CN115414930A

CN115414930A - Ru(bpy) 32+ Anode or cathode coreactant and method of making same

Info

Publication number: CN115414930A
Application number: CN202211033508.2A
Authority: CN
Inventors: 王诗君; 康子琪; 邓紫欣; 雷惠麟; 胡坤; 陈之行; 雷子衿; 王嘉逸; 臧广超
Original assignee: Chongqing Medical University
Current assignee: Chongqing Medical University
Priority date: 2022-08-26
Filing date: 2022-08-26
Publication date: 2022-12-02
Anticipated expiration: 2042-08-26
Also published as: CN115414930B

Abstract

The invention discloses a Ru (bpy) ₃ ²⁺ The anode or cathode coreactant and the preparation method thereof are Au-rGO compounds, and the particle size of Au nano particles in the anode coreactant is 10-15nm; the particle size of Au nano particles in the cathode coreactant is 2-4nm. The prepared anode coreactant has better performance of catalyzing OER reaction and can promote the anode luminescence of the terpyridyl ruthenium; the cathode coreactant has better catalytic ORR reactionCan promote the cathodoluminescence of the terpyridyl ruthenium.

Description

Ru(bpy) 32+ Anode or cathode coreactant and method of making same

Technical Field

The present invention belongs to Ru (bpy) ₃ ²⁺ Anode or cathode coreactant technical field, in particular relating to Ru (bpy) ₃ ²⁺ Anode or cathode coreactants and methods for their preparation.

Background

The statements herein merely provide background information related to the present disclosure and may not necessarily constitute prior art.

In recent years, the development of sensitive and specific tumor marker detection means is a hot point of research. Among them, electrochemiluminescence has been receiving wide attention due to its advantages such as high sensitivity and good stability. Electrochemiluminescence refers to the process that when a certain voltage or current is applied, a luminophor in a system generates excited state substances through potential excitation and a series of redox reactions, and the excited state substances emit light and emit energy when the excited state substances transition back to a ground state. Wherein the noble metal complex ruthenium (II) terpyridyl (Ru (bpy) ₃ ²⁺ ) And the derivative thereof is a luminous body which has high luminous efficiency and good stability and can be recycled. The compound can show potential-resolved luminescence property when promoted by different corresponding coreactants, namely electrochemiluminescence is generated under the action of different potentials, and can be selected as a luminophor of a single-luminophor multi-coreactant system.

However, most ECL analysis systems are typically based on a single signal ("signal on" or "signal off" mode), with disadvantages in detection: which is disadvantageous for the stability, accuracy and efficiency of signal output, and the integration and miniaturization of the biosensor.

The multi-signal output ECL detection system can avoid most defects of a single-signal ECL system, and is more flexible, convenient and accurate in detection. Multi-signal ECL output typically relies on introducing distinguishable signal output probes or constructing multi-channel detection. In the resolution ECL strategy, although the potential resolution ECL has the advantages of low instrument requirement, shortened detection time, improved sample flux and the like, a large number of potential resolution multi-signal ECL systems mostly use dual luminophores, two potential resolution complex luminophores and coreactants for combination, and are troubled by limited potential resolution luminescence pairs, troublesome assembly steps, complex marking processes, and inevitable mutual crosstalk between the coreactants and luminophores, between the coreactants and between the luminophores, so that the development of a ratio ECL detection system is greatly limited.

In the related research of the double signal ratio ECL strategy of a single luminophor, the selection of coreactant is very critical, the research on the coreactant under different potentials of the luminophor is relatively less and mostly difficult to synthesize and prepare, and researchers try to synthesize the coreactant of a cathode and an anode together or introduce the coreactant into an electrolytic reaction to generate the coreactant in situ so as to achieve the purposes of simplifying the processes of preparing, adding and the like of the coreactant. However, none of these studies essentially solves the relative lack of co-reactant studies, and the synthesis of cathode-anode co-reactant complexes is equally complex, with systems that generate co-reactants in situ being highly susceptible to environmental interference.

Disclosure of Invention

In view of the deficiencies of the prior art, it is an object of the present invention to provide a Ru (bpy) ₃ ²⁺ The anode coreactant or cathode coreactant and the preparation method thereof, the prepared anode coreactant has better performance of catalyzing OER reaction and can promote the anode luminescence of terpyridyl ruthenium; the cathode coreactant has better performance of catalyzing ORR reaction and can promote cathodoluminescence of terpyridyl ruthenium.

In order to achieve the purpose, the invention is realized by the following technical scheme:

in a first aspect, the present invention provides Ru (bpy) ₃ ²⁺ The anode or cathode coreactant is an Au-rGO compound, and the particle size of Au nanoparticles in the anode coreactant is 10-15nm; yin bodyThe particle size of Au nano-particles in the polar coreactant is 2-4nm.

In a second aspect, the present invention provides the Ru (bpy) ₃ ²⁺ A method for preparing an anode or cathode co-reactant comprising the steps of:

HAuCl is added ₄ Mixing the aqueous solution and the r-GO suspension in proportion, and performing ultrasonic dispersion to obtain a first mixture;

adding NaBH into the mixture I ₄ Mixing, adding sodium citrate, and mixing;

after the reaction is finished, separating and washing the solid product, and then re-dispersing the solid product to obtain a re-suspending solution;

centrifuging the re-suspended solution at 11000-12500rpm for 10-30min, and collecting the non-precipitated components of the non-solution.

The beneficial effects achieved by one or more of the embodiments of the invention described above are as follows:

the conversion of the terpyridyl ruthenium cathode and anode coreactant is realized by adjusting the size of the gold nano particle size loaded on the reduced graphene oxide. The crosstalk between the cathode and anode coreactants is greatly reduced in a single-illuminant multi-signal output system;

by designing ORR and OER catalysts with proper catalytic capability as cathode and anode coreactants of ruthenium, the precise design of the cathode and anode coreactants of terpyridyl ruthenium is realized.

The key point of the technical scheme of the invention is that the conversion of ruthenium cathode and anode coreactants is realized by adjusting the catalytic capability of ORR and OER by changing the particle size of Au-gamma GO.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

In FIG. 1, (a) is a large-scale Transmission Electron Microscope (TEM) of Au-rGO, (b) is an annular dark-field SEM of Au-rGO, and (c) is a scanning electron microscope SEM image of Au-rGO;

FIG. 2 is a atlas of Au/rGO with different sizes grown on a rGO substrate in the example of the present invention, where A is a transmission electron microscope image and B is a corresponding size histogram of Au/rGO-1; c is the corresponding size histogram of Au/rGO-2, D is the corresponding size histogram of Au/rGO-3, and E is the corresponding size histogram of Au/rGO-4.

