規模低碳氫能供應體系。因此，開發適用於鹼性與海水環境下高活性與高穩定性的電催化劑，成為未來潔淨能源與永續發展的關鍵技術方向。
本研究運用超臨界流體輔助合成技術，成功將鈀奈米粒子均勻且高分散性地負載於二維過渡金屬碳化物(MXene)基材上。藉由超臨界流體高擴散性與低表面張力的特性，有效調控鈀奈米粒子尺寸與分佈，提升催化劑之活性位點利用率與電子傳輸能力。催化劑之結構、形貌與化學價態透過X射線繞射(XRD)、掃描式電子顯微鏡(SEM)、穿透式電子顯微鏡(TEM)與原位拉曼光譜(In-situ Raman spectroscopy)等技術進行全面性分析，並搭配線性掃描伏安法(LSV)與塔菲爾斜率(Tafel slope)評估其在鹼性析氫反應(HER)中的電催化表現。實驗結果顯示，(SCF)Pd@MXene催化劑於鹼性介質中展現優異HER活性，於10 mA cm⁻²電流密度下具有相對低的過電位，優於純MXene與傳統鈀基催化劑。
本研究證實，結合超臨界流體合成與二維MXene基材之策略，不僅有效提升奈米粒子分散性與界面接觸性，更透過In-situ Raman光譜即時觀察HER反應過程中活性位點與表面中間體變化，深入解析催化反應機制，為鹼性環境下高效電解水產氫電催化劑開發提供嶄新設計概念，展現未來應用於綠氫生產與潔淨能源轉型的應用潛力。
;With the global advancement toward net-zero carbon emissions, hydrogen energy has emerged as a crucial clean energy carrier within renewable energy systems due to its high energy density and zero-carbon combustion characteristics. Among various green hydrogen production technologies, water electrolysis holds the greatest potential, offering high-purity hydrogen generation with no carbon emissions and minimal environmental impact. Considering that seawater accounts for approximately 97% of the Earth′s water resources, the development of efficient, corrosion-resistant, and stable alkaline or seawater electrolysis technologies would not only alleviate the pressure on freshwater consumption but also reduce the cost of green hydrogen production, accelerating the realization of large-scale, low-carbon hydrogen energy supply systems. Consequently, the design of highly active and durable electrocatalysts suitable for operation in alkaline and seawater environments has become a critical direction in the pursuit of clean energy and sustainable development.
In this study, a supercritical fluid-assisted synthesis strategy was employed to uniformly and highly disperse palladium (Pd) nanoparticles onto two-dimensional transition metal carbide (MXene) substrates. Owing to the high diffusivity and low surface tension of supercritical fluids, the size and distribution of Pd nanoparticles could be effectively controlled, enhancing the exposure of active sites and the electronic conductivity of the catalyst. The structural, morphological, and chemical properties of the synthesized electrocatalysts were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and in-situ Raman spectroscopy. Electrochemical performance for the hydrogen evolution reaction (HER) in alkaline media was evaluated through linear sweep voltammetry (LSV) and Tafel slope analysis. The results demonstrate that the (SCF)Pd@MXene catalyst exhibits superior HER activity, achieving a lower overpotential at a current density of 10 mA cm⁻² compared to pristine MXene and conventional Pd-based catalysts.
This work confirms that combining supercritical fluid synthesis with two-dimensional MXene substrates not only significantly improves nanoparticle dispersion and interfacial contact but also enables real-time monitoring of active site behavior and surface intermediates during the HER process via in-situ Raman spectroscopy. The findings offer valuable insights into the reaction mechanism and propose an innovative strategy for developing efficient alkaline electrocatalysts for water splitting, with promising prospects for future applications in green hydrogen production and clean energy transition. |
