Graphene-supported palladium iridium nanoparticle catalyst preparation method and its Oxidation of Formic Acid electricity are urged
Change application
Technical field
The invention belongs to loaded catalyst preparation technical fields, and in particular to a kind of graphene-supported palladium iridium nano particle
Method for preparing catalyst and its Oxidation of Formic Acid electro-catalysis application.
Background technique
It is high, environmental-friendly by the direct methanoic acid fuel cell energy conversion efficiency of fuel of liquid formic acid, as automobile
Power and portable power etc. show huge application potential.Oxidation of Formic Acid is must as direct methanoic acid fuel cell
Indispensable anode-catalyzed reaction.For at present, common palladium/carbon catalyst is not excellent enough to Oxidation of Formic Acid catalytic activity
It is difficult to meet the needs of Current commercial.For the commercialization process for accelerating direct methanoic acid fuel cell, research and preparation high-performance
Oxidation of Formic Acid catalyst is particularly important.It is compared with palladium, iridium metals price is relatively cheap, and iridium is to the chemical stability of acid
High is also most corrosion resistant metal.Suitable iridium is added into palladium not only can change the original electronic structure of palladium and surface knot
Structure reduces while reducing Oxidation of Formic Acid reaction activity to the absorption of species is poisoned, to show higher catalytic
Energy.
Catalysis reaction is related to catalyst granules surface and interface charge transfer process.The nano particle of small particle clean surface is not only
Specific surface area and utilization rate with superelevation, while effective progress that more active sites promote catalysis reaction can be shown
With the raising of kinetics of electrode process.The preparation of the uniform palladium iridium alloy particle of current small particle generally requires living by means of surface
Property agent (such as polyvinylpyrrolidone, cetyl trimethylammonium bromide) and highly toxic reducing agent (such as sodium borohydride,
Oleyl amine, hydrazine hydrate) etc..Since the metal nanoparticle surface that surfactant is easy to be coated on preparation is difficult to clean off, to cover
Cover active site causes catalytic performance to be unable to give full play;And the use of high toxicity reducing agent, it be easy to cause environmental pollution
And there are security risks.In addition, graphene has the specific surface area of excellent conduction and mechanical performance and superelevation, to help
In the effective progress for reducing charge transfer resistance and mass transport process, obtained in terms of as fuel-cell catalyst carrier wide
General application.
Therefore, studying a kind of green method easy to operate, being suitble to large-scale production, carrier surface is clean on the surface of graphene
Only, extra small and evenly dispersed palladium iridium nano particle is as Oxidation of Formic Acid catalyst, for accelerating the quotient of direct methanoic acid fuel cell
Industryization development is of great significance.
Summary of the invention
In consideration of it, the purpose of the present invention is to provide ultrasonic assistance method, to prepare graphene-supported clean surface extra small and uniform
Disperse the method for palladium iridium nanoparticle catalyst, the catalyst of preparation has very high electrochemically active specific surface area and formic acid oxygen
Change catalytic activity, and this method is not related to the use of high toxicity material, easy to operate, repeatability is high, is suitble to large-scale production.
The technical solution adopted by the invention is as follows:
A kind of preparation method of graphene-supported palladium iridium nanoparticle catalyst, comprising the following steps:
1) that graphene is added to ultrasonic mixing in formic acid solution is uniform;
2) it is uniformly dispersed under the mixed solution ultrasound condition that chloro-iridic acid and chlorine palladium acid sodium are prepared;
3) mixed solution obtained by step 2) is heated;
4) mixed solution obtained by step 3) is rapidly injected in the mixed solution of step 1) graphene and formic acid, is being sealed
Under the conditions of be ultrasonically treated;
5) the once purged drying of products therefrom.
In the step 1), concentration of the graphene in formic acid solution is 1~5mg/mL, and ultrasound is carried out at 75-95 DEG C
Processing.
In the step 2), the molar ratio of palladium and iridium is 1:1~4:1.
In the step 2), ultrasonic time is 0.5h~5h, and power is 100~600W.
In the step 3), solution is heated to 60 DEG C~95 DEG C.
In the step 4), the mass ratio of palladium iridium alloy and graphene is 1:5~1:1.
It in the step 4), is ultrasonically treated under 60 DEG C~95 DEG C air-proof conditions, ultrasonic time is 2h~10h, function
Rate is 100~600W.
In the step 5), drying temperature is 40 DEG C~100 DEG C, and the time is 10~20h.
The graphene-supported palladium iridium nanoparticle catalyst that the method is prepared.
Application of the graphene-supported palladium iridium nanoparticle catalyst in Oxidation of Formic Acid electrocatalytic reaction.
