SU1097367A1 - Catalyst for oxidation carbon monoxide - Google Patents

Abstract

CATALYST FOR OXIDE OXIDATION AND CARBON, including a mixed oxide of perovskite structure, where A is an alkaline earth metal, B is a transition metal and 0.1-0.5, characterized in that, in order to increase activity, it contains as a transition metal a mixture of nickel and cobalt and the composition of the catalyst corresponds to the following empirical formula AnLa (K1 | .Sou) Oz,. where 0, t-0,93; Ai-values given above,

Description

WITH

00 od

The invention relates to catalysts for the oxidation of carbon monoxide, as the most toxic impurity of exhaust gases of automobiles and exhaust gases of industrial enterprises.

The most effective catalysts for the oxidation of carbon monoxide are catalysts of a noble metal 1 J.

However, due to the scarcity and high cost of noble metals, catalysts based on them are used by & w in special cases - in neutral, vehicle lizators working in quarries and mines.

A series of oxide catalysts of perovskite structure is known for the oxidation of carbon monoxide of the general formula, CoO3, where, 02-0.1, containing CeO and in the following ratio of components, wt.%: Ce02 1-50, Coj04 0.5-23; {Remaining C 23. However, these catalysts are characterized by insufficient activity.

Closest to the proposed technical essence and the achieved effect is a catalyst C3 for the oxidation of carbon monoxide, comprising a packed oxide of perovskite structure, corresponding to the empirical formula.

,

where A is an alkaline earth metal; B is a transition metal, for example cobalt, platinum, palladium, RHODE; 1-0.5.

However, the known catalyst is characterized by insufficient activity. Thus, the known catalyst, whose composition is cooTBetcTByeT with the empirical formula

. ,

allows to achieve a 50% conversion of CO at 100% at 235 ° C.

The purpose of the invention is to increase the activity of the catalyst.

This goal is achieved by the fact that a catalyst for the oxidation of carbon monoxide, including a mixed oxide of perovskite structure

where A is an alkaline earth metal; B - transition metal | f p - 0.1-0.5,

containing as a transition metal binary mixture of nickel and cobalt and the composition of the catalyst corresponds to the following empirical formulas

() 0, where Y is 0.1-0.95,

A and p - the values indicated above

The proposed catalyst in comparison with the known possesses poppy activity. So, the proposed catalyst, whose composition, for example, corresponds to the empirical formula

Sro, (Od 9) 03, allows to achieve a 50% conversion of CO at 195 ° C, 100% at.

The catalyst is prepared as follows.

Mix aqueous solutions of alkaline earth metal salts (Ce, Sr, Ba), lanthanum, nickel and cobalt in the required proportions with a solution of ammonium trisubstituted citrate. The molar ratio of trisubstituted ammonium citrate to the amount of nitrate salts is 0.6-0.8. The complex solution is evaporated, dried under an incandescent lamp until the nitrate salts of the metals decompose. The resulting oxide mixture of metals is crushed, pelletized, crushed to a grain size of 1-2 mm and calcined in air in the temperature range of 700-1000 ° C (preferably for 10-12 hours

Example 1. The catalyst of the empirical formula Bajj2Lap g () 02 composition, wt.%: Bao 12,8,, 7; NiO 6.2i Co-jO 27.3 is prepared as follows.