FIG. 3 is a DPV test chart of Au/rGO-2 in an embodiment of the invention, and the electrolyte is terpyridyl ruthenium with pH value = 6;

FIG. 4 is an EDS mapping image of Au-rGO in an example of the invention, wherein A is an SEM image of Au-rGO at the 100nm scale; b is an EDS mapping image of carbon elements of Au-rGO at the scale of 100 nm; c is an EDS mapping image of nitrogen element of Au-rGO under the scale of 100 nm; d is an EDS mapping image of the oxygen element of Au-rGO under the scale of 100 nm; e is an EDS mapping image of a gold element of Au-rGO at the scale of 100 nm; f is an EDS mapping image of carbon, nitrogen, oxygen and gold elements of Au-rGO under the scale of 100 nm; g is an element content analysis chart obtained by EDS mapping of Au-rGO at the scale of 100 nm;

FIG. 5 is an XRD pattern of Au/rGO in an example of the invention;

FIG. 6 is an ultraviolet-visible absorption spectrum image of Au/rGO in the example of the present invention, wherein A is the ultraviolet-visible absorption spectrum of GO thin film and AuNPs/rGO nano-composite thin film; b is the ultraviolet visible absorption spectrum of Au/rGO with different reduction time of rGO. Wherein Au/rGO-A, B, C respectively represents that the reduction events of rGO are 3h, 6h and 12h;

FIG. 7 is a Zeta potential image of Au/rGO in an embodiment of the present invention;

in fig. 8, a) XPS survey spectra of the original graphene oxide film and AuNPsrGO nanocomposite film after 15min Ar plasma treatment; b) Graphene oxide films and C) high resolution C1 deconvolution spectra of AuNPsrGO films; d) Au4f XPS spectra of AuNPsrGO;

FIG. 9 is a Raman spectrum of Au/rGO in the example of the present invention;

FIG. 10 shows the ECL and CV performance of AuNPs-rGO with different AuNPs particle size in the examples of the present invention, where A is Au/rGO vs. Ru (bpy) with different AuNPs particle size ₃ ²⁺ ECL performance of action; b is CV expression of Au/rGO with different grain diameters of AuNPs; c is a cathode coreactant Au/rGO-2 and bare cellIn Ru (bpy) ₃ ²⁺ And CV performance in PBS; d is anode coreactant Au/rGO-3 and a bare electrode are respectively arranged on Ru (bpy) ₃ ²⁺ And CV performance in PBS;

FIG. 11 shows Au-rGO with different particle sizes in A) N ₂ In an atmosphere, B) in an air atmosphere, C) in an oxygen atmosphere; d) LSV images of Au-rGO-2 at different rotating speeds; e) Cathode co-reactant and F) anode co-reactant in an argon atmosphere.

FIG. 12 is an ECL image of different metal/reduced graphene oxide hybrids in an embodiment of the present invention, wherein A is the different metal/reduced graphene oxide hybrid pair Ru (bpy) ₃ ²⁺ ECL images of the effect; b is an LSV image of a different metal/reduced graphene oxide hybrid;

FIG. 13 is an ECL representation of the effect of Au-rGO-2 and Au-rGO-3 on ruthenium terpyridyl under different atmospheres in an example of the invention, wherein A is the ECL representation of the effect of the cathode co-reactant Au-rGO-2 on Ru (bpy) 32+ in a nitrogen, air and oxygen atmosphere; b is ECL expression of an anode coreactant Au-rGO-3 on Ru (bpy) 32+ in the atmosphere of nitrogen, air and oxygen;

in FIG. 14, A) after addition of superoxide anion inhibitor, cathode coreactant Au/rGO-2 vs. Ru (bpy) ₃ ²⁺ ECL performance of action; b) After addition of hydroxyl radical inhibitor, anode coreactant Au/rGO-3 vs Ru (bpy) ₃ ²⁺ ECL performance of action;

in FIG. 15, ru (bpy) ₃ ²⁺ Elimination of all involved O under Ar atmosphere in acetonitrile solution ₂ Comparing A) the promotion effect of Au-rGO-2 on cathode luminescence and B) the promotion effect of Au-rGO-3 on cathode luminescence in ORR and OER processes of dissolved oxygen and oxygen atoms;

FIG. 16 is a diagram showing ECL characteristics of Au-rGO;

FIG. 17 is a graph showing the change of Ic/Ia with reduction time in the example of the present invention.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

The inventors tried to innovatively use ruthenium terpyridyl (Ru (bpy) without introducing excess reactants ₃ ²⁺ ) As a single emitter, by virtue of its property of emitting both anode and cathode under the action of corresponding co-reactants, similar co-reactants are found to achieve signal changes of opposite potential separation.

The inventor finds that Ru (bpy) ₃ ²⁺ The cathodic process of (a) is associated with an Oxygen Reduction Reaction (ORR), and the generation of Reactive Oxygen Species (ROS), an intermediate of the ORR reaction, can significantly enhance luminescence. The anodic process of ruthenium terpyridyl can be performed by O ₂ Quenching, but enhancement by OH ", both final and intermediate products of the OER process (the reverse reaction of ORR), respectively. Since Au and its related alloy clusters have catalytic capability of ORR and OER, and adjustable catalytic performance by changing particle size of AuNPs, it becomes to realize Ru (bpy) ₃ ²⁺ Anode and cathode luminescence conversion reagents.

In a first aspect, the present invention provides Ru (bpy) ₃ ²⁺ The anode or cathode coreactant is an Au-rGO compound, and the particle size of Au nanoparticles in the anode coreactant is 10-15nm; the particle size of Au nano particles in the cathode coreactant is 2-4nm.

It was found that AuNPs and rGO alone do not catalyze Ru (bpy) significantly ₃ ²⁺ Anode or cathode emission of (a); auNPs with small particle size have good cathode promoting effect. This is because the smaller size Au particles have greater electrocatalytic activity for the Oxygen Reduction Reaction (ORR) than the larger size AuNPs, and a significant fraction of the surface atoms may absorb and activate oxygen molecules.

In some embodiments, the degree of reduction of rGO in the anode co-reactant is 5.5 to 6.5h in hydrazine hydrate vapor.

The graphene oxide has certain anode stimulation characteristics, and the reduction of the graphene oxide by hydrazine hydrate can change the anode stimulation characteristics, so that the cathode luminescence promotion capability of the graphene oxide is greater than that of the graphene oxide.

Incomplete reduction reaction formed by the defective graphene substrate can accelerate charge transfer from AuNPs to O ₂ By destabilizing ORR intermediate species and reducing O ₂ The activation energy of dissociation reduces the energy barrier of the rate limiting step resulting in more active oxygen production.

In some embodiments, the extent of rGO reduction in the cathode co-reactant is 5.5 to 6.5h in hydrazine hydrate vapor.

In a second aspect, the present invention provides the Ru (bpy) ₃ ²⁺ A method for the preparation of an anode or cathode co-reactant comprising the steps of:

adding HAuCl ₄ Mixing the aqueous solution and the r-GO suspension in proportion, and performing ultrasonic dispersion to obtain a first mixture;

adding NaBH into the mixture I ₄ Mixing, adding sodium citrate, and mixing;

centrifuging the re-suspended solution at 11000-12500rpm for 10-30min, and collecting un-precipitated components of the un-suspended solution.

