Long-term electrocatalytic N2 fixation by MOF-derived Y-stabilized ZrO2: An insight into deactivation mechanism
作者：Shijian Luo, Xiaoman Li, Mingyuan Wang, Xu Zhang, Wanguo Gao, Sen-Da Su, Guiwu Liu and Min Luo
關(guān)鍵字：MOF-derived Y-stabilized ZrO2
論文來源：期刊
具體來源：Journal of Materials Chemistry A（JMCA）
發(fā)表時(shí)間：2020年
成果簡介：
電催化固氮中的催化活性中心是什么？一些催化劑經(jīng)過長時(shí)間反應(yīng)后發(fā)生了失活作用，失活機(jī)制到底是什么？這些問題一直困擾著電催化固氮研究。為了深入探究這一問題，我們在實(shí)驗(yàn)中合成金屬有機(jī)框架材料衍生的ZrO2/C復(fù)合催化劑，發(fā)現(xiàn)長時(shí)間反應(yīng)3天后催化活性完全消失了。通過DFT理論計(jì)算，表明材料中氧空位并不穩(wěn)定，來自水溶液中含氧離子會(huì)不斷填充不穩(wěn)定的氧空位，最終導(dǎo)致催化劑失活。進(jìn)而我們通過原位摻雜Y制備了Y-ZrO2,發(fā)現(xiàn)低價(jià)雜質(zhì)原子的摻雜穩(wěn)定了材料中的氧空位，在長達(dá)7天的催化實(shí)驗(yàn)中催化活性僅下降了10%不到。為了進(jìn)一步驗(yàn)證氧空位的填充情況，通過納克級質(zhì)量敏感的電化學(xué)石英晶體微天平（EQCM）原位測試研究證明了在這兩種催化劑中氧空位的穩(wěn)定性差異是造成其催化壽命懸殊的直接原因。這一研究結(jié)果為室溫常壓固氮電催化劑的設(shè)計(jì)提供了理論依據(jù)和設(shè)計(jì)原則。該成果“Long-term electrocatalytic N2 fixation by MOF-derived Y-stabilized ZrO2: An insight into deactivation mechanism”在線發(fā)表在JMCA期刊。
Abstract: Industrially, NH3 synthesis largely dependent on the Haber-Bosch method which consumes a lot of energy and emits huge CO2. Recently, Electrochemical N2 reduction reaction (NRR) has been recognized as a promising method to achieve clean and sustainable NH3 production, thus the high-efficient and durable catalysts are urgently desired. In this paper, we report a MOF-derived carbon/Y-stabilized ZrO2 nanocomposite (C@YSZ) works as an efficien telectrocatalyst for NRR in 0.1 M Na2SO4. It achieves a large NH3 production of 24.6 μg h-1 mg-1cat. and a high Faradaic efficiency of 8.2% at -0.5 V vs. reversible hydrogen electrode. Experimental results demonstrate the surface oxygen vacancies are the main catalytic sites for NRR. Introducing of Y3+ into ZrO2 lattice has significant effect to increase and stabilize the O-vacancies. Meanwhile, this catalyst displays remarkable stability and durability for NRR performance, showing a negligible change after 7 days reaction, better than most reported NRR electrocatalysts. Moreover, in-situ electrochemical quartz-crystal microbalance (EQCM) was firstly applied in NRR field and successfully combined with density functional theory (DFT) calculations to reveal the deactivation mechanism.
文章鏈接：
https://doi.org/10.1039/D0TA01154A