A porous carbon-coated bismuth oxychloride nanoparticle catalyst for electrocatalytic carbon dioxide synthesis of formic acid, and a preparation method and application thereof

Abstract

This invention belongs to the field of catalyst technology, and relates to a porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide, its preparation method, and its application. The porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide comprises the following steps: S1. Mixing Bi metal salt, hydroxylamine hydrochloride, and tricresylbenzene in a solvent to obtain a solution; S2. Subjecting the solution from step S1 to a hydrothermal reaction, drying, and carbonization treatment sequentially to obtain the porous carbon-coated bismuth oxychloride nanoparticle catalyst. This invention exhibits high formic acid Faradaic efficiency in the electrocatalytic synthesis of formic acid from carbon dioxide, and also possesses excellent electrochemically active specific surface area and a larger current density, solving the problem of limited electron transport rate.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and more specifically, to a porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide, its preparation method, and its application. Background Technology

[0002] Due to carbon emissions caused by global warming and fossil fuel consumption, reducing carbon emissions has become a crucial and urgent issue. Electrocatalytic carbon dioxide reduction (CO2RR), which utilizes renewable and clean electricity to convert CO2 into various value-added chemicals, thus achieving carbon resource recycling, has attracted widespread attention. Among these products, formic acid (HCOOH) is of great significance because it is an important liquid fuel and chemical intermediate, can be directly used as a hydrogen source for fuel cells, and has wide applications in the pharmaceutical and chemical industries. However, the thermodynamic stability of CO2 molecules and its competition with the hydrogen evolution reaction (HER) pose challenges to this process, including slow kinetics, low selectivity, insufficient current density, and poor stability, severely limiting its conversion efficiency and application prospects. Therefore, there is an urgent need to develop electrocatalysts that can maintain high selectivity and stability for formic acid products even at high current densities.

[0003] BiOCl has a typical two-dimensional layered crystal structure, and its surface readily forms oxygen vacancies, which can stabilize the key COOH in the electrocatalytic reduction of carbon dioxide. Intermediates, thereby lowering the activation energy barrier of CO2 and promoting electron transfer. However, traditional sheet-like BiOCl nanosheets are prone to stacking and overlapping during electrode construction, resulting in limited effective exposed active sites. Under high current density conditions, they are often affected by mass transfer limitations and polarization effects, which restricts further improvement of their electrochemical active surface area and overall current density.

[0004] Existing technologies use BiOCl nanosheets as catalysts for the electrocatalytic synthesis of formic acid from carbon dioxide. These technologies mainly rely on the surface-to-surface contact between the two-dimensional layers of BiOCl nanosheets to improve conductivity. However, the stacking of sheet-like BiOCl nanosheets inevitably leads to problems such as severely reduced electrochemical surface area, insufficient utilization of active sites, and low electron transport rate, which prevents the improvement of current density. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects and deficiencies of the above-mentioned technical problems and provide a porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide. In the electrocatalytic synthesis of formic acid from carbon dioxide, it has a high formic acid Faradaic efficiency, and also has excellent electrochemical active specific surface area and larger current density, thus solving the problem of limited electron transport rate.

[0006] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0007] A porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide, the preparation method of the catalyst includes the following steps:

[0008] S1. Mix Bi metal salt, hydroxylamine hydrochloride, and benzoic acid in a solvent to obtain a solution;

[0009] S2. The solution from step S1 is subjected to hydrothermal reaction, drying, and carbonization treatment in sequence to obtain porous carbon-coated bismuth oxychloride nanoparticle catalyst;

[0010] In step S1, the molar ratio of Bi metal salt to benzoic acid is 1:(0.5~1.5); the molar ratio of hydroxylamine hydrochloride to benzoic acid is 1:(0.5~1.5).

[0011] In step S2, the hydrothermal reaction temperature is 140~180℃, and the hydrothermal reaction time is 12~20h;

[0012] The carbonization temperature is 400~650℃, and the carbonization time is 2~5h.

[0013] Bi, as a non-precious metal element, is abundant in the Earth's crust and has suitable carbon-hydrogen binding energy.

[0014] This invention prepares porous carbon-coated bismuth oxychloride nanoparticles. During the preparation process, tricresylbenzene not only acts as a carbon support but also regulates the crystallization behavior of metal ions through coordination and steric hindrance. Hydroxylamine hydrochloride serves as a chlorine source and also as a metal reducing agent in the synthesis of BiOCl precursors, thus preparing a porous carbon-coated bismuth oxychloride nanoparticle catalyst.