NaBH ₄ Is used for introducing HAuCl ₄ Reducing to Jin Shanzhi, and further forming gold nanoparticles.

The effect of adding sodium citrate is to further reduce the gold nanoparticles.

Because the particle sizes of the gold nanoparticles in the solution are not uniform and have large difference before the step, the heavy suspension solution is centrifuged at 11000-12500rpm for 10-30min, and in the process, the gold nanoparticles with large particle sizes and the undesirable products such as the compound of the gold nanoparticles and the reduced graphene oxide are centrifuged and removed. And removing the gold nanoparticles with larger particle size in the precipitate by adopting a method of centrifuging at a proper rotating speed for a proper time and then taking the supernatant.

In some embodiments, the method further comprises a step of preparing reduced graphene oxide by reducing graphene oxide with hydrazine hydrate steam, specifically: respectively placing the suspension of the graphene oxide in water and hydrazine hydrate in two containers, placing the two containers in the same closed space, and stirring for reaction.

In some embodiments, during the preparation of the anode co-reactant, HAuCl ₄ 、r-GO、NaBH ₄ In a mixed reaction system of sodium citrate and HAuCl ₄ The concentration of (A) is 18-22mg/ml;

the concentration of r-GO is 1.8-2.2mg/ml;

NaBH ₄ the concentration of (A) is 0.005-0.015M;

the concentration of sodium citrate is 0.005-0.015M.

In some embodiments, during the preparation of the cathodic co-reactant, HAuCl ₄ 、r-GO、NaBH ₄ In a mixed reaction system with sodium citrate, HAuCl ₄ The concentration of (A) is 18-22mg/ml;

the concentration of r-GO is 1.8-2.2mg/ml;

NaBH ₄ the concentration of (A) is 0.005-0.015M;

the concentration of sodium citrate is 0.005-0.015M.

In some embodiments, in the step of separating and washing the solid product after the reaction is completed, the separation is centrifugal separation, the rotation speed of the centrifugal separation is 14500-15500rpm, and the centrifugal time is 30-60min.

The centrifugation is carried out at a relatively high rotation speed for a relatively long centrifugation time in order to allow residual reducing agent (NaBH) ₄ Sodium citrate) and AuNPs/rGO are completely separated, and the influence of the residual reducing agent on the AuNPs/rGO is avoided.

In some embodiments, the HAuCl is reacted with a carboxylic acid ₄ After the aqueous solution and the r-GO suspension are mixed in proportion, the method comprises the steps of ultrasonic treatment and stirring, wherein the ultrasonic treatment time is 5-15min, and the stirring time is 1.5-2.5h. Ultrasonic agitation causes HAuCl ₄ Mixing with r-GO thoroughly and uniformly. The ultrasonic power is 200w.

Preferably, for HAuCl ₄ The process of ultrasonic treatment and stirring of the mixed solution of the aqueous solution and the r-GO suspension is repeated for 2-4 times. Repeated ultrasonic stirring to enable HAuCl ₄ Fully mixing with r-GO and uniformly dispersing.

In some embodiments, to HAuCl ₄ Adding NaBH into mixed solution of aqueous solution and r-GO suspension ₄ Then, after preliminary stirring, carrying out ultrasonic treatment; the primary stirring time is 10-20min, and the ultrasonic treatment time is 5-15min. Stirring for uniform mixing and sonication for particle size dispersion. The ultrasonic power is 200w.

In some embodiments, after adding sodium citrate to the mixed solution, after preliminary stirring, sonication; the primary stirring time is 20-40min, and the ultrasonic treatment time is 5-15min. Stirring for uniform mixing and sonication for particle size dispersion. The ultrasonic power is 200w.

The present invention will be further described with reference to the following examples.

Experimental Material

Tetrachloroauric acid (HAuCl) ₄ ) Silver nitrate (AgNO) ₃ ) And sodium citrate from Biotechnology engineering (Shanghai) GmbH;

triterpyridine (2,2' -bipyridine) ruthenium (II) (Ru (bpy) ₃ ²⁺ ) Purchased from nakai technologies, suzhou;

the natural graphite powder (325 meshes) is purchased from Nanjing Xiancheng nano material technology Co., ltd;

sodium borohydride (NaBH) ₄ ) Ethanethiol, ascorbic Acid (AA) and isopropanol were purchased from national pharmaceutical group Chemicals, inc.

Adding 0.1M KCl into KH prepared in proper proportion ₂ PO ₄ And Na ₂ HPO ₄ In the mixture, phosphate buffer (PBS, 0.1M pH 7.4) was obtained for ECL detection. All other chemicals were analytical grade chemicals and no further purification was required for use. All aqueous solutions were freshly prepared and diluted with ultrapure water (. Gtoreq.18 M.OMEGA., milli-Q, millipore).

Instrumentation and equipment

ECL measurements were performed on an MPI-E multifunctional electrochemiluminescence analyzer (siennamei analyzer, llc). Three-electrode ECL battery working electrode composed of modified glassy carbon

An Ag/AgCl (saturated KCl) electrode as a reference electrode and a platinum wire as a counter electrode. The photomultiplier tube (PMT) was biased at 600V. The scanning voltage is 1.5 to-2V, and the scanning speed is 100mV/s.

Ultraviolet-visible (UV-vis) absorption spectra and fluorescence spectra were obtained using a spectrophotometer (Model UV2450, shimadzu, japan) and a spectrophotometer (Model F-7000, hitachi, japan), respectively.

X-ray photoelectron spectroscopy (XPS) characterization was measured by VG Multilab 2000X X ray photoelectron spectrometer (us thermoelectric corporation, usa).

Fourier transform infrared spectroscopy (FT-IR) was observed on an infrared spectrometer (ALPHA, bruker, germany).

Transmission Electron Microscope (TEM) images were obtained using a JEM-2010 Transmission Electron microscope (JEOL, japan).

Cyclic Voltammograms (CVs) and Electrochemical Impedance Spectroscopy (EIS) were obtained by an electrochemical workstation (Ivium, netherlands).

CVs were at 5mM K with 0.1M KCL ₃ (CN) ₆ ]/K ₄ (CN) ₆ ]In solution, between-0.2V and +0.6V, at a scan rate of 100mV/s.

EIS measurements were performed by applying a voltage of 5mV amplitude in the frequency range of 0.01Hz to 106 Hz.

Inductively coupled plasma mass spectrometry (ICP-MS, iCAP Q, thermo Fisher, america) was used to analyze real samples.

The preparation method comprises the following steps:

1) GO synthesis:

synthesizing oxidized graphene from oxidized natural graphite powder by a Hummer method. Graphite powder (3.0 g) was added to concentrated sulfuric acid (70 mL) while stirring vigorously in an ice bath. Potassium permanganate (9.0 g) was then added gently to keep the suspension temperature below 20 ℃. The reaction was transferred to a 40 ℃ oil bath in sequence and stirred actively for about 30 minutes. Then, 150mL of water was added, and the solution was stirred at 95 ℃ for 15 minutes. An additional 500mL of water was added followed by a steady addition of 15mL of hydrogen peroxide (30%) to change the color of the solution from dark brown to yellow.

