Acidic zirconium hydroxide

Abstract

This invention relates to azirconium hydroxideor zirconium oxide comprising, on an oxide basis, up to 30 wt % of a dopant comprising one or more of silicon, sulphate, phosphate, tungsten, niobium, aluminium, molybdenum, titanium or tin, and having acid sites, wherein the majority of the acid sites are Lewis acid sites. In addition, the invention relates to a catalyst, catalyst support or precursor, binder, functional binder, coating or sorbent comprising the zirconium hydroxide or zirconium oxide. The invention also relates to a process for preparing zirconium hydroxide, the process comprising the steps of:(a) dissolving a zirconium salt in an aqueous acid, (b) addingone or more complexing agents to the resulting solution or sol, the one or more complexing agents being an organic compound comprising at least one of the following functional groups: an amine, an organosulphate, a sulphonate, a hydroxyl, an ether or a carboxylic acid group, (c) heating the solution or sol formed in step (b), (d) adding a sulphating agent, and (e) adding a base to form a zirconium hydroxide, and (f) optionally adding a dopant.

Claims

1. A zirconium hydroxide comprising, on an oxide basis, less than 0.1 wt % of a dopant comprising one or more of silicon, sulphate, phosphate, tungsten, niobium, aluminium, molybdenum, titanium or tin, and having acid sites, wherein the zirconium hydroxide is porous and, in relation to the pores having a pore diameter of up to 155 nm, at least 70% of the pore volume provided by pores having a pore diameter of 3.5-155 nm as measured using the BJH method.

2. The zirconium hydroxide as claimed in claim 1, wherein, in relation to the pores having a pore diameter of up to 155 nm, at least 75% of its pore volume provided by pores having a pore diameter of 3.5-155 nm as measured using the BJH method.

3. A catalyst, catalyst support or precursor, binder, functional binder, coating or sorbent comprising the zirconium hydroxide as claimed in claim 1 or an oxide obtained therefrom.

4. The zirconium hydroxide as claimed in claim 1 wherein the majority of the acid sites are Lewis acid sites.

5. A zirconium oxide comprising at least 99 w t% zirconium oxide including hafnium oxide or hydroxide impurity and, on an oxide basis, less than 0.1 wt % of a dopant comprising one or more of silicon, sulphate, phosphate, tungsten, niobium, aluminium, molybdenum, titanium, tin or a rare earth metal, and having acid sites, having a total pore volume as measured by N.sub.2 physisorption of at least 0.10 cm.sup.3/g after calcination at 900° C. in an air atmosphere for 2 hours.

6. The zirconium oxide of claim 5 having an acid loading of at least 100 μmol/g as measured by propylamine TPD after calcination at 600° C. in an air atmosphere for 2 hours.

7. A zirconium oxide comprising at least 99 wt % zirconium oxide including hafnium oxide or hydroxide impurity and, on an oxide basis, less than 0.1 wt % of a dopant comprising one or more of silicon, sulphate, phosphate, tungsten, niobium, aluminium, molybdenum, titanium, tin or a rare earth metal, and having acid sites, having at least 80 wt % of monoclinic phase as measured by XRD after calcination at 450° C. in an air atmosphere for 2 hours, having a CO.sub.2 uptake of at least 14 μmol/g at 400-600° C. as measured by TPD after calcination at 600° C. for 2 hours.

8. A doped zirconium hydroxide comprising, on an oxide basis, 0.1-30 wt % of a sulphate, having acid sites, having a surface area of at least 375m.sup.2/g and having a total pore volume as measured by N.sub.2 physisorption of at least 0.60 cm.sup.3/g.

9. The doped zirconium hydroxide as claimed in claim 8 comprising, on an oxide basis, 1-12 wt % of a sulphate.

10. The doped zirconium hydroxide as in claim 8 comprising one or more of an additional dopant selected from a rare earth hydroxide or oxide, yttrium hydroxide or oxide, or another transition metal hydroxide or oxide, such that the total zirconium content of the zirconium hydroxide is not less than 50 wt % on an oxide basis.

