Metal oxide-triazole hybrids as heterogeneous or reaction-induced self-separating catalysts

•Synthesis of the W analogue (2) of the hybrid solid [MoO3(1,2,4-triazole)0.5] (1).•Use of 2 as a heterogeneous catalyst for cyclooctene epoxidation with aq. H2O2.•Use of 1 as a self-separating catalyst with alcohol, olefin and sulfide substrates.•Insoluble 1 reacts with H2O2 to give a homogeneous oxoperoxo molecular catalyst.•Exhaustion of the oxidant induces spontaneous reassembly of the 2D structure of 1.