改善镁氢化镁水解放氢性能研究进展

改善镁/氢化镁水解放氢性能研究进展基金项目：国家自然科学基金资助项目（基金项目：国家自然科学基金资助项目（51771112）NationalScienceFoundation(No.51771112)杨波，邹建新，曾小勤，丁文江（上海交通大学材料科学与工程学院，上海200240）摘要为了提高Mg/MgH2水解产氢性能，科研人员做了大量的改进工作。本文概述了Mg/MgH2水解产氢过程中遇到的问题，以及提高水解反应动力学的方法：一是增大Mg/MgH2的比表面积，二是打破水解过程中产生的Mg(OH)2保护层对水解的限制。因此可以通过降低粉末尺寸、在溶液中添加不同催化剂（酸、盐等）和复合具有催化作用的第二相（金属氧化物、氯化物、金属氢化物、金属、石墨等）来改善水解性能。重点阐述了催化剂对Mg/MgH2水解性能的影响及作用机理，并提出了一些建议与看法。关键字：镁；氢化镁；水解；催化；氢气中图分类号：TK91文献标识码：ARecentadvancesinimprovingthehydrolysisperformanceofmagnesium/magnesiumhydride200240,ChinaAbstractInordertoimprovethehydrolysisperformanceofMg/MgH2,researchershavedonelotsofimprovementwork.TheproblemsinthehydrogenproductionfromMg/MgH2hydrolysisandthemethodstoincreasethekineticsofhydrolysisreactionaresummarizedinthispaper.First,increasethespecificsurfaceareaofMg/MgH2.Second,breakthelimitationofMg(OH)2protectivelayerproducedinthehydrolysisprocess.Therefore,thehydrolysisperformancecanbeimprovedbyreducingthepowdersize,addingdifferentcatalysts(acids,salts,etc.)intothesolutionandcompositingcatalyticsecondphases(metaloxides,chlorides,metalhydrides,metals,graphite,etc.).TheeffectsandmechanismsofcatalystsonthehydrolysisperformanceofMg/MgH2arehighlighted.Furthermore,somesuggestionsandideasareproposed.Keywordsmagnesium,magnesiumhydride,hydrolysis,catalyze,hydrogen由于环境污染及能源紧缺问题日益严重，发展新型清洁高效的新能源、新材料成为中国制造2025的重大战略目标ADDINEN.CITE<EndNote><Cite><Author>气候变化研究进展</Author><Year>2019</Year><RecNum>447</RecNum><DisplayText><styleface="superscript">[1]</style></DisplayText><record><rec-number>447</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1550328289">447</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>姜克隽%J气候变化研究进展</author></authors></contributors><titles><title>一个强有力的2050碳减排目标将非常有利于中国的社会经济发展</title></titles><pages>103-106</pages><volume>15</volume><number>1</number><dates><year>2019</year></dates><isbn>1673-1719</isbn><urls></urls></record></Cite></EndNote>[1]。氢气具有清洁、环保、可再生、高能量密度等特点ADDINEN.CITE<EndNote><Cite><Author>伊文婧</Author><Year>2018</Year><RecNum>449</RecNum><DisplayText><styleface="superscript">[2]</style></DisplayText><record><rec-number>449</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1550328993">449</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>伊文婧</author><author>梁琦</author><author>裴庆冰%J环境保护</author></authors></contributors><titles><title>氢能促进我国能源系统清洁低碳转型的应用及进展</title></titles><pages>30-34</pages><volume>2</volume><dates><year>2018</year></dates><urls></urls></record></Cite></EndNote>[2]，其产热量是汽油的3倍ADDINEN.CITE<EndNote><Cite><Author>王朔</Author><Year>2017</Year><RecNum>450</RecNum><DisplayText><styleface="superscript">[3]</style></DisplayText><record><rec-number>450</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1550329138">450</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>王朔</author><author>张军%J储能科学与技术</author></authors></contributors><titles><title>我国制氢技术发展态势与技术路线研究——基于专利分析</title></titles><pages>1</pages><dates><year>2017</year></dates><isbn>2095-4239</isbn><urls></urls></record></Cite></EndNote>[3]，在新能源领域具有广泛的应用前景。