Palladium iridium/graphene prepared by the present invention has bigger electro-chemical activity ratio compared with being commercialized palladium/carbon catalyst
Surface area and higher Oxidation of Formic Acid catalytic activity, alternative commercialization palladium/carbon catalyst are applied to direct methanoic acid fuel cell
And other energy conversion fields, have higher practical value;And the method for the present invention is not related to the use of high toxicity material,
Easy to operate, repeatability is high, can expand and prepare other nano particles and have broad field of application and prospect.
Detailed description of the invention
In order to keep the purpose of the present invention, technical scheme and beneficial effects clearer, the present invention provides following attached drawing and carries out
Illustrate:
Fig. 1 is palladium iridium/graphen catalyst transmission electron microscope picture prepared by embodiment 1;
Fig. 2 is palladium iridium/graphen catalyst prepared by embodiment 1 and commercialization palladium/carbon catalyst in 0.5M H2SO4Solution
In cyclic voltammetry curve compare figure;
Fig. 3 is palladium iridium/graphen catalyst prepared by embodiment 1 and commercialization palladium/carbon catalyst in 0.5M H2SO4+
Catalytic activity in 0.5M HCOOH solution compares figure;
Fig. 4 is palladium iridium/graphen catalyst transmission electron microscope picture prepared by embodiment 2;
Fig. 5 is palladium iridium/graphen catalyst prepared by embodiment 2 and commercialization palladium/carbon catalyst in 0.5M H2SO4Solution
In cyclic voltammetry curve compare figure;
Fig. 6 is palladium iridium/graphen catalyst prepared by embodiment 2 and commercialization palladium/carbon catalyst in 0.5M H2SO4+
Catalytic activity in 0.5M HCOOH solution compares figure;
Fig. 7 is palladium iridium/- 1 catalyst of graphene transmission electron microscope picture prepared by embodiment 3;
Fig. 8 is palladium iridium/- 1 catalyst of graphene prepared by embodiment 3 and commercialization palladium/carbon catalyst in 0.5M H2SO4It is molten
Cyclic voltammetry curve in liquid compares figure;
Fig. 9 is palladium iridium/- 1 catalyst of graphene prepared by embodiment 3 and commercialization palladium/carbon catalyst in 0.5M H2SO4+
Catalytic activity in 0.5M HCOOH solution compares figure;
Figure 10 is palladium iridium/- 2 catalyst of graphene transmission electron microscope picture prepared by embodiment 4;
Figure 11 is palladium iridium/- 2 catalyst of graphene prepared by embodiment 4 and commercialization palladium/carbon catalyst in 0.5M H2SO4
Cyclic voltammetry curve in solution compares figure;
Figure 12 is palladium iridium/- 2 catalyst of graphene prepared by embodiment 4 and commercialization palladium/carbon catalyst in 0.5M H2SO4+
Catalytic activity in 0.5M HCOOH solution compares figure.
Specific embodiment
Below in conjunction with attached drawing, a preferred embodiment of the present invention will be described in detail.
Embodiment 1
The palladium iridium of the present embodiment/graphene high-performance Oxidation of Formic Acid catalyst preparation method, comprising the following steps:
1) 15mg graphene is added in 8mL formic acid solution at 90 DEG C to ultrasonic mixing is uniform, ultrasonic power 300W.
2) 0.286mL chloro-iridic acid (7mgmL-1 Ir) and 0.221mL chlorine palladium acid sodium (20mgmL-1 Pd) prepare mixing it is molten
Liquid ultrasound 1h, ultrasonic power 300W.
3) solution of the step 2) ultrasonic mixing after uniform is heated to 90 DEG C.
4) step 3) mixed solution is rapidly injected in the mixed solution of step 1) graphene and formic acid, is sealed at 90 DEG C
Under the conditions of carry out ultrasonic treatment 5h, ultrasonic power 300W.
5) 60 DEG C of dry 10h after the product cleaning that reaction obtains, as palladium iridium/graphene high-performance Oxidation of Formic Acid catalysis
Agent.
Fig. 1 is palladium iridium/graphen catalyst transmission electron microscope picture prepared by embodiment 1;Can clearly it find out from figure
Extra small palladium iridium alloy even particulate dispersion on the surface of graphene on, average grain diameter is in 3.4 rans.
Fig. 2 is palladium iridium/graphen catalyst prepared by embodiment 1 and commercialization palladium/carbon catalyst in 0.5M H2SO4Solution
In cyclic voltammetry curve compare figure;It was found that comparing (26.6m with commercialization palladium/carbon catalyst2g-1), palladium prepared by embodiment 1
Iridium/graphen catalyst shows higher electrochemically active specific surface area (76.3m2g-1), illustrate palladium prepared by embodiment 1
Iridium/graphen catalyst has more active sites.
