Method for promoting selective oxidation of electrocatalytic polyol and co-producing hydrogen through photo-assisted strategy

Abstract

The invention discloses a method for promoting selective oxidation of electrocatalytic polyol and co-producing hydrogen through a photo-assisted strategy, which comprises the following steps: respectively preparing an anode and a cathode, assembling an electrolytic tank, carrying out high-selectivity conversion on the polyol by adopting a photo-assisted electro-catalytic reaction, and simultaneously co-producing hydrogen. According to the method for promoting the selective oxidation of the electrocatalytic polyhydric alcohol and co-producing hydrogen through the photo-assisted strategy, the electrocatalytic oxidation current density of the polyhydric alcohol is greatly improved through the photo-thermal effect, and adsorption of a reaction intermediate can be regulated and controlled through the local plasma resonance effect of precious metal, so that the selectivity of a target product is improved; and a new way is provided for green and efficient preparation of high-added-value products by electrocatalytic oxidation of polyhydric alcohols.

Description

Technical Field

[0001] The present invention relates to the technical field of polyol conversion, and in particular to a method for promoting electrocatalytic selective oxidation of polyols to co-produce hydrogen through a light-assisted strategy. Background Art

[0002] With the increasing global emphasis on ecological and environmental protection and resource recycling, research on converting waste materials into high-value-added products is gradually emerging. Polyols, as a common byproduct of chemical production, have a significant output. According to statistics, approximately 4 million tons of glycerol are produced annually during biodiesel production worldwide, while the recycling of polyethylene terephthalate (PET) plastics also generates millions of tons of ethylene glycol waste. Currently, most of this polyol waste is not effectively utilized but is directly incinerated or landfilled, resulting in not only a waste of resources but also potential environmental pollution.

[0003] Polyols can be selectively oxidized to produce biodegradable plastic monomers such as lactic acid and glycolic acid, which can then be further polymerized to produce biodegradable materials such as polylactic acid (PLA) and polyglycolic acid (PGA), which are used in packaging, medical care, and agriculture. However, existing polyol conversion methods, such as aerobic oxidation, make it difficult to selectively oxidize polyols to polyol acids. Side reactions such as over-oxidation are prone to occur, resulting in the generation of impurities such as organic acids in the product, reducing the purity and yield of the polyol acids. Although thermal catalytic polyol oxidation has made some progress, it requires reactions under high temperature and high pressure conditions, and the product selectivity and atom economy are low, making it difficult to meet industrial production needs.

[0004] As a green and efficient alternative technology, electrocatalysis has received widespread attention in recent years. This method uses electrochemical reactions driven by renewable energy to directly convert polyols into target products, with the advantages of mild reaction conditions and environmental friendliness. However, since polyol molecules contain multiple hydroxyl groups, side reactions such as CC bond breakage are prone to occur during the electrocatalytic process, resulting in the product being mainly formic acid with low added value. Although some studies have achieved the selective preparation of some lactic acid and glycolic acid by designing precious metal-based catalysts, the current density currently reported (<200mA / cm 2 ) still cannot meet the requirements of industrial production. Therefore, developing and building a green and sustainable polyol resource utilization system has become a scientific and engineering problem that needs to be solved urgently in this field. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present invention proposes a method for preparing high-value-added products through light-assisted electrocatalytic oxidation of polyols while simultaneously releasing hydrogen to achieve efficient resource utilization of polyols.

[0006] The present invention provides a method for promoting the selective oxidation of polyols to produce hydrogen by light-assisted electrocatalysis, comprising the following steps:

[0007] S1: Assemble the electrolytic cell. The anode is made of a substrate material loaded with precious metals, precious metal alloys, or precious metals / hydroxides, and the cathode is made of a platinum sheet. These are then assembled together with the electrolyte to form an electrolytic cell.