[0015] This invention combines carbon coating with bismuth oxychloride, introducing the carbon source benzoic acid to enable the organic carbon precursor to react with Bi. 3+ Strong coordination inhibits the lateral growth of bismuth oxychloride along a specific crystal plane ({001}). At the same time, the hydrothermal reaction enables bismuth oxychloride to nucleate during the precursor synthesis process, promoting the transformation of the original two-dimensional sheet structure into a more uniformly dispersed nanoparticle morphology.

[0016] The introduction of the carbon coating layer not only enables carbon loading of BiOCl but also forms a continuous and porous carbon phase structure on the exterior of the BiOCl nanoparticles, causing the layered BiOCl units to exhibit a spherical or near-spherical aggregate morphology. This morphological transformation effectively reduces the layer stacking phenomenon and significantly increases the exposure of the catalyst's outer surface, thereby enhancing the electrochemically active specific surface area. Simultaneously, the porous carbon coating layer provides continuous electron transport channels and open mass transfer pathways for the reaction system, facilitating the rapid diffusion of CO2 molecules and the efficient exchange of reactants and products.

[0017] Furthermore, the carbon coating can stably generate Bi in situ during electrolysis. 0 Nanocrystals inhibit aggregation and deactivation, further improving the utilization efficiency of active metal sites. The synergistic effect of the above structure and interface enables the carbon-coated BiOCl nanoparticle catalyst of this invention to significantly increase the electrochemically active specific surface area while maintaining the intrinsic catalytic properties of layered BiOCl, and exhibits higher current response and formic acid selectivity under high current density conditions, demonstrating high formic acid Faradaic efficiency.

[0018] The catalyst preparation method in this invention is convenient, green, and environmentally friendly, providing a new method for converting CO2 into formic acid.

[0019] Preferably, in step S2, the carbonization temperature is 550~600℃.

[0020] Preferably, in step S1, the molar ratio of Bi metal salt to benzoic acid is 1:(0.75~1.25).

[0021] Preferably, in step S1, the molar ratio of hydroxylamine hydrochloride to tricresyl triacetic acid is 1:(0.75~1.25).

[0022] Preferably, in step S1, the Bi metal salt is one or more of bismuth nitrate, bismuth sulfate, basic bismuth nitrate, or bismuth acetate.

[0023] In a specific embodiment, in step S1, Bi salt, hydroxylamine hydrochloride, and benzoic acid are mixed and stirred in a solvent at a speed of 200-800 rpm.

[0024] In a specific implementation, in step S2, the drying method is vacuum drying at 60°C.

[0025] In a specific embodiment, in step S2, the atmosphere for carbonization is an inert atmosphere; the inert atmosphere is one or more of nitrogen, helium and argon, preferably nitrogen.

[0026] Preferably, in step S1, the solvent is methanol.

[0027] Preferably, the catalyst has a spherical morphology and an average particle size of 100-150 nm.

[0028] This invention also protects a method for electrocatalytic synthesis of formic acid from carbon dioxide, which uses the porous carbon-coated bismuth oxychloride nanoparticle catalyst described in any of the above-mentioned methods as a catalyst to electrocatalyze the synthesis of formic acid from carbon dioxide in solution.

[0029] Preferably, the solution is a KOH solution.

[0030] Preferably, the voltage is 0.6~1.1V.

[0031] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention discloses a porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide. The preparation method of the catalyst includes the following steps: S1. Mixing Bi metal salt, hydroxylamine hydrochloride, and tricresylbenzene in a solvent to obtain a solution; S2. Subjecting the solution from step S1 to a hydrothermal reaction, drying, and carbonization treatment sequentially to obtain the porous carbon-coated bismuth oxychloride nanoparticle catalyst. The catalyst of this invention exhibits high formic acid Faradaic efficiency in the electrocatalytic synthesis of formic acid from carbon dioxide, and also possesses excellent electrochemically active specific surface area and a larger current density, thus solving the problem of limited electron transport rate. Attached Figure Description

[0032] Figure 1 The image shows the XRD pattern of the catalyst in Example 1 of this invention.

[0033] Figure 2 This is a transmission electron microscope (TEM) image of the catalyst in Example 1 of the present invention.

[0034] Figure 3 This is a scanning electron microscope (SEM) image of the catalyst in Example 1 of the present invention.

[0035] Figure 4 The LSV curve of the catalyst in Example 1 in saturated argon or saturated carbon dioxide is shown.

[0036] Figure 5 This is a pore size distribution diagram of the catalyst in Example 1.

[0037] Figure 6 This is a diagram showing the electrochemical active area of ​​the catalyst in Example 1 in 1M KOH solution. Detailed Implementation

[0038] To more clearly and completely describe the technical solution of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Various changes can be made within the scope of the claims of the present invention.