Fig. 3 is palladium iridium/graphen catalyst prepared by embodiment 1 and commercialization palladium/carbon catalyst in 0.5M H2SO4+
Current density in 0.5M HCOOH solution compares figure;It was found that comparing (286.1mA mg with commercialization palladium/carbon catalyst-1 metal), palladium iridium/graphen catalyst prepared by embodiment 1 shows higher peak current density (576.4mA mg-1 metal),
Simultaneously in the case where just inswept journey is with uniform current density in have more negative electrode potential, illustrate embodiment 1 prepare palladium iridium/graphene
Catalyst has higher Oxidation of Formic Acid catalytic activity.
Above-mentioned experimental data shows that palladium iridium/graphen catalyst prepared by embodiment 1 has more Oxidation of Formic Acid activity
Specific surface area and higher catalytic activity, so that alternative commercialization palladium/carbon catalyst is applied to direct methanoic acid fuel cell
And other energy conversion fields.
Embodiment 2
The palladium iridium of the present embodiment/graphene high-performance Oxidation of Formic Acid catalyst preparation method, comprising the following steps:
1) 15mg graphene is added in 5mL formic acid solution at 80 DEG C to ultrasonic mixing is uniform, ultrasonic power 300W.
2) 0.286mL chloro-iridic acid (7mgmL-1 Ir) and 0.221mL chlorine palladium acid sodium (20mgmL-1 Pd) prepare mixing it is molten
Liquid ultrasound 2h, ultrasonic power 500W.
3) solution of the step 2) ultrasonic mixing after uniform is heated to 80 DEG C.
4) step 3) mixed solution is rapidly injected in the mixed solution of step 1) graphene and formic acid, is sealed at 80 DEG C
Under the conditions of carry out ultrasonic treatment 8h, ultrasonic power 500W.
5) 80 DEG C of dry 16h after the product cleaning that reaction obtains, as palladium iridium/graphene high-performance Oxidation of Formic Acid catalysis
Agent.
Fig. 4 is palladium iridium/graphen catalyst transmission electron microscope picture prepared by embodiment 2;Can clearly it find out from figure
Extra small palladium iridium alloy even particulate dispersion on the surface of graphene on, average grain diameter is in 3.6 rans.
Fig. 5 is palladium iridium/graphen catalyst prepared by embodiment 2 and commercialization palladium/carbon catalyst in 0.5M H2SO4Solution
In cyclic voltammetry curve compare figure;It was found that comparing (26.6m with commercialization palladium/carbon catalyst2g-1), palladium prepared by embodiment 2
Iridium/graphen catalyst shows higher electrochemically active specific surface area (74.6m2g-1), illustrate palladium prepared by embodiment 2
Iridium/graphen catalyst has more active sites.
Fig. 6 is palladium iridium/graphen catalyst prepared by embodiment 2 and commercialization palladium/carbon catalyst in 0.5M H2SO4+
Current density in 0.5M HCOOH solution compares figure;It was found that comparing (286.1mA mg with commercialization palladium/carbon catalyst-1 metal), palladium iridium/graphen catalyst prepared by embodiment 2 shows higher peak current density (509.9mA mg-1 metal),
Simultaneously in the case where just inswept journey is with uniform current density in have more negative electrode potential, illustrate embodiment 2 prepare palladium iridium/graphene
Catalyst has higher Oxidation of Formic Acid catalytic activity.
Above-mentioned experimental data shows that palladium iridium/graphen catalyst prepared by embodiment 2 has more Oxidation of Formic Acid activity
Specific surface area and higher catalytic activity, so that alternative commercialization palladium/carbon catalyst is applied to direct methanoic acid fuel cell
And other energy conversion fields.
Embodiment 3
The palladium iridium of the present embodiment/graphene Oxidation of Formic Acid catalyst preparation method, comprising the following steps:
1) 15mg graphene is added in 8mL sodium borohydride aqueous solution (2mg/mL) at 90 DEG C to ultrasonic mixing is uniform,
Ultrasonic power is 300W.
2) 0.286mL chloro-iridic acid (7mgmL-1 Ir) and 0.221mL chlorine palladium acid sodium (20mgmL-1 Pd) prepare mixing it is molten
Liquid ultrasound 1h, ultrasonic power 300W.
3) solution of the step 2) ultrasonic mixing after uniform is heated to 90 DEG C.
4) step 3) mixed solution is rapidly injected in the mixed solution of step 1) graphene and sodium borohydride, at 90 DEG C
Ultrasonic treatment 5h, ultrasonic power 300W are carried out under air-proof condition.
5) 60 DEG C of dry 10h, as -1 Oxidation of Formic Acid catalyst of palladium iridium/graphene after the product cleaning that reaction obtains.