To remove metal ions, the post-reaction mixture was first quenched with 250mL 1: the 10 hydrochloric acid and water mixed solution was filtered and washed, and then the resultant solid was dried in air and diluted to 600mL with water to form an aqueous graphite oxide dispersion. Then, the molecular weight is 8000-14,000g mol ^-1 The dialysis membrane (from Beijing Chemical Reagent co., china) was dialyzed for one week to eliminate residual metals.

The graphite oxide aqueous solution dispersion from which the metal ions were removed was diluted to 1.2L, stirred overnight, sonicated for 30 minutes, and exfoliated into graphene oxide. Finally, the graphene oxide dispersion was centrifuged at 3000rpm for 40 minutes to remove the non-exfoliated graphite.

2) Synthesis of reduced graphene oxide r-GO

Dissolving 2mg of graphene oxide in 2ml of ultrapure water; the obtained 2mg/ml graphene oxide and 2ml hydrazine hydrate are respectively placed in two clean small beakers, and a large beaker is covered on the two beakers. After 6 hours of stirring, the color of the graphene oxide fabric changed from light brown to black, indicating the formation of reduced graphene oxide.

3) Synthesis of cathode coreactant Au-rGO-2 and anode coreactant Au-rGO-3 of terpyridyl ruthenium

HAuCl ₄ (2% of HAuCl for Au-rGO-2,2.5. Mu.l ₄ Diluting with ultrapure water to 10 μ l; 2% of 10. Mu.l of HAuCl for Au-rGO-3 ₄ Used undiluted) was added 2ml of r-GO and the solution was stirred, followed by 10 minutes of sonication, then 2 hours of stirring at room temperature, and this procedure was repeated three times.

After 10 minutes of ultrasonography, 25. Mu.l of 0.01M freshly prepared NaBH was added rapidly ₄ Stirring for 15 minutes, and then carrying out ultrasonic treatment for 10 minutes;

then 10. Mu.l of 0.01M sodium citrate was added to the solution, stirred for 25 minutes, and then sonicated for 10 minutes.

Thereafter, centrifugation was carried out at 15,000rpm for 45 minutes to remove excess NaBH ₄ And sodium citrate, rinsed thoroughly with water and finally redispersed in 2mL of ultrapure water. The resuspended solution was then centrifuged at 12,000rpm for 20 minutes to collect the non-precipitated components of the solution for further use and characterization.

Characterization of the Synthesis

Electron microscopy and particle size analysis

The nanostructure of the composite material can be verified by morphological analysis. Large scale Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) images show typical rugate texture of Au-rGO thin films, illustrating the presence of flexible ultra-thin rGO flakes (as shown in fig. 1). In addition, obviously visible spherical AuNPs particles appear on the background reduced graphene oxide flakes, namely black dots in a TEM image and bright dots in an SEM image, and the in-situ growth of AuNPs on the reduced graphene oxide flakes is verified. TEM images (fig. 1 b) show that AuNPs are uniformly spread on the surface of rGO sheet, with no loose clusters formed on the outside. The inset in fig. 1b shows that the AuNPs have a diameter of about 3.8nm on Au/rGO, smaller than the size of individual AuNPs, indicating that the electrostatic or pi-pi stacking interaction between the AuNPs and rGO surface is relatively strong.

According to the Plieth equation:

where Ebulk is the oxidation potential of the bulk metal (taken as 1.15V) and γ is the surface tension (1880 erg cm) ^-2 )，V _m Is the molar volume (10.21 cm) ³ mol ^-1 ) Z is the number of electrons (1), F is the Faraday constant, and d is the NP diameter (3.4 nm).

Therefore, the peak oxidation potential of AuNPs (E AuNPs) (Au (0) to Au (I)) in Au/rGO-2 was calculated to be 0.92V (compared to SHE). E AuNPs and Ag/AgCl electrodes are converted according to the Nernst equation:

E°vs Ag/AgCl＝E°vs SHE-E° _Ag/AgCl -(RT/(zF·lge))pH；

wherein the E DEG vs SHE of AuNPs is 0.92V _Ag/AgCl Is 0.22V vs SHE. The pH of the system was 6.

Thus, the comparison of E ° AuNPs to Ag/AgCl was calculated to be 0.35eV, which is consistent with the CV peak at 0.37V for AuNPs (Au (0) to Au (I)) when 2mol/L Au/rGO-2 was loaded on the electrode (FIG. 3).

EDS

The analysis of the chemical composition was performed by EDS mapping. Mapping of Au-rGO composites by EDS further confirmed the presence of AuNPs on rGO, which showed characteristic peaks of C, N, O and Au, consistent with the chemical composition of graphene and AuNPs. The presence of an oxygen characteristic peak in the EDS spectrum indicates that the oxygen-containing group on the graphene oxide is not completely reduced (as shown in fig. 3).

XRD

The crystallographic phase composition of Au/rGO was analyzed using XRD (FIG. 5). As GO decreases, the diffraction peak of GO at 10.2 (0 2) disappears (fig. 5, dark blue curve) and appears as a new peak at 29.0 (0 2) (fig. 5, light blue curve) for rGO production. The characteristic diffraction peaks of rGO, which also appear in the diffraction spectrum Au/rGO, have a significant characteristic diffraction peak at 38.3 ° and two peaks with poor intensity at 44.5 ° and 82.4 °, respectively, corresponding to Au (1 1 1), au (2 0) and Au (2 22 2), respectively, due to the recombination of the face-centered-cubic (fcc) structure of AuNPs on rGO.

Ultraviolet-visible absorption spectrum

To further demonstrate the double reduction effect, the uv-vis absorption spectrum of the Au-rGO composite film was also recorded, and as shown in a in fig. 6, rGO spectrum showed a characteristic absorption peak at 227nm and a shoulder peak at 315nm, corresponding to the pi-pi transition of the aromatic Csingle bond C bond and the n-pi transition of the Csingle bond O bond, respectively. In the Au-rGO spectrum, the peak at 227nm was red-shifted to 258nm and the peak at 315nm disappeared, confirming the presence of rGO. In addition, a new absorption peak at 535nm appears in the Au-rGO spectrum, which is attributed to surface plasmon resonance in Au and confirms the formation of Au.

