| 摘要: | 電化學水分解是解決環境問題和日益枯竭的傳統能源之具有前景的解決方案，然而析氫反應和析氧反應的緩慢動力學阻礙了這一過程，因此高活性和耐久性電催化劑的應用為克服這一挑戰的關鍵，而開發酸鹼值通用的電催化劑以實現可持續和可再生的氫氣生產至關重要。本研究提出了一種Pd基電催化劑作為替代Pt的有效方案，採用簡單的油胺法合成鈀鈷氫化物析氫電催化劑(PdCo0.3H0.2/C)，它結合了PdCo(鈷通過協同作用改變了鈀的電子結構，並提高了其水解能力)和PdH (氫減弱了Pd-H鍵並隨之提高了析氫活性)的優點。值得注意的是，PdCo0.3H0.2/C優於對照組(包含 Pd/C 和 PdH0.2/C)，在酸性和鹼性溶液中表現出優異的穩定性和活性，包括最低的過電位(18、32 mV)，極佳之Tafel斜率(19、82 mV dec-1)和最高的質量活性(分別比PdH0.2/C高出5倍和2倍)，以及 5000 次循環的出色穩定性。此外，經過鹼性穩定性測試後，PdCo0.3H0.2/C的電化學性能進一步提升，這歸因於氫化物提供的活性位點和親氧鈷作為優異水解中心。此外，通過原位X光吸收光譜(X-ray absorption spectroscopy, XAS)和感應耦合電漿放射光譜儀(Inductively coupled plasma optical emission, ICP-OES)分析提供了對鈀鈷氫化物析氫電催化劑(PdCo0.3H0.2/C)穩定性的分析。In-situ XAS顯示穩定度測試後結構穩定無變化，而ICP-OES結果表明適當的氫插入可以有效地緩和金屬溶解速率並提高 析氫反應的耐久性。此外，為了瞭解Co/H的含量對於析氫效能的影響，製備了包括PdHX、PdCo0.3HX和PdCoXHY的三種系列樣品，發現H和Co的最佳比例可以最大化Pd的析氫活性和穩定性。 我們的研究不僅提供了一種合成高效且耐久的Pd-Co氫化物析氫催化劑的簡單策略，而且深入了解了其出色性能背後的機制。這些結果為開發高效和長效析氫催化劑提供了一個有前景的方法。;Electrochemical water splitting presents a promising solution to environmental concerns and energy shortage, yet the sluggish kinetics of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) reactions impede the process. The use of high-activity and durable electrocatalysts is critical in overcoming this challenge. Hence, developing pH-universal electrocatalysts for sustainable and renewable hydrogen production is imperative. This study presents the development of a Pd-based electrocatalyst as a promising alternative to Pt. A Pd-Co hydride HER electrocatalyst (PdCo0.3H0.2/C) was synthesized via a simple oleylamine method, which combines the benefits of PdCo (Co modifies the electronic structure of Pd and improves its hydrolysis ability by a synergistic effect) and PdH (H weakening the Pd-H bond and subsequently improving the HER activity). Notably, PdCo0.3H0.2/C outperformed the control group (comprising Pd/C and PdH0.2/C) by displaying superior stability and activity in acidic and alkaline solutions, including the lowest overpotential (18 and 32 mV), impressive Tafel slope (19 and 82 mV dec-1), and the highest mass activity (5 and 2 times greater than PdH0.2/C), respectively, as well as outstanding stability of 5000 cycles. Moreover, after undergoing the alkaline stability test, the electrochemical performance of PdCo0.3H0.2/C was significantly improved, attributed to the active sites provided by the hydride phase and the presence of oxophilic Co as an excellent hydrolysis center. Furthermore, our study provides insights into the stability of the Pd-Co hydride HER electrocatalyst (PdCo0.3H0.2/C) through in-situ X-ray absorption spectroscopy (XAS) and Inductively coupled plasma optical emission analysis (ICP-OES). In-situ XAS revealed no significant structural changes during the stability test, while ICP-OES results indicated that the appropriate insertion of hydrogen and Co alloying can effectively moderate the metal dissolution rate and enhance the durability of HER. In addition, to further investigate the relationship between Co/H contents and HER performance, three different series of samples, including PdHX, PdCo0.3HX, and PdCoXHY were evaluated revealing that the optimal ratio of H and Co could maximize the HER activity and stability of Pd. Our study not only provides a simple strategy for the synthesis of efficient and durable Pd-Co hydride HER electrocatalysts, but also advances our understanding of the mechanisms behind the exceptional performance. These results offer a promising approach for the development of efficient and long-lasting HER electrocatalysts. |
