【《提升碳化钼析氢性能的策略综述》4100字】

提升碳化钼析氢性能的策略综述能量因素、几何因素是影响阴极材料电催化析氢活性的主要原因。能量因素是指金属-氢键（M-H）的键能，具有合适吸附氢特性的金属，M-H键能小，容易形成性能较好的析氢材料。几何因素是指电极材料的结构、形貌及比表面积。从能量因素和几何因素出发，有助于从理论上指导碳化钼HER活性的进一步提高。为此，科研者围绕构建碳化钼纳米结构、异质原子掺杂、复合催化剂等方向开展了大量研究。纳米化2012年，Vrubel和Hu等[ADDINEN.CITE<EndNote><Cite><Author>Vrubel</Author><Year>2012</Year><RecNum>12</RecNum><DisplayText><styleface="superscript">42</style></DisplayText><record><rec-number>12</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1587716079">12</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Vrubel,H.</author><author>Hu,X.</author></authors></contributors><auth-address>LaboratoryofInorganicSynthesisandCatalysis,InstituteofChemicalSciencesandEngineering,EcolePolytechniqueFederaledeLausanne,ISIC-LSCI,BCH3305,Lausanne1015,Switzerland.</auth-address><titles><title>Molybdenumborideandcarbidecatalyzehydrogenevolutioninbothacidicandbasicsolutions</title><secondary-title>AngewChemIntEdEngl</secondary-title></titles><periodical><full-title>AngewChemIntEdEngl</full-title></periodical><pages>12703-6</pages><volume>51</volume><number>51</number><edition>2012/11/13</edition><dates><year>2012</year><pub-dates><date>Dec14</date></pub-dates></dates><isbn>1521-3773(Electronic) 1433-7851(Linking)</isbn><accession-num>23143996</accession-num><urls><related-urls><url>/pubmed/23143996</url></related-urls></urls><electronic-resource-num>10.1002/anie.201207111</electronic-resource-num><research-notes>43-firstHERofMo2C</research-notes></record></Cite></EndNote>42]发现商业Mo2C微米颗粒在酸性和碱性电解质溶液中都有较高的活性和稳定性，然而仍与Pt/C电极相差甚远，这主要是因为碳化钼颗粒尺寸较大，比表面积较小。纳米化作为一种简单有效的方法，可有效增加Mo2C比表面积，使其暴露更多活性位点，提高其催化活性。迄今为止，已成功制备出纳米纤维、纳米管、纳米片、纳米球等结构，HER性能相比商业碳化钼、块状碳化钼大幅提高。Han等[ADDINEN.CITE<EndNote><Cite><Author>Han</Author><Year>2019</Year><RecNum>18</RecNum><DisplayText><styleface="superscript">63</style></DisplayText><record><rec-number>18</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1587716267">18</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Han,Weiwei</author><author>Chen,Lulu</author><author>Ma,Biao</author><author>Wang,Jun</author><author>Song,Weiyu</author><author>Fan,Xiaobin</author><author>Li,Yang</author><author>Zhang,Fengbao</author><author>Peng,Wenchao</author></authors></contributors><titles><title>Ultra-smallMo2Cnanodotsencapsulatedinnitrogen-dopedporouscarbonforpH-universalhydrogenevolution:insightsintothesynergisticenhancementofHERactivitybynitrogendopingandstructuraldefects</title><secondary-title>JMaterChemA</secondary-title></titles><periodical><full-title>JMaterChemA</full-title></periodical><pages>4734-4743</pages><volume>7</volume><number>9</number><section>4734</section><dates><year>2019</year></dates><isbn>2050-7488 2050-7496</isbn><urls></urls><electronic-resource-num>10.1039/c8ta11098k</electronic-resource-num><research-notes><styleface="normal"font="default"size="100%">64</style><styleface="normal"font="default"charset="134"size="100%">、</style><styleface="normal"font="default"size="100%">MCnanodots</style></research-notes></record></Cite></EndNote>63]采用一锅热策略合成了N掺杂多孔碳层负载的超细纳米Mo2C（Mo2C/N-PC），颗粒尺寸仅为3~5nm，比表面积增大到57.1m2g-1，是商用微米Mo2C（4.6m2g-1）的十几倍不等。