11. The doped zirconium hydroxide as claimed in claim 8 wherein the majority of the acid sites are Lewis acid sites.

12. The doped zirconium hydroxide of claim 8 having an uncalcined mean pore diameter of at least 5.5 nm and a mean pore diameter of not more than 40.0 nm after calcination at 900° C. in an air atmosphere for 2 hours.

13. A catalyst, catalyst support or precursor, binder, functional binder, coating or sorbent comprising the doped zirconium hydroxide as claimed in claim 8 or an oxide obtained therefrom.

14. A doped zirconium hydroxide comprising, on an oxide basis, 0.1-30 wt % of a tungsten hydroxide or oxide, having acid sites and having a surface area of at least 400 m.sup.2/g.

15. The doped zirconium hydroxide as claimed in claim 14 having a total pore volume as measured by N.sub.2 physisorption of at least 0.7 cm.sup.3/g.

16. The doped zirconium hydroxide as claimed in claim 14 comprising, on an oxide basis, 12-20 wt % of a tungsten hydroxide or oxide.

17. The doped zirconium hydroxide as in claim 14 comprising one or more of an additional dopant selected from a rare earth hydroxide or oxide, yttrium hydroxide or oxide, or another transition metal hydroxide or oxide, such that the total zirconium content of the zirconium hydroxide is not less than 50 wt % on an oxide basis.

18. A catalyst, catalyst support or precursor, binder, functional binder, coating or sorbent comprising the doped zirconium hydroxide as claimed in claim 14 or an oxide obtained therefrom.

19. A zirconium oxide comprising at least 99wt% zirconium oxide including hafnium oxide or hydroxide impurity and, on an oxide basis, less than 0.1 wt % of a dopant comprising one or more of silicon, sulphate, phosphate, tungsten, niobium, aluminium, molybdenum, titanium, tin or a rare earth metal, and having acid sites, having a CO.sub.2 uptake of at least 14 μmol/g at 400-600° C. as measured by TPD after calcination at 600° C. for 2 hours.

Description

(1) This invention will be further described by reference to the following Figures which are not intended to limit the scope of the invention claimed, in which:

(2) FIG. 1 shows nitrogen adsorption isotherms for the acidic zirconium hydroxides of Comparative Example 2 and Preparative Example 2,

(3) FIG. 2a shows NH.sub.3-TPD profiles for the acidic zirconium oxides of Comparative Examples 1 and 2, and Preparative Examples 1 and 2, when calcined at 600° C/2 hours,

(4) FIG. 2b shows CO.sub.2-TPD profiles for the acidic zirconium oxides of Comparative Examples 1 and 2, and Preparative Examples 1 and 2, when calcined at 600° C/2 hours,

(5) FIG. 3 shows XRD data for the acid zirconium hydroxides of Comparative

(6) Examples 1 and 2, and Preparative Examples 1-4, when dried at 110° C.,

(7) FIG. 4 shows XRD data for the acid zirconium oxides of Comparative Examples 1 and 2, and Preparative Examples 1 and 2, when calcined at 450° C/2 hours,

(8) FIG. 5 shows TPD-MS data showing the intensity at 41 amu as a function of temperature for a) the fresh materials of Comparative Examples 1, 2 and 5, and Preparative Examples 1 and 2; and b) the doped materials after calcination of Comparative Examples 4 and 8 and Preparative Examples 5, 6 and 7.

(9) FIG. 6 shows DRIFT spectra of pyridine-saturated acidic zirconia samples recorded at 100° C. in vacuo, for a) fresh and calcined samples of zirconium hydroxide materials from Preparative Examples 1 and 2 and Comparative Examples 1, 2 and 5; and b) doped zirconium oxides after calcination for Preparative Examples 5-7 and Comparative Examples 4, 5 and 8.