然而，制氢和储氢技术严重限制了氢能的发展与应用，庆幸的是科研人员发现镁具有优异的储氢性能和简单的制氢工艺，是氢能发展领域最有潜力的轻金属材料之一。镁是地球上储量最丰富的轻合金元素之一ADDINEN.CITE<EndNote><Cite><Author>Jain</Author><Year>2010</Year><RecNum>175</RecNum><DisplayText><styleface="superscript">[4]</style></DisplayText><record><rec-number>175</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1540885560">175</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Jain,I.P.</author><author>Lal,Chhagan</author><author>Jain,Ankur</author></authors></contributors><titles><title>HydrogenstorageinMg:Amostpromisingmaterial</title><secondary-title>InternationalJournalofHydrogenEnergy</secondary-title></titles><periodical><full-title>InternationalJournalofHydrogenEnergy</full-title></periodical><pages>5133-5144</pages><volume>35</volume><number>10</number><section>5133</section><dates><year>2010</year></dates><isbn>03603199</isbn><urls></urls><electronic-resource-num>10.1016/j.ijhydene.2009.08.088</electronic-resource-num></record></Cite></EndNote>[4]，我国的镁储量十分丰富，居世界第二位。镁不仅具有价格低廉、密度低（1.8gcm-3）、比强度高等优点ADDINEN.CITE<EndNote><Cite><Author>孟天宇</Author><Year>2016</Year><RecNum>453</RecNum><DisplayText><styleface="superscript">[5]</style></DisplayText><record><rec-number>453</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1550383076">453</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>孟天宇</author><author>张涛</author><author>李月</author><author>刘悦</author><author>朱晶</author><author>王忠军%J辽宁科技大学学报</author></authors></contributors><titles><title>Mg-Al和Mg-Li镁合金板在NaCl水溶液中的腐蚀行为</title></titles><pages>446-454</pages><volume>39</volume><number>6</number><dates><year>2016</year></dates><urls></urls></record></Cite></EndNote>[5]，而且储氢容量高达7.6wt.%，超过了美国能源部（DOE）5.5wt.%的要求（2025年目标、终极目标是6.5wt.%）ADDINEN.CITE<EndNote><Cite><Author>李璐伶</Author><Year>2018</Year><RecNum>451</RecNum><DisplayText><styleface="superscript">[6]</style></DisplayText><record><rec-number>451</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1550329545">451</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>李璐伶</author><author>樊栓狮</author><author>陈秋雄</author><author>杨光</author><author>温永刚%J储能科学与技术</author></authors></contributors><titles><title>储氢技术研究现状及展望</title></titles><pages>586-594</pages><volume>7</volume><number>4</number><dates><year>2018</year></dates><isbn>2095-4239</isbn><urls></urls></record></Cite></EndNote>[6]，是金属储氢材料中的佼佼者。Mg氢化后得到的MgH2可以通过热分解和水解两种方式来制备氢气，但热分解的放氢焓变较高（74.5kJmol-1），导致需要在350℃以上才能分解放出氢气。与此相反，水解在室温下就能进行，放氢量为15.2wt.%（不把水计算在内），是热分解放氢量的2倍，水解反应方程式可见式（1）ADDINEN.CITE<EndNote><Cite><Author>Huang</Author><Year>2015</Year><RecNum>114</RecNum><DisplayText><styleface="superscript">[7]</style></DisplayText><record><rec-number>114</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1540195312">114</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Huang,Minghong</author><author>Ouyang,Liuzhang</author><author>Wang,Hui</author><author>Liu,Jiangwen</author><author>Zhu,Min</author></authors></contributors><titles><title>HydrogengenerationbyhydrolysisofMgH2andenhancedkineticsperformanceofammoniumchlorideintroducing</title><secondary-title>InternationalJournalofHydrogenEnergy</secondary-title></titles><periodical><full-title>InternationalJournalofHydrogenEnergy</full-title></periodical><pages>6145-6150</pages><volume>40</volume><number>18</number><section>6145</section><dates><year>2015</year></dates><isbn>03603199</isbn><urls></urls><electronic-resource-num>10.1016/j.ijhydene.2015.03.058</electronic-resource-num></record></Cite></EndNote>[7]。与MgH2相似，Mg也可以水解放出氢气，反应方程式如（2）所示ADDINEN.CITE<EndNote><Cite><Author>Huang</Author><Year>2017</Year><RecNum>239</RecNum><DisplayText><styleface="superscript">[8]</style></DisplayText><record><rec-number>239</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1540888952">239</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Huang,Minghong</author><author>Ouyang,Liuzhang</author><author>Ye,Jianshan</author><author>Liu,Jiangwen</author><author>Yao,Xiangdong</author><author>Wang,Hui</author><author>Shao,Huaiyu</author><author>Zhu,Min</author></authors></contributors><titles><title>HydrogengenerationviahydrolysisofmagnesiumwithseawaterusingMo,MoO2,MoO3andMoS2ascatalysts</title><secondary-title>JournalofMaterialsChemistryA</secondary-title></titles><periodical><full-title>JournalofMaterialsChemistryA</full-title></periodical><pages>8566-8575</pages><volume>5</volume><number>18</number><section>8566</section><dates><year>2017</year></dates><isbn>2050-7488 2050-7496</isbn><urls></urls><electronic-resource-num>10.1039/c7ta02457f</electronic-resource-num></record></Cite></EndNote>[8]。虽然水解反应具有反应条件温和、放氢量大等优点，但水解副产物Mg(OH)2附在MgH2的表面严重限制了水解反应的进行ADDINEN.CITE<EndNote><Cite><Author>Tegel</Author><Year>2017</Year><RecNum>110</RecNum><DisplayText><styleface="superscript">[9]</style></DisplayText><record><rec-number>110</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1536930791">110</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Tegel,Marcus</author><author>Schöne,Sebastian</author><author>Kieback,Bernd</author><author>Röntzsch,Lars</author></authors></contributors><titles><title>AnefficienthydrolysisofMgH2-basedmaterials</title><secondary-title>InternationalJournalofHydrogenEnergy</secondary-title></titles><periodical><full-title>InternationalJournalofHydrogenEnergy</full-title></periodical><pages>2167-2176</pages><volume>42</volume><number>4</number><section>2167</section><dates><year>2017</year></dates><isbn>03603199</isbn><urls></urls><electronic-resource-num>10.1016/j.ijhydene.2016.09.084</electronic-resource-num></record></Cite></EndNote>[9]。MgH2+2H2O→Mg(OH)2+2H2↑,∆H=-277kJmol-1（1）Mg+2H2O→Mg(OH)2+H2↑,∆H=-384kJmol-1（2）为了打破Mg(OH)2保护层对Mg/MgH2水解产氢的限制，改善水解反应的动力学，提升水解反应速度和水解放氢量，科研工作者做了大量改善工作，期望Mg/MgH2水解产氢能够在生产生活方面（尤其在新能源汽车领域）得到广泛的应用。1降低粉末尺寸降低Mg/MgH2的颗粒尺寸能够增大比表面积，增大Mg/MgH2与水的接触面积，提高水解反应动力学。目前降低颗粒颗粒尺寸的主要方法有球磨法和直流电弧等离子体法等。