High activity loading type Rh
xAu
1-xThe preparation method of/Y nanocatalyst
Technical field
The present invention relates to support type Rh
xAu
1-xThe preparation method of/Y (Y=metal oxide) nanocatalyst is specifically related to adopt a series of support type Rh of ultrasonic barrier diffusion method (UAMR) preparation
xAu
1-xThe preparation method of/Y (y=metal oxide) nanocatalyst belongs to the preparation field of nano catalytic material, and the catalyst of this method preparation can be used for purifying vehicle exhaust.
Background technology
The application of noble metal catalyst in purifying vehicle exhaust receives people's very big concern always.Vehicle exhaust mainly contains CO, HC and NO
xDeng pollutant, how effectively purifying automobile tail gas has become one of focus of paying close attention in the current whole world.At present commercially available cleaning catalyst for tail gases of automobiles major part is to be active component with Pt, Pd and Rh, with La
2O
3And CeO
2Be auxiliary agent, with γ-Al
2O
3It is the second carrier loaded noble metal type catalyst to ceramic honeycomb.Precious metals pt, Pd and Rh cost an arm and a leg and resource exhaustion day by day, are present urgent problems so reduce the noble metal dosage and the manufacturing cost of three-way catalyst.In the past few decades, people have carried out a large amount of utilize base metal or rare earth metal and have replaced the exploration of noble metal in the three-way catalyst, but, the result shows that noble metal can not be replaced fully, can only utilize improvement catalyst preparation process and the optimization of C consumption with the noble metal of reduction catalyst.Recently, if we find that the Rh metallic on the support type Rh metallic catalyst is prepared into nano particle can improve this activity of such catalysts, the Au element is introduced in the support type Rh metallic catalyst, make Au and Rh form alloy or bimetal nano particle, can improve and keep under the condition that three-effect catalysis model reaction activity do not reduce, reduce the consumption of metal Rh significantly.This catalyst has very strong practicality, can be used for the preparation of auto-pollution emission control triple effect catalytic converter.
At present, the preparation method of traditional preparation support type alloy catalyst mainly contains infusion process, coprecipitation, sol-gal process, chemical reduction method etc.The active component of the loaded catalyst of traditional preparation method's preparation is skewness often, and metal dispersity is low, and content of metal is big, the production cost height.Utilization of the present invention utilizes ultrasonic barrier diffusion method (UAMR) to prepare Rh
xAu
1-x/ Y (Y=metal oxide) nanocatalyst, its catalyst three-effect catalysis reactive activity is higher than the pure Rh metallic catalyst by immersion process for preparing.
Summary of the invention
The object of the present invention is to provide a kind of high activity loading type RhAu alloy nano Preparation of catalysts method.This catalyst can be used for replacing noble metal Rh catalyst, to reduce the cost of three-way catalyst.The present invention utilizes the Rh of ultrasonic barrier diffusion method (UAMR) preparation
xAu
1-x/ Y (Y=metal oxide) nanocatalyst is to the carbon monoxide oxidation, and reactions such as NO reduction have good active, can be used for the automobile exhaust pollution emission control.Its preparation method has overcome the shortcoming of conventional immersion process for preparing load type metal catalyst, and the nanometer alloy catalyst of preparation has the particles of active components epigranular, narrow diameter distribution, the advantage that catalytic activity is high.
Preparation equipment has been applied for patent of invention, denomination of invention: a kind of preparation method of load-type nanometer metal catalyst and equipment, application number: 200710118756.6, preparation equipment is characterized in that: complete equipment comprises measuring pump 1, metal salt solution storage tank 2, tubular reactor 4, supersonic generator 5, infusion pump 8, product storage tank 9, hollow ceramic membranes pipe 10; (figure-1)
Built-in hollow ceramic membranes pipe 10 (at least 3) in the tubular reactor 4, hollow ceramic membranes pipe 10 are evenly distributed and be fixed on epoxy resin on the black box 6 at tubular reactor 4 two ends (figure-2, figure-3) on the circle in the center of circle at the central shaft with tubular reactor 4.
Tubular reactor 4 places in the supersonic generator 5, and hollow ceramic membranes pipe 10 inlet 3 by tubular reactor 4 one end cavitys 11 and tubular reactor 4 is connected with measuring pump 1, and measuring pump 1 is connected with metal salt solution storage tank 2;
Tubular reactor 4 outlet 7 links to each other with product storage tank 9 by pipeline, and the another one inlet 12 of tubular reactor 4 is connected (scheming-1) by the pipelines of infusion pump 8 with product storage tank 9.