[0039] Example 1

[0040] A porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide is disclosed. The catalyst preparation method includes the following steps:

[0041] (1) Add 1 mmol Bi(NO)3, 1 mmol hydroxylamine hydrochloride and 1 mmol benzoic acid (i.e., the molar ratio of Bi(NO)3 to benzoic acid is 1:1; the molar ratio of hydroxylamine hydrochloride to benzoic acid is 1:1) to 60 mL of methanol and stir at room temperature at 500 rpm to form a homogeneous solution.

[0042] (2) After the solution obtained in step (1) was hydrothermally reacted at 160°C for 16 hours, it was washed with methanol and water and centrifuged, and then transferred to a vacuum drying oven to dry for 24 hours to obtain the BiOCl nanocatalyst precursor. The catalyst precursor was then carbonized by calcining at 550°C for 3 hours under N2, and the white powder was washed with deionized water by centrifugation several times to obtain a porous carbon-coated bismuth oxychloride nanoparticle catalyst.

[0043] Example 2

[0044] A porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide is disclosed. The preparation method of the catalyst differs from that in Example 1, in step S1 of this example, the molar ratio of Bi(NO)3 to tribenzoic acid is 1:0.75.

[0045] Example 3

[0046] A porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide is disclosed. The preparation method of the catalyst differs from that in Example 1, in step S1 of this example, the molar ratio of Bi(NO)3 to tribenzoic acid is 1:1.25.

[0047] Example 4

[0048] A porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide is disclosed. The preparation method of the catalyst differs from that in Example 1, in step S1 of this example, the molar ratio of hydroxylamine hydrochloride to benzotricarboxylic acid is 1:0.75.

[0049] Example 5

[0050] A porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide is disclosed. The preparation method of the catalyst differs from that in Example 1, in step S1 of this example, the molar ratio of hydroxylamine hydrochloride to benzotricarboxylic acid is 1:1.25.

[0051] Example 6

[0052] A porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide is disclosed. The preparation method of the catalyst differs from that in Example 1, in step S2 of this example, carbonization treatment is carried out by calcination at 400°C for 3 h.

[0053] Example 7

[0054] A porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide is disclosed. The preparation method of the catalyst differs from that in Example 1, in step S2 of this example, carbonization treatment is carried out by calcination at 600°C for 3 h.

[0055] Comparative Example 1

[0056] A porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide is disclosed. The preparation method of the catalyst differs from that in Example 1, in step S2 of this comparative example, carbonization treatment is carried out by calcination at 250°C for 3 h.

[0057] Comparative Example 2

[0058] A BiOCl catalyst, the preparation method of which is as follows:

[0059] (1) Add 1 mmol Bi(NO)3 and 1 mmol hydroxylamine hydrochloride to 60 mL of methanol and stir at room temperature to form a homogeneous solution;

[0060] (2) After the solution obtained in step (1) was hydrothermally reacted at 160 °C for 16 hours, it was washed with methanol and water and centrifuged, and then transferred to a vacuum drying oven to dry for 24 hours to obtain the BiOCl nanocatalyst precursor. The catalyst precursor was then carbonized by calcining at 550 °C for 3 hours under N2, and the black powder was washed by centrifugation with deionized water several times to obtain the BiOCl nanocatalyst.

[0061] Comparative Example 3

[0062] A Bi@C catalyst, the preparation method of which is as follows:

[0063] (1) Add 1 mmol Bi(NO)3 and 1 mmol benzoic acid to 60 mL of methanol and stir at room temperature to form a homogeneous solution;

[0064] (2) After the solution obtained in step (1) was hydrothermally reacted at 160 °C for 16 hours, it was washed with methanol and water and centrifuged, and then transferred to a vacuum drying oven to dry for 24 hours to obtain the Bi@C catalyst precursor. The catalyst precursor was then carbonized by calcining at 550 °C for 3 hours under N2, and the black powder was washed by centrifugation with deionized water several times to obtain the Bi@C catalyst.

[0065] Comparative Example 4

[0066] This comparative example provides an H3BTC catalyst, the preparation method of which is as follows:

[0067] (1) Add 1 mmol of hydroxylamine hydrochloride and 1 mmol of benzoic acid to 60 mL of methanol and stir at room temperature to form a homogeneous solution;

[0068] (2) After the solution obtained in step (1) was hydrothermally reacted at 160°C for 16 hours, it was washed with methanol and water and centrifuged in sequence, and then transferred to a vacuum drying oven to dry for 24 hours to obtain the H3BTC catalyst precursor. The catalyst precursor was then carbonized by calcining at 550°C for 3 hours under N2, and the black powder was washed by centrifugation with deionized water several times to obtain the H3BTC catalyst.