Hu等人ADDINEN.CITE<EndNote><Cite><Author>Hu</Author><Year>2005</Year><RecNum>379</RecNum><DisplayText><styleface="superscript">[10]</style></DisplayText><record><rec-number>379</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1544754354">379</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hu,Lian-Xi</author><author>Wang,Er-De%JTransactionsofNonferrousMetalsSocietyofChina</author></authors></contributors><titles><title>HydrogengenerationviahydrolysisofnanocrystallineMgH2andMgH2-basedcomposites</title></titles><pages>965-970</pages><volume>15</volume><number>5</number><dates><year>2005</year></dates><isbn>1003-6326</isbn><urls></urls></record></Cite></EndNote>[10]使用球磨法研磨MgH2以达到降低颗粒尺寸的目的。球磨15h后发现MgH2的颗粒尺寸减小到了13nm。由于球磨增加了比表面积，具有独特的纳米晶体结构，使得球磨后的MgH2比商业的多晶MgH2具有更好的动力学性能，水解放氢量得到了显著的提升。在70min内水解产氢量由理论值的7.5%增加到了25%。球磨法所使用的器械虽然价格低廉，但生产效率低下，只适合实验室小批量生产，无法满足工业大批量生产的需求。直流电弧等离子体法相对于球磨法，制备的粉末颗粒更加均匀细腻，生产效率高，适合大批量工业生产，具有更大的应用前景。Mao等ADDINEN.CITE<EndNote><Cite><Author>Mao</Author><Year>2017</Year><RecNum>115</RecNum><DisplayText><styleface="superscript">[11]</style></DisplayText><record><rec-number>115</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1540522960">115</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Mao,Jianfeng</author><author>Zou,Jianxin</author><author>Lu,Chong</author><author>Zeng,Xiaoqin</author><author>Ding,Wenjiang</author></authors></contributors><titles><title>Hydrogenstorageandhydrolysispropertiesofcore-shellstructuredMg-MFx(M=V,Ni,LaandCe)nano-compositespreparedbyarcplasmamethod</title><secondary-title>JournalofPowerSources</secondary-title></titles><periodical><full-title>JournalofPowerSources</full-title></periodical><pages>131-142</pages><volume>366</volume><section>131</section><dates><year>2017</year></dates><isbn>03787753</isbn><urls></urls><electronic-resource-num>10.1016/j.jpowsour.2017.09.015</electronic-resource-num></record></Cite></EndNote>[11]用直流电弧等离子体法制备了纳米Mg颗粒，氢化处理后，在室温下、0.1mol/LMgCl2水溶液中水解，发现水解放氢量与商业购买的MgH2相比是商业MgH2的7倍左右，并且水解放氢速度远超商业MgH2。2在溶液中添加酸和盐2.1在溶液中添加酸在溶液中添加酸，能够破坏Mg(OH)2保护层，提升水解动力学。Tayeh等ADDINEN.CITE<EndNote><Cite><Author>Tayeh</Author><Year>2014</Year><RecNum>244</RecNum><DisplayText><styleface="superscript">[12]</style></DisplayText><record><rec-number>244</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1540888983">244</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Tayeh,T.</author><author>Awad,A.S.</author><author>Nakhl,M.</author><author>Zakhour,M.</author><author>Silvain,J.F.</author><author>Bobet,J.L.</author></authors></contributors><titles><title>Productionofhydrogenfrommagnesiumhydrideshydrolysis</title><secondary-title>InternationalJournalofHydrogenEnergy</secondary-title></titles><periodical><full-title>InternationalJournalofHydrogenEnergy</full-title></periodical><pages>3109-3117</pages><volume>39</volume><number>7</number><section>3109</section><dates><year>2014</year></dates><isbn>03603199</isbn><urls></urls><electronic-resource-num>10.1016/j.ijhydene.2013.12.082</electronic-resource-num></record></Cite></EndNote>[12]研究了不同种类强酸对MgH2水解性能的影响，发现在PH=2酸溶液中，H2SO4溶液中的水解放氢量和放氢速度均高于在HCl和HNO3，他们认为这是由于H2SO4是二元酸，且H2SO4的生成焓高于Mg(OH)2所导致的。