“…After oxidation, due to the XRD peak for montmorillonite occurs at basal spacing greater than 11.3 Å, MnO 2 controls the basal spacing of the oxidized clay mineral system, the basal spacing increased to 12.2 Å. The approximate thickness of a montmorillonite sheet alone is 9.6 Å (Johnson et al 1988), hence the vertical thickness of formed MnO 2 particles in the clay interlayer is ~2.6 Å, which is great smaller than nano-MnO 2 synthesized from traditional methods (Murray, 1974), indicating higher surface area and more active reaction sites, hence exhibiting higher reactivity (Gu et al, 2010 andZhang et al, 2015).…”