【摘要】：質(zhì)子交換膜燃料電池(PEMFC)以氫氣作為燃料，質(zhì)量輕、無污染、效率高，在電動(dòng)汽車及各種可移動(dòng)設(shè)備的動(dòng)力電源方面具有潛在的應(yīng)用前景。近年來，由于NH3具有儲氫密度高、運(yùn)輸和生產(chǎn)等技術(shù)較完備、價(jià)格低廉、分解后無COx生成等優(yōu)點(diǎn)，被作為燃料電池的原位供氫法而備受關(guān)注。但氨是一種非常穩(wěn)定的分子，它的分解過程是可逆和吸熱的反應(yīng)，需要很高的溫度才能完全分解。因此，利用氨分解制氫作為移動(dòng)氫源，低溫氨分解催化劑的設(shè)計(jì)是關(guān)鍵問題。 鈣鈦礦具有熱穩(wěn)定性、強(qiáng)氧化還原能力、品種多樣性、高凈化廢氣能力、成本低廉等優(yōu)點(diǎn)，本文將其用于氨分解制氫反應(yīng)研究，以期獲得利于氨分解反應(yīng)的新型催化劑。 首先，本文制備了一系列鈣鈦礦型LaBO3（B=Ni，Co，F(xiàn)e，Cr）催化劑，，采用氨分解活性評價(jià)測試、TPR、XRD表征手段分析了決定鈣鈦礦催化氨分解的主要因素，確定了B位最佳元素為Ni，氨在LaNiO3上，10000h-1、640℃條件下可達(dá)到100%的轉(zhuǎn)化率。同時(shí)，將Ni系鈣鈦礦與普通Ni氧化物進(jìn)行對比，發(fā)現(xiàn)鈣鈦礦的結(jié)構(gòu)有利于提高催化劑的氨分解活性。在此基礎(chǔ)上還探討了La1-xMxNiO3(M=Sr、Y、Ce，x=0.2，0.4，0.6，0.8)的氨分解活性，得出M最佳元素是Ce，當(dāng)Ce的摻雜量x=0.4時(shí)活性最好，低溫和高溫的活性均明顯提高。 其次，本文將LaNiO3負(fù)載于不同的載體（MgO、SiO2、γ-Al2O3）上，考察載體對鎳系鈣鈦礦催化氨分解性能的影響，研究結(jié)果表明，以SiO2為載體的負(fù)載型催化劑的氨分解活性較好，且NiO的負(fù)載量對氨分解活性有很大的影響，w(NiO)=20%時(shí)，在640℃可獲得100%的氨轉(zhuǎn)化率，與非負(fù)載LaNiO3活性相當(dāng)，在保持相同活性的基礎(chǔ)上，減少了活性組分的用量，從而降低了生產(chǎn)成本。 另外，本文探討了載體MCM-41介孔分子篩對LaNiO3催化氨分解活性的影響，研究發(fā)現(xiàn)，介孔分子篩MCM-41大的比表面和規(guī)整的介孔結(jié)構(gòu)，更有利于活性組分的分散，增加了有效活性位，提高了活性組分的反應(yīng)能力，表現(xiàn)出很好的氨分解催化活性。最后，在上述研究的基礎(chǔ)上制備了一種新型催化劑，以NiO計(jì)，負(fù)載量為20%wt的La0.6Ce0.4NiO3/MCM-41，并對其進(jìn)行氨分解活性測試，結(jié)果表明其具有很好的催化活性，在536℃時(shí)氨即可完全分解。
[Abstract]:Proton exchange membrane fuel cell (PEMFC), which uses hydrogen as fuel, is light, pollution-free and efficient, and has potential applications in power supply for electric vehicles and various mobile devices. In recent years, because of the advantages of high density of hydrogen storage, complete technology of transportation and production, low price and no formation of COx after decomposition, NH3 has attracted much attention as an in-situ hydrogen supply method for fuel cells. However, ammonia is a very stable molecule, its decomposition process is reversible and endothermic reaction, which requires a high temperature to completely decompose. Therefore, the design of low temperature ammonia decomposition catalyst is a key problem. Perovskite has the advantages of thermal stability, strong redox ability, variety diversity, high purification capacity and low cost. In this paper, perovskite has been used in the study of ammonia decomposition to produce hydrogen, in order to obtain a new catalyst for ammonia decomposition. Firstly, a series of perovskite-type LaBO3 catalysts were prepared. The main factors determining the ammonia decomposition of perovskite catalysts were analyzed by means of ammonia decomposition activity evaluation and TPR,XRD characterization. The best element at position B is Ni, ammonia on LaNiO3, and the conversion rate can reach 100% at 10000h-1640 鈩

本文編號：2287541