[0008] S2: Using a light-assisted electrocatalytic reaction, polyols are added to the electrolyte under light conditions, the solution temperature is kept constant, and then a voltage is applied. The polyols are oxidized to form high-value-added products, and water is reduced to hydrogen at the cathode;

[0009] Among them, the solution temperature is 32-60°C. Maintaining the solution temperature within this range helps to accelerate the diffusion of reactant molecules and the interfacial mass transfer rate, while reducing the activation energy of the reaction, kinetically promoting the polyol oxidation process, and significantly increasing the current density. However, excessively high temperatures can lead to rapid evaporation of the electrolyte, change the reactant concentration, and even cause system instability, affecting the electrode structure and long-term reaction continuity. On the other hand, the CC bond in the polyol substrate has poor thermal stability. When the temperature is too high, it is easy to induce non-selective CC bond cleavage reactions, reducing the selectivity of the target multi-carbon product (such as lactic acid, glycolic acid, etc.), and instead leading to excessive reaction to generate by-products (such as formic acid or CO2). Stably controlling the system temperature between 32-60°C, while ensuring an increase in the reaction rate, can take into account the stability of the catalytic system and the precise regulation of product selectivity, which is one of the key factors in achieving the light-assisted enhancement effect of the present invention.

[0010] The present invention provides a method for promoting the selective oxidation of electrocatalytic polyols to co-produce hydrogen through a light-assisted strategy. A noble metal-based catalyst is constructed as an anode electrocatalyst, the photothermal effect is utilized to greatly increase the current density of the electrocatalytic oxidation of polyols, the local plasma resonance effect of the noble metal is utilized to increase the product selectivity, and hydrogen is co-produced at the cathode. Through the light-assisted electrocatalytic strategy, a new and efficient method is provided for the green and efficient oxidation of polyols to prepare high-value-added products at high current density.

[0011] Furthermore, the substrate material loaded with precious metals can be selected from nickel foam loaded with gold particles. The following is an exemplary method for preparing an anode:

[0012] S1: Pretreating the nickel foam by first placing it in ethanol, ultrasonicating it for 5-6 minutes, rinsing it with deionized water for 3-4 times, then placing it in dilute hydrochloric acid for ultrasonicating for 5-7 minutes, rinsing it again with deionized water for 3-4 times, then continuing to ultrasonicate it in deionized water for 5-6 minutes, and finally soaking the nickel foam in deionized water to obtain the pretreated nickel foam;

[0013] S2: Prepare nickel foam loaded with gold particles, prepare a chloroauric acid solution with a concentration of 5-7 mmol per liter, and construct a three-electrode system, in which the pretreated nickel foam serves as the working electrode, the platinum sheet serves as the counter electrode, and the saturated calomel electrode serves as the reference electrode. Use constant current electrodeposition method and set the parameters to a current density of 5 mA per square centimeter and a deposition time of 3600 seconds to obtain nickel foam loaded with gold particles.

[0014] Furthermore, the precious metal is any one or more of gold, ruthenium, iridium, rhodium, copper, silver, platinum or palladium.

[0015] Furthermore, the hydroxide is any one of cobalt-based, nickel-based, copper-based hydroxide or hydrotalcite material.

[0016] Furthermore, the base material is any one of nickel sheet, nickel foam, copper sheet, copper foam, titanium mesh, titanium sheet, carbon cloth, carbon paper, nickel mesh, and copper mesh.

[0017] Furthermore, the electrolyte is any one of potassium hydroxide, potassium bicarbonate, sodium bicarbonate, sodium hydroxide, sodium carbonate, lithium hydroxide, and potassium carbonate solution; and the concentration of the electrolyte in the electrolyte is 5 g / L to 500 g / L.

[0018] Furthermore, the light source of the illumination condition is any one or more of sunlight, incandescent lamp, xenon lamp, fluorescent lamp, sodium lamp, and mercury lamp. By introducing illumination conditions through a light-assisted strategy, the performance of the electrocatalytic oxidation reaction of polyols is significantly enhanced. The main mechanism of action includes two aspects: First, the photothermal effect plays a key role in improving the reaction rate. On the one hand, precious metal catalysts will produce a local photothermal effect under strong light, which can quickly heat the surface of the catalytic site and reduce the activation energy of the reaction; on the other hand, the overall absorption of light energy by the reaction solution increases the temperature, thereby accelerating the diffusion of reactants and the interface reaction rate. Under the combined effect, the reaction current density can be increased by 10%-200%. The temperature rise caused by photothermal heat (such as 40-60°C) can effectively accelerate the rate of multi-step oxidation reactions, especially providing a breakthrough for the mass transfer limitation stage in conventional catalytic reactions.