经HER性能测试，Mo2C/N-PC在酸性、中性、碱性介质下仅需178、224、100mV即可达到10mAcm-2的电流密度，明显优于微米Mo2C（246、319、205mV）。从析氢反应动力学上来说，Mo2C/N-PC具有更低的Tafel斜率、更小的电子转移电阻（Rct）。Ji及其团队[ADDINEN.CITEADDINEN.CITE.DATA64]通过静电纺丝技术制备了一维多孔中空的碳化钼纳米纤维，丰富的孔隙和中空通道暴露出大量的活性位点，促进了界面反应的电荷/质量转移，从而使材料在碱性析氢（HER）、析氧（OER）反应中均表现出较高的活性。此外，将该催化剂用作自制水分解装置的双功能催化剂电极，仅需要1.68V的电池电压就能达到10mAcm-2的电流密度。Hui等[ADDINEN.CITE<EndNote><Cite><Author>Hui</Author><Year>2020</Year><RecNum>216</RecNum><DisplayText><styleface="superscript">65</style></DisplayText><record><rec-number>216</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1614854891">216</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hui,Yang</author><author>Yingxi,Chen</author><author>Chunbao,Wang</author><author>Guangjin,Wang</author></authors></contributors><titles><title>ConfinedgrowthofultrafineMo2CnanoparticlesembeddedinN-dopedcarbonnanosheetforwatersplitting</title><secondary-title>JournalofAlloysandCompounds</secondary-title></titles><periodical><full-title>JournalofAlloysandCompounds</full-title></periodical><volume>842</volume><section>155939</section><dates><year>2020</year></dates><isbn>09258388</isbn><urls></urls><electronic-resource-num>10.1016/j.jallcom.2020.155939</electronic-resource-num><research-notes><styleface="normal"font="default"size="100%">66</style><styleface="normal"font="default"charset="134"size="100%">、</style><styleface="normal"font="default"size="100%">NaCl</style><styleface="normal"font="default"charset="134"size="100%">硬模板</style></research-notes></record></Cite></EndNote>65]采用天然多糖瓜尔胶（GG）和NaCl作为碳源和硬模板，合成了超细Mo2C（平均直径约为2.5nm）颗粒嵌入的2D碳纳米片。NaCl作为构造超薄碳纳米片的硬模板，同时调节Mo2C的成核和生长，控制纳米晶体的直径。该材料具有丰富的纳米孔，这些纳米孔通过毛细作用力将电解质泵送到催化剂表面，并抑制气体在气固界面上的吸附，加速了气体从活性位点表面的释放，对于提高HER效率具有积极作用。图1.8三维uf-Mo2C/CF材料的合成路线图[ADDINEN.CITE<EndNote><Cite><Author>Kou</Author><Year>2018</Year><RecNum>124</RecNum><DisplayText><styleface="superscript">66</style></DisplayText><record><rec-number>124</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1595258126">124</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Kou,Zongkui</author><author>Wang,Tingting</author><author>Cai,Yi</author><author>Guan,Cao</author><author>Pu,Zonghua</author><author>Zhu,Changrong</author><author>Hu,Yating</author><author>Elshahawy,AbdelnabyM.</author><author>Wang,John</author><author>Mu,Shichun</author></authors></contributors><titles><title>UltrafineMolybdenumCarbideNanocrystalsConfinedinCarbonFoamsviaaColloid-ConfinementRouteforEfficientHydrogenProduction</title><secondary-title>Small</secondary-title></titles><periodical><full-title>Small</full-title></periodical><pages>1700396</pages><volume>2</volume><number>4</number><section>1700396</section><dates><year>2018</year></dates><isbn>23669608</isbn><urls></urls><electronic-resource-num>10.1002/smtd.201700396</electronic-resource-num><research-notes><styleface="normal"font="default"size="100%">67</style><styleface="normal"font="default"charset="134"size="100%">、</style><styleface="normal"font="default"size