Electro-catalytic Iodoplumbate Incorporating Two Types of Polymeric Anions

The development of the most promising electro-catalysts for the high-performance hydrogen evolution reaction (HER) in neutral media is exceedingly desirable. Here, the convenient hydrothermal reaction of PbI₂, 3-pyrazinyl-1,2,4-triazole (3-pt), KI, and methanol in HI aqueous solution acquired an organic hybrid iodoplumbate [mtp][Pb₂I₅][PbI₃]·0.5H₂O (denoted as PbI-1, mtp²⁺ = 3-(1,4-dimethyl-1H-1,2,4-triazol-4-ium-3-yl)-1-methylpyrazin-1-ium), which not only provided an infrequent in situ organic mtp²⁺ cation that originated from the hydrothermal N-methylation reaction of 3-pt in acidic KI solution but also offered the rare example of organic hybrid iodoplumbate incorporating both one-dimensional (1-D) [PbI₃^-]_n and two-dimensional (2-D) [Pb₂I₅^-]_n polymeric anions with one configuration of the mtp²⁺ cation. PbI-1 was applied for the construction of a Ni nanoparticle decorating the PbI-1 electrode (Ni/PbI-1/NF) via successive coating and electrodeposition onto the porous Ni foam (NF) support. The fabricated Ni/PbI-1/NF electrode that served as the cathodic catalyst showed excellent HER electro-catalytic activity.