In FIG. 6B, au/rGO-A, au/rGO-B and Au/rGO-C indicate that the degree of reduction of rGO in Au/rGO is: reducing in hydrazine hydrate steam for 3h, 6h and 12h. red-shift of characteristic peaks of rGO, indicating an increase in rGO reduction time.

zeta potential

Zeta potential measurements were made for GO, rGO and Au/rGO to detect surface charge characteristics. The average zeta potential of GO is about-44 mV, and comes from the negatively charged oxygen-containing functional groups on the GO surface, such as carboxyl and epoxy groups. The 23.5mV value of RGO becomes more negative after the reduction process, probably because the functionalization of RGO during partial reduction results in a higher surface negative charge density compared to GO. This results in stable dispersion of RGOs in aqueous solution by electrostatic repulsion with water molecules. An estimate of the Zeta potential of Au/rGO NCs was found to be 7.95mV. The reduction in negative charge of Au/rGO NCs compared to rGO indicates that Au NPs were successfully synthesized on rGO, as shown in FIG. 7.

XPS

The chemical structures of rGO and Au/rGO were further confirmed by X-ray photoelectron spectroscopy (XPS). As is apparent from A in FIG. 8, carbon (C) and oxygen (O) are the main components of RGO, and Au-RGO is composed of C, O and gold (Au). The proportion of nitrogen (N) in rGO and Au-RGO is very small. In fig. 8B shows a high resolution C1s deconvolution spectrum of Au-rGO, separable into four peaks centered at 284.6 eV (C-C/C = C in the aromatic ring), 286.3eV (C-O), 287.2eV (C = O) and 288.4eV (O-C = O), with relatively high C = O peaks indicating that rGO is not completely reduced. The high resolution N1 s spectrum of C in fig. 8 can be deconvoluted into three gauss-lorentn Ji Feng with binding energies of 398.6eV (sp 2 bonded nitrogen in N-containing aromatic rings (C-N = C)), 399.7eV (tertiary nitrogen N- (C) 3 group) and 400.7eV (amino group (C-N-H)), confirming the presence of amino groups on Au/rGO.

The high resolution Au4f spectra obtained from the Au-RGO samples, as shown in D in FIG. 8, found more prominent Au4f 7/2 and Au4f 5/2 spin-orbit bidaughter at 88.3eV and 84.5eV and weaker Au4f 5/2 and Au4f 7/2 at 87.2V and 83.4eV due to Au (0) in the binding energy scale of Au (I). Thus, the chemistry of gold in Au-rGO has been identified as the combination of metals-Au (0) and Au (I) present in Au-N bonds. The slight negative bias (0.4 eV) exhibited by the Au4f spin-orbit doublet region relative to the conventional reference position of metal-Au means that there is a strong interaction between Au and the RGO framework.

Raman spectroscopy

And performing Raman spectrum test on Au/rGO and rGO. Given that the raman spectra between Au/rGO and rGO are nearly identical (fig. 9), it can be reasonably assumed that the formation of AuNPs has little effect on the in-plane sp2 domain size of graphene, probably because the low loading volume (0.01 atomic%) of AuNPs does not seem to be sufficient to structurally damage rGO.

ECL characterization

For the purpose of research and demonstration, a series of Au-rGO (Au-rGO-1, au-rGO-2, au-rGO-3 and Au-rGO-4) with particle sizes of 3.1, 3.4, 13.5 and 30.6nm are synthesized.

In FIG. 10, A shows Ru (bpy) ₃ ²⁺ And the corresponding ECL performance of the Au/rGO prepared. With Au/rGO-1 as a co-reactant, stronger Ru (bpy) was observed at-1.7V ₃ ²⁺ (iii) cathodoluminescence (red line) (5123a.u). Au/rGO-2 is in the condition of-1.7V (blue line), ru (bpy) ₃ ²⁺ Has super-strong cathodoluminescence (14488a. U) which is stronger than the corresponding peak of Au/rGO-1. Au/rGO-3 and Au/rGO-4 show poor cathode catalytic performance, and the lowest cathode peak is lower than that of naked GCE. Thus, the ECL results demonstrate that Au/rGO can exhibit Ru (bpy) at medium-small AuNPs particle sizes ₃ ²⁺ The strong cathode co-reaction characteristic of (2).

Mechanism for controlling a motor

Cathodic coreactant of ruthenium with ORR

The cathodic co-reactant of ruthenium terpyridyl is an ORR catalyst that is strong enough to generate both sufficient ROS and to avoid complete reaction to produce excess water. Au/rGO has tunable catalytic performance, which can be enhanced by scaling down AuNPs, and vice versa. Furthermore, according to the d-band theory, as the core size of Au nanoclusters decreases, the d-band narrows and moves to the fermi level, indicating that smaller Au clusters are energetically more favorable for O ₂ Adsorption of (3). Therefore, based on the above theory, moderateAu/reduced graphene oxide of particle size vs Ru (bpy) ₃ ²⁺ The promotion of cathodoluminescence is greatest.

A series of Au-rGO (Au-rGO-1, au-rGO-2, au-rGO-3 and Au-rGO-4) with particle sizes of 3.1, 3.4, 13.5 and 30.6nm are synthesized. The ECL results demonstrate that Au/rGO can exhibit Ru (bpy) at medium-small AuNPs particle sizes ₃ ²⁺ The strong cathode co-reaction characteristic (as shown in fig. 10 a).

Cyclic Voltammograms (CVs) show the addition of Ru (bpy) ₃ ²⁺ Reversible peaks for redox reaction (at 1.13V and +1.05V, respectively) and Ru (bpy) ₃ ²⁺ In addition to the redox reactions of (1.65V and-1.60V, respectively) (FIG. 10B), in PBS and Ru (bpy) ₃ ²⁺ A small peak of-0.65V observed on GCE in/PBS was attributed to the Oxygen Reduction Reaction (ORR). The peak at-0.65V was greatly increased after modification of Au/rGO-2 on GCE, indicating its catalytic performance in the ORR process (FIG. 10C).

By O at room temperature ₂ Or N ₂ Cyclic voltammetry was performed in saturated 0.1M KOH aqueous solution to compare the catalytic performance of a series of Au/rGO. As shown in FIG. 11B, the ORR onset potential was about-0.08V (vs Ag/AgCl) and the reduction peak was about-0.22V (vs Ag/AgCl). The inhibition and enhancement of the reduction peaks in nitrogen and oxygen atmospheres indicated that oxygen was involved in the reaction, which demonstrates the ORR process (fig. 11A-C). The tunable catalytic properties of Au/RGO were demonstrated by varying the particle size of Au/RGO under the same atmosphere. Wherein the Au/rGO-1 catalyst with the smallest particle size has the best ORR catalytic performance, and the catalytic performance is reduced along with the increase of the particle size. These findings indicate that Au/rGO-2 with moderate ORR catalytic ability will have superior cathode co-reactant performance.

At O ₂ In a saturated 0.1M KOH solution, the electron transfer number during the catalysis was calculated using Linear Sweep Voltammetry (LSV) at different rotation speeds (. Omega.) from 225rpm to 3600rpm for the Rotating Disk Electrode (RDE) (FIG. 11D). The ORR initial potential of the Au/rGO-2 modified electrode at 1600rpm is about-0.20V (vs Ag/AgCl), and the ORR current density at 0.8V (vs Ag/AgCl) is about 0.28mA/cm ² . Illustration of FIG. 11D depictsThe Koutecky-Levich equation (J-1 vs. omega-1/2) at different electrode potentials (from 0.5V to 0.7 vsAg/AgCl) was developed. The number of transfer electrons per molecule of oxygen (N) catalyzed by Au/rGO-2 is 1.2-1.7 in the potential range of-0.5 to-0.7V (vs Ag/AgCl) according to the K-L equation.