="100%">22-SiO2</style><styleface="normal"font="default"charset="134"size="100%">模板</style></research-notes></record></Cite></EndNote>66]Figure1.8Syntheticrouteof3Duf-Mo2C/CFmaterial[ADDINEN.CITE<EndNote><Cite><Author>Kou</Author><Year>2018</Year><RecNum>124</RecNum><DisplayText><styleface="superscript">66</style></DisplayText><record><rec-number>124</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1595258126">124</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Kou,Zongkui</author><author>Wang,Tingting</author><author>Cai,Yi</author><author>Guan,Cao</author><author>Pu,Zonghua</author><author>Zhu,Changrong</author><author>Hu,Yating</author><author>Elshahawy,AbdelnabyM.</author><author>Wang,John</author><author>Mu,Shichun</author></authors></contributors><titles><title>UltrafineMolybdenumCarbideNanocrystalsConfinedinCarbonFoamsviaaColloid-ConfinementRouteforEfficientHydrogenProduction</title><secondary-title>Small</secondary-title></titles><periodical><full-title>Small</full-title></periodical><pages>1700396</pages><volume>2</volume><number>4</number><section>1700396</section><dates><year>2018</year></dates><isbn>23669608</isbn><urls></urls><electronic-resource-num>10.1002/smtd.201700396</electronic-resource-num><research-notes><styleface="normal"font="default"size="100%">67</style><styleface="normal"font="default"charset="134"size="100%">、</style><styleface="normal"font="default"size="100%">22-SiO2</style><styleface="normal"font="default"charset="134"size="100%">模板</style></research-notes></record></Cite></EndNote>66].Hou等开发了在碱性HER中表现优越的介孔三明治状碳化钼催化剂。分布均匀的小尺寸Mo2C纳米颗粒，为反应提供了丰富的活性位点。而高度石墨化的多孔碳基底赋予了材料较高的比表面积和良好的导电性，大量的活性位点得以暴露在电解液中，反应物质或电子通过孔道结构快速地进行转移，加速了HER动力学过程。Kou等[ADDINEN.CITE<EndNote><Cite><Author>Kou</Author><Year>2018</Year><RecNum>124</RecNum><DisplayText><styleface="superscript">66</style></DisplayText><record><rec-number>124</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1595258126">124</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Kou,Zongkui</author><author>Wang,Tingting</author><author>Cai,Yi</author><author>Guan,Cao</author><author>Pu,Zonghua</author><author>Zhu,Changrong</author><author>Hu,Yating</author><author>Elshahawy,AbdelnabyM.</author><author>Wang,John</author><author>Mu,Shichun</author></authors></contributors><titles><title>UltrafineMolybdenumCarbideNanocrystalsConfinedinCarbonFoamsviaaColloid-ConfinementRouteforEfficientHydrogenProduction</title><secondary-title>Small</secondary-title></titles><periodical><full-title>Small</full-title></periodical><pages>1700396</pages><volume>2</volume><number>4</number><section>1700396</section><dates><year>2018</year></dates><isbn>23669608</isbn><urls></urls><electronic-resource-num>10.1002/smtd.201700396</electronic-resource-num><research-notes><styleface="normal"font="default"size="100%">67</style><styleface="normal"font="default"charset="134"size="100%">、</style><styleface="normal"font="default"size="100%">22-SiO2</style><styleface="normal"font="default"charset="134"size="100%">模板</style></research-notes></record></Cite></EndNote>66]以胶体SiO2纳米球约束Mo2C生长的策略（图1.8），制取了均匀组装在原位形成的3D碳泡沫上的Mo2C纳米晶（uf-Mo2C/CF）。