Ultrastable Polymolybdate-Based Metal-Organic Frameworks as Highly Active Electrocatalysts for Hydrogen Generation from Water.
Two novel polyoxometalate (POM)-based metal-organic frameworks (MOFs), [TBA]3[ε-PMo(V)8Mo(VI)4O36(OH)4Zn4][BTB]4/3·xGuest (NENU-500, BTB = benzene tribenzoate, TBA(+) = tetrabutylammonium ion) and [TBA]3[ε-PMo(V)8Mo(VI)4O37(OH)3Zn4][BPT] (NENU-501, BPT = [1,1'-biphenyl]-3,4',5-tricarboxylate), were isolated. In these compounds, the POM fragments serving as nodes were directly connected with organic ligands giving rise to three-dimensional (3D) open frameworks. The two anionic frameworks were balanced by TBA(+) ions residing inside the open channels. They exhibit not only good stability in air but also tolerance to acidic and basic media. Furthermore, they were employed as electrocatalysts for the hydrogen evolution reaction (HER) owing to the combination of the redox activity of a POM unit and the porosity of a MOF. Meanwhile, the HER activities of ε(trim)(4/3), NENU-5, and HKUST-1 were also studied for comparison. Remarkably, as a 3D hydrogen-evolving cathode operating in acidic electrolytes, NENU-500 exhibits the highest activity among all MOF materials. It shows an onset overpotential of 180 mV and a Tafel slope of 96 mV·dec(-1), and the catalytic current density can approach 10 mA·cm(-2) at an overpotential of 237 mV. Moreover, NENU-500 and NENU-501 maintain their electrocatalytic activities after 2000 cycles.
†Institute of Functional Material Chemistry, Key Lab of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
Jun-Sheng
JS
Qin
†Institute of Functional Material Chemistry, Key Lab of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
Dong-Ying
DY
Du
†Institute of Functional Material Chemistry, Key Lab of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
Wei
W
Guan
†Institute of Functional Material Chemistry, Key Lab of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
Xiang-Jie
XJ
Bo
‡School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, P. R. China.
Ya-Fei
YF
Li
†Institute of Functional Material Chemistry, Key Lab of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
Li-Ping
LP
Guo
†Institute of Functional Material Chemistry, Key Lab of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
Zhong-Min
ZM
Su
†Institute of Functional Material Chemistry, Key Lab of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
Yuan-Yuan
YY
Wang
†Institute of Functional Material Chemistry, Key Lab of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.|‡School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, P. R. China.
Ya-Qian
YQ
Lan
Hong-Cai
HC
Zhou