Catalyst for thermally stable degradation of VOCs, preparation method thereof and use thereof
The present application discloses a catalyst for thermally stably degradation of VOCs, a preparation method thereof and a use thereof. The catalyst includes: a substrate, and an auxiliary agent and an active component which are on the substrate. The auxiliary agent includes a first auxiliary agent and a second auxiliary agent; the first auxiliary agent includes a cobalt-containing auxiliary agent and/or an iron-containing auxiliary agent; and the second auxiliary agent includes an aluminum-based auxiliary agent. The combination of specific first and second auxiliary agents is introduced into the catalyst of the present application, so that oxygen molecules can be quickly adsorbed and activated during the catalytic combustion process of VOCs with forming a catalytic synergy center with the active component, thereby improving the removal efficiency for VOCs and facilitating the long-term stable operation of the catalyst under harsh conditions such as high-temperature and high-humidity conditions.
1 . A catalyst for thermally stable degradation of volatile organic compounds (VOCs), comprising a substrate, and an auxiliary agent and an active component which are on the substrate, wherein
the auxiliary agent comprises a first auxiliary agent and a second auxiliary agent;
the first auxiliary agent comprises at least one of a cobalt-containing auxiliary agent or an iron-containing auxiliary agent;
the second auxiliary agent comprises an aluminum-based auxiliary agent;
a content of an active element of the first auxiliary agent is 2% to 8% of a total mass of the catalyst;
the active element comprises at least one of cobalt or iron;
the active component comprises at least one of platinum, ruthenium or palladium;
a content of the active component is 0.002% to 0.1% of the total mass of the catalyst; and
the VOCs comprise at least one of toluene, propylene or xylene.
2 . The catalyst according to claim 1 , wherein the substrate comprises at least one of honeycomb mullite or honeycomb cordierite;
the first auxiliary agent comprises at least one of Co 3 O 4 , CoO, Fe 3 O 4 or Fe 2 O 3 ; and
the second auxiliary agent comprises at least one of Al 2 O 3 or pseudoboehmite.
3 . A method for preparing the catalyst according to claim 1 , comprising:
performing first stirring and mixing on a first auxiliary agent dispersion liquid and a second auxiliary agent dispersion liquid to obtain a first mixture, and then performing first calcination on the first mixture to obtain a composite auxiliary agent, wherein:
the first auxiliary agent dispersion liquid is obtained by dispersing the first auxiliary agent in a first solvent; and
the second auxiliary agent dispersion liquid is obtained by dispersing a first portion of the second auxiliary agent in a second solvent;
performing second stirring and mixing on the composite auxiliary agent and an active component dispersion liquid to obtain a second mixture, and then performing second calcination on the second mixture to obtain a catalyst composite powder;
performing ball milling on the catalyst composite powder, a second portion of the second auxiliary agent and a concentrated acid to obtain a gelled mixture; and
combining the gelled mixture with the substrate, and then performing third calcination to obtain the catalyst for thermally stable degradation of the VOCs.
4 . The method according to claim 3 , wherein a mass ratio of the first auxiliary agent in the first auxiliary agent dispersion liquid to the first portion of the second auxiliary agent in the second auxiliary agent dispersion liquid is (0.1-0.4):1.
5 . The method according to claim 3 , wherein a temperature of the first calcination is 600° C. to 850° C.; and a time of the first calcination is 2 h to 10 h.
6 . The method according to claim 3 , wherein the active component dispersion liquid is obtained by dispersing an active substance in a third solvent; and
the active substance comprises at least one of platinum nitrate, tetraammine platinum nitrate, chloroplatinic acid, tetraammine platinum chloride, ruthenium chloride, ruthenium nitrosyl nitrate, palladium chloride, palladium nitrate or tetraammine palladium nitrate.
7 . The method according to claim 6 , wherein a mass ratio of the composite auxiliary agent to the active substance in the active component dispersion liquid is 1:(0.01-0.5).
8 . The method according to claim 3 , wherein a temperature of the second calcination is 400° C. to 600° C.; and a time of the second calcination is 1 h to 5 h.
9 . The method according to claim 3 , wherein a mass ratio of the concentrated acid to the second portion of the second auxiliary agent during the ball milling is (0.01-0.08):1; and
a mass ratio of the second portion of the second auxiliary agent to the catalyst composite powder during the ball milling is (0.05-0.5):1.
10 . The method according to claim 3 , wherein a time of the ball milling is 30 min to 120 min.
11 . The method according to claim 10 , wherein a mass ratio of grinding balls to materials during the ball milling is (2-20):1.
12 . The method according to claim 3 , wherein a temperature of the third calcination is 400° C. to 600° C.; and a time of the third calcination is 1 h to 5 h.