Trace holmium assisting delaminated OMS-2 catalysts for total toluene oxidation at low temperature

•Ho species was firstly applied for the preparation of delaminated OMS-2 catalysts.•Using Ho3+ species to reconstruct active oxygen species on OMS-2 was firstly proposed.•Moderate oxygen circulation was firstly considered to be important in the catalysis process.•Toluene oxidation at T100% of 228 °C with high stability and durability was achieved.•Different roles of H2O in toluene oxidations over OMS-2 and x% Ho-OMS-2 were found.