材料比表面积高达257m2g-1，纳米晶体平均尺寸为1.9nm，在超细微粒和连通性良好的多孔通道作用下，uf-Mo2C/CF在pH=7和14时表现出良好的HER活性，只需要174和185mV的过电位即可驱动10mAcm-2的电流密度。原子掺杂从能量因素来看，纯碳化钼的强Mo-H键致其吸附活性H原子的能力太强，不利于HER反应，而碳化钼d带的移动会引起氢原子吸附能的变化，故通过改变Mo2C的d带电子结构特性可以实现其电催化析氢性能的调控。引入非金属原子（N、S、P、B等）是提高碳化钼HER性能的常用手段，这些非金属原子通过取代半径相似的碳原子，在结构中形成缺陷，或者与钼原子发生电子转移效应，从而引起电子结构和电催化剂表面性质的改变。理论计算表明，非金属原子掺杂促进了Mo→C→非金属原子的电子转移，从而激发相邻C原子的HER催化活性，而掺杂原子本身也能起到催化作用[ADDINEN.CITEADDINEN.CITE.DATA67,68]。由于引入了极性键，非金属原子掺杂还被认为是提高碳化钼催化剂亲水性的有效策略，有益于电解水反应的界面接触[ADDINEN.CITEADDINEN.CITE.DATA69]。Jia及其课题组[ADDINEN.CITEADDINEN.CITE.DATA70]以MoO3为模板，制备了N掺杂的超薄Mo2C纳米片（N-Mo2CNSs），相比纯相Mo2C，该催化剂的HER性能大幅提高，为达到10mAcm-2的电流密度，纯相Mo2C需要463mV，而N-Mo2CNSs只需99mV。掺杂N通过取代Mo2C中的C原子，改变了Mo和C原子的ΔGH*值（图1.9），并引入了新的析氢活性位点：位于顶部的N原子（N-T）及与其相邻的顶部Mo原子（Mo-3-T），其ΔGH*分别为0.3eV、0.07eV，大大提高了材料的催化活性。Huang等[71]对不同N掺杂量的碳化钼Mo原子的d轨道价电子进行了电荷分析，随着掺杂量的增加，Mo原子的d轨道价电子减少，d带中心向高能级移动，ΔGH*也由负转为正，表明掺杂引起了Mo2C对氢原子中间体由强吸附到弱吸附的过渡，也意味着只有适量的N掺杂才能提高催化剂的性能，过量掺杂反而会束缚材料的活性。Fu等[ADDINEN.CITEADDINEN.CITE.DATA72]报道了一种由碳片支撑的具有暴露（001）晶面的单晶Mo2C六角形纳米片阵列，并在此基础上进一步实现了P原子的原子级分散（SAP-Mo2C-CS）。其中，P原子以占据晶面的3个Mo原子间隙的形式稳定存在于结构中，并吸引了相邻Mo原子的电子，与其形成不同的杂化轨道，产生强电子耦合效应。DFT计算表明了Mo2C载体上P单原子的ΔGH*为0.009eV，几乎接近理想值0，意味着获得电子的P原子可以充当氢吸附和活化的高活性中心。此外，与P键合的Mo原子d带中心明显降低，弱化了氢原子中间体在催化剂上的强吸附。在P原子的双向调节下，SAP-Mo2C-CS在10mAcm-2的电流密度下实现了36mV的低过电势。图1.9Mo2C（a，d）和N-Mo2C（b，c，e）不同位置上H*吸附的理论结构模型和ΔGH*[ADDINEN.CITEADDINEN.CITE.DATA70]Figure1.9ThetheoreticalstructuremodelandΔGH*ofH*adsorptionatdifferentpositionsofMo2C(a,d)andN-Mo2C(b,c,e)[ADDINEN.CITEADDINEN.CITE.DATA70].相比单掺杂，Wang等人[ADDINEN.CITE<EndNote><Cite><Author>Wang</Author><Year>2018</Year><RecNum>22</RecNum><DisplayText><styleface="superscript">67</style></DisplayText><record><rec-number>22</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1587716454">22</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Wang,Dezhi</author><author>Liu,Tianying</author><author>Wang,Junchao</author><author>Wu,Zhuangzhi</author></authors></contributors><titles><title>N,P(S)Co-dopedMo2C/Chybridelectrocatalystsforimprovedhydrogengeneration</title><secondary-title>Carbon</secondary-title></titles><periodical><full-title>Carbon</full-title></periodical><pages>845-852</pages><volume>139</volume><section>845</section><dates><year>2018</year></dates><isbn>00086223</isbn><urls></urls><electronic-resource-num>10.1016/j.carbon.2018.07.043</electronic-resource-num><research-notes>68-Y28-NP(S)Codoped</research-notes></record></Cite></EndNote>67]揭示了N，P和N，S双掺杂的Mo2C催化剂更高的HER活性。与单独的N掺杂相比，N，P和N，S杂原子的共掺杂明显增加了材料中活性位点的数量，并进一步调控了碳基底的电子结构，提高了材料的导电性。同时，双重掺杂引发了协同效应，显着增强了每个析氢位点的固有活性。此外，Mo2C中的部分C原子被N，P或N，S原子取代，Mo-H键被削弱，改善了氢原子中间体的解吸，加快了HER动力学。