[0019] Secondly, the noble metal material, when stimulated by light, produces a localized surface plasmon resonance (LSPR) effect, which induces a localized increase in charge density and electron redistribution on the catalyst surface. This in turn modulates the adsorption configuration and reaction pathway of reactants or intermediates, effectively promoting the formation of target products. The LSPR effect can increase the selectivity of target products (such as lactic acid and glycolic acid) by 3%-15%.

[0020] In summary, the photo-assisted strategy has significant advantages in improving reaction rate and product selectivity, has a strong theoretical basis and application prospects, and provides an innovative path for building a high-performance green catalytic system.

[0021] Furthermore, the light power of the illumination condition is 100-1000 mW·cm -2 , preferably 300-800mW / cm 2 , controlling the light power within this range can take into account both sufficient temperature rise effect and the excitation efficiency of the noble metal plasma resonance activity. When the light power is too low, due to insufficient photothermal effect, the temperature rise of the system is limited, and the reaction kinetics process cannot be effectively accelerated. At the same time, the excitation intensity of the LSPR effect is weak, and the improvement in product selectivity is not obvious, resulting in an insignificant overall enhancement effect; and when the light power is too high, the system temperature will be too high, causing the catalyst structure to sinter or deactivate, and accompanied by local evaporation of the solution, which will reduce the reaction stability and may induce the occurrence of non-selective oxidation pathways, affecting the selectivity of the target product. Therefore, controlling the light power within a specific range not only helps to stably maintain the local temperature and plasma excitation intensity required for the reaction, but also ensures the stability of the catalyst structure and the selective control of the reaction system, thereby improving the overall electrocatalytic efficiency.

[0022] Furthermore, the polyol is any one of ethylene glycol, glycerol, sorbitol, arabinose, xylitol or glucose; and the concentration of the polyol in the electrolyte is 1 g / L to 100 g / L.

[0023] Furthermore, the electrocatalytic condition in step S2 is at room pressure and a voltage of 0.3 V to 1.5 V vs RHE.

[0024] The present invention also provides a high value-added product prepared by the method.

[0025] Furthermore, the high value-added product is any one of lactic acid, glyceric acid, glycolic acid, gluconic acid, and glucaric acid.

[0026] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0027] (1) The method provided by the present invention for promoting the selective oxidation of polyols to produce hydrogen through photocatalysis is highly selective and can significantly increase the current density;

[0028] (2) The method provided by the present invention for promoting the selective oxidation of polyols to produce hydrogen through photocatalysis by means of photoassisted strategy is simple and convenient, and is conducive to the large-scale production of high value-added products;

[0029] (3) The light-assisted strategy provided by the present invention promotes the electrocatalytic selective oxidation of polyols to produce hydrogen, which is green, efficient, capable of producing hydrogen, and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 Schematic diagram of the principle of promoting the selective oxidation of polyols to produce hydrogen by the light-assisted strategy of the present invention;

[0032] Figure 2 This is a scanning electron microscope image of the nickel foam loaded with gold particles in Example 1 of the present invention;

[0033] Figure 3 Schematic diagram of the reaction device in Example 1 of the present invention with xenon lamp irradiation applied and in Comparative Example 1 without xenon lamp irradiation applied;

[0034] Figure 4 Graphs showing linear polarization curves of electrocatalytic glycerol oxidation of nickel foam-supported gold particles under illumination and without illumination in Example 1 of the present invention and Comparative Example 1;

[0035] Figure 5 Graphs showing linear polarization curves of the electrocatalytic oxidation of ethylene glycol by AuPd alloy supported on nickel foam in Example 2 of the present invention and Comparative Example 3 under illumination and without illumination;

[0036] Figure 6 This is a chromatographic result diagram of the product in Example 1 of the present invention using high performance liquid chromatography;

[0037] Figure 7 This is a scanning electron microscope image of the nickel foam loaded AuPd alloy in Example 2 of the present invention;

[0038] Figure 8 This is a chromatographic result diagram of the product in Example 2 of the present invention using high performance liquid chromatography;

[0039] Figure 9 This is a scanning electron microscope image of Pt / Co(OH)2 supported on nickel foam in Example 3 of the present invention;

[0040] Figure 10 The chromatographic result of the product in Example 3 of the present invention using high performance liquid chromatography detection is shown. DETAILED DESCRIPTION

[0041] In order to help those skilled in the art better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts should fall within the scope of protection of the present invention.