[0069] Comparative Example 5

[0070] A PG / BiOCl 1-X The catalyst is prepared as follows:

[0071] (1) Dissolve 0.2425 g Bi(NO3)3·5H2O in 30 mL of ethylene glycol, add 28.5 mg NaCl under vigorous stirring, and continue stirring for 30 min to form a homogeneous solution; then add 30 mg of porous graphene (PG) to the above precursor solution, and after full dispersion, obtain a mixed system.

[0072] (2) The resulting mixed solution was transferred to a reaction vessel and subjected to a hydrothermal reaction at 120 °C for 12 h. After the reaction was completed and cooled to room temperature, the product was collected by centrifugation and washed three times each with deionized water and ethanol, and then dried in an oven at 60 °C to obtain the PG / BiOCl nanosheet precursor.

[0073] (3) The obtained PG / BiOCl precursor was placed in a mixed atmosphere of N2 and NH3 and incubated at 3 °C·min. -1 The temperature was increased to 300 °C at a heating rate and calcined for 240 min. Chlorine vacancies were introduced during the annealing process, ultimately yielding PG / BiOCl. 1-X catalyst.

[0074] Performance testing

[0075] (1) The catalyst of Example 1 was analyzed by XRD and electron microscopy. The XRD pattern, transmission electron microscopy (TEM) pattern and scanning electron microscopy (SEM) pattern of the catalyst of Example 1 are shown below. Figure 1 , Figure 2 and Figure 3 As shown, from Figure 1It can be seen that Example 1 successfully prepared a carbon-coated bismuth oxychloride catalyst. From Figure 2 It can be seen that the bismuth oxychloride catalyst prepared in Example 1 is encapsulated by a carbon layer. From Figure 3 It can be seen that the catalyst prepared in Example 1 is loosely spherical, with an average particle size of 100-150 nm. The XRD, TEM, and SEM images of the catalysts in Examples 2-7 are respectively compared with... Figure 1 , Figure 2 and Figure 3 similar.

[0076] (2) Polarization curves of the catalysts in each example and comparative example were tested at room temperature using a three-electrode system (with a platinum sheet electrode as the counter electrode, Hg / HgO as the reference electrode, and a platinum sheet electrode clamp as the working electrode), and a carbon dioxide flow rate of 20 cm⁻¹ was set using a mass flow meter. 3 The test was conducted at a rate of [speed / min], with carbon dioxide continuously introduced during the process. Electrochemical testing took place in a 1 mol / L KOH solution saturated with either argon or carbon dioxide. Gas chromatography was used for quantitative and qualitative analysis of the gaseous products.

[0077] Table 1 shows the formic acid faradaic efficiencies of the catalysts in Examples 1-7 and Comparative Examples 1-5 in 1M KOH solution at a constant voltage of -1.0V (vs. RHE).

[0078] Table 1: Catalytic activity results of catalysts in Examples 1-7 and Comparative Examples 1-5

[0079]

[0080] The formic acid faradaic efficiency of the catalyst in Example 1 was tested under different voltages in 1M KOH solution. The test results are shown in Table 2.

[0081] Table 2: Catalytic activity results of Example 1

[0082]

[0083] As can be seen from Table 2 above, in the range of -0.6V to -1.1V (vs. RHE), the formic acid faradaic efficiency of the catalyst in Example 1 can reach 40.5% to 88.5%, which is a high formic acid faradaic efficiency.

[0084] As can be seen from the test results in Tables 1 and 2 above, the catalysts prepared in Examples 1 to 7 of the present invention can be used for electrocatalytic carbon dioxide reduction, and can achieve a high formic acid conversion rate. At the same time, the catalysts can maintain a stable current under long-term electrolysis.

[0085] In Comparative Example 1, the carbonization temperature was too low, and the conversion rate of formic acid synthesized from carbon dioxide by electrocatalysis was significantly lower than that in the Example.

[0086] Comparative Examples 2-4, due to the use of catalysts prepared without carbon sources, bismuth sources, or chlorine sources, resulted in a significantly lower conversion rate of carbon dioxide catalytic reduction of formic acid compared to the Examples.

[0087] Figure 4 This is an LSV curve of the catalyst in Example 1 in saturated argon or saturated carbon dioxide. From... Figure 4 It can be seen that under argon conditions, the catalyst undergoes the hydrogen evolution reaction, while under saturated carbon dioxide conditions, the current density curve gradually increases from approximately -1.37 V, approaching the onset potential of carbon dioxide reduction. At -0.5 V, a significant difference in current density appears between the two, indicating that in addition to the hydrogen evolution reaction, the catalyst also exhibits activity in the carbon dioxide reduction reaction.