这也就说明H2SO4分解出H+的过程中会放出比HCl和HNO3更多的热量，这些热量对水解动力学的提升具有促进的作用。然而，由于强酸腐蚀性较强、严重污染坏境且水解放出的氢气大部分来自强酸的H+，实际应用价值较小。Kushch等ADDINEN.CITE<EndNote><Cite><Author>Kushch</Author><Year>2011</Year><RecNum>260</RecNum><DisplayText><styleface="superscript">[13]</style></DisplayText><record><rec-number>260</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1541078623">260</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Kushch,S.D.</author><author>Kuyunko,N.S.</author><author>Nazarov,R.S.</author><author>Tarasov,B.P.</author></authors></contributors><titles><title>Hydrogen-generatingcompositionsbasedonmagnesium</title><secondary-title>InternationalJournalofHydrogenEnergy</secondary-title></titles><periodical><full-title>InternationalJournalofHydrogenEnergy</full-title></periodical><pages>1321-1325</pages><volume>36</volume><number>1</number><section>1321</section><dates><year>2011</year></dates><isbn>03603199</isbn><urls></urls><electronic-resource-num>10.1016/j.ijhydene.2010.06.115</electronic-resource-num></record></Cite></EndNote>[13]认为使用有机弱酸，比如柠檬酸，作为添加剂，具有较好的经济效益，由于柠檬酸是弱酸，能够及时补充溶液中消耗掉的H+，从而使水解放氢反应更加稳定、更加安全。Jen等ADDINEN.CITE<EndNote><Cite><Author>Jen</Author><Year>2016</Year><RecNum>458</RecNum><DisplayText><styleface="superscript">[14]</style></DisplayText><record><rec-number>458</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1550387918">458</key></foreign-keys><ref-typename="ConferenceProceedings">10</ref-type><contributors><authors><author>Jen,Tien-Chien</author><author>Adeniran,Joshua</author><author>Akinlabi,Esther</author><author>Chao,Chung-Hsing</author><author>Ho,Yen-Hsi</author><author>DeKoker,Johan</author></authors></contributors><titles><title>Hydrogengenerationfromaceticacidcatalyzedmagnesiumhydrideusinganon-demandhydrogenreactor</title><secondary-title>ASME2016InternationalMechanicalEngineeringCongressandExposition</secondary-title></titles><pages>V06AT08A034-V06AT08A034</pages><dates><year>2016</year></dates><publisher>AmericanSocietyofMechanicalEngineers</publisher><urls></urls></record></Cite></EndNote>[14]研究了醋酸浓度、温度和MgH2的含量对放氢性能的影响，发现：1）放氢速度随着醋酸浓度的增高先增加后减小，当醋酸浓度为60wt.%时放氢速度最高；2）温度（30℃~60℃）对放氢速度与放氢量的影响不大；3）MgH2的含量对放氢量起到决定性的作用。由此可见，在室温下使用60wt.%的醋酸就能使MgH2达到良好的放氢效果。Jen等之所以得出这样的结论是因为随着醋酸浓度的增高，溶液中H+的浓度虽然在逐渐增高但H+的总量却在先增加后减少，所以在浓度超过60wt.%时，溶液中H+总量成了限制水解快慢的因素。在他们的实验中由于使用的醋酸浓度较高，反应速度极快，使得温度的影响变得不明显，并且由于使用的醋酸是过量的所以添加的MgH2的质量成了放氢总量的限制性因素。总之，醋酸在提升Mg/MgH2水解性能方面是一种相对较好的催化剂。2.2在溶液中加入盐在溶液中加入酸，即使是弱酸也很难使水解产生的H2全部来自于H2O，然而在溶液中加入盐却能够达到这一点。一般认为，Mg/MgH2在酸式盐溶液的水解效果高于其他盐溶液。酸式盐提供的酸性环境与弱酸提供的酸性环境在破坏Mg(OH)2保护层方面具有异曲同工之妙。