[0042] Example

[0043] The present invention is further described below with reference to specific examples and comparative examples. The following specific examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and are particularly not limited to the types of the various component raw materials used in the following specific examples.

[0044] 1. The sources of raw materials for the embodiments and comparative examples are as follows:

[0045] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present invention are commercially available.

[0046] Anode preparation:

[0047] Anode #1: Nickel foam loaded with gold particles: S1: Pre-treat the nickel foam by placing it in ethanol, sonicating it for 6 minutes, rinsing it three times with deionized water, then sonicating it in dilute hydrochloric acid for 5 minutes, rinsing it again with deionized water three times, and then sonicating it in deionized water for another 5 minutes. Finally, soak the nickel foam in deionized water to obtain the pre-treated nickel foam.

[0048] S2: Prepare nickel foam loaded with gold particles. Prepare a 6 mmol / L chloroauric acid solution and construct a three-electrode system, in which the pretreated nickel foam serves as the working electrode, the platinum sheet serves as the counter electrode, and the saturated calomel electrode serves as the reference electrode. Use constant current electrodeposition with parameters set at a current density of 5 mA / cm2 and a deposition time of 3600 seconds to obtain nickel foam loaded with gold particles.

[0049] Figure 2 This is a scanning electron microscope image of the obtained nickel foam loaded with gold particles;

[0050] Anode #2: AuPt alloy loaded nickel foam: S1: Pre-treat the nickel foam by placing it in ethanol, sonicating it for 6 minutes, rinsing it three times with deionized water, then sonicating it in dilute hydrochloric acid for 7 minutes, rinsing it again with deionized water three times, and then sonicating it in deionized water for another 5 minutes. Finally, soak the nickel foam in deionized water to obtain the pre-treated nickel foam.

[0051] S2: Prepare nickel foam loaded with AuPt alloy. Use the pretreated nickel foam as the working electrode, a platinum counter electrode, and a saturated calomel reference electrode to form a three-electrode system. Prepare a mixed solution containing 5 mM gold chloride and 5 mM chloroplatinic acid. Use constant voltage electrodeposition with the parameter set to (-1) V (vs. SCE) and a deposition time of 600 seconds to obtain nickel foam loaded with AuPt alloy.

[0052] Figure 7 This is the scanning electron microscope image of the obtained nickel foam loaded AuPd alloy;

[0053] Anode #3: Nickel foam loaded with Pt / Co(OH)2: S1: The nickel foam was pretreated by first placing it in ethanol, ultrasonicating it for 5 minutes, rinsing it with deionized water three times, then ultrasonicating it in dilute hydrochloric acid for 6 minutes, rinsing it again with deionized water four times, and then ultrasonicating it in deionized water for another 5 minutes. Finally, the nickel foam was immersed in deionized water to obtain the pretreated nickel foam;

[0054] S2: Prepare 0.3 mol / L cobalt nitrate solution to construct a three-electrode system, with pretreated nickel foam as the working electrode, platinum sheet as the counter electrode, and saturated calomel electrode as the reference electrode. Use constant voltage electrodeposition with the parameter set to (-1) V (vs. SCE) for 600 seconds to load Co(OH)2 on the nickel foam. Then prepare 5 mmol / L chloroplatinic acid solution and construct a similar three-electrode system again, using nickel foam loaded with Co(OH)2 as the working electrode. Use constant voltage electrodeposition with the parameter adjusted to (-1.2) V (vs. SCE) for 600 seconds to finally obtain Pt / Co(OH)2 loaded on the anode nickel foam.

[0055] Figure 9 This is the scanning electron microscope image of the obtained nickel foam loaded Pt / Co(OH)2, which shows that the Pt particles are loaded on the Co(OH)2 nanosheet array, and the particle size of the Pt particles is 300-400nm;

[0056] Cathode preparation: Cut the platinum sheet into a size of 15mm*15mm*2mm. After cutting, rinse the platinum sheet with deionized water and it is ready for use.

[0057] 2. Various performance test methods

[0058] (1) Current density test: The electrochemical test was performed using a Chenhua electrochemical workstation (CHI 760E, CH Instruments, Inc.) with a standard three-electrode system. The reference electrode was an Ag / AgCl electrode, and all potentials were finally converted to vs. RHE.

