. Result and discussions
Au/HAP precursors were prepared by DP method, drying at 95 °C (denoted as Au/HAP-95). After calcination at 350 °C, the catalysts were denoted as Au/HAP-95-Re. The real gold content of two series loading amounts Au/HAP-95-Re samples were determined by ICP-AES. The average measured gold contents were 0.93 and 2.8 wt.% respectively, which was basically the same as the target Au loadings (1.0 and 3.0 wt.%) for both series. As shown in Table 1, an ICP measurement showed the different loss of Au on three HAP supports in both desirable series. It was interesting to find no matter whether the nominal Au loading is 1.0 or 3.0 wt.%, the loss of Au in the three fresh samples increased in the following order: Au/HR-95 < Au/HA12–95 < Au/HA0–95. It indicated that the Au loadings of Au/HA0–95 was the lowest while that of Au/HR–95 was the highest.