(10) FIG. 7 shows NH.sub.3-TPD profiles for the tungsten stabilised zirconium oxides of Comparative Examples 3 and 4, and Preparative Examples 5 and 8, when calcined at 700° C/2 hours,

(11) FIG. 8 shows XRD data for the tungsten stabilised zirconium oxides of Comparative Examples 3 and 4, and Preparative Examples 5 and 8, when calcined at 700° C/2 hours,

(12) FIG. 9 shows NH.sub.3-TPD profiles for the silica stabilised zirconium oxides of Comparative Examples 7 and 8, and Preparative Examples 7 and 10, when calcined at 850° C/2 hours,

(13) FIG. 10 shows XRD data for the silica stabilised zirconium oxides of Comparative Examples 7 and 8, and Preparative Examples 7 and 10, when calcined at 850° C/2 hours,

(14) FIG. 11 shows NH.sub.3-TPD profiles for the sulphate stabilised zirconium oxides of Comparative Examples 5 and 6, and Preparative Examples 6, 9, 11 and 12, when calcined at 600° C/2 hours,

(15) FIG. 12 shows XRD data for the sulphate stabilised zirconium oxides of Comparative Examples 5 and 6, and Preparative Examples 6 and 9, when calcined at 600° C/2 hours, and

(16) FIG. 13 shows TG-DTA profiles for the acidic zirconium hydroxides of Comparative Examples 1 and 2, and Preparative Examples 1 and 2, when dried at 110° C.

(17) The invention will now be described by way of example with reference to the following Examples.

(18) Comparative Example 1

(19) A slurry of zirconium basic sulphate in deionised water was prepared, containing the equivalent of 200 g ZrO.sub.2. 28 wt % aqueous sodium hydroxide was added dropwise until the solution reached pH 13. The resulting precipitated zirconium hydroxide was then filtered and washed. The wet cake was reslurried in deionised water to give 2000 g of slurry and this was hydrothermally treated at 1 barg for 1 hour and then dried at 110° C.

(20) Comparative Example 2

(21) A sample was prepared according to the method described in patent EP 1 984 301 B1. That is, 394.84 g of 20 wt % aqueous sulphuric acid, 18.28 g deionised water and 966.18 g zirconium oxychloride (20.7 wt % ZrO.sub.2) were mixed and cooled to −2° C. 10 wt % aqueous sodium hydroxide was then added dropwise until the solution reached pH 8. 28 wt % aqueous sodium hydroxide was then added until the solution reached pH 13. The resulting precipitated zirconium hydroxide was then filtered and washed. The wet cake was reslurried in deionised water and hydrothermally treated at 1 barg for 1 hour and then dried at 110° C.

(22) Comparative Example 3

(23) A sample was prepared according to Comparative Example 1, except that prior to the hydrothermal treatment to the 2000 g slurry an 8 wt % aqueous solution of sodium tungstate was added to target 15.8 wt % WO.sub.3 on an oxide basis in the resulting zirconium hydroxide. This slurry was adjusted to pH 6.7 with nitric acid, and the resulting slurry was then filtered and washed with deionised water.

(24) Comparative Example 4

(25) A sample was prepared according to Comparative Example 2, except that prior to hydrothermal treatment 328 g of 8 wt % aqueous solution of sodium tungstate was added to target 15.8 wt % WO.sub.3 on an oxide basis in the resulting zirconium hydroxide. This slurry was then adjusted to pH 6.7 with nitric acid, and the resulting slurry was then filtered and washed with deionised water.

(26) Comparative Example 5

(27) A sample was prepared according to Comparative Example 1, except that prior to hydrothermal treatment 390 g of the wet cake was slurried in deionised water and 127.1 g of 20 wt % aqueous sulphuric acid was added to target 10 wt % SO.sub.3 on an oxide basis in the resulting zirconium hydroxide.

(28) Comparative Example 6

(29) A sample was prepared according to Comparative Example 2 except that prior to hydrothermal treatment 977 g of the wet cake was slurried in deionised water and 180.9 g of 20 wt % aqueous sulphuric acid was added to target 10% SO.sub.3 on an oxide basis in the resulting zirconium hydroxide.

(30) Comparative Example 7

(31) 24.17 g of 30 wt % colloidal silica solution (Ludox AS-30) was added to 1761.22 g of the slurry prepared according to Comparative Example 1 prior to hydrothermal treatment. Aqueous 28 wt % sodium hydroxide was added dropwise until the solution reached pH 11. The resulting precipitated mixed zirconium hydroxide was then filtered and washed. The wet cake was reslurried and hydrothermally treated at 1 barg for 5 hour and then dried at 110° C.

