阅读说明：本技术 一种Pt-IrO2双效氧电催化剂及其制备和在一体化再生质子交换膜燃料电池中的应用 (Pt-IrO2Double-effect oxygen electrocatalyst, preparation thereof and application thereof in integrated regenerated proton exchange membrane fuel cell ) 是由 宋玉江 吕洋 于 2021-07-07 设计创作，主要内容包括：本发明属于电催化领域,具体涉及一种Pt-IrO-(2)双效氧电催化剂及其制备方法和在一体化再生质子交换膜燃料电池中的应用。通过控制该电催化剂的组分、尺寸及形貌等,得到具有较好的氧还原/氧析出双效氧电催化剂,该Pt-IrO-(2)电催化剂制备方法简单、环境友好、制备周期短,易于放大合成,可以应用在电催化领域。(The invention belongs to the field of electrocatalysis, and particularly relates to Pt-IrO 2 A double-effect oxygen electro-catalyst, a preparation method thereof and application thereof in an integrated regeneration proton exchange membrane fuel cell. The Pt-IrO electrocatalyst with good oxygen reduction/oxygen precipitation double effects is obtained by controlling the components, size, morphology and the like of the electrocatalyst 2 The preparation method of the electrocatalyst is simple, environment-friendly, short in preparation period, easy to amplify and synthesize and capable of being applied to the field of electrocatalysis.)

1. Pt-IrO₂The preparation method of the double-effect oxygen electrocatalyst is characterized by comprising the following steps of:

(1) preparing a Pt nanowire net: adding the Pt salt aqueous solution into a hydrophobic solvent containing a surfactant, and stirring for more than 0.5h at 20-30 ℃ and 10-300 rpm; adding water into the hydrophobic phase for dilution to keep the concentration of Pt salt in the system at 0.1-10mM, adjusting the rotation speed to 500-2000rpm, adding a reducing agent aqueous solution, and reacting for more than 5min to obtain a black suspension;

the concentration of the Pt salt aqueous solution is 0.1-500 mM;

the concentration of the surfactant is 0.1-500 mM;

the volume ratio of the Pt salt aqueous solution to the hydrophobic solvent containing the surfactant is 0.1-10;

the concentration of the reducing agent aqueous solution is 1-5000 mM;

the volume ratio of the hydrophobic phase to the aqueous solution of the reducing agent is 0.1-10;

(2) adding iridium salt aqueous solution into the suspension, reacting at above 70 deg.C for above 5 hr, centrifuging, and drying to obtain Pt-IrO₂A dual-effect oxygen electrocatalyst;

the Pt-IrO₂Double effectIrO in oxygen electrocatalyst₂The loading is 0.1-80 wt%.

2. The method according to claim 1, wherein the Pt salt is one or a mixture of two or more of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, ammonium chloroplatinate, and ammonium chloroplatinate.

3. The method according to claim 1, wherein the surfactant is one or a mixture of two or more of cetyltrimethylammonium bromide, polyoxyethylene lauryl ether, octadecyltrimethylammonium chloride, sodium dodecylbenzenesulfonate, sodium hexadecylsulfonate, potassium stearate, sodium oleoyl polyamino acid, sodium dodecylaminopropionate, sodium lauryl sulfate, polyoxyethylene lauryl ether, sorbitan laurate, diethanolamide oleate, dodecyl dimethyl betaine, and tetradecyl dimethyl sulfoethyl betaine.

4. The method according to claim 1, wherein the hydrophobic solvent is one or a mixture of two or more of chloroform, acetone, toluene, xylene, n-hexane, cyclohexane, cyclohexanone, carbon tetrachloride, methyl isobutyl ketone, and isopropyl acetate.

5. The method according to claim 1, wherein the reducing agent is one or more of lithium borohydride, sodium borohydride, potassium borohydride, ascorbic acid, oxalic acid, malic acid, citric acid, glucose, and sucrose.

6. The production method according to claim 1, wherein the iridium salt is one or a mixture of two or more of iridium chloride, chloroiridic acid, sodium chloroiridate, ammonium hexachloroiridate, potassium hexachloroiridate (IV), potassium hexachloroiridate (III), and iridium bromide.

7. According to the rightPt-IrO prepared by the method of any one of claims 1 to 6₂Double-effect oxygen electrocatalyst.

8. The Pt-IrO according to claim 7₂The double-effect oxygen electrocatalyst is characterized in that the Pt-IrO is₂The double-effect oxygen electro-catalyst is in a nanowire net structure, and the diameter of a nanowire is 1-5 nm.