[0059] (2) Reaction product selectivity test: After the reaction is completed, 1 mL of the reaction solution is taken and neutralized, shaken and evenly mixed. After filtering out impurities, the product is detected by high performance liquid chromatography (HPLC; Angilent 1200 Infinity Series), and the selectivity is analyzed based on the chromatographic results.

[0060] Example 1

[0061] S1: Assemble an electrolytic cell. Use nickel foam loaded with gold particles as the anode and platinum sheet as the cathode. Add 2.8 g of glycerol to 100 mL of a 168 g / L KOH aqueous solution to obtain an electrolyte. Assemble the two together to form an electrolytic cell.

[0062] S2: Use a xenon lamp to apply light power of 300mW·cm -2 The reaction solution temperature was raised to 40°C and kept constant, and then electrolyzed at a bias of 0.95 V vs RHE for 1 h to obtain lactic acid.

[0063] The anode reaction formula is: C3H8O3+2OH - -2e - →C3H6O3+2H2O;

[0064] The cathode reaction formula is: 2H2O+2e - →H2+2OH - ;

[0065] Figure 3 A diagram of a reaction device with and without xenon lamp illumination;

[0066] Figure 4 Figure 2 shows the linear polarization curves of electrocatalytic glycerol oxidation by gold particles on nickel foam under illumination and without illumination. It can be seen that the current density after illumination is much higher than that without additional illumination, indicating that the light-assisted strategy can significantly increase the current density of glycerol oxidation. Moreover, at ultra-low voltage (<1.1 V vs RHE, far below the potential of oxygen evolution reaction), the current density of glycerol oxidation by gold particles can reach 300 mA cm -2 ;

[0067] Figure 6 This is the chromatographic result of the product of Example 1 detected by high performance liquid chromatography. It can be seen that the selectivity of lactic acid in Example 1 after application of light is 81%, while the selectivity of lactic acid in Comparative Example 1 without application of light is 75%, indicating that the light-assisted strategy can further improve the selectivity of lactic acid.

[0068] Example 2

[0069] S1: Assemble an electrolytic cell. Use nickel foam loaded with AuPd alloy as the anode and platinum sheet as the cathode. Add 4 g of ethylene glycol to 200 mL of 140 g / L NaOH aqueous solution to obtain an electrolyte. Assemble the two together to form an electrolytic cell.

[0070] S2: Use a xenon lamp to apply light power of 200mW·cm -2 The reaction solution temperature was raised to 35°C and kept constant, and then electrolyzed at a bias of 1.1 V vs RHE for 1 h to obtain glycolic acid.

[0071] The anode reaction formula is: C2H6O2+4OH - -4e - →C2H4O3+3H2O;

[0072] The cathode reaction formula is: 2H2O+2e - →H2+2OH - ;

[0073] Figure 5 Figure 2 shows the linear polarization curves for the electrocatalytic oxidation of ethylene glycol by AuPd alloy supported on nickel foam under illumination and without illumination. It can be seen that the current density after illumination is much higher than that without additional illumination, indicating that the light-assisted strategy can significantly increase the current density of ethylene glycol oxidation. Furthermore, at an ultra-low voltage (<1.1 V vs RHE, far below the potential of the oxygen evolution reaction), the current density of ethylene glycol oxidation by AuPd alloy can reach 448 mA cm-3. -2 , its maximum current density can reach 1000mA / cm 2 ;

[0074] Figure 8 This is a chromatographic result diagram of the product in Example 2 using high performance liquid chromatography.

[0075] Example 3

[0076] S1: Assemble an electrolytic cell, using nickel foam-supported Pt / Co(OH)2 as the anode and platinum sheet as the cathode. Add 10 g of glycerol to 150 mL of a 50 g / L KOH aqueous solution to obtain an electrolyte, and assemble them together into an electrolytic cell.

[0077] S2: Use a xenon lamp to apply light power of 400mW·cm -2 The reaction solution temperature was raised to 50°C and kept constant, and then electrolyzed at a bias of 0.85 V vs RHE for 1 h to obtain glyceric acid.

[0078] The anode reaction formula is: C3H8O3+4OH - -4e - →C3H6O4+3H2O;

[0079] The cathode reaction formula is: 2H2O+2e - →H2+2OH - ;

[0080] Figure 10 This is a chromatographic result diagram of the product in Example 3 of the present invention detected by high performance liquid chromatography.