(32) Comparative Example 8

(33) A sample was prepared according to Comparative Example 2, except that prior to hydrothermal treatment 900 g of the washed wet cake was slurried in deionised water and 22.6 g of 30 wt % colloidal silica solution (Ludox AS-30) was added.

(34) Preparative Example 1

(35) 537.63 g of zirconium basic carbonate (containing 37.2% ZrO.sub.2) was dissolved in 490.81 g of dilute nitric acid (to target NO.sub.3/Zr ratio of 1.2). This solution was then heated to 60° C. 2.759 g of mandelic acid was added to the solution, along with 390.8 g of water. This solution was then heated again to 94° C. for 2 hours.

(36) The obtained solution was mixed with 465.31 g of de-ionised water and 394.84 g of 20 wt % aqueous sulphuric acid was then added to the mixture. The pH of the obtained solution was then adjusted to pH 13.0 with a dilute sodium hydroxide solution. The resulting slurry was then filtered and washed. The wet cake was hydrothermally treated at 1 barg for 1 hour and then dried at 110° C.

(37) Preparative Example 2

(38) 537.63 of zirconium basic carbonate (containing 37.2% ZrO.sub.2) was dissolved in 490.81 g of dilute nitric acid (to target NO.sub.3/Zr ratio of 1.45). This solution was then heated. 2.759 g of mandelic acid was added to the solution, along with 390.8 g of water. This solution was then heated to 94° C.

(39) The obtained solution was mixed with 564.01 g of de-ionised water and 394.84 of 20 wt % aqueous sulphuric acid was added to the mixture. The pH of the obtained solution was then adjusted to pH 13.0 with a dilute sodium hydroxide solution. The resulting slurry was then filtered and washed. The wet cake was then hydrothermally treated at 1 barg for 1 hour and then dried at 110° C.

(40) Preparative Example 3

(41) A sample was prepared according to the procedures described in Preparative Example 1, but using a lower amount of mandelic acid-13 1.226 g.

(42) Preparative Example 4

(43) A sample was prepared according to the procedures described in Preparative Example 2, but using a lower amount of mandelic acid-13 1.226 g.

(44) Preparative Example 5

(45) A sample was prepared according to Preparative Example 1 except that prior to hydrothermal treatment 1891.2 g of slurry was mixed with 258 g of aqueous sodium tungstate to target 15.8 wt % WO.sub.3 on an oxide basis in the resulting zirconium hydroxide. The slurry was then adjusted to pH 6.7 with a dilute nitric acid the resulting slurry was then filtered and washed with deionised water.

(46) Preparative Example 6

(47) A sample was prepared according to the procedure described in the Preparative Example 1, except that dilute sulphuric acid was added after the hydrothermal treatment, but prior to drying. The sample was then dried at 110° C. to give a target SO.sub.3 content of 10 wt % on an oxide basis.

(48) Preparative Example 7

(49) A sample of zirconium hydroxide wet cake was prepared according to Preparative Example 1. 12.46 g of 30 wt % colloidal silica solution (Ludox AS-30) was added prior to hydrothermal treatment. The sample was then dried at 110° C. to give a target SiO.sub.2 content of 3.5% on an oxide basis.

(50) Preparative Example 8

(51) A sample was prepared according to the procedure described in Preparative Example 5, but using a different ratio of initial reagents such that NO.sub.3/Zr=1.45.

(52) Preparative Example 9

(53) A sample was prepared according to the procedure described in Preparative Example 6, but using a different ratio of initial reagents such that NO.sub.3/Zr=1.45.

(54) Preparative Example 10

(55) A sample was prepared according to the procedure described in Preparative Example 7, but using a different ratio of initial reagents such that NO.sub.3/Zr=1.45.

(56) Preparative Example 11

(57) A sample was prepared according to the procedure described in Preparative Example 1, except that prior to hydrothermal treatment 1812.7 g of the washed slurry was adjusted to pH 6.5 with a dilute sulphuric acid. This gave a resulting SO.sub.3 content of 6.5 wt % on oxide basis.

