In situ growth of polyoxometalate-based metal-organic framework nanoflower arrays for efficient hydrogen evolution

• Published in: 中国化学快报（英文版） Vol. 34; no. 4; pp. 547 - 550
• Main Authors: Lei Wang, A-Ni Wang, Zhen-Zhen Xue, Yan-Ru Wang, Song-De Han, Guo-Ming Wang
• Format: Journal Article
• Language: English
• Published: College of Chemistry and Chemical Engineering,Qingdao University,Qingdao 266071,China 2023
• Subjects: Nanoflower arrays; Hydrogen evolution; Polyoxometalate; Metal-organic framework; DFT calculations
• ISSN: 1001-8417; 1878-5964

The conversion of traditional polymolybdate-based metal-organic frameworks(POMOFs)crystals to well-aligned nanoarrays are highly attractive for electrocatalytic hydrogen evolution but remains signifi-cant challenge.Herein,we demonstrated that the POMOFs nanoarrays as self-supported electrode to-ward hydrogen evolution with high catalytic activity and stability.Single-crystal X-ray analysis reveal the{ε-PMoⅤ8MoⅥ4O37Zn4}(Zn-ε-Keggin)serve as secondary building blocks and directly connected to BPB organic ligands(BPB=1,4-bis(pyrid-4-yl)benzene)to obtain novel[e-PMoⅤ8MoⅥ4O37(OH)3Zn4][BPB]3(named as ZnMo-POMOF).Particularly,ZnMo-POMOF nanoflower arrays grown in-situ on a Ni foam sub-strate exhibiting excellent electrocatalytic hydrogen evolution performance of 180 mV at a current den-sity of 10 mA/cm2 with the Tafel slope of 66 mV/dec,thus among one of the best POMOF-based electro-catalysts reported so far.DFT calculations reveal that the bridging oxygen active sites(Oa)significantly optimizes Gibbs free energy of H* adsorption for Zn-ε-Keggin polymolybdate units(-0.07 eV),thereby increasing the intrinsic activity of the ZnMo-POMOF.