同样地，Mohsin等人[ADDINEN.CITE<EndNote><Cite><Author>Anjum</Author><Year>2018</Year><RecNum>23</RecNum><DisplayText><styleface="superscript">68</style></DisplayText><record><rec-number>23</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1587716513">23</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Anjum,MohsinAliRaza</author><author>Lee,MinHee</author><author>Lee,JaeSung</author></authors></contributors><titles><title>Boron-andNitrogen-CodopedMolybdenumCarbideNanoparticlesImbeddedinaBCNNetworkasaBifunctionalElectrocatalystforHydrogenandOxygenEvolutionReactions</title><secondary-title>ACSCatalysis</secondary-title></titles><periodical><full-title>ACSCatalysis</full-title></periodical><pages>8296-8305</pages><volume>8</volume><number>9</number><section>8296</section><dates><year>2018</year></dates><isbn>2155-5435 2155-5435</isbn><urls></urls><electronic-resource-num>10.1021/acscatal.8b01794</electronic-resource-num><research-notes><styleface="normal"font="default"size="100%">69</style><styleface="normal"font="default"charset="134"size="100%">、</style><styleface="normal"font="default"size="100%">B-N</style><styleface="normal"font="default"charset="134"size="100%">共掺</style></research-notes></record></Cite></EndNote>68]也报道了B，N共掺杂的Mo2C纳米颗粒在HER、OER中的优越反应活性。根据Brewer-Engel价键理论，过渡系金属，如：Fe、Co、Ni，具有丰富的外层电子，容易和含有空的或半满d轨道的金属Mo产生协同作用，或改变原子间结合力，或改变Mo原子的电子层状态，进而提高HER活性[ADDINEN.CITE<EndNote><Cite><Author>Safizadeh</Author><Year>2015</Year><RecNum>219</RecNum><DisplayText><styleface="superscript">72</style></DisplayText><record><rec-number>219</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1614854915">219</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Safizadeh,Fariba</author><author>Ghali,Edward</author><author>Houlachi,Georges</author></authors></contributors><titles><title>Electrocatalysisdevelopmentsforhydrogenevolutionreactioninalkalinesolutions–AReview</title><secondary-title>InternationalJournalofHydrogenEnergy</secondary-title></titles><periodical><full-title>InternationalJournalofHydrogenEnergy</full-title><abbr-1>IJHE</abbr-1></periodical><pages>256-274</pages><volume>40</volume><number>1</number><section>256</section><dates><year>2015</year></dates><isbn>03603199</isbn><urls></urls><electronic-resource-num>10.1016/j.ijhydene.2014.10.109</electronic-resource-num><research-notes><styleface="normal"font="default"size="100%">73</style><styleface="normal"font="default"charset="134"size="100%">、</style><styleface="normal"font="default"size="100%">BE</style><styleface="normal"font="default"charset="134"size="100%">价键理论</style></research-notes></record></Cite></EndNote>73]。Xu等[ADDINEN.CITE<EndNote><Cite><Author>Xu</Author><Year>2016</Year><RecNum>26</RecNum><DisplayText><styleface="superscript">73</style></DisplayText><record><rec-number>26</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1587716629">26</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Xu,Xiaobin</author><author>Nosheen,Farhat</author><author>Wang,Xun</author></authors></contributors><titles><title>Ni-DecoratedMolybdenumCarbideHollowStructureDerivedfromCarbon-CoatedMetal–OrganicFrameworkforElectrocatalyticHydrogenEvolutionReaction</title><secondary-title>ChemistryofMaterials</secondary-title></titles><periodical><full-title>ChemistryofMaterials</full-title></periodical><pages>6313-6320</pages><volume>28</volume><number>17</number><section>6313</section><dates><year>2016</year></dates><isbn>0897-4756 1520-5002</isbn><urls></urls><electronic-resource-num>10.1021/acs.chemmater.6b02586</electronic-resource-num><research-notes><styleface="normal"font="default"size="100%">74</style><styleface="normal"font="default"charset="134"size="100%">、镍掺杂</style></research-notes></record></Cite></EndNote>74]用酸蚀去除掺杂在Mo2C中的金属Ni以后，材料的HER性能明显降低。