(58) Preparative Example 12

(59) 28 g of a sample prepared according to the procedure described in the Preparative Example 1 was mixed with dilute sulphuric acid. This was then further dried at 110° C. for 3 hours to give a target SO.sub.3 content of 10 wt % on an oxide basis.

(60) Materials and Methods

(61) The samples prepared in the various examples were analysed as prepared, but samples were also calcined at various temperatures under static air for 2 hours for analysis purposes. The level of Na was confirmed by liquid ion-chromatography (Methrom IC 761) to be less than 200 ppm in all cases.

(62) SO.sub.3% content was measured by Eltra Carbon Sulfur Analyzer CS800.

(63) Porosity Characteristics

(64) Surface area, pore diameter and total pore volume measurements were made by liquid nitrogen adsorption at −196° C. in a Micromeritics TriStar 3020 analyser. Samples were degassed at 90° C. under vacuum for 30 minutes before analysis. Surface area: Surface area was measured using BET multipoint determination. Total Pore Volume: Pore volume measurement was taken during desorption at p/p°=0.9814. Pore size distribution and average pore diameter: Determination of pore size distribution was done using BJH method (desorption branch) as “Average width vs Incremental Pore Volume” in range 1.7 to 300 nm. The portion of meso+macro-or micropores in % was estimated based on BJH pore size distribution plots.

(65) Particle Size

(66) Particle size distribution was measured via a light scattering method using a Microtrac X100 equipped with an ASVR unit. A standard was run prior to the analysis to confirm the validity of the results. The ASVR unit is automatically filled to a pre-set level with 0.05% Nopcosant K dispersant, approximately 0.100 g of the dry sample was added and then treated for 60 seconds with an internal ultrasonic probe set at 40 Ws. Pre-circulation time was 30 seconds with a run time set at 50 seconds. The sample was measured 3 times (via Mie scattering theory) and an average result was obtained and reported.

(67) Thermogravimetric Analysis (TGA)

(68) The TG-DTA (thermogravimetric analysis-differential thermal analysis) experiments (measurement of samples weight loss (TG) and the exothermic DTA signal (e.g. crystallisation temperature)) were carried out using a Setsys-EVO-DTA Instrument. 50 mg of sample was placed into 100μI Pt crucible and heated in the temperature range 20-1000° C., with the heating rate 10° C./min in the atmosphere of 20% O.sub.2/He atmosphere (flowing rate—20 ml/min). Experiment run and data analysis were performed using Data Acquisition Setsys-1750 CS Evol software.

(69) X-Ray Diffraction (XRD)

(70) The powder XRD crystallographic phase analysis of zirconia-based materials was carried out on a Bruker D8 Advance X-ray diffusion system (Diffrac. EVA software, Bragg-Brentano geometry, LYNXEYE detector, Cu radiation (λ=1.5418 Å) in the 2θ range from 10° to 70°, 0.015° per step, time per step 0.2 s, 0.02 mm Ni filter, applied power 40 mV/40 mA). Quantitative phase analysis was carried out for diffraction patterns of zirconia samples using TOPAS software (version 4.2). Reference materials were used for peak identification (tetragonal zirconia/monoclinic zirconia loaded by Bruker). Data evaluation included peak search, manual/automatic background subtraction and data smoothing. The crystallite size determination was done via the Scherrer method, K=0.9.

(71) Loss Over Ignition (LOI)

(72) Loss over ignition (LOI) was determined using a Vecsrar unit under constant flow of an air atmosphere. Samples (2 g) were heated at a rate of 3° C./min to the desired temperature (generally 1000° C., but for tungsten doped samples this would need to be 800° C.) and held at this temperature for at least 60 minutes and until no change in weight over time is observed.