Huang等ADDINEN.CITE<EndNote><Cite><Author>Huang</Author><Year>2015</Year><RecNum>114</RecNum><DisplayText><styleface="superscript">[7]</style></DisplayText><record><rec-number>114</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1540195312">114</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Huang,Minghong</author><author>Ouyang,Liuzhang</author><author>Wang,Hui</author><author>Liu,Jiangwen</author><author>Zhu,Min</author></authors></contributors><titles><title>HydrogengenerationbyhydrolysisofMgH2andenhancedkineticsperformanceofammoniumchlorideintroducing</title><secondary-title>InternationalJournalofHydrogenEnergy</secondary-title></titles><periodical><full-title>InternationalJournalofHydrogenEnergy</full-title></periodical><pages>6145-6150</pages><volume>40</volume><number>18</number><section>6145</section><dates><year>2015</year></dates><isbn>03603199</isbn><urls></urls><electronic-resource-num>10.1016/j.ijhydene.2015.03.058</electronic-resource-num></record></Cite></EndNote>[7]发现NH4Cl能够显著地提高MgH2水解的动力学性能。水解放氢量和激活能如表（1）所示。从表中数据可以看出，4.5wt.%的NH4Cl水溶液显著降低了MgH2的水解激活能，并极大提高了水解放氢量和水解放氢速度。与NH4Cl相似，AlCl3也可以提高Mg/MgH2的水解性能ADDINEN.CITE<EndNote><Cite><Author>Gan</Author><Year>2018</Year><RecNum>454</RecNum><DisplayText><styleface="superscript">[15]</style></DisplayText><record><rec-number>454</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1550383563">454</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Gan,Deyu</author><author>Liu,Yana</author><author>Zhang,Jiguang</author><author>Zhang,Yao</author><author>Cao,Chuntao</author><author>Zhu,Yunfeng</author><author>Li,Liquan%JInternationalJournalofHydrogenEnergy</author></authors></contributors><titles><title>KineticperformanceofhydrogengenerationenhancedbyAlCl3viahydrolysisofMgH2preparedbyhydridingcombustionsynthesis</title></titles><pages>10232-10239</pages><volume>43</volume><number>22</number><dates><year>2018</year></dates><isbn>0360-3199</isbn><urls></urls></record></Cite></EndNote>[15]。表1MgH2在不同浓度NH4Cl水溶液中水解不同时间的放氢量和水解激活能Table1ThehydrogenyieldsandactivationenergiesofhydrolysisofMgH2indifferentconcentrationsofNH4Clsolutionindifferenttime.NH4Cl溶液浓度5min(mLg-1)10min(mLg-1)30min(mLg-1)激活能（kJmol-1H2）去离子水11417420958.060.5wt.%50164198050.864.5wt.%13101604166030.37（全英表格）TheconcentrationsofNH4Clsolution5min(mLg-1)10min(mLg-1)30min(mLg-1)Activationenergies(kJmol-1H2)deionizedwater11417420958.060.5wt.%50164198050.864.5wt.%13101604166030.37Zhao等ADDINEN.CITE<EndNote><Cite><Author>Zhao</Author><Year>2012</Year><RecNum>131</RecNum><DisplayText><styleface="superscript">[16]</style></DisplayText><record><rec-number>131</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1540792113">131</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Zhao,Z.</author><author>Zhu,Y.</author><author>Li,L.</author></authors></contributors><auth-address>CollegeofMaterialsScienceandEngineering,NanjingUniversityofTechnology,5XinmofanRoad,Nanjing,Jiangsu,PRChina.</auth-address><titles><title>EfficientcatalysisbyMgCl2inhydrogengenerationviahydrolysisofMg-basedhydridepreparedbyhydridingcombustionsynthesis</title><secondary-title>ChemCommun(Camb)</secondary-title></titles><periodical><full-title>ChemCommun(Camb)</full-title></periodical><pages>5509-11</pages><volume>48</volume><number>44</number><edition>2012/04/28</edition><dates><year>2012</year><pub-dates><date>Jun4</date></pub-dates></dates><isbn>1364-548X(Electronic) 1359-7345(Linking)</isbn><accession-num>22538836</accession-num><urls><related-urls><url>/pubmed/22538836</url></related-urls></urls><electronic-resource-num>10.1039/c2cc32353b</electronic-resource-num></record></Cite></EndNote>[16]发现MgCl2对Mg基氢化物的水解起到了显著的催化作用。