The catalytic activity of Au/rGO and different metal/reduced graphene oxide hybrids under different AuNPs particle sizes is characterized by recording an RDE curve (1600 rpm) corresponding to ORR. As shown in FIG. 11, the ORR onset potential (-0.20V) of Au/rGO-2 is more positive than that of Au/rGO-3 (-0.25V), but more negative than that of Au/rGO-1 (-0.18V). In addition, au/RGO-2 (0.28 mA/cm) ² ) The ORR current density (e.g., at-0.8V vsAg/AgCl.) is significantly greater than Au/RGO-3 (0.18 MA/cm) ² ) But lower than Au/rGO-1 (0.38 MA/cm 2).

As shown in FIG. 12B, the ORR onset potentials of Au/rGO-2 (-0.20V) are more negative than those of Ag/rGO (-0.15V), cu/rGO and Pt/rGO (-0.10V). These metal nanoparticles/graphene were compared as Ru (bpy) ₃ ²⁺ The electrochemiluminescence property of the co-reactant(s) (fig. 12A). Therefore, the superior cathode coreactant performance of Au/rGO-2 can also be explained by the moderate ORR catalytic activity thereof.

Reaction of anodic co-reactant of ruthenium terpyridyl with OER

OH in promoting Ru (bpy) ₃ ²⁺ Plays an important role in anodic oxidation, and oxygen is toxic to anodic luminescence. Thus, au/rGOs act as controlled Ru (bpy) ₃ ²⁺ An advantage of the cathode or anode promoter is that it exhibits an increase in OER catalytic performance with decreasing particle size. Therefore, suitable anode promoters should not only catalyze H ₂ O loses one electron to generate a large amount of OH, and excessive O generation should be avoided ₂ . Therefore, a weaker OER reaction catalyst is required to shift the reaction to reaction (equation 2-1) rather than reaction (equation 2-2), while also considering the d-band theory, so the larger particle size Au-rGO has better anodic co-reactant properties of ruthenium.

H ₂ O-e→HO ^˙ +H ⁺ (2-1)

O2 ^˙ --e→O ₂ (2-2)

As shown in FIG. 10A, when Au/RGO-3, au/RGO-4 having medium, large (13 Nm) and maximum (30 Nm) sizes of AuNPs are loaded on the electrodes, ru (bpy) ₃ ²⁺ The anode luminescence at 1.1V is significantly amplified. And Au/rGO-1 and Au/rGO-2 with small AuNPs particle size only react with Ru (bpy) ₃ ²⁺ Produces weak fluorescence, weaker than naked GCE, probably due to O produced by OER ₂ The quenching effect of (1). And Ru (bpy) ₃ ²⁺ The electroluminescence on the Au/rGO-3 catalyst is superior to Au/RGO-4 because Au/RGO-4 catalysts with too large AuNPs particle size are too weak to catalyze OER to generate enough OH, as evidenced by cyclic voltammograms.

In Ru (bpy) ₃ ²⁺ Anode scanning of the exposed GCE in solution due to Ru (bpy) ₃ ²⁺ The background current at +1.0V rises and then increases more rapidly due to the oxidation of water and peaks at + 1.3V. The peak current at +1.3V can be used as an indication of the extent of OER, cyclic voltammetry was used to evaluate the OER catalytic performance of a range of synthesized Au/rGO, and FIG. 10B shows the gradual decrease in OER catalytic ability of Au/rGO-1 to Au/rGO-4. The results also demonstrate that the anode promoter Au/rGO-3 with medium and weak OER catalytic performance can slow down the OER reaction, thereby prolonging the retention time of the product OH & on the catalyst surface. In addition, the larger AuNPs particle size may make OH more prone to desorption from Au/rGO-3, resulting in a large concentration of OH in the vicinity of the electrode, which is beneficial for strong ECL luminescence.

The enhancement of ECL luminescence by the cathode and anode Au/rGOs in nitrogen and oxygen atmospheres was characterized.

In nitrogen atmosphere, cathode promoters Au/rGO-2 (deep blue line) are paired with Ru (bpy) ₃ ²⁺ The promotion of cathodoluminescence is reduced because the nitrogen in the system removes dissolved oxygen, thereby inhibiting the occurrence of the ORR reaction. While the enhancement of the anode luminescence is due to the dissolved oxygen to Ru (bpy) ₃ ^2+* The quenching effect of (2) disappears. In contrast, the ORR process is at O ₂ Stimulation in the Environment (light blue line) leads to Ru (bpy) ₃ ²⁺ Cathode luminescence enhancementIs strong.

FIG. 13B shows anode promoters Au/rGO-3 in different atmospheres versus Ru (bpy) ₃ ²⁺ The effect of luminescence. Under nitrogen (dark blue line), ru (bpy) ₃ ²⁺ The anode luminescence of (2) is significantly enhanced. This is probably due to the fact that the Au/rGO-3 catalyzed OER reaction produces intermediate OH and other active oxygen components that promote anode luminescence, while the by-product O ₂ And dissolved oxygen is removed by a nitrogen gas stream. Introduction of O ₂ Rear, ru (bpy) ₃ ²⁺ The luminescence of the anode is obviously weakened, and the luminescence of the cathode is not obviously enhanced. This is because Au/rGO-3 lacks a strong ORR catalytic ability, and the increase of dissolved oxygen in the electrolyte has a strong quenching effect on the luminescence of the anode.

The above results indicate that the ORR catalytic ability of Au/rGO-2 can promote Ru (bpy) ₃ ²⁺ The dissolved oxygen in the solution reacts with the OER on the surface of the electrode to produce O ₂ Can inhibit Ru (bpy) ₃ ²⁺ The anode of (2) emits light.

Thus, OH inhibitors-superoxide dismutase SOD and isopropanol, and O2-inhibitor Benzoquinone (BQ) were introduced to independently reflect the various catalytically active oxygen components vs. Ru (bpy) ₃ ²⁺ The specific effect of the cathode and anode luminescence.

As shown in FIG. 14, SOD, isopropanol, and Benzoquinone (BQ) all significantly reduced the cathodoluminescence promoted by Au/rGO-2, indicating that Au/rGO-2 promoted cathodoluminescence mainly by catalytic reduction of oxygen to O2-, (FIG. 14A).

For the anode promoter Au/rGO-3, ru (bpy) was added when Benzoquinone (BQ), SOD and isopropanol were added separately ₃ ²⁺ The anode luminescence of (a) was significantly reduced, confirming that Au/rGO-3 was successfully prepared as a weak OER catalyst, thus demonstrating that OH "was generated at the electrode surface as the main OER product to promote anode luminescence (fig. 14B).

