Table 1. Physicochemical Properties and Catalytic Activity of m-ZrP Catalysts Calcined at Different Temperatures.
| acid
sites (mmol/g) |
P/Zr
ratio |
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| catalyst | surface area [m2/g] | pore volume [cm3/g] | av pore diameter [nm] | totala | Brönsted (B)b | Lewis (L)b | B/L ratio | total basic sites (mmol/g)a | XPSc | EDSd | XGlu. (%)e | YHMF (%) | YFru. (%)f |
| m-ZrP-80 | 322.3 | 0.61 | 9.1 | 0.92 | 90.0 | 26.1 | 4.0 | ||||||
| m-ZrP-500 | 213.0 | 0.49 | 9.9 | 1.25 | 0.032 | 0.116 | 0.27 | 0.35 | 0.95 | 1.18 | 84.2 | 40.3 | 4.5 |
| m-ZrP-600 | 197.0 | 0.48 | 10.9 | 1.06 | 0.034 (0.079)g | 0.115 (0.03)g | 0.29 (2.6)g | 0.29 | 0.96 (1.1)g | 1.15 | 81.5 | 43.2 | 5.0 |
| m-ZrP-700 | 143.8 | 0.43 | 11.8 | 0.93 | 0.025 | 0.111 | 0.22 | 0.24 | 0.92 | 1.13 | 78.7 | 39.6 | 5.4 |
| m-ZrP-800 | 114.5 | 0.37 | 13.7 | 0.44 | 0.008 | 0.063 | 0.13 | 0.13 | 0.91 | 1.22 | 70.0 | 32.7 | 7.2 |
a
Total acid and basic sites were calculated from NH3-TPD and CO2-TPD, respectively.
b
Brönsted and Lewis acid sites at 150 °C were calculated by a molar extinction coefficient method [33].
c
Surface P/Zr ratios were calculated by using the area of P2p divided by that of Zr3d5/2.
d
P/Zr ratio was calculated from SEM-EDS analysis by using the values of atomic% on the P K/Zr L.
e
Reaction conditions: glucose = 0.2 g; H2O = 40 g; catalyst = 0.1 g; temperature = 155 °C; reaction duration = 6 h.
f
Levulinic, formic, and lactic acids were also observed.
g
The values were for the used catalyst after 3 runs.