Mg基氢化物在30℃去离子水中水解3min的水解放氢量为192mLg-1，而在0.5mol/LMgCl2水溶液中水解3min的放氢量达到了927mLg-1，将近去离子水中的5倍，并且当反应后的溶液被循环使用9次后，30min的水解放氢量人仍高达1600mLg-1，转化率为94%。他们认为这是由于MgCl2溶液提供的酸性环境导致MgH2的水解放氢量和水解速率得到了明显的提升。但Chen等ADDINEN.CITE<EndNote><Cite><Author>Chen</Author><Year>2014</Year><RecNum>132</RecNum><DisplayText><styleface="superscript">[17]</style></DisplayText><record><rec-number>132</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1540793143">132</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Chen,Jun</author><author>Fu,He</author><author>Xiong,Yifu</author><author>Xu,Jinrong</author><author>Zheng,Jie</author><author>Li,Xingguo</author></authors></contributors><titles><title>MgCl2promotedhydrolysisofMgH2nanoparticlesforhighlyefficientH2generation</title><secondary-title>NanoEnergy</secondary-title></titles><periodical><full-title>NanoEnergy</full-title></periodical><pages>337-343</pages><volume>10</volume><section>337</section><dates><year>2014</year></dates><isbn>22112855</isbn><urls></urls><electronic-resource-num>10.1016/j.nanoen.2014.10.002</electronic-resource-num></record></Cite></EndNote>[17]认为这是因为MgH2水解过程中产生的OH-与溶液中的Mg2+相结合在溶液中形成Mg(OH)2悬浮颗粒并沉淀下来，而不是在MgH2表面形成Mg(OH)2保护层的缘故。MgH2水解产生的Mg2+补充了溶液中损失的Mg2+，从而使溶液中的Mg2+处于平衡的状态，反应示意图如图1所示。由于溶液中Mg2+的浓度不变，所以反应后的溶液能够反复使用，这也是MgCl2比NH4Cl和AlCl3具有更好应用前景的原因。图1MgH2在去离子水中（a）和0.5mol/LMgCl2水溶液中（b）水解反应示意图ADDINEN.CITE<EndNote><Cite><Author>Chen</Author><Year>2014</Year><RecNum>132</RecNum><DisplayText><styleface="superscript">[17]</style></DisplayText><record><rec-number>132</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1540793143">132</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Chen,Jun</author><author>Fu,He</author><author>Xiong,Yifu</author><author>Xu,Jinrong</author><author>Zheng,Jie</author><author>Li,Xingguo</author></authors></contributors><titles><title>MgCl2promotedhydrolysisofMgH2nanoparticlesforhighlyefficientH2generation</title><secondary-title>NanoEnergy</secondary-title></titles><periodical><full-title>NanoEnergy</full-title></periodical><pages>337-343</pages><volume>10</volume><section>337</section><dates><year>2014</year></dates><isbn>22112855</isbn><urls></urls><electronic-resource-num>10.1016/j.nanoen.2014.10.002</electronic-resource-num></record></Cite></EndNote>[17]Fig.1SchematicdiagramofhydrolysisreactionofMgH2indeionizedwater(a)and0.5mol/LMgCl2aqueoussolution(b)[17]Kravchenko等ADDINEN.CITE<EndNote><Cite><Author>Kravchenko</Author><Year>2014</Year><RecNum>386</RecNum><DisplayText><styleface="superscript">[18]</style></DisplayText><record><rec-number>386</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1544794118">386</