9. The Pt-IrO according to claim 7 or 8₂The application of the double-effect oxygen electrocatalyst in the integrated regeneration proton exchange membrane fuel cell.

Technical Field

The invention relates to a Pt-IrO₂A double-effect oxygen electro-catalyst, a preparation method thereof and an application thereof in an integrated regeneration proton exchange membrane fuel cell belong to the field of electro-catalysis.

Background

The increasing demand for energy sources has prompted intensive research into electrochemical technologies for energy storage and energy conversion, such as integrated regenerative proton exchange membrane fuel cells (UR-PEMFC). UR-PEMFC combines Proton Exchange Membrane Fuel Cell (PEMFC) and proton exchange membrane water electrolysis cell (PEMEC), has high specific energy (0.4-1.0kWh/kg), has long-term storage capability due to elimination of self-discharge, and has advantages of power output capability and energy storage capability, etc. which are widely noticed. Nevertheless, UR-PEMFCs need further improvement and optimization in order to reach the level of fuel cells and electrolyzers in terms of energy efficiency and durability. Currently, the main challenges faced by UR-PEMFC technology are: the oxygen electrode involves a complex four electron transfer process during discharge and charge, with slow ORR and OER kinetics, requiring the use of large amounts of noble metal electrocatalysts (Pt, Ru, Ir and their oxides) to improve their performance, and the high price of noble metals has hindered the commercialization of UR-PEMFC technology. Therefore, the development of novel electrocatalysts having high activity and durability is urgently needed.

The unsupported Pt black electrocatalyst is of particular interest to researchers due to its excellent ORR catalytic performance and better stability under acidic conditions, but at high positive potentials of OER, Pt is easily converted into oxide and is not suitable for OER, and the best performing OER catalyst is RuO₂Or IrO₂Therefore, Pt and IrO were commercialized earlier₂The two electrocatalysts are physically mixed and applied to the oxygen electrode, the two active components are poor in dispersion, and IrO₂The poor conductivity of (A) can result in low utilization rate of each effective component, poor reversibility of oxygen electrode and high catalyst loading, which is not beneficial to reducing the cost of UR-PEMFC. Therefore, a novel Pt-IrO was developed₂The double-effect oxygen catalyst has important significance. Chinese application patent (application number: CN201910559444.1) discloses a method for preparing Pt-IrO by adopting electrostatic spinning₂The nano wire is used for preparing the electro-catalyst, but the efficiency of electrostatic spinning preparation is low, and the diameter size of the nano wire is large, so that the cost of the electro-catalyst is not reduced.

Disclosure of Invention

The invention provides a Pt-IrO₂A dual-effect oxygen electrocatalyst, its preparation and application in integrated regenerated proton exchange membrane fuel cell are nanowire network Pt-IrO₂The double-effect oxygen electrocatalyst and the nanowire net structure are favorable for improving the utilization efficiency of Pt, further improving the oxygen reduction activity, and simultaneously, the amorphous IrO₂Uniformly dispersed on the surface of the Pt nanowire net, and is beneficial to Pt-IrO₂The electro-catalyst is exposed from oxygen precipitation active sites, and the appearance of the electro-catalyst is IrO₂Amorphous thin layer modified Pt nanowire network and IrO₂The dispersion is uniform.

The technical scheme of the invention comprises the following steps:

Pt-IrO₂The preparation method of the double-effect oxygen electrocatalyst comprises the following steps:

(1) preparing a Pt nanowire net: adding the Pt salt aqueous solution into a hydrophobic solvent containing a surfactant, and stirring at 20-30 ℃ and 10-300rpm for more than 0.5h to completely transfer a compound containing Pt ions into the hydrophobic solvent; then adding water into the hydrophobic phase for dilution to keep the concentration of Pt salt in the system at 0.1-10mM, adjusting the rotating speed to 500-2000rpm, quickly adding a reducing agent aqueous solution, and reacting for more than 5min to obtain a black suspension;

the concentration of the Pt salt aqueous solution is 0.1-500mM, and the preferred range is 1-100 mM;

the surfactant concentration is 0.1-500mM, preferably in the range of 1-100 mM;

the volume ratio of the Pt salt aqueous solution to the hydrophobic solvent containing the surfactant is 0.1-10;

the concentration of the reducing agent aqueous solution is 1-5000mM, and the preferred range is 50-2000 mM;

the volume ratio of the hydrophobic phase to the aqueous solution of the reducing agent is 0.1-10;

(2) adding iridium salt aqueous solution into the suspension, reacting at above 70 deg.C for more than 5 hr, centrifuging, and drying to obtain Pt-IrO₂A dual-effect oxygen electrocatalyst; the better oxygen reduction/oxygen precipitation double-effect oxygen electrocatalyst is obtained by controlling the components, the size, the morphology and the like of the electrocatalyst;

the Pt-IrO₂Iro in nanowire electrocatalysts₂The loading is 0.1 to 80 wt%, preferably in the range of 0.1 to 30 wt%.

