Fe-substituted cobalt-phosphate polyoxometalates as enhanced oxygen evolution catalysts in acidic media  

铁取代的钴-磷多酸作为酸性介质中性能增强的析氧催化剂

作　　者：Xin-Bao Han Dong-Xue Wang Eduardo Gracia-Espino Yu-Hui Luo Yuan-Zhi Tan Dong-Fei Lu Yang-Guang Li Thomas Wagberg En-Bo Wang Lan-Sun Zheng 韩新豹;王冬雪;Eduardo Gracia-Espino;骆昱晖;谭元植;卢冬飞;李阳光;Thomas Wagberg;王恩波;郑兰荪(厦门大学化学化工学院,化学系,固体表面物理化学国家重点实验室,福建 厦门 361005;东北师范大学化学学院多酸科学教育部重点实验室,吉林 长春 130024;于默奥大学物理系,于默奥 90187,瑞典;淮海工学院化学工程学院,江苏 连云港 222000)

机构地区：[1]State Key Laboratory of Physical Chemistry of Solid Surfaces,and Department of Chemistry,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,Fujian,China [2]Key Laboratory of Polyoxometalate Science of the Ministry of Education,Faculty of Chemistry,Northeast Normal University,Changchun 130024,Jilin,China [3]Department of Physics,Ume?University,Ume?90187,Sweden [4]Department of Chemical Engineering,Huaihai Institute of Technology,Lianyungang 222000,Jiangsu,China

出　　处：《Chinese Journal of Catalysis》2020年第5期853-857,共5页催化学报（英文）

基　　金：国家自然科学基金(21771155,21721001);国家重点基础研究发展计划(2014CB845603,2017YFA0204902);国家重点研发计划(2017YFA0204902);瑞典Vetenskapsr?det(2017-04862);瑞典能源署(Energimyndigheten,45419-1).

摘　　要：All-inorganic and earth-abundant bi-/trimetallic hydr(oxy)oxides are widely used as oxygen evolution electrocatalysts owing to their remarkable performance.However,their atomically precise structures remain undefined,complicating their optimization and limiting the understanding of their enhanced performance.Here,the underlying structure-property correlation is explored by using a well-defined cobalt-phosphate polyoxometalate cluster [{(Co4)(OH)3(PO4)}4(SiW9 O34)4]^32-(1),which may serve as a molecular model of multimetal hydr(oxy)oxides.The catalytic activity is enhanced upon replacing Co by Fe in 1,resulting in a reduced overpotential(385 mV) for oxygen evolution(by 66 mV) compared to that of the parent 1 at 10 mA cm^-2 in an acidic medium;this overpotential is comparable to that for the IrO2 catalyst These abundant-metal-based polyoxometalates exhibit high stability,with no evidence of degradation even after 24 h of operation.纯无机的非贵金属基双/三金属氢氧(氧)化物因其优异的析氧反应(OER)性能而得到广泛关注及研究.但这些催化剂的原子精度的结构表征较为困难,阻碍了人们对其构效关系的认识,从而影响了进一步对催化性能的精确调控.金属有机框架(MOFs)材料因具有明确的结构及化学组成可调等优点,可以作为一类结构确定的OER电催化剂,但是MOFs为有机配体和金属离子配位形成的框架材料,与金属氢氧(氧)化物结构类型不同.多酸是由高氧化态的Mo^Ⅵ/Ⅴ,W^Ⅵ/Ⅴ,V^Ⅴ/Ⅳ,Nb^Ⅴ和Ta^Ⅴ等组成的金属-氧簇.多酸尺寸介于分子与块体氧化物之间,可以被看作一种具有明确结构的分子氧化物.因此,多酸可用作模型体系从分子水平上探究金属氢氧(氧)化物催化剂的反应机理.此外,多酸已被证明是很有前景的非贵金属水氧化催化剂.对于OER,酸性介质更具优势,因为它与碱性介质相比具有高能效、低欧姆损耗、易于产物分离等优点.但是,非贵金属OER电催化剂在酸性介质中很难稳定且性能通常不如贵金属催化剂.制备酸性介质中高效和稳定的非贵金属OER电催化剂仍然是一大挑战.在本论文中,我们首先采用'原位同构取代'策略,将结构明确的[{Co4(OH)3PO4}4(SiW9O34)4]^32-(1)钴-磷多酸阴离子中的Co原子替换成Fe原子,合成了不同Fe含量的[{Fe2Co2(OH)3PO4}4(SiW9O34)4]^24-(2)和[{FeCo3(OH)3PO4}4(SiW9O34)4]^28-(3).然后通过离子交换,向1,2和3中引入Ba^2+,成功合成了不溶于水的多酸阴离子结构维持的多相催化剂Ba[1],Ba[2]和Ba[3].性能最好的Ba[3]在0.5 mol L^-1 H2SO4溶液中达到10 mA cm^-2的电流密度仅需要385 mV过电位(无iR校正),比相同条件下无Fe取代的Ba[1]和商业IrO2催化剂的过电位分别低66 mV和8 mV.经过2000圈的循环伏安测试和24 h的长时间电解测试,Ba[1],Ba[2]和Ba[3]均表现出较高的稳定性.另外,采用红外光谱(FT-IR)以及电感耦合等离子体质谱

关 键 词：Colbalt-phosphate POLYOXOMETALATE Oxygen evolution reaction Isostructural substitution 

分 类 号：O643.36[理学—物理化学]