Preparation method of the present invention is as follows:
(I) according to Rh
xAu
1-x, x=0.4~1.0 preparing metal salting liquids adds carrier material and stirs into pulpous state solution, and transfers in the storage tank 9;
(II) preparation reductant solution, reductant solution is 1: 1~15: 1 with metal molar ratio in the above-mentioned metal salt solution, reductant solution is transferred in the storage tank 2 then;
(III) start infusion pump 8, flow velocity is 500-1000ml/min, the pulpous state solution that contains slaine and carrier material is injected into the tubular reactor 4 through infusion pump 8 from storage tank 9, and is back in the storage tank 9, start supersonic generator 6 then, tranmitting frequency is 40-120KHz;
(IV) start measuring pump 1, flow velocity is 0.1-10ml/min, reductant solution is entered in hollow ceramic membranes 10 pipelines in the tubular reactor 4, be diffused into by the micropore on the hollow ceramic membranes duct wall in the exocoel of tubular reactor 4, contact with the pulpous state solution that contains slaine and carrier material, metal ion is at the carrier surface absorbing and reducing, the slurries that obtain are through centrifugation, the precipitate with deionized water washing was dried 4 hours for 80 ℃, and 500 ℃ of calcinations obtained support type Rh in 3 hours in muffle furnace
xAu
1-x/ Y metal nano catalyst.
The catalyst that obtains carries out tem observation, and choose model reaction in vent gas treatment three validity responses (CO oxidation reaction, NO+CO reaction) and carry out the catalyst activity property testing, and compare with the Rh/Y catalyst activity of the equal content of metal of traditional immersion process for preparing.
The chemical molecular expression formula of RhAu alloy catalyst of the present invention is Rh
xAu
1-x/ Y (Y=metal oxide), described a kind of support type alloy nano catalyst is characterized in that: Rh
xAu
1-xThe x value can be 0.4~1.0 in/Y (Y=metal oxide) catalyst.
The preparation raw material of AuRh alloy catalyst of the present invention is AuCl
3, HAuCl
4, Au (NO
3)
3, RhCl
3NH
2O, H
3RhCl
6, Rh
2O
3NH
2O, Rh (NO
3)
3.nH
2O, Rh
2(CH
3CO
2)
3, Rh (NO
3)
3
Carrier material comprises γ-Al for high-ratio surface material commonly used
2O
3, SiO
2, TiO
2, ZrO
2, Ce
1-xZr
xO
2(x=0~1.0), molecular sieve, kaolin and clay etc.
Described reducing agent is N
2H
4, NaBH
4, ascorbic acid, oxalic acid, formaldehyde or ethanol.
The invention has the beneficial effects as follows:
The support type alloy nano catalyst that utilizes the present invention to prepare has that cost is low, metal dispersity is high, activated centre component even particle size distribution, the little and catalytic activity advantages of higher of particle diameter.
Description of drawings
Fig. 1 prepares the apparatus system schematic diagram of load type metal nanocatalyst;
Fig. 2 tubular reactor structural representation;
Fig. 3 tubular reactor inner ceramic film distribution map;
Fig. 4 Rh (0.50wt%)/γ-Al
2O
3The TEM figure of nanocatalyst;
Fig. 5 Rh
0.5Au
0.5(0.50wt%)/γ-Al
2O
3The TEM figure of nanocatalyst;
The Rh of Fig. 6 UAMR method preparation
xAu
1-x(0.50wt%)/the Catalyst for CO oxidation activity figure of the equal content of metal of Y nanocatalyst (x=1,0.8,0.6,0.5,0.4) and immersion process for preparing;
The Rh of Fig. 7 UAMR method preparation
xAu
1-x(0.50wt%)/Catalyst for CO+NO reactivity figure of the equal content of metal of Y nanocatalyst (x=1,0.8,0.5) and immersion process for preparing;
The specific embodiment
Embodiment 1:
With 0.05 gram radium chloride (RhCl
3) be dissolved in the 200ml deionized water, add 5 gram γ-Al then
2O
3, fully stirring is transferred in the storage tank 9 after forming slurries; With 0.5 gram sodium borohydride (NaBH
4) be dissolved in the 50ml deionized water and transfer in the storage tank 2.Start infusion pump 8, make RhCl
3And γ-Al
2O
3Mixed serum between storage tank 9 and tubular reactor 4, circulate, flow velocity is 600ml/min, starts supersonic generator 5, the frequency that supersonic generator is set is 80KHZ, bath temperature is 40 ℃, measuring pump 1 with the speed of 1.0ml/min with NaBH
4Solution is injected in the pipeline of the hollow ceramic membranes pipe 10 in the tubular reactor 4, NaBH
4Solution is diffused into by the micropore on the hollow ceramic membranes tube wall and contains RhCl
3And γ-Al
2O
3Mixed serum in, work as NaBH
4After all adding, solution closes measuring pump 1, supersonic generator 5, utilize infusion pump 8 that the slurries in the tubular reactor 4 are all imported in the storage tank 9, close infusion pump 8, slurries are separated with centrifuge, after the precipitate with deionized water washing that obtains 3 times, 80 ℃ of oven dry 4 hours, 500 ℃ of calcinations were 3 hours in muffle furnace, promptly obtain Rh
1Au
0(0.50wt%)/γ-Al
2O
3Carrier nanometer catalyst is at γ-Al
2O
3On the carrier, the little and narrow particle size distribution (Fig. 4) of metal Rh particle diameter.Its CO oxidation and NO reduction reaction activity all be far superior to the same metal content of immersion process for preparing catalyst (Fig. 6, Fig. 7).