In the above technical solution, further, the Pt salt is one or a mixture of two or more of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, ammonium chloroplatinate, and ammonium chloroplatinate.

In the above technical solution, further, the surfactant is one or a mixture of two or more of cetyltrimethylammonium bromide, polyethylene oxide lauroyl ether, octadecyltrimethylammonium chloride, sodium dodecylbenzenesulfonate, sodium hexadecylsulfonate, potassium stearate, sodium oleoyl polyamino acid, sodium dodecylaminopropionate, sodium lauryl sulfate, polyethylene oxide lauroyl ether, sorbitan laurate, diethanolamide oleate, dodecyl dimethyl betaine, and tetradecyl dimethyl sulfoethyl betaine.

In the above technical solution, further, the hydrophobic solvent is one or a mixture of two or more of chloroform, acetone, toluene, xylene, n-hexane, cyclohexane, cyclohexanone, carbon tetrachloride, methyl isobutyl ketone, and isopropyl acetate.

In the above technical solution, further, the reducing agent is one or a mixture of two or more of lithium borohydride, sodium borohydride, potassium borohydride, ascorbic acid, oxalic acid, malic acid, citric acid, glucose, and sucrose.

In the above technical solution, the iridium salt is one or a mixture of two or more of iridium chloride, chloroiridic acid, sodium chloroiridate, ammonium hexachloroiridate, potassium hexachloroiridate (IV), potassium hexachloroiridate (III) and iridium bromide.

The invention also relates to protection of Pt-IrO prepared by the method₂A two-way oxygen electrocatalyst, said Pt-IrO₂The double-effect oxygen electro-catalyst is in a nanowire net structure, and the diameter of a nanowire is 1-5 nm.

The invention also relates to the protection of the Pt-IrO₂The application of the double-effect oxygen electrocatalyst in the integrated regeneration proton exchange membrane fuel cell.

The invention has the beneficial effects that:

Pt-IrO prepared by the invention₂The nanowire mesh electrocatalyst has oxygen reduction and oxygen precipitation activities at the same time. The Pt nanowire network has high electrochemical activity specific surface area, is beneficial to improving the utilization rate of Pt atoms, and can ensure that the electrocatalyst has good electron transmission capacity relative to dispersed particles, thereby ensuring that the electrocatalyst has excellent oxygen reduction performance, and in addition, IrO₂The active sites are uniformly dispersed on the surface of the Pt nanowire net, so that the active sites for oxygen precipitation can be fully exposed, and the oxygen precipitation performance is improved. Nanowire mesh Pt-IrO₂The preparation method of the double-effect oxygen electrocatalyst is simple, environment-friendly, short in preparation period, easy for large-scale synthesis and applicable to the field of electrocatalysis.

Drawings

FIG. 1 shows Pt-IrO in example 1₂Transmission electron micrograph of electrocatalyst.

FIG. 2 shows Pt-IrO in example 1₂Electrocatalyst in (a) 0.1M HClO saturated with Nitrogen₄Medium cyclic voltammogram, (b) oxygen saturated 0.1M HClO₄The oxygen reduction polarization curve after internal resistance correction.

FIG. 3 shows Pt-IrO in example 1₂Electrocatalyst 0.1M HClO saturated in Nitrogen₄Oxygen evolution polarization curve in (1).

FIG. 4 shows (a-b) Pt-IrO in example 2₂TEM photograph of electrocatalyst, (c) Pt-IrO₂High-angle annular dark field scanning transmission electron microscope (HAADF-STEM) photos of the electrocatalyst, and (d-f) are element distribution photos of Ir and Pt + Ir in a graph c respectively; wherein the insert in (b) is Pt-IrO₂Diameter size distribution histogram of nanowires.

FIG. 5 shows Pt-IrO in example 2₂Electrocatalyst in (a) 0.1M HClO saturated with Nitrogen₄Medium cyclic voltammogram, (b) oxygen saturated 0.1M HClO₄The oxygen reduction polarization curve after internal resistance correction.

FIG. 6 shows Pt-IrO in example 2₂Electrocatalyst 0.1M HClO saturated in Nitrogen₄The oxygen evolution polarization curve after internal resistance correction in (1).