(73) Acidity Measurements (for Pre-Calcined Samples)

(74) NH.sub.3/CO.sub.2—Temperature Programmed Desorption (TPD)—Measurements were taken using AMI200 instrument. 0.2 g of the sample was heated from ambient up to the maximum temperature of the experiment (undoped samples=600° C.; sulphated=544° C.; tungstated=700° C.; silica doped=800° C.) in flowing argon (20 ml/min) at a ramp rate of 20° C./min. The sample was then dwelled at this temperature for 45 mins before being cooled back down to 100° C. 5% NH.sub.3/He (or 5% CO.sub.2/He) is then flowed over the sample at 100° C. for 30 mins (20 ml/min). The sample was then exposed to flowing helium at 100° C. for 1 hr to remove any non-adsorbed NH.sub.3/or CO.sub.2 from the system and to allow a steady baseline on the Thermal Conductivity Detector (TCD). A TPD experiment was carried out from 100° C. to the maximum temperature of the experiment at 10° C./min in flowing helium (20 ml/min), with a 2 hr dwell time. The NH.sub.3 or CO.sub.2 uptake is monitored based on the TCD response. Quantitative analysis was performed based on pulse calibration, whereby a series of pulses of known volume (527 microlitres) of 5% NH.sub.3/He or 5% CO.sub.2/He were injected into a helium carrier stream and the TCD response was recorded.

(75) Propylamine adsorption/Thermogravimetric Analysis/Mass Spectrometry (TGA-MS)—This was performed by exposing the samples to propylamine overnight. Excess physisorbed propylamine was removed in vacuo at 30° C. prior to temperature programmed desorption on a Mettler Toledo TGA/DSC 2 STARe System equipped with a Pfeiffer Vacuum ThermoStar™ GSD 301 T3 mass spectrometer. The number of acid sites was then calculated based on the mass loss in the temperature range of 200-800 ° C., taking into account the mass change of the clean samples.

(76) Ex-situ pyridine adsorption—This was performed by impregnation of samples with neat pyridine. Excess physisorbed pyridine was removed in a vacuum oven overnight at 30° C. The samples were then diluted (10 wt % in KBr) prior to sample loading in the environmental cell, with Diffuse Reflectance Infra-red Fourier Transform (DRIFT) spectra. Samples were subjected to additional drying under vacuum at 100° C. for 15 min prior to measurements to remove any moisture physisorbed during air exposure.

(77) Results

(78) The results of the testing are set out in Tables 1-7 below. The tables show the following: Table 1—various properties of the acidic zirconium hydroxides Table 2—surface properties of the acidic zirconium hydroxides when calcined at 600° C. for 2 hours as measured by NH.sub.3/CO.sub.2-TPD Table 3—XRD phase ratio analysis for samples calcined at 450° C. for 2 hours Table 4—surface properties of the acidic zirconium hydroxides, fresh and calcined at 600° C. for 2 hours, when measured by propylamine-TPD Table 5—surface properties of tungsten stabilised zirconium hydroxides when calcined at 700° C. for 2 hours as measured by NH.sub.3-TPD Table 6—surface properties of silica stabilised zirconium hydroxides when calcined at 850° C. for 2 hours as measured by NH.sub.3-TPD Table 7—surface properties of sulphate stabilised zirconium hydroxides when calcined at 600° C. for 2 hours as measured by NH.sub.3-TPD.

(79) The process route of the invention shows improved thermostability for undoped zirconium hydroxides and corresponding oxides after calcination at high temperature (900° C.), retaining good porosity with a significant portion of mesopores. The calcined undoped zirconium hydroxide materials show more influence by the monoclinic phase, which can be important for particular uses of the materials. The porosity of the doped hydroxides has also been improved in comparison with the tested benchmarks. There is a general significant increase in acidity (strength of acid sites) has been noticed for both types of materials (undoped/doped).

(80) With regards to acidity: concentration of acid sites, their strength and type have been confirmed by propylamine adsorption/TGA-MS (FIG. 5) and ex-situ pyridine adsorption (DFTIR) (FIG. 6). Data (peak area) presented in FIG. 5a shows significantly higher acid loading for the undoped zirconium hydroxides samples compared to the commercial sulphated zirconia—a well-known superacid. Also, strong acidity for all samples has been proven by the temperature of propene release (41 amu). It has been found that acid strength increases from the sample 1 and 2 (comparative, peak centred around 368° C.,) to inventive samples 3 (352° C.) and 4 (346° C.) respectively, and exceed the value for the standard benchmark (423° C.). The obtained data demonstrates that the materials of the invention are strongly acidic even without the addition of stabilising dopants, which makes them unique among other well-known zirconias.