Adopt Ru (bpy) ₃ ²⁺ Luminescence under Ar atmosphere of acetonitrile solution to eliminate all involved O ₂ Influence of ORR and OER procedures of dissolved oxygen and oxygen atoms to examine Au/rGO and Ru (bpy) ₃ ²⁺ The direct action of (1).

The results are shown in FIG. 15A, comparing with bare GCE, au/rGO-2 modified electrode pair Ru (bpy) ₃ ²⁺ The promotion effect of cathode luminescence is weaker, while Au/rGO-3 can remarkably promote Ru (bpy) ₃ ²⁺ Anode emission (FIG. 15B), indicating that Au/rGO can not only indirectly promote Ru (bpy) by catalyzing OER or ORR reaction ₃ ²⁺ Emitting, and can also be directly connected with Ru (bpy) ₃ ²⁺ And carrying out reduction-oxidation reaction and oxidation-reduction reaction to directly enhance luminescence.

Detecting Ru (bpy) ₃ ²⁺ Co-reaction characteristics of AuNPs, graphene oxide, reduced graphene oxide, and various combinations thereof isolated in solution. As shown in FIG. 16, auNPs and rGO alone can be found not to significantly catalyze the anode or cathode emission of Ru (bpy) 32 +. This is probably because, in previous studies, both experimental results and calculations of Density Function Theory (DFT) indicate that they do not exhibit significant ORR or OER catalytic performance. In addition, we also changed the particle size of AuNPs, as shown in fig. 16A, the AuNPs with smaller particle size had better cathode promoting effect. This is because the smaller size Au particles have greater electrocatalytic activity for Oxygen Reduction Reaction (ORR) than the larger size AuNPs, and a significant fraction of the surface atoms may absorb and activate oxygen molecules. In addition, the degree of reduction of the reduced graphene oxide also has some effect on the properties of its coreactants. As can be seen from fig. 16C, graphene oxide has certain anodic stimulation characteristics, and reduction of graphene oxide by hydrazine hydrate changes the anodic stimulation characteristics, and the cathodoluminescence promoting capability of graphene oxide is greater than that of graphene oxide. From the XPS elemental ratio and the lower amino group ratio (5% of N) indicated by the infrared spectrum than the oxygen-containing functional groups, it is presumed that it is possible to reduce the relatively weak anode co-reactivity of graphene oxide because the anode promoting function of reducing the amino groups on graphene oxide cannot offset the reduction in anode luminescence caused by the reduction of the oxygen-containing functional groups.

The reduction degree of the reduced graphene oxide has certain influence on the properties of coreactants of the reduced graphene oxide, and Au/rGO and Ru (bpy) reduced by different reduction time of the reduced graphene oxide are measured ₃ ²⁺ Further measures the effect of the degree of reduction of reduced graphene oxide on the performance of the Au/rGO co-reaction. The red-shift of the uv-vis spectrum indicated that Ic/Ia reached a maximum at 6h reduction time and then decreased with increasing reduction time as the degree of reduction of graphene oxide increased (see FIG. 17). Ru (bpy) ₃ ²⁺ The optimal Ic/Ia for catalytic reduction of Au/rGO by partially reduced graphene can be attributed to the fact that: incomplete reduction reaction of defective graphene substrate formation can accelerate charge transfer from AuNPs to O ₂ By destabilizing ORR intermediate species and reducing O ₂ The activation energy of dissociation of (a) reduces the energy barrier of the rate limiting step resulting in more active oxygen production.

It is speculated that the relatively weak anodic co-reactive nature of reduced graphene oxide may be due to the inability of the anodic promoting function of the amino groups on the reduced graphene oxide to counteract the reduction in anodic luminescence due to the reduction in oxygen-containing functional groups. As can be seen from fig. 16C, graphene oxide has certain anodic stimulation characteristics, and reduction of graphene oxide by hydrazine hydrate changes the anodic stimulation characteristics, and the cathodoluminescence promoting ability is greater than that of graphene oxide. This is because the incomplete reduction reaction due to the formation of the defective graphene substrate can accelerate the transfer of charge from AuNPs to O ₂ By destabilizing ORR intermediate species and reducing O ₂ The activation energy of dissociation reduces the energy barrier of the rate limiting step resulting in more active oxygen production.

Equation of reaction

The principle of cathodoluminescence is shown in fig. 16. First, ru (bpy) ₃ ²⁺ And water is reduced at a negative potential and converted to Ru (bpy) ₃ ⁺ And O ₂ H. Then, highly oxidized O ₂ H can directly couple Ru (bpy) ₃ ⁺ Oxidation to Ru (bpy) ₃ ^2+* Or formation of Au/rGO from Au/rGO] _ox And then indirectly oxidize Ru (bpy) ₃ ⁺ . In this process,. O ₂ H can be reduced into hydrogen peroxide, and then further reduced into OH, and the hydrogen peroxide has stronger oxidizing property. Likewise, OH can oxidize Ru (b)py) ₃ ²⁺ Form a high energy state Ru (bpy) ₃ ^2+* Thereby triggering the cathode to emit light. In addition, since ROS has a higher oxidation potential, O ₂ H and OH can directly oxidize Ru (bpy) ₃ ²⁺ Generating Ru (bpy) ₃ ³⁺ Then with Ru (bpy) ₃ ⁺ Reaction, releasing light by annihilation reaction.

The reaction equation of Au-rGO-2 for promoting the light emission of the terpyridyl ruthenium cathode is shown as follows:

Ru(bpy) ₃ ²⁺ +e ^- →Ru(bpy) ₃ ⁺ (1)

Primary Pathway：

Pathway 1：

O ₂ +e ^- +H ⁺ →·O ₂ H (2)

Ru(bpy) ₃ ⁺ +·O ₂ H+H ⁺ →Ru(bpy) ₃ ^2+* +H ₂ O ₂ (3)

Pathway 2：

Au/rGO+·O ₂ H→[Au/rGO] _ox ^· +H ₂ O ₂ (4)

Ru(bpy) ₃ ⁺ +[Au/rGO] _ox ^· →Ru(bpy) ₃ ^2+* +[Au/rGO] _ox ^· +Au/rGO (5)

Secondary Pathway：

Pathway 3：

H ₂ O ₂ +H ⁺ +e ^- →H ₂ O+·OH (6)

Ru(bpy) ₃ ⁺ +·OH+H ⁺ →Ru(bpy) ₃ ^2+* +H ₂ O (7)

Pathway 4：

Au/rGO+·OH→[Au/rGO] _ox ^· +H ₂ O (8)

Ru(bpy) ₃ ⁺ +[Au/rGO] _ox ^· →Ru(bpy) ₃ ^2+* +[Au/rGO] _ox ·+Au/rGO (5)

Pathway 5：

Ru(bpy) ₃ ²⁺ +·O ₂ H+H ⁺ →Ru(bpy) ₃ ³⁺ +H ₂ O ₂ (9)