Detailed Description

The following examples further illustrate the invention but are not intended to limit the invention thereto.

Example 1

(1) Preparing a Pt nanowire net: adding potassium chloroplatinite (20mM, 10mL) aqueous solution into 10mL chloroform containing hexadecyl trimethyl ammonium bromide (145.8mg), stirring at 25 deg.C and 150rpm for 1h to completely transfer the compound containing Pt ions into chloroform, taking chloroform phase, adding water to dilute, keeping Pt concentration in the system at 2mM, and adjusting rotation speed to 1600rpm, rapid addition of NaBH₄Reacting for 10min in a (10mL, 300mM) solution, wherein the reaction system gradually becomes a black suspension and is reserved for later use;

(2) adding sodium chloroiridate (62.6 μ L, 20mM) aqueous solution into 5mL of the suspension, reacting at 100 deg.C for 12h, centrifuging, and drying to obtain Pt-IrO₂Nanowire networks (electrocatalysts).

FIG. 1 shows Pt-IrO in example 1₂Transmission Electron micrograph of electrocatalyst, Pt-IrO₂Is a nanowire net structure.

FIG. 2 shows Pt-IrO in example 1₂Electrocatalyst in (a) 0.1M HClO saturated with Nitrogen₄Medium cyclic voltammetry with an electrochemically active specific surface area of 29.7m²/g_Pt，Pt-IrO₂Electrocatalyst in (b) oxygen-saturated 0.1M HClO₄The oxygen reduction polarization curve after internal resistance correction in (1) has a scanning rate of 10mV/s, a rotating speed of 1600rpm, a half-wave potential of 0.914V and an MA of 81.1mA/mg at 0.9V vs. RHE_Pt。

FIG. 3 shows Pt-IrO in example 1₂Electrocatalyst 0.1M HClO saturated in Nitrogen₄The oxygen precipitation polarization curve after internal resistance correction in (1) has a scanning rate of 10mV/s, a rotating speed of 2000rpm and a concentration of 10mA/cm²The potential at the current density of (1.560V) and the MA of 1038.1mA/mg_Ir。

Example 2

(1) Preparing a Pt nanowire net: adding potassium chloroplatinite (20mM, 10mL) aqueous solution into 10mL chloroform containing hexadecyl trimethyl ammonium bromide (145.8mg), stirring at 25 deg.C and 150rpm for 1h to completely transfer the compound containing Pt ions into chloroform, taking the chloroform phase, adding water to dilute, keeping the concentration of Pt in the system at 2mM, adjusting the rotation speed to 1600rpm, and rapidly adding NaBH₄Reacting for 10min in a (10mL, 300mM) solution, wherein the reaction system gradually becomes a black suspension and is reserved for later use;

(2) adding sodium chloroiridate (141 μ L, 20mM) aqueous solution into 5mL of the suspension, reacting at 100 deg.C for 12h, centrifuging, and drying to obtain Pt-IrO₂Nanowire networks (electrocatalysts).

FIG. 4 shows (a-b) Pt-I in example 2rO₂TEM photograph of electrocatalyst, (c) Pt-IrO₂The HAADF-STEM picture of (a), (d) is a picture of the distribution of Ir element in the graph c, (e) is a picture of the distribution of Pt element in the graph c, (f) is a picture of the distribution of Pt + Ir element in the graph c, and the inset in the graph b is Pt-IrO₂Diameter size distribution histogram of nanowires, Pt-IrO₂The diameter of the nano-wire is 2.6 +/-0.5 nm, and the HAADF-STEM picture and the element distribution diagram thereof show that the distribution areas of Pt and Ir are basically coincident and IrO₂The nano-wire mesh is uniformly dispersed on the surface of the Pt nano-wire mesh, and no particles are deposited on the surface of the nano-wire mesh.

FIG. 5 shows Pt-IrO in example 2₂Electrocatalyst in (a) 0.1M HClO saturated with Nitrogen₄Medium cyclic voltammetry with an electrochemically active specific surface area of 38.3m²/g_Pt，Pt-IrO₂Electrocatalyst in (b) oxygen-saturated 0.1M HClO₄The scanning speed of the oxygen reduction polarization curve after internal resistance correction is 10mV/s, the rotating speed is 1600rpm, the half-wave potential is 0.914V, and the MA is 92.9mA/mg at 0.9V vs. RHE_Pt。

FIG. 6 shows Pt-IrO in example 2₂Electrocatalyst 0.1M HClO saturated in Nitrogen₄The oxygen precipitation polarization curve after internal resistance correction in (1) has a scanning rate of 10mV/s, a rotating speed of 2000rpm and a concentration of 10mA/cm²The potential at the current density of (1.540V) and the MA of 1255.1mA/mg_Ir。

