Acid site change resulted from

Acid site change resulted from Mn addition on Pd0.5Mn2 was studied by exposing Pd0.5 and Pd0.5Mn2 to NH3 with increasing temperatures. Fig. 10(a) shows the ammonia species adsorbed over Pd0.5 catalyst. Below 200 °C, the typical adsorbed NH3 (1377 cm−1) and asymmetric and symmetric bending vibrations of NH4+ species adsorbed on Br?nsted 2-Deoxy-D-glucose sites (1428, 1652, 3063, and 2882 cm−1) [34], [35] and [36] appeared. The weak peaks attributed to asymmetric bending vibration of NHx (x = 0–2) adsorbed on Lewis acid site (at 1600 cm−1) and adsorbed water (at 1630 cm−1) also appeared. As the temperature increased to 350 °C, the intensities of the bands at 1600 and 1652 cm−1 gradually decreased, accompanied by the appearance of four peaks at 1331, 1396, 1485 and 3129 cm−1, which was attributed to asymmetric and symmetric bending vibrations of NH4+ species adsorbed on Br?nsted acid sites [34] and [40]. It is clear that Br?nsted acid sites were predominant over Pd0.5 catalyst in the temperature range of 30–350 °C.