对此，研究者作出了解释：Ni与Mo2C的电子协同效应可以降低催化剂对氢原子中间体（Hads）的吸附自由能，从而促进Hads的解吸和H2的释放。图1.10Ni掺杂MoxC的XPS高分辨率窄谱：（a）Ni2p；（b）Mo3d[ADDINEN.CITE<EndNote><Cite><Author>Das</Author><Year>2018</Year><RecNum>220</RecNum><DisplayText><styleface="superscript">74</style></DisplayText><record><rec-number>220</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1614854923">220</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Das,D.</author><author>Santra,S.</author><author>Nanda,K.K.</author></authors></contributors><auth-address>MaterialsResearchCentre,IndianInstituteofScience,Bangalore560012,India.</auth-address><titles><title>InSituFabricationofaNickel/MolybdenumCarbide-AnchoredN-DopedGraphene/CNTHybrid:AnEfficient(Pre)catalystforOERandHER</title><secondary-title>ACSApplMaterInterfaces</secondary-title></titles><periodical><full-title>ACSApplMaterInterfaces</full-title></periodical><pages>35025-35038</pages><volume>10</volume><number>41</number><edition>2018/09/25</edition><keywords><keyword>CNT-graphenehybrid</keyword><keyword>electrocatalysis</keyword><keyword>hydrogenevolutionreaction(HER)</keyword><keyword>molybdenumcarbide</keyword><keyword>oxygenevolutionreaction(OER)</keyword></keywords><dates><year>2018</year><pub-dates><date>Oct17</date></pub-dates></dates><isbn>1944-8252(Electronic) 1944-8244(Linking)</isbn><accession-num>30244572</accession-num><urls><related-urls><url>/pubmed/30244572</url></related-urls></urls><electronic-resource-num>10.1021/acsami.8b09941</electronic-resource-num><research-notes><styleface="normal"font="default"size="100%">75</style><styleface="normal"font="default"charset="134"size="100%">、</style><styleface="normal"font="default"size="100%">NI-Mo2C</style></research-notes></record></Cite></EndNote>75]Figure1.10(a)High-resolutionNi2pand(b)Mo3dXPSspectraofNidopedMoxC[ADDINEN.CITE<EndNote><Cite><Author>Das</Author><Year>2018</Year><RecNum>220</RecNum><DisplayText><styleface="superscript">74</style></DisplayText><record><rec-number>220</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1614854923">220</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Das,D.</author><author>Santra,S.</author><author>Nanda,K.K.</author></authors></contributors><auth-address>MaterialsResearchCentre,IndianInstituteofScience,Bangalore560012,India.