Control of nanometer-scale tunnel sizes of porous manganese oxide octahedral molecular sieve nanomaterials

Manganese oxide octahedral molecular sieves with increasing nanoscale tunnel sizes are systematically synthesized using hydrothermal treatment of Na-birnessite under increasing pH conditions. OMS-5 (2x4), OMS-6 (2x3), and OMS-7 (1x1; see Figure) tunnel structures have been synthesized at pH values of 13, 7.0, and 1.0, respectively.