(81) DRIFT spectra of pyridine impregnated samples (FIG. 6) prove the Lewis acid nature of the tested samples due to the presence of an absorbance peak at 1446 and 1604 cm.sup.−1—the main characteristics of Lewis acid sites.

(82) Doped materials (sulphate, tungsten or silica etc) showed similar trends in terms of acidity and porosity characteristics. Significant improvement has been noticed (porosity increased by 30%, acidity (measured by NH.sub.3-TPD) by 25% (Tables 5, 6 and 7) compared to standard commercial grades, which has a positive impact on catalytic activity and makes them competitive on the heterogeneous catalysis market.

(83) TABLE-US-00001 TABLE 1 Particle size, laser light scattering Surface Total pore Pore Low ultrasonic/high ultrasonic area SA, volume TPV, diameter d10 d50 d90 LOI % T cryst, Reference (m.sup.2/g) (ml/g) d, nm (microns) (microns) (microns) @1000° C. ° C. Preparative 490 0.85 6.9 6.1/0.6 42/1.1 106/10  28.5 458 Example 3 Preparative 520 0.94 7.2 6.7/1.9 47/10  110/48  37.0 457 Example 1 Preparative 540 0.99 7.3 6.5/1.0 44/3.8 94/17 29.9 456 Example 4 Preparative 540 0.99 7.3 6.8/0.6 40/1.0 87/10 37.0 460 Example 2 Comparative 520 0.73 5.6 4.5/1.5 28/5.6 70/14 27.5 441 Example 2 Comparative 570 0.39 2.7 6.4/1.5 43/6.7 95/11 21.4 451 Example 1 SA TPV d, nm ASA TPV, d, nm 600° C./ 600° C./ 600° C./ Meso + 900° C./ 900° C./ 900° C./ 2 hours 2 hours 2 hours Micr Macro 2 hours 2 hours 2 hours Reference (m.sup.2/g) (ml/g) (nm) % (m.sup.2/g) (ml/g) (nm) Preparative 55 0.37 26.6 21 79 20 0.2 40.0 Example 3 Preparative 55 0.42 30.4 20 80 19 0.19 40.0 Example 1 Preparative 55 0.36 27.4 22 78 17 0.11 27.1 Example 4 Preparative 60 0.36 24.1 19 81 20 0.13 26.7 Example 2 Comparative 45 0.25 22.0 34 66 13 0.08 24.4 Example 2 Comparative 41 0.31 13.1 74 26 9.6 0.05 22.0 Example 1

(84) TABLE-US-00002 TABLE 2 Total Total T.sub.max Total Total CO.sub.2, T.sub.max NH.sub.3, NH.sub.3, NH.sub.3 CO.sub.2, CO.sub.2, , μmol/g at CO.sub.2, Reference μmol/g μmol/m.sup.2 (° C.) μmol/g μmol/m.sup.2 T = 400-600 C. (° C.) Preparative 217.8 3.96 337 126.0 2.29 16.8 172 Example 1 Preparative 290.7 4.84 318 163.3 2.72 18.6 175 Example 2 Comparative 215.3 4.78 324 124.5 2.77 9.2 176 Example 2 Comparative 200.1 4.88 315 104.8 2.56 12.6 174 Example 1

(85) TABLE-US-00003 TABLE 3 Conditions % monoclinic % tetragonal Comparative Example 2 74.82 25.18 Comparative Example 1 77.45 22.55 Preparative Example 1 85.61 14.39 Preparative Example 2 83.68 16.32

(86) TABLE-US-00004 TABLE 4 Sample (key for Total propylamine FIGS. 5 uptake (acid Reference and 6) Dopant loading)/μmol g.sup.−1 T.sub.max/° C. Comparative 1 None 1210 368 Example 2 Comparative 2 None 1270 368 Example 1 Preparative 3 None 1340 352 Example 1 Preparative 4 None 1320 346 Example 2 Comparative 5 None 90 336 Example 2 - calcined Comparative 6 None 80 336 Example 1 - calcined Preparative 8 None 120 336 Example 2 calcined Comparative SZ SO.sub.3 750 423 Example 5 - calcined Preparative 20 WO.sub.3 300 390 Example 5 calcined Comparative 22 WO.sub.3 250 390 Example 4 calcined Preparative 10 SO.sub.3 940 415 example 6 calcined Preparative 16 SiO.sub.2 180 433 Example 7 calcined Comparative 18 SiO.sub.2 160 427 example 8 Calcined