Example 3

(1) Preparing a Pt nanowire net: adding a chloroplatinic acid (20mM, 10mL) aqueous solution into 10mL chloroform containing hexadecyl trimethyl ammonium bromide (145.8mg), stirring at 25 ℃ and 150rpm for 1h to completely transfer a compound containing Pt ions into the chloroform, taking a chloroform phase, adding water for dilution to keep the concentration of Pt in the system at 2mM, adjusting the rotating speed to 1600rpm, quickly adding an oxalic acid (10mL, 300mM) solution, reacting for 30min, and gradually changing the reaction system into a black suspension for later use;

(2) 5mL of the suspension was added with an aqueous solution of iridium chloride (62.6. mu.L, 20mM), reacted at 100 ℃ for 12 hours, centrifuged, and dried to obtain Pt-IrO₂Nanowire networks (electrocatalysts).

Example 4

(1) Preparing a Pt nanowire net: adding chloroplatinic acid (0.1mM, 10mL) aqueous solution into 10mL chloroform containing hexadecyltrimethylammonium bromide (145.8mg), stirring at 25 deg.C and 200rpm for 1h to completely transfer the Pt ion-containing compound into chloroform, taking the chloroform phase, adding water to dilute, keeping the Pt concentration in the system at 0.01mM, adjusting the rotation speed to 1600rpm, and rapidly adding NaBH₄Reacting for 10min in a (10mL, 300mM) solution, wherein the reaction system gradually becomes a black suspension and is reserved for later use;

(2) adding sodium chloroiridate (62.6 μ L, 20mM) water solution into 5mL of the suspension, reacting at 120 deg.C for 12h, centrifuging, and drying to obtain Pt-IrO₂Nanowire networks (electrocatalysts).

Example 5

(1) Preparing a Pt nanowire net: adding chloroplatinic acid (500mM, 1mL) aqueous solution into 10mL chloroform containing hexadecyltrimethylammonium bromide (145.8mg), stirring at 25 ℃ and 300rpm for 1h to completely transfer the Pt ion-containing compound into the chloroform, taking the chloroform phase, adding water to dilute the chloroform phase so that the concentration of Pt in the system is kept at 10mM, adjusting the rotation speed to 1600rpm, and rapidly adding NaBH₄Reacting for 10min in a (10mL, 300mM) solution, wherein the reaction system gradually becomes a black suspension and is reserved for later use;

(2) adding sodium chloroiridate (8.701mL, 20mM) aqueous solution into 5mL of the suspension, reacting at 70 deg.C for 5h, centrifuging, and drying to obtain Pt-IrO₂Nanowire networks (electrocatalysts).

Example 6

(1) Preparing a Pt nanowire net: adding chloroplatinic acid (500mM, 1mL) aqueous solution into 10mL chloroform containing hexadecyltrimethylammonium bromide (145.8mg), stirring at 25 ℃ and 200rpm for 1h to completely transfer the Pt ion-containing compound into the chloroform, taking the chloroform phase, adding water to dilute the chloroform phase so that the concentration of Pt in the system is kept at 10mM, adjusting the rotation speed to 1600rpm, and rapidly adding NaBH₄Reacting the solution (1000mM, 1mL) for 10min, wherein the reaction system gradually becomes a black suspension and is reserved for later use;

(2) 5mL of the suspension was added with an aqueous solution of sodium chloroiridate (8.701mL, 20mM) and reacted at 70 ℃ for 5 hoursThen centrifuging and drying to obtain Pt-IrO₂Nanowire networks (electrocatalysts).

Example 7

(1) Preparing a Pt nanowire net: adding a chloroplatinic acid (0.1mM, 10mL) aqueous solution into 10mL chloroform containing hexadecyl trimethyl ammonium bromide (145.8mg), completely transferring a compound containing Pt ions into the chloroform at 25 ℃ for 1h at 200rpm, taking a chloroform phase, adding water for dilution to keep the concentration of Pt in the system at 0.01mM, adjusting the rotating speed to 1600rpm, quickly adding a potassium borohydride (1.5mM, 10mL) solution, reacting for 10min, and gradually changing the reaction system into a black suspension for standby;

(2) 5mL of the suspension was added with an iridium chloride (141. mu.L, 20mM) aqueous solution, reacted at 100 ℃ for 12 hours, centrifuged, and dried to obtain Pt-IrO₂Nanowire networks (electrocatalysts).