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Kravchenko,OV</author><author>Sevastyanova,LG</author><author>Urvanov,SA</author><author>Bulychev,BM%JInternationalJournalofHydrogenEnergy</author></authors></contributors><titles><title>FormationofhydrogenfromoxidationofMg,MgalloysandmixturewithNi,Co,CuandFeinaqueoussaltsolutions</title></titles><pages>5522-5527</pages><volume>39</volume><number>11</number><dates><year>2014</year></dates><isbn>0360-3199</isbn><urls></urls></record></Cite></EndNote>[18]机械球磨Mg粉后在不同盐溶液中测试Mg的产氢率，结果如图2所示。在溶液中加入NH4Cl、NaCl、MgCl2、KCl、CaCl2对Mg水解产氢具有明显的提升作用，而NaBr、KBr、NaI的提升作用不明显。这是因为除了阳离子的作用（NH4+提供的酸性环境、Mg2+的催化作用）外，Cl-相比于Br-和I-更加有利于Mg在水中的腐蚀。由此可见，阴离子Cl-对Mg(OH)2保护膜具有一定的破坏作用。图21gMg在分别在30mL碱金属、碱土金属卤化物和氯化铵水溶液中的产氢率图（卤素离子浓度为0.85M（曲线1~7）、0.93mol/LNH4Cl（曲线9）、0.31mol/LNH4Cl和0.85mol/LNaCl混合溶液（曲线8））[18]Fig.2Curvesofhydrogenyieldrateof1gMgin30mLalkalimetal,alkalineearthmetalhalideandammoniumchloridesolution(halogenionconcentration0.85mol/L(curve1~7),0.93mol/LNH4Cl(curve9),0.31mol/LNH4Cland0.85mol/LNaClmixedsolution(curve8))[18]3添加第二相3.1添加金属氧化物过渡族金属氧化物对Mg水解具有催化的作用。Huang等ADDINEN.CITE<EndNote><Cite><Author>Huang</Author><Year>2017</Year><RecNum>240</RecNum><DisplayText><styleface="superscript">[19]</style></DisplayText><record><rec-number>240</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1540888958">240</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Huang,Minghong</author><author>Ouyang,Liuzhang</author><author>Chen,Zhiling</author><author>Peng,Chenghong</author><author>Zhu,Xiaoke</author><author>Zhu,Min</author></authors></contributors><titles><title>HydrogenproductionviahydrolysisofMg-oxidecomposites</title><secondary-title>InternationalJournalofHydrogenEnergy</secondary-title></titles><periodical><full-title>InternationalJournalofHydrogenEnergy</full-title></periodical><pages>22305-22311</pages><volume>42</volume><number>35</number><section>22305</section><dates><year>2017</year></dates><isbn>03603199</isbn><urls></urls><electronic-resource-num>10.1016/j.ijhydene.2016.12.099</electronic-resource-num></record></Cite></EndNote>[19]探究了廉价金属氧化物Fe2O3、CaO、MoO3、Fe3O4、Nb2O5和TiO2对Mg水解性能的影响。将Mg和5wt.%金属氧化物机械球磨1h后在3.5%NaCl水溶液中水解，发现除了CaO，其他的金属氧化物对Mg的水解均起到了促进作用，其中MoO3、Fe2O3和Fe3O4的促进作用最为明显，分别达到了888mLg-1、869mLg-1、826mLg-1，纯镁的为257mLg-1，而CaO的只有137mLg-1。他们认为添加金属氧化物的水解性能之所以不同是由于他们与Mg原子的粘附力不同所导致的。他们还发现过渡族金属Fe的价态越高对Mg的水解性能的提升作用越明显。无独有偶，当添加Mo的不同价态氧化物及硫化物时，同样发现Mo的价态越高对Mg水解的催化活性越高ADDINEN.CITE<EndNote><Cite><Author>Huang</Author><Year>2017</Year><RecNum>239</RecNum><DisplayText><styleface="superscript">[8,20]</style></DisplayText><record><rec-number>239</rec-number><foreign-keys><keyapp="EN"db-id="tz00tepesapdeye9a9vp9wpkwfes0swpfvp0"timestamp="1540888952">239</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Huang,Minghong</author><author>Ouyang,Liuzhang</author><author>Ye,Jianshan</author><author>Liu,Jiangwen</author><author>Yao,Xiangdong</author><author>Wang,Hui</author><author>Shao,Huaiyu</author><author>Zhu,Min</author></authors></contributors><