(87) TABLE-US-00005 TABLE 5 Total Total T.sub.max Total SA TPV d, nm NH.sub.3, NH.sub.3, NH.sub.3, wt % Surface pore Pore Particle size, laser light scattering 700° 700° 700° 700° 70° 700° WO.sub.3 area, volume, diam- d10 d50 d90 C./2 C./2 C./2 C./2 C./2 C./2 (on SA TPV eter, (mi- (mi- (mi- hours hours hours hours, hours, hours Reference oxide) (m.sup.2/g) (ml/g) d nm crons) crons) crons) (m.sup.2/g) (ml/g) (nm) μmol/g μmol/m.sup.2 (° C.) Preparative 16.1 520 0.97 7.45 6.5 46 97 116 0.44 15.4 509 4.39 303 Example 5 Preparative 16.1 580 0.91 6.3 5.0 44 93 108 0.34 12.6 503 4.65 305 Example 8 Comparative 15.7 360 0.57 6.3 2.0 37 215 96 0.32 13.3 408 4.25 309 Example 4 Comparative 15.5 370 0.4 4.2 1.4 5.6 9.6 117 0.26 8.8 390 3.33 301 Example 3

(88) TABLE-US-00006 TABLE 6 Total Total T.sub.max Total SA TPV d, nm NH.sub.3, NH.sub.3, NH.sub.3, wt % Surface pore Pore Particle size, laser light scattering 850° 850° 850° 850° 850° 850° SiO.sub.2 area, volume, diam- d10 d50 d90 C./2 C./2 C./2 C./2 C./2 C./2 (on SA TPV eter, (mi- (mi- (mi- hours hours hours hours, hours, hours Reference oxide) (m.sup.2/g) (ml/g) d (nm) crons) crons) crons) (m.sup.2/g) (ml/g) (nm) μmol/g μmol/m.sup.2 (° C.) Preparative 3.4 530 1.02 7.7 6.8 46 100 95 0.37 15.5 427 4.49 296 example 7 Preparative 3.1 580 0.94 6.5 3.7 36 87 85 0.27 12.8 384 4.52 292 example 10 Comparative 4.0 540 0.98 7.3 4.3 29 114 95 0.36 15.1 312 3.28 275 example 8 Comparative 3.6 530 0.39 2.9 1.3 3.9 6.6 80 0.13 6.5 261 3.26 274 example 7

(89) TABLE-US-00007 TABLE 7 Total Total T.sub.max Total SA TPV d, nm NH.sub.3, NH.sub.3, NH.sub.3, wt % Surface pore Pore Particle size, laser light scattering 600° 600° 600° 600° 600° 600° SO.sub.3 area, volume, diam- d10 d10 d10 C./2 C./2 C./2 C./2 C./2 C./2 (on SA TPV, eter, (mi- (mi- (mi- hours hours hours hours hours hours Reference oxide) (m.sup.2/g) (ml/g) d, nm crons) crons) crons) (m.sup.2/g) (ml/g) (nm) μmol/g μmol/m.sup.2 (° C.) Preparative 8.0 530 0.82 0.82 5.4 37 83 165 0.42 10.2 967.2 5.86 253 Example 6 Preparative 10.0 420 0.71 6.8 5.5 40 86 160 0.36 9.1 1002 6.26 264 Example 9 Comparative 9.5 350 0.45 5.2 1.8 63 312 120 0.25 8.2 716 5.96 247 Example 6 Comparative 9.6 350 0.30 2.9 1.3 3.0 5.3 120 0.14 4.8 589 4.90 274 Example 5 Preparative 6.5 620 1.09 7.1 6.6 42 95 170 0.45 10.7 1100 9.96 228 example 11 Preparative 9.5 540 0.91 6.7 7.1 43 100 170 0.46 11.1 1067 6.27 256 example 12