[0088] Figure 5 The image shows the pore size distribution of the catalyst in Example 1. It can be seen that the contribution span is large across multiple pore sizes, exhibiting typical hierarchical pore characteristics. This pore size distribution also indicates that the catalyst has a wide mesopore distribution and higher mass transport efficiency.

[0089] (3) Electrochemically Active Specific Surface Area: The electrochemically active surface area (ECSA) of a catalyst is one of the important parameters for evaluating the electrochemical reaction properties of a catalyst. We used cyclic voltammetry (CV) to measure the double-layer capacitance (C0). dl The ECSA of the catalyst in Example 1 was evaluated at a voltage of -0.18V to 0.18V at a rate of 20 mV·s. -1 40 mV·s -1 60 mV·s -1 80mV·s -1 100 mV·s -1 The speed was scanned back and forth for 20 revolutions, and the final result was obtained through calculation. Figure 6 As shown in Table 3, the electrochemical activity specific surface area results of the catalysts in Examples 2-7 and Comparative Example 5 are shown in Table 3.

[0090] Table 3: Electrochemical activity specific surface area test results of catalysts in Examples 1-7 and Comparative Example 5

[0091]

[0092] (4) Maximum current density: Linear sweep voltammetry (LSV) was performed on Example 1. Argon or carbon dioxide was introduced for 30 min before the test, and the scan rate was set to 10 mV·s. -1Electrochemical signals were obtained by scanning from low to high voltage within a voltage range of 0.6V to -1.1V (vs. RHE). For example... Figure 4 As shown, in Example 1, when the catalyst reaches its maximum voltage in a carbon dioxide-saturated environment, the current density (i.e., the maximum current density) of the curve is 349.8 mA·cm⁻¹. -2 The maximum current density results for the catalysts in Examples 2-7 and Comparative Example 5 are shown in Table 4.

[0093] Table 4: Maximum current density test results of catalysts in Examples 1-7 and Comparative Example 5

[0094]

[0095] As can be seen from the above data, the catalyst of the present invention has excellent formic acid Faraday efficiency, electrochemical active specific surface area and maximum current density. The catalyst of the present invention, through carbon coating-induced nanoparticle formation and interface confinement effect, simultaneously reduces electron transport impedance and breaks through the upper limit of active component loading and doping, thereby significantly improving the electrochemical active specific surface area and supporting stable reaction under high current density, and has significant advantages in electrocatalytic carbon dioxide to formic acid synthesis.

[0096] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide, characterized in that, The preparation method of the catalyst includes the following steps: S1. Mix Bi metal salt, hydroxylamine hydrochloride, and benzoic acid in methanol to obtain a solution; S2. The solution from step S1 is subjected to solvothermal reaction, drying, and carbonization treatment in sequence to obtain porous carbon-coated bismuth oxychloride nanoparticle catalyst; In step S1, the molar ratio of Bi metal salt to benzoic acid is 1:(0.5~1.5); the molar ratio of hydroxylamine hydrochloride to benzoic acid is 1:(0.5~1.5). In step S2, the temperature of the solvothermal reaction is 140~180℃, and the reaction time is 12~20h; The carbonization temperature is 400~650℃, and the carbonization time is 2~5h.

2. The porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide according to claim 1, characterized in that, In step S2, the carbonization temperature is 550~600℃.

3. The porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide according to claim 1, characterized in that, In step S1, the molar ratio of Bi metal salt to benzoic acid is 1:(0.75~1.25).

4. The porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide according to claim 1, characterized in that, In step S1, the molar ratio of hydroxylamine hydrochloride to benzoic acid is 1:(0.75~1.25).

5. The porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide according to claim 1, characterized in that, In step S1, the Bi metal salt is one or more of bismuth nitrate, bismuth sulfate, basic bismuth nitrate, or bismuth acetate.

6. The porous carbon-coated bismuth oxychloride nanoparticle catalyst for the electrocatalytic synthesis of formic acid from carbon dioxide according to claim 1, characterized in that, The catalyst has a spherical morphology and an average particle size of 100~150 nm.

7. A method for the electrocatalytic synthesis of formic acid from carbon dioxide, characterized in that, The porous carbon-coated bismuth oxychloride nanoparticle catalyst described in any one of claims 1 to 6 is used as a catalyst to electrocatalyze the synthesis of formic acid from carbon dioxide in solution.

8. The method according to claim 7, characterized in that, The solution is a KOH solution.

9. The method according to claim 7, characterized in that, The voltage is 0.6~1.1V.

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