To extract the template, the particles were redispersed in 3 mL of ethanolic ammonium nitrate solution (1 g/50 mL) and heated to a temperature setpoint of 72 °C for the heating blocks (internal temperature ca. 57 °C), under stirring at 300 rpm for 1.5 h. Following that, they were washed twice with ethanol (5 mL) as described above.