Embodiment 2:
With 0.04 gram rhodium nitrate (Rh (NO
3)
3) and 0.016 gram gold chloride (HAuCl
4) be dissolved in the 200ml deionized water, add 5 gram TiO then
2, fully stirring is transferred in the storage tank 9 after forming slurries; With 0.2 gram sodium borohydride (NaBH
4) be dissolved in the 50ml deionized water and transfer in the storage tank 2.Start infusion pump 8, make Rh (NO
3)
3, HAuCl
4And TiO
2Mixed serum between storage tank 9 and tubular reactor 4, circulate, flow velocity is 800ml/min, starts supersonic generator 5, the frequency that supersonic generator is set is 60KHZ, bath temperature is 40 ℃, measuring pump 1 with the speed of 3.0ml/min with NaBH
4Solution is injected in the pipeline of the hollow ceramic membranes pipe 10 in the tubular reactor 4, NaBH
4Solution is diffused into by the micropore on the hollow ceramic membranes tube wall and contains Rh (NO
3)
3, HAuCl
4And TiO
2Mixed serum in, work as NaBH
4After all adding, solution closes measuring pump 1, supersonic generator 5, utilize infusion pump 8 that the slurries in the tubular reactor 4 are all imported in the storage tank 9, close infusion pump 8, slurries are separated with centrifuge, after the precipitate with deionized water washing that obtains 3 times, 80 ℃ of oven dry 4 hours, 500 ℃ of calcinations were 3 hours in muffle furnace, promptly obtain Rh
0.8Au
0.2(0.50wt%)/TiO
2Carrier nanometer catalyst is with Rh (0.5wt%)/γ-Al of immersion process for preparing
2O
3Catalyst is compared, the Rh of UAMR method preparation
0.8Au
0.2(0.5wt%)/TiO
2The CO oxidation of catalyst, the reactivity of CO+NO all be better than the former (Fig. 6, Fig. 7).
Embodiment 3:
With 0.031 gram chlorine rhodium acid (H
3RhCl
6) and 0.02 gram chlorauride (AuCl
3) be dissolved in the 200ml deionized water, add 5 gram SiO then
2, fully stirring is transferred in the storage tank 9 after forming slurries; With 0.5mlN
2H
4Be dissolved in the 50ml deionized water and transfer in the storage tank 2.Start infusion pump 8, make H
3RhCl
6, AuCl
3And TiO
2Mixed serum between storage tank 9 and tubular reactor 4, circulate, flow velocity is 1000ml/min, starts supersonic generator 5, the frequency that supersonic generator is set is 100KHZ, bath temperature is 40 ℃, measuring pump 1 with the speed of 0.1ml/min with N
2H
4Solution is injected in the pipeline of the hollow ceramic membranes pipe 10 in the tubular reactor 4, N
2H
4Solution is diffused into by the micropore on the hollow ceramic membranes tube wall and contains H
3RhCl
6, AuCl
3And SiO
2Mixed serum in, work as N
2H
4After all adding, solution closes measuring pump 1, supersonic generator 5, utilize infusion pump 8 that the slurries in the tubular reactor 4 are all imported in the storage tank 9, close infusion pump 8, slurries are separated with centrifuge, after the precipitate with deionized water washing that obtains 3 times, 80 ℃ of oven dry 4 hours, 500 ℃ of calcinations were 3 hours in muffle furnace, promptly obtain Rh
0.6Au
0.4(0.50wt%)/SiO
2Carrier nanometer catalyst is with Rh (0.5wt%)/γ-Al of immersion process for preparing
2O
3Catalyst is compared, the Rh of UAMR method preparation
0.6Au
0.4(0.5wt%)/SiO
2The CO oxidation activity of catalyst be better than the former (Fig. 6).
