Structure, stability and photocatalytic H2 production by Cr-, Mn-, Fe-, Co-, and Ni-substituted decaniobate clusters

Abstract

Here we report synthesis and characterization of early transition-metal(TM)-substituted decaniobates as a continuation of our previous report of tetramethylammonium (TMA) salt of FeNb₉ and NiNb₉: TMA₆[H₂Cr^IIINb₉O₂₈]·14H₂O (1, CrNb₉), TMA₈[Mn^IIINb₉O₂₈]·29H₂O (2, MnNb₉) and TMA₇[H₂Co^IINb₉O₂₈]·25H₂O (3, CoNb₉). Among the TM-substituted decaniobates, CoNb₉ or NiNb₉ exhibit a higher photocatalytic H₂ evolution activity in methanol–water mixtures than others.