Ru(bpy) ₃ ²⁺ +·OH+H ⁺ →Ru(bpy) ₃ ³⁺ +H ₂ O ₂ (10)

Ru(bpy) ₃ ⁺ +Ru(bpy) ₃ ³⁺ →Ru(bpy) ₃ ^2+* +Ru(bpy) ₃ ²⁺ (11)

for anodic reactions, au/rGO-3 can act as a co-reactant and OER catalyst to promote Ru (bpy) ₃ ²⁺ The light emission of (1). Au/rGO-3 and Ru (bpy) ₃ ²⁺ Mainly through the surface containing oxygen radical (carboxyl, hydroxyl) and amino radical Ru (bpy) ₃ ²⁺ Is converted into an excited state. In addition, au/rGO-3 acts as a weak catalyst for the OER process and can catalyze the oxidation of water to form OH. Then, OH can enhance decarboxylation of Au/rGO-COO to Au/rGO, which can transfer electrons to Ru (bpy) ₃ ³⁺ To generate Ru (bpy) ₃ ^2+* . In addition, small amounts of OH and Au/rGO-COO ^- Possible interaction to produce CO with reduced properties ₂ ^-· Thus Ru (bpy) ₃ ²⁺ Reduced to Ru (bpy) ₃ ⁺ Then with Ru (bpy) ₃ ³⁺ And (4) interaction. The specific equation is as follows:

Ru(bpy) ₃ ²⁺ -e ^- →Ru(bpy) ₃ ³⁺ (1)

Pathway 1：

Au/rGO(ArCHOHR)-e ^- →[Au/rGO(ArCHOHR)] ^+· →[Au/rGO(ArCOHR)] ^· (2)

[Au/rGO(ArCOHR)] ^· +Ru(bpy) ₃ ³⁺ →Ru(bpy) ₃ ^2+* +Au/rGO(ArCOR) (3)

Pathway 2：

Au/rGO(ArNCH ₂ R)-e ^- →[Au/rGO(ArNCH ₂ R)] ^+· (4)

[Au/rGO(ArNCH ₂ R)] ^+· -H ⁺ →[Au/rGO(ArNCH ₂ R)] ^· +H ₂ O (5)

[Au/rGO(ArNCH ₂ R)] ^· +Ru(bpy) ₃ ³⁺ →Ru(bpy) ₃ ²⁺ +[Au/rGO(ArN＝CHR)] ⁺ (6)

[Au/rGO(ArN＝CHR)] ⁺ +H ₂ O→Au/rGO-NH ₂ +Au/rGO-CHO (7)

Pathway 3：

H ₂ O-e ^- →H ⁺ +·OH (8)

Au/rGO-COO ^- +·OH+H ⁺ →Au/rGO-COO·+H ₂ O→Au/rGO ^· +CO ₂ +H ₂ O (9)

Ru(bpy) ₃ ²⁺ -e ^- →Ru(bpy) ₃ ³⁺ (10)

Au/rGO ^· +Ru(bpy) ₃ ³⁺ →Au/rGO ⁺ +Ru(bpy) ₃ ^2+* →Ru(bpy) ₃ ²⁺ +hv (11)

the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1.Ru(bpy) ₃ ²⁺ An anodic or cathodic co-reactant characterized by: the Au-rGO compound is adopted, and the particle size of Au nano particles in the anode coreactant is 10-15nm; the particle size of Au nano particles in the cathode coreactant is 2-4nm.

2. The Ru (bpy) of claim 1 ₃ ²⁺ An anodic or cathodic co-reactant characterized by: in the anode coreactant, the reduction degree of rGO is reduced in hydrazine hydrate steam for 5.5-6.5h;

or in the cathode co-reactant, the reduction degree of rGO is reduced in hydrazine hydrate steam for 5.5-6.5h.

3. Ru (bpy) according to claim 1 or 2 ₃ ²⁺ A process for the preparation of an anode or cathode co-reactant characterized in that: the method comprises the following steps:

adding NaBH into the mixture I ₄ Mixing, adding sodium citrate, and mixing;

4. Ru (bpy) according to claim 3 ₃ ²⁺ A process for the preparation of an anode or cathode co-reactant characterized in that: the method also comprises the step of preparing reduced graphene oxide by reducing graphene oxide with hydrazine hydrate steam, and specifically comprises the following steps: respectively placing the water suspension of the graphene oxide and hydrazine hydrate in two containers, placing the two containers in the same closed space, and stirring for reaction, wherein the stirring reaction time is 5-7h, preferably 5.5-6.5h.

5. During the preparation of the anodic co-reactant, HAuCl ₄ 、r-GO、NaBH ₄ In a mixed reaction system with sodium citrate, HAuCl ₄ The concentration of (A) is 18-22mg/ml;

the concentration of r-GO is 1.8-2.2mg/ml;

NaBH ₄ the concentration of (A) is 0.005-0.015M;

the concentration of the sodium citrate is 0.005-0.015M;

or, during the preparation of the cathodic coreactant, HAuCl ₄ 、r-GO、NaBH ₄ HAuCl in mixed reaction system of sodium citrate and ₄ the concentration of (A) is 18-22mg/ml;

the concentration of r-GO is 1.8-2.2mg/ml;

NaBH ₄ the concentration of (A) is 0.005-0.015M;

the concentration of sodium citrate is 0.005-0.015M.

6. Ru (bpy) according to claim 3 ₃ ²⁺ A method for preparing an anode or cathode co-reactant, characterized by: and after the reaction is finished, in the step of separating and washing the solid product, the separation is centrifugal separation, the rotating speed of the centrifugation is 14500-15500rpm, and the centrifugation time is 30-60min.

7. Ru (bpy) according to claim 3 ₃ ²⁺ A method for preparing an anode or cathode co-reactant, characterized by: adding HAuCl ₄ After the aqueous solution and the r-GO suspension are mixed in proportion, the method comprises the steps of ultrasonic treatment and stirring, wherein the ultrasonic treatment time is 5-15min, and the stirring time is 1.5-2.5h.

8. Ru (bpy) according to claim 3 ₃ ²⁺ A method for preparing an anode or cathode co-reactant, characterized by: for HAuCl ₄ The process of ultrasonic treatment and stirring of the mixed solution of the aqueous solution and the r-GO suspension is repeated for 2-4 times.

9. Ru (bpy) according to claim 3 ₃ ²⁺ A method for preparing an anode or cathode co-reactant, characterized by: to HAuCl ₄ Adding NaBH into mixed solution of aqueous solution and r-GO suspension ₄ Then, after preliminary stirring, carrying out ultrasonic treatment; the primary stirring time is 10-20min, and the ultrasonic treatment time is 5-15min.

10. Ru (bpy) according to claim 3 ₃ ²⁺ A method for preparing an anode or cathode co-reactant, characterized by: adding sodium citrate into the mixed solution, primarily stirring, and performing ultrasonic treatment; the primary stirring time is 20-40min, and the ultrasonic treatment time is 5-15min.