Asap 2010 physisorption analyzer

BET surface areas of the samples were obtained from nitrogen adsorption isotherms acquired using an ASAP 2010 physisorption analyzer (Micromeritics Instrument Corp., Norcross, GA, USA). Before the measurement each sample was pre-treated at 200 °C in vacuum for 12 h.

Phase identification was performed by X-ray powder diffraction analysis using a Philips PW1830 diffractometer (Philips, Amsterdam, The Netherlands) using Bragg–Brentano geometry; Cu Kα; Ni filtered; 2θ range 20–80°; step 0.025°; sampling time 10 s. Brunauer–Emmett–Teller (BET) analysis was carried out using an ASAP 2010 physisorption analyzer (Micromeritics Instrument Corp., Norcross, GA, USA). Samples were pre-treated at 200 °C in vacuum, before analysis.
Microstructural characterization was performed with a high-resolution scanning electron microscope (SEM, TESCAN Mira 3 XMU, TESCAN, Brno, Czech Republic) operated at 25 kV. The composition microanalysis was determined by energy-dispersive spectroscopy (EDS, EDAX Inc., Mahwah, NJ, USA). The samples were previously coated with carbon using a Cressington coater HR 208. DRS spectra were acquired in the wavelength range of 300–800 nm by using a 145 Jasco V-750 spectrophotometer (Jasco Europe, Lecco, Italy) equipped with an integrating sphere (Jasco ISV-922, Jasco Europe, Lecco, Italy). Quartz 146 cuvettes (VWR International, Milano, Italy) with 1 mm optical path were used.