Fig. 7 is palladium iridium/- 1 catalyst of graphene transmission electron microscope picture prepared by embodiment 3;It can be clearly from figure
Out in the dispersion on the surface of graphene of palladium iridium alloy particle, but its particle size span is big, inhomogenous.
Fig. 8 is palladium iridium/- 1 catalyst of graphene prepared by embodiment 3 and commercialization palladium/carbon catalyst in 0.5M H2SO4It is molten
Cyclic voltammetry curve in liquid compares figure;It was found that comparing (26.6m with commercialization palladium/carbon catalyst2g-1), prepared by embodiment 3
- 1 catalyst of palladium/graphene shows higher electrochemically active specific surface area (49.6m2g-1), illustrate palladium prepared by embodiment 3
- 1 catalyst of iridium/graphene has more active site.
Fig. 9 is palladium iridium/- 1 catalyst of graphene prepared by embodiment 3 and commercialization palladium/carbon catalyst in 0.5M H2SO4+
Current density in 0.5M HCOOH solution compares figure;It was found that comparing (286.1mA mg with commercialization palladium/carbon catalyst-1 metal), palladium iridium/graphen catalyst prepared by embodiment 3 shows higher peak current density (374.2mA mg-1 metal),
Simultaneously in the case where just inswept journey is with uniform current density in there is relatively negative electrode potential, illustrate palladium iridium/graphene prepared by embodiment 3
Catalyst has certain Oxidation of Formic Acid catalytic activity.
Above-mentioned experimental data shows in embodiment 3 using palladium iridium/- 1 catalyst of graphene formic acid of sodium borohydride preparation
Oxidation activity specific surface area and catalytic activity are above commercialization palladium/carbon catalyst and are but below in embodiment 1 and embodiment 2
Palladium iridium/graphen catalyst of preparation.
Embodiment 4
The palladium iridium of the present embodiment/graphene Oxidation of Formic Acid catalyst preparation method, comprising the following steps:
1) 15mg graphene is added in 8mL formic acid solution at 90 DEG C to ultrasonic mixing is uniform, ultrasonic power 300W.
2) 0.286mL chloro-iridic acid (7mgmL-1 Ir) and 0.221mL chlorine palladium acid sodium (20mgmL-1 Pd) prepare mixing it is molten
Liquid ultrasound 1h, ultrasonic power 300W.
3) solution of the step 2) ultrasonic mixing after uniform is heated to 90 DEG C.
4) step 3) mixed solution is rapidly injected in the mixed solution of step 1) graphene and formic acid, is sealed at 90 DEG C
Under the conditions of be stirred 5h.
5) 60 DEG C of dry 10h, as -2 Oxidation of Formic Acid catalyst of palladium iridium/graphene after the product cleaning that reaction obtains.
Figure 10 is palladium iridium/- 2 catalyst of graphene transmission electron microscope picture prepared by embodiment 4;It can be clearly from figure
Out in the dispersion on the surface of graphene of palladium iridium alloy particle, but its particle size span is big, inhomogenous.
Figure 11 is palladium iridium/- 2 catalyst of graphene prepared by embodiment 4 and commercialization palladium/carbon catalyst in 0.5M H2SO4
Cyclic voltammetry curve in solution compares figure;It was found that comparing (26.6m with commercialization palladium/carbon catalyst2g-1), it is prepared by embodiment 4
- 1 catalyst of palladium/graphene show higher electrochemically active specific surface area (46.3m2g-1), illustrate prepared by embodiment 4
Palladium iridium/- 2 catalyst of graphene has more active site.
Figure 12 is palladium iridium/- 2 catalyst of graphene prepared by embodiment 4 and commercialization palladium/carbon catalyst in 0.5M H2SO4+
Current density in 0.5M HCOOH solution compares figure;It was found that comparing (286.1mA mg with commercialization palladium/carbon catalyst-1 metal), palladium iridium/- 2 catalyst of graphene prepared by embodiment 4 shows higher peak current density (350.2mA mg-1 metal), while in the case where just inswept journey is with uniform current density in there is relatively negative electrode potential, illustrate palladium prepared by embodiment 4
- 2 alkene catalyst of iridium/graphite has certain Oxidation of Formic Acid catalytic activity.
Above-mentioned experimental data shows to urge in step 4) without palladium iridium/graphene -2 prepared by the embodiment of ultrasonic treatment 4
The Oxidation of Formic Acid specific surface area active of agent and catalytic activity are above commercialization palladium/carbon catalyst and are but below embodiment 1
With the palladium iridium/graphen catalyst prepared in embodiment 2.
Finally, it is stated that preferred embodiment above is only used to illustrate the technical scheme of the present invention and not to limit it, although logical
It crosses above preferred embodiment the present invention is described in detail, however, those skilled in the art should understand that, can be
Various changes are made to it in form and in details, without departing from claims of the present invention limited range.