The crystal structure and oxygen reduction reaction of Ni(II)-complex templated borate-sulfate and borate.

Three nickel borate compounds, [Ni(1-MI)6]·[B(OH)3]4·SO4 (1-MI = 1-methylimidazole) (1), [Ni(H2O)3(1-MI)3]·[B5O6(OH)4]2 (2) and [Ni(DMA3)]·[B6O7(OH)6]·3.5H2O (DMA3 = N,N-dimethylethylenediamine) (3), have been synthesized. It is noteworthy that the structures of 1 and 2 can be adjusted by varying the ratio of amine. Compound 3 has shown an unexpected example of unique water clusters in its structure. The three frameworks exhibit different interlinkage modes, resulting in channels varying in their size and shape. These compounds have been characterized by FTIR, UV-vis and PXRD. In addition, 1, 2, and 3 exhibited different wide band gaps (4.4 eV for 1, 4.5 eV for 2 and 4.4 eV for 3), and ORR activities with a half-wave potential of 0.78 V for 1, 0.74 V for 2 and 0.79 V for 3.