All chemical reagents used in this experiment were of analytical
grade and used without further purification. A typical synthesis
procedure of the porous ZnSnO3 cubes was as follows: 0.158 g of
tin tetrachloride pentahydrate (SnCl4·5H2O) and 0.07 g of sodium
hydroxide (NaOH) were dissolved in 20 ml of deionized water
under vigorous stirring at room temperature, followed by addition
of 3 M NaOH aqueous solution to adjust the pH value of the
mixed solution equal to 12.0, 12.4 and 12.6. Then, 0.1295 g zinc sulfate
heptahydrate (ZnSO4·7H2O) was added into the mixed solution
at the temperature of 60 ◦C under magnetic stirring until uniform
suspension formed. After continuous stirring for 1 min, the mixed
solution was aged at 60 ◦C for 12 h. Then the solution was allowed to
cool down to room temperature. The white precipitate was filtered,
washed with distilled water and alcohol for 6 times to remove the
ions possibly remaining in the final products, and finally dried in air
at 60 ◦C for more than 10 h. The as-obtained precipitate was then
calcined at 580 ◦C in a muffle furnace for 2 h in air to get porous
ZnSnO3 cubes.