The amount of acidic sites on the surface was estimated using temperature programmed desorption of ammonia (NH3-TPD) by heating up to 600 °C with 10 K/min and on-line gas analysis by FTIR (MultiGas™ Analyzer, MKS instruments). For this NMS-873 purpose 400 mg of catalyst were fixed with glass wool in a tubular glass reactor. The reactor was heated up with a rate of 10 K/min and the catalyst was pretreated for 1 h at 500 °C in synthetic air (500 ml/min). After cooling down to room temperature, the gas was changed to pure nitrogen and the tubes were flushed to remove oxygen. After saturation with ammonia at 50–60 °C using 500 ml/min with a radiation composition of 1000 ppm NH3 in N2, the excess amount of NH3 was removed (flushing with N2 until steady minimum of NH3 in the exit gas). Quantitative nitrogen analysis was carried out using hot gas extraction method (LECO TC 600). The samples were heated in a graphite crucible under flowing helium and thermally decomposed. The amount of N2 gas was determined by a thermal conductivity detector. Each measurement was repeated twice and a standard deviation was calculated.