Embodiment 4:
With 0.025 gram rhodium oxide (Rh
2O
3H
2O) and 0.032 gram gold chloride (HAuCl
4) be dissolved in the 200ml deionized water, add 5 gram γ-Al then
2O
3, fully stirring is transferred in the storage tank 9 after forming slurries; 1 gram oxalic acid is dissolved in the 50ml deionized water and transfers in the storage tank 2.Start infusion pump 8, make Rh
2O
3H
2O, HAuCl
4And γ-Al
2O
3Mixed serum between storage tank 9 and tubular reactor 4, circulate, flow velocity is 500ml/min, start supersonic generator 5, the frequency that supersonic generator is set is 40KHZ, bath temperature is 60 ℃, measuring pump 1 is injected into oxalic acid solution in the pipeline of the hollow ceramic membranes pipe 10 in the tubular reactor 4 with the speed of 10ml/min, and oxalic acid solution is diffused into by the micropore on the hollow ceramic membranes tube wall and contains Rh
2O
3H
2O, HAuCl
4And γ-Al
2O
3Mixed serum in, after all adding, oxalic acid solution closes measuring pump 1, supersonic generator 5, utilize infusion pump 8 that the slurries in the tubular reactor 4 are all imported in the storage tank 5, close infusion pump 8, slurries are separated with centrifuge, after the precipitate with deionized water that obtains is washed 3 times, 80 ℃ of oven dry 4 hours, 500 ℃ of calcinations are 3 hours in muffle furnace, promptly obtain Rh
0.5Au
0.5(0.50wt%)/γ-Al
2O
3Carrier nanometer catalyst is at γ-Al
2O
3On the carrier, the alloy particle particle diameter is 4-6nm and narrow particle size distribution (Fig. 5).Rh (0.5wt%)/γ-Al with immersion process for preparing
2O
3Catalyst is compared, the Rh of UAMR method preparation
0.5Au
0.5(0.5wt%)/γ-Al
2O
3The CO oxidation activity of catalyst be better than the former (Fig. 6), the reactivity of CO+NO similar to the former (Fig. 7).
Embodiment 5:
With 0.013 gram radium chloride (RhCl
3) and 0.035 gram nitric acid gold (Au (NO
3)
3) be dissolved in the 200ml deionized water, add 5 gram ZrO then
2, fully stirring is transferred in the storage tank 9 after forming slurries; Be dissolved in ascorbic acid in the 50ml deionized water and transfer in the storage tank 2.Start infusion pump 8, make RhCl
3, Au (NO
3)
3And ZrO
2Mixed serum between storage tank 9 and tubular reactor 4, circulate, flow velocity is 700ml/min, start supersonic generator 5, the frequency that supersonic generator is set is 120KHZ, bath temperature is 40 ℃, measuring pump 1 is injected into ascorbic acid solution in the pipeline of the hollow ceramic membranes pipe 10 in the tubular reactor 4 with the speed of 7.0ml/min, and ascorbic acid solution is diffused into by the micropore on the hollow ceramic membranes tube wall and contains RhCl
3, Au (NO
3)
3And ZrO
2Mixed serum in, after all adding, ascorbic acid solution closes measuring pump 1, supersonic generator 5, utilize infusion pump 8 that the slurries in the tubular reactor 4 are all imported in the storage tank 9, close infusion pump 8, slurries are separated with centrifuge, after the precipitate with deionized water that obtains is washed 3 times, 80 ℃ of oven dry 4 hours, 500 ℃ of calcinations are 3 hours in muffle furnace, promptly obtain Rh
0.4Au
0.6(0.50wt%)/ZrO
2Carrier nanometer catalyst, the Rh of UAMR method preparation
0.4Au
0.6(0.5wt%)/ZrO
2The CO oxidation activity of catalyst is better than Rh (0.5wt%)/γ-Al of immersion process for preparing
2O
3Catalyst (Fig. 6)