</auth-address><titles><title>InSituFabricationofaNickel/MolybdenumCarbide-AnchoredN-DopedGraphene/CNTHybrid:AnEfficient(Pre)catalystforOERandHER</title><secondary-title>ACSApplMaterInterfaces</secondary-title></titles><periodical><full-title>ACSApplMaterInterfaces</full-title></periodical><pages>35025-35038</pages><volume>10</volume><number>41</number><edition>2018/09/25</edition><keywords><keyword>CNT-graphenehybrid</keyword><keyword>electrocatalysis</keyword><keyword>hydrogenevolutionreaction(HER)</keyword><keyword>molybdenumcarbide</keyword><keyword>oxygenevolutionreaction(OER)</keyword></keywords><dates><year>2018</year><pub-dates><date>Oct17</date></pub-dates></dates><isbn>1944-8252(Electronic) 1944-8244(Linking)</isbn><accession-num>30244572</accession-num><urls><related-urls><url>/pubmed/30244572</url></related-urls></urls><electronic-resource-num>10.1021/acsami.8b09941</electronic-resource-num><research-notes><styleface="normal"font="default"size="100%">75</style><styleface="normal"font="default"charset="134"size="100%">、</style><styleface="normal"font="default"size="100%">NI-Mo2C</style></research-notes></record></Cite></EndNote>75].Das等[ADDINEN.CITE<EndNote><Cite><Author>Das</Author><Year>2018</Year><RecNum>220</RecNum><DisplayText><styleface="superscript">74</style></DisplayText><record><rec-number>220</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1614854923">220</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Das,D.</author><author>Santra,S.</author><author>Nanda,K.K.</author></authors></contributors><auth-address>MaterialsResearchCentre,IndianInstituteofScience,Bangalore560012,India.</auth-address><titles><title>InSituFabricationofaNickel/MolybdenumCarbide-AnchoredN-DopedGraphene/CNTHybrid:AnEfficient(Pre)catalystforOERandHER</title><secondary-title>ACSApplMaterInterfaces</secondary-title></titles><periodical><full-title>ACSApplMaterInterfaces</full-title></periodical><pages>35025-35038</pages><volume>10</volume><number>41</number><edition>2018/09/25</edition><keywords><keyword>CNT-graphenehybrid</keyword><keyword>electrocatalysis</keyword><keyword>hydrogenevolutionreaction(HER)</keyword><keyword>molybdenumcarbide</keyword><keyword>oxygenevolutionreaction(OER)</keyword></keywords><dates><year>2018</year><pub-dates><date>Oct17</date></pub-dates></dates><isbn>1944-8252(Electronic) 1944-8244(Linking)</isbn><accession-num>30244572</accession-num><urls><related-urls><url>/pubmed/30244572</url></related-urls></urls><electronic-resource-num>10.1021/acsami.8b09941</electronic-resource-num><research-notes><styleface="normal"font="default"size="100%">75</style><styleface="normal"font="default"charset="134"size="100%">、</style><styleface="normal"font="default"size="100%">NI-Mo2C</style></research-notes></record></Cite></EndNote>75]采用XPS表征明确了掺杂Ni降低MoxC中Mo原子化学价态同时自身原子价态提高的现象（图1.10）。在金属Ni向MoxC转移电子的作用下，Mo原子周围的电子增多，化学位移随即发生变化，向低结合能移动了0.4~0.7eV，而金属Ni由于失去了部分电子，产生了新的化学状态——Ni2+。这种电子转移效应使得催化剂在HER和OER反应中发挥出良好的活性，因而金属Ni是促进碳化钼催化剂HER活性提高的重要因素。