[0081] Example 4

[0082] The difference between Example 4 and Example 1 is that in step S2, the temperature of the reaction solution is kept constant after rising to 32°C.

[0083] Example 5

[0084] The difference between Example 5 and Example 1 is that in step S2, the temperature of the reaction solution is kept constant after rising to 58°C.

[0085] Comparative Example 1

[0086] The difference between Comparative Example 1 and Example 1 is that no light is applied in step S2.

[0087] Comparative Example 2

[0088] The difference between Comparative Example 2 and Example 1 is that in step S2, the temperature of the reaction solution is kept constant after rising to 30°C.

[0089] Comparative Example 3

[0090] The difference between Comparative Example 3 and Example 2 is that no light is applied in step S2.

[0091] Table 1 Performance effects of embodiments and comparative examples

[0092]

[0093] In Examples 1-5, the specific light-assisted strategy of the present invention is simultaneously introduced to promote the selective oxidation of electrocatalytic polyols. During the electrocatalytic reaction, high current density can be achieved at low voltage, and the reaction is highly selective for high value-added products, thereby achieving efficient utilization of polyols.

[0094] Comparative Examples 1-2 are compared with Example 1. Comparative Example 1 does not apply light conditions. The solution temperature in step S2 of Comparative Example 2 is too low. Comparative Example 3 is compared with Example 2 and does not apply light conditions. The current density at low voltage and the conversion selectivity of polyols in the above comparative examples will be significantly reduced.

[0095] Based on the test data of current density and product selectivity at a voltage of 1.1 V in Table 1, the photo-assisted strategy of promoting the electrocatalytic polyol selective oxidation method of Examples 1-5 can achieve highly selective conversion of polyols while maintaining a high current density at a low voltage, which has obvious advantages over the comparative example and can effectively meet the high standards of customers and the market.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for promoting the selective oxidation of polyols to produce hydrogen by light-assisted electrocatalysis, characterized in that: The following steps are involved: S1: Assemble the electrolytic cell. The anode is made of a substrate material loaded with precious metals, precious metal alloys, or precious metals / hydroxides, and the cathode is made of a platinum sheet. These are then assembled together with the electrolyte to form an electrolytic cell. S2: Using a light-assisted electrocatalytic reaction, polyols are added to the electrolyte under light conditions, the solution temperature is kept constant, and then a voltage is applied. The polyols are oxidized to form high-value-added products, and water is reduced to hydrogen at the cathode; Wherein, the solution temperature is 32-60°C.

2. The method according to claim 1, characterized in that The noble metal is any one or more of gold, ruthenium, iridium, rhodium, copper, silver, platinum or palladium.

3. The method according to claim 1, characterized in that The hydroxide is any one of cobalt-based, nickel-based, copper-based hydroxide or hydrotalcite material.

4. The method according to claim 1, wherein The base material is any one of nickel sheet, nickel foam, copper sheet, copper foam, titanium mesh, titanium sheet, carbon cloth, carbon paper, nickel mesh, and copper mesh.

5. The method according to claim 1, wherein The electrolyte is any one of potassium hydroxide, potassium bicarbonate, sodium bicarbonate, sodium hydroxide, sodium carbonate, lithium hydroxide, and potassium carbonate solutions; and the concentration of the electrolyte in the electrolyte is 5 g / L to 500 g / L.

6. The method according to claim 1, characterized in that The light source of the illumination condition is any one or more of sunlight, incandescent lamp, xenon lamp, fluorescent lamp, sodium lamp, and mercury lamp; the light power is 100-1000mW·cm -2 .

7. The method according to claim 1, characterized in that The polyol is any one of ethylene glycol, glycerol, sorbitol, arabinose, xylitol or glucose; and the concentration of the polyol in the electrolyte is 1 g / L to 100 g / L.

8. The method according to claim 1, characterized in that The electrocatalytic conditions in step S2 are as follows: at room pressure, the voltage is 0.3 V to 1.5 V vs RHE.

9. A high value-added product prepared by the method according to any one of claims 1 to 8.

10. The high value-added product according to claim 9, characterized in that The high value-added product is any one of lactic acid, glyceric acid, glycolic acid, gluconic acid and glucaric acid.

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