氫氣被視為未來最有發展的能源之ㄧ。在氫能源的發展中，燃料 的補充方法、氫氣儲存材料，以及氫能源設備都是重要的關鍵技術。 有效的氫氣儲存技術對於氫能源經濟的發展有決定性的影響。 氮化鋰具有高的氫氣儲存量 (10.4 wt%)而被視為非常有潛力的 儲氫材料。在本研究中，藉由著鈀、鈀鎳合金還有鈀鈷合金觸媒的添 加使得儲氫材料氮化鋰改變其氫化性質。其氫化的性質藉由程式溫度 控制系統 (TPR) 量測。並使用X光粉末繞射儀(XRD)量測在氫化反應 前後的結構變化。在未添加氮化鋰的氫化研究中，吸氫的起始溫度大 約在450 K，並且在高溫會有脫氫的訊號位於660 K，意味著氮化鋰的 氫化會在高溫形成不穩定的氫化物。為了增益其氫化性質，藉由添加 鈀鎳與鈀鈷的合金觸媒改質。結果顯示鈀鎳與鈀鈷合金觸媒添加，會 因溢流效應能使起始氫化溫度下降。此外，原本氮化鋰在高溫產生不 穩定氫化物的情形，也藉由鈀鎳與鈀鈷觸媒的添加而趨於穩定，高溫 產生脫氫的訊號消失。當氮化鋰和鈀鎳(15:85)、鈀鈷(15:85)合金觸 媒以1:1的比例混合，可使起始氫化溫度分別從原本氮化鋰的450 K降 至440 K和370 K。若以1:4比例混合，兩者的起始吸氫溫度進一步下 降至420 K以及360 K，且吸氫量分別為107 %以及58%。因此，氮化 鋰的氫化動力學藉著鈀鈷與鈀鎳(15:85)合金觸媒的添加能有效的提 升。 Hydrogen is viewed as one kind of promising clean fuel of the future. The refueling method, the hydrogen storage, and the handling facilities are critical factors in the development of a hydrogen technology for transportation. An effective hydrogen storage technology is required to make this source of energy economically viable. Li3N is a potential hydrogen storage material owing to its high theoretical H2 capacity (10.4 wt%). In this study, the Pd, Pd-Ni and Pd-Co alloy catalysts were used to modify Li3N to enhance its hydrogenation kinetics. The hydrogenation properties were investigated by a technique of temperature programmed reduction (TPR). The identification of phase structures of materials before and after hydrogenation was carried out by the X-ray powder diffraction (XRD) method. The hydrogenation curves by TPR measurements displayed that the initial hydrogenation temperature (Ti) for Li3N was about 450 K. A following desorption peak starting at 660 K indicates that the hydride formed was not stable. For the modified Li3N, the Ti and absorption capacity was both changed by catalyzing with Pd-Ni and Pd-Co alloy catalysts. The hydrogenation kinetics of Li3N was promoted due to the spillover of hydrogen from alloy catalysts to Li3N and their Ti was lower than that of unmodified Li3N. Moreover, the Li3N hydride formed was stabilized by the PdxNi100-x PdxCo100-x modification and no hydrogen desorption peak was observed at high temperature. When 1:1 ratio of materials and catalysts is used, Pd15Ni85 and Pd15Co85 can decrease the Ti from 450 to 440 K and 370 K, respectively. In the case of Li3N : Pd15Ni85 = 1:4, the Ti of PdNi and PdCo modified Li3N further decreases to 420 K and 360 K and the their hydrogenation capacity is 107 % and 58 % of Li3N, respectively. As a result, the hydrogenation kinetic could effectively be promoted by addition of Pd15Ni85 and Pd15Co85 alloy catalysts.