Ma等人[ADDINEN.CITE<EndNote><Cite><Author>Ma</Author><Year>2020</Year><RecNum>221</RecNum><DisplayText><styleface="superscript">75</style></DisplayText><record><rec-number>221</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1614854930">221</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Ma,Yufei</author><author>Chen,Meng</author><author>Geng,Hongbo</author><author>Dong,Huafeng</author><author>Wu,Ping</author><author>Li,Xiumin</author><author>Guan,Guoqing</author><author>Wang,Tiejun</author></authors></contributors><titles><title>SynergisticallyTuningElectronicStructureofPorousβ‐Mo 2 CSpheresbyCoDopingandMo‐VacanciesDefectEngineeringforOptimizingHydrogenEvolutionReactionActivity</title><secondary-title>AdvancedFunctionalMaterials</secondary-title></titles><periodical><full-title>AdvancedFunctionalMaterials</full-title></periodical><volume>30</volume><number>19</number><section>2000561</section><dates><year>2020</year></dates><isbn>1616-301X 1616-3028</isbn><urls></urls><electronic-resource-num>10.1002/adfm.202000561</electronic-resource-num><research-notes><styleface="normal"font="default"size="100%">76</style><styleface="normal"font="default"charset="134"size="100%">、</style><styleface="normal"font="default"size="100%">Co-MC-</style><styleface="normal"font="default"charset="134"size="100%">缺陷工程</style></research-notes></record></Cite></EndNote>76]通过DFT计算表明，Co掺杂及酸蚀部分Co后产生的Mo空位，可以丰富Mo原子周围的电子，导致其费米能级（EF）附近的价电子浓度增加，d带中心（εd）下降，从而优化了Mo-H键的强度，有效提高HER反应动力。由于Co的电负性低于Mo，电子由Co向Mo迁移，这种转移导致εd迅速下降，而Mo空位的屏蔽作用会削弱电子转移程度，避免εd的过度下降，从而使其处于最佳位置。因而，该材料在酸性环境下显示出较低的过电位（η10=125mV）。Yu等人[ADDINEN.CITEADDINEN.CITE.DATA77]在相同条件下制备了一系列含有不同金属掺杂剂的Mo2C纳米材料（TM-Mo2C，TM=Fe、Co、Ni、Cr），并通过DFT计算和电催化实验证实了TM掺杂剂对Mo2C的ΔGH*和催化活性的显著影响。ΔGH*的变化如下：Ni-Mo2C>Co-Mo2C>Fe-Mo2C>Cr-Mo2C>Mo2C，与实验测得的酸性HER活性规律一致。当Ni-Mo2C进一步包裹于N掺杂碳壳（Ni-Mo2C@C）时，ΔGH*降低到0.19eV，氢解吸更容易。因而，Ni-Mo2C@C具有最佳的HER性能，当电流密度为10mAcm-2时过电位仅为72mV，Tafel斜率为64.8mVdec-1。Koverga等[ADDINEN.CITEADDINEN.CITE.DATA78]也探究了Fe、Co、Ni、Cu在弱酸性（pH=5）、弱碱性（pH=9）环境下对α-Mo2CHER性能的影响，却发现了与Yu等人不同的实验结论。当pH=5时，未掺杂的α-Mo2C催化性能最佳，金属掺杂后性能反而有所降低，而在碱性介质下，析氢活性遵循Co-Mo2C>Ni-Mo2C>Fe-Mo2C>Cu-Mo2C>Mo2C的规律，说明过渡金属掺杂提高了Mo2C的碱性析氢活性。这种差异主要归因于材料的制备方法、使用原料、添加比例的不同，因此元素掺杂时需综合考虑。复合由于碳化钼的制备温度通常在700℃以上，团聚和烧结现象明显，严重限制了材料的本征电催化活性。因此，具有突出比表面积的碳纳米管、石墨烯、多孔碳常用作碳化钼的复合载体，改善其HER活性。在复合载体的限域效应下，Mo2C颗粒的生长被限制在纳米级别，并实现了颗粒的均匀分散。同时，碳载体优异的导电性更加速了反应中物质、离子的运输，碳纳米管、石墨烯还可以作为碳化钼的保护壳，减缓碳化钼在空气中的氧化与在强酸碱环境下的腐蚀，提高催化剂的使用寿命。C.Tranca团队[ADDINEN.CITE<EndNote><Cite><Author>Tranca</Author><Year>2020</Year><RecNum>223</RecNum><DisplayText><styleface="superscript">78</style></DisplayText><record><rec-number>223</rec-number><foreign-keys><keyapp="EN"db-id="sdaasdwx8pzdd9epw0fxvz2e2tsprtp0vatx"timestamp="1614854945">223</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Tranca,D.C.</author><author>Rodríguez-Hernández,F.</author><author>Seifert,G.</author><author>Zhuang,X.</author></authors></contributors><titles><title>TheoreticalmodelsforhydrogenevolutionreactionatcombinedMo2CandN–dopedgraphene</title><secondary-title>JournalofCatalysis</secondary-title></titles><periodical><full-title>JournalofCatalysis</full-title></periodical><pages>234-247</pages><volume>381</volume><section>234</section><dates><year>2020</year></dates><isbn>00219517</isbn><urls></urls><electronic-resource-num>10.1016/j.jcat.2019.10.028</electronic-resource-num><research-notes>79-TheroreticmodelsforHER</research-notes></record></Cite></EndNote>79]从理论计算的角度出发，对比了纯相Mo2C、纯相石墨烯、Mo2C复合石墨烯的氢原子吸附自由能（ΔGH*），结果表明单一Mo2C或石墨烯对氢原子吸附过强，