931492.fig.003a
(a)
931492.fig.003b
(b)
931492.fig.003c
(c)
931492.fig.003d
(d)
Figure 3: Nitrogen adsorption-desorption isotherms of nanoporous monetite after calcination at (a) 200°C, (b) 400°C, (c) 470°C, and (d) 550°C.