To 12 ml of a 0.5 M solution of Ba (NOj) 2, 12 ml of 2M La (NOa) -t xSHjO solution is added, then 3 ml of a 2M solution of M (She) 2-eHjO and 12 ml of a 2M solution of Co (NOg) 2-. Under stirring, 16 ml of a 1M solution of trisubstituted ammonium citrate is added to the mixture of solutions. Then this mixture of solutions is evaporated in a water bath to a gum. The mass is dried under an incandescent lamp while operating before decomposition of metal salts. The mixture of metal oxides is thoroughly crushed, tableted, and crushed to a grain of 1-2 ml. The catalyst grains are heated in air before and kept at this temperature for 12 hours. 310 The activity of the finished catalyst is determined in a flow installation at a temperature range of 100-250 ° C at a yo-azo rate of 1,800 with a mixture of carbon dioxide containing,%: 10.0 oxygen pairs 12.3, nitrogen-containing. Chromatographic analysis of the effluent gases from the installation shows that at a reaction temperature of 155 ° C, the degree of conversion of carbon monoxide is 50%, and at 100%. Example 2. Catalyst of empirical formula Ba Laflg () Oz. l ft XVftt composition, wt.%: BaO 12,9; NiO 18.8; , 9 is prepared analogously to example 1. To 12 ml of a 0.5 M solution of Ba (NO3) 2 are poured 12 ml of a 2M solution of LaCNO), 9 ml of a 2M solution of Ni (rt05) 2.6H20 and 6 ml of 2M Co (NO3) 2-6H20. with stirring, the resulting mixture of solutions is added 16 ml of a 1 M solution of trisubstituted ammonium citrate. The following operations are analogous to Example 1. The activity of the finished catalyst is determined as in Example 1. The temperature of the 50% conversion of carbon monoxide is 100%. Example 3. The catalyst of the empirical formula is La aBan- (NirtjCcjj Oj composition, wt.%: BaO 12.9; ha-O-ZZ, NiO 28.5;, 3.5 are prepared analogously to example 1. To 12 ml 0.5 M a solution of BaCNOj) poured 12 ml of a 2M solution of Ni (NOj), j-6Hj, O, and t, 5 ml of a 2M solution of Co (NOj) 2 bNaO. To the semi- -. 8 ml of 2M trisubstituted ammonium citrate solution is poured into the complex solution with stirring. Subsequent operations are analogous to Example 1. The activity of the finished catalyst is determined as in Example 1. The temperature of the 50% carbon monoxide conversion is 100%. Example 4. The catalyst of the empirical formula LaogBap2 (Nij, YCq, j) 0 composition, wt.%: Laso 53f, 9; BaO 12, NiO 2.7 Со20J 30.8 are prepared analogously to Example 1. To a 12 ml of 2 M solution of La (LO3) bicNO, 12 ml of a 0.5 M solution of Ba (NOj) .j, 13.5 ml of a 2M Co solution ( NOj) -BNzO and 1.5 ml of a 2M solution of NiCNOj). To the resulting 54.4 7 mixture of solutions, 16 MP 1 m solution of trisubstituted ammonium citrate are added with stirring. Further operations are similar to Example 1. The activity of the finished catalyst is determined as in Example 1. The 50% conversion of carbon monoxide is, and 100% is, Example 5. The catalyst of the empirical formula Ca La jCNiQjJjCoj Oj composition, wt.% : CaO2,4; La O 62.5; NiO 1,6i CojO 33.5 is prepared analogously to example 1. 18 ml of a 2M solution of LaCNOj), 1 ml of a 2M solution of Ni (NO03) and 19 ml of a 2M solution of Co (NOj) j are added to 2 ml of a 2M solution of Ca (NOj) 2. Under stirring, 12 ml of a 2 M solution of trisubstituted ammonium citrate is added to the mixture of solutions. Subsequent operations are analogous to example 1. The difference is that the catalyst is calcined with the activity of the finished catalyst determined as in example 1. The temperature of 50% conversion of carbon monoxide is 100% zcr c.:. I,. Example 6. Catalyst of empirical formula. composition, wt.%: Sao 14,7; 42.8; NiO 9.8; CojO 32.7 is prepared analogously to example 1. To a 10 mp 2M solution of Ca (NOi) 2 4H20 is added 10 ml of a 2M solution of la (Koz) 3; HjO, 5 mp 2M solution NiCNOj) and 15 mp CoCKOj solution). Under stirring, 12 ml of a 2M solution of trisubstituted ammonium citrate is added to the mixture of solutions. Subsequent operations are similar to example 1. The difference is that the catalyst is instilled at. The activity of the finished catalyst is determined as in Example 1. The temperature of 50% conversion of carbon monoxide is, and 100% is 210.C. Example 7. The catalyst of the empirical formula of the composition, wt.%: SrO 8,9; LajO 55.9-, NiO 4.9, CojO 30.3 are prepared as in Example 1. To 4 ml of a 2M solution of SrCNOs) is poured 16. MP 2M solution of LaCNOj)} - 6N.O., 3 MP 2M solution of Ni (N03 6H20 and 17 MP 2M solution of CoCNOjJlj-. To the mixture of solutions obtained with stirring, pour 12 ml of 2m solution of trisubstituted ammonium citrate ammonium. Subsequent operations are analogous to example 1. The difference is that the catalyst was catalyzed at. The activity of the finished catalyst was determined as in example 1. The 50% carbon dioxide conversion temperature is 100% - The test results of the samples of the proposed and known catalysts are given in Table 1. The results of the evaluation of thermal b The most active catalysts of the empirical formula Var2LaQg (C ° o, fl) j manufactured according to Example 1 are shown in. Temperatures 50 and 100% of the conversion of carbon monoxide are determined. The activity of the proposed and known catalysts

After one preheat of the catalyst sample in air at 850,925 and for 12 hours, the activity is determined as in Example 1. From the data obtained, it can be seen that the activity of the proposed catalyst slightly decreases with increasing temperature of heating. the same time, it is higher than the activity of the known. Thus, using the catalyst of the proposed composition with increased activity and thermal stability, it is possible to significantly intensify the process of afterburning of a highly toxic impurity, carbon monoxide, which is especially important for cleaning the waste gases of industrial enterprises.

nsr Sr I a gCoOj

215

235 Determination of thermal stability of catalysts

850

925

1000

1000 (prototype)

1097367

8 Table 2

175 189 203 350 proposed and known

Claims (1)

CATALYST FOR ^OXIDATION OF ^{CARBON OXIDE} , including mixed perovskite oxide oxide ^ApAa M1 ^B0 E 'where A is an alkaline earth metal *, B is a transition metal J η = 0.1-0.5, characterized in that, in order to increase activity, it contains a binary mixture of nickel and cobalt as a transition metal and the composition of the catalyst corresponds to the following empirical formula An ^ a ^ _ | ^ (Ni ^. UCoy) 0, where Y = 0.1-0.95 ^ A and η are the values indicated above. SU „„ 1097367