| 摘要: | 隨著全球氣候變遷和能源危機的加劇，氫能作為一種清潔的替代能源在應對這些挑戰中扮演著重要的角色。氫氣儲存技術是氫能應用的核心之一，儲氫材料的發展對於氫能的實際應用至關重要。石墨相氮化碳 (g-C₃N₄）作為一種二維材料，具有優異的化學穩定性、高比表面積和環保特性，成為氫氣儲存領域的研究熱點。然而，純 g-C₃N₄ 的氫氣儲存性能受到其較大的帶隙限制，這使得其氫氣吸附和解離過程的效率較低。為了改善這一問題，許多研究指出，通過摻雜過渡金屬可顯著提升 g-C₃N₄ 的儲氫能力。
本研究通過基於密度泛函理論（DFT）的第一性原理計算，系統地探討了純 g-C₃N₄ 及摻雜過渡金屬（Pd、Pt）後的氫氣吸附行為、電子結構變化以及氫氣儲存性能。計算結果顯示，原始 g-C₃N₄ 的帶隙為 1.175 eV，其顯示出強烈的半導體特性，限制了氫氣分子與材料的有效相互作用。氫氣傾向於以垂直方式吸附於氮原子上，這樣的吸附模式雖然穩定，但其效率仍受到帶隙過大的限制。
進一步探討過渡金屬（Pd、Pt）摻雜對氫氣儲存性能的影響。研究結果顯示，過渡金屬的引入對 g-C₃N₄ 的結構與形貌未產生明顯影響，並確定了最穩定的過渡金屬摻雜位置及氫分子的最佳吸附位點。 此外，此計算分析了不同的吸附距離與構型，並透過能隙計算與電荷轉移分析，證實材料由半導體轉變為金屬導體結構，且吸附過程主要受化學吸附機制主導。這些結果證實，過渡金屬摻雜可有效提升 g-C₃N₄ 的氫氣儲存能力，為先進氫氣儲存材料的設計提供了寶貴的理論依據。
;With the increasing global climate change and energy crisis, hydrogen energy, as a clean alternative energy source, plays a crucial role in addressing these challenges. Hydrogen storage technology is one of the core aspects of hydrogen energy applications, and the development of hydrogen storage materials is essential for the practical use of hydrogen energy. Graphitic carbon nitride (g-C₃N₄), as a two-dimensional material, has attracted significant research attention in the hydrogen storage field due to its excellent chemical stability, high specific surface area, and environmental friendliness. However, the hydrogen storage performance of pure g-C₃N₄ is limited by its large band gap, which results in low efficiency for hydrogen adsorption and dissociation processes. To address this issue, many studies have pointed out that doping with transition metals can significantly enhance the hydrogen storage capacity of g-C₃N₄.
This study systematically investigates the hydrogen adsorption behavior, electronic structure changes, and hydrogen storage performance of pure g-C₃N₄ and transition metal-doped (Pd, Pt) systems using density functional theory (DFT) based first-principles calculations. The calculation results show that the band gap of pure g-C₃N₄ is 1.175 eV, demonstrating strong semiconductor properties, which limits the effective interaction between hydrogen molecules and the material. Hydrogen tends to adsorb perpendicularly to nitrogen atoms, and while this adsorption mode is stable, its efficiency is still limited by the large band gap.
Further exploration of the impact of transition metal (Pd, Pt) doping on hydrogen storage performance reveals that the introduction of transition metals does not significantly affect the structure or morphology of g-C₃N₄, and the most stable doping sites for the transition metals and the optimal hydrogen adsorption sites were identified. Additionally, different adsorption distances and configurations were analyzed, and through band gap calculations and charge transfer analysis, it was confirmed that the material undergoes a transition from semiconductor to metallic conductor structure, with the adsorption process mainly governed by chemisorption mechanisms. These results confirm that transition metal doping can effectively enhance the hydrogen storage capacity of g-C₃N₄, providing valuable theoretical guidance for the design of advanced hydrogen storage materials. |
