Liquid metal-ammonia decomposition method with light coupling enhancement and reaction device thereof

Abstract

The application relates to the technical field of hydrogen production by ammonia decomposition, and particularly discloses a liquid metal ammonia decomposition method with enhanced light coupling and a reaction device thereof. The liquid metal ammonia decomposition method is characterized by introducing a light field to the contact interface region between liquid metal and ammonia. The reaction device comprises a reaction cavity, a gas inlet pipe and a gas outlet pipe. The reaction cavity contains liquid metal. The gas inlet pipe is fixed to the center of the upper cover of the reaction cavity and extends into the reaction cavity. The gas outlet pipe is located on the side wall of the reaction cavity and close to the upper cover. A plurality of through holes are arranged on the pipe wall of the gas inlet pipe below the liquid level of the liquid metal. A plurality of optical fibers are connected to a light source and extend into the liquid metal through the through holes. The application applies the light field to the contact interface between the liquid metal and the ammonia, so that the interface is more likely to reach the activation state of ammonia decomposition. Moreover, the optical fibers are arranged on the through holes of the gas inlet pipe wall, so that the through holes have a dual function, thereby reducing the loss of light energy in the transmission process and improving the efficiency of the liquid metal ammonia decomposition reaction.

Description

Technical Field

[0001] This application relates to the field of ammonia decomposition for hydrogen production technology, and more specifically, to a method and apparatus for optically enhanced liquid metal ammonia decomposition. Background Technology

[0002] Ammonia decomposition for hydrogen production, with its advantages of high energy density, easy storage and transportation, and zero carbon emissions, is gradually becoming an important research direction in the hydrogen energy system. In recent years, liquid metals, due to their high thermal conductivity, interface reconfigurability, resistance to sintering, and ability to adaptively renew active interfaces, have been regarded as potential catalytic media to overcome the bottlenecks of traditional solid catalysts and have been gradually applied to ammonia decomposition reactions.

[0003] However, existing liquid metal ammonia decomposition systems primarily rely on thermally driven mechanisms for interfacial reactions, resulting in relatively singular interfacial activation methods and a lack of tunable excitation pathways. While liquid metals possess reconfigurable interfaces, the bubble-metal interface is encased within a high-density metal bulk phase, and the interfacial electronic structure and reaction pathways are mainly dominated by the temperature field, making it difficult to modulate through external stimulation. During the ammonia bubble's ascent, dissociation occurs solely through natural contact and thermal excitation, resulting in limited interfacial reaction intensity and insufficient activation, thus limiting the overall reaction rate. Furthermore, the high reflectivity, opacity, and strong interfacial tension of liquid metals hinder the effective coupling of external energy forms to the gas-liquid interface within the metal bulk phase, preventing direct regulation of interfacial bond breaking or electronic state distribution. Especially under conditions requiring lower reaction temperatures or higher interfacial reaction efficiency, existing systems lack effective pathways to introduce external energy or additional excitation mechanisms, leaving liquid metal catalysis systems constrained by inherent reaction bottlenecks under single thermal drive.

[0004] Therefore, there is an urgent need for a reaction structure and method that can construct new energy input or interface excitation modes inside liquid metals, in order to expand the interface excitation mechanism of liquid metal catalytic systems and improve ammonia decomposition efficiency. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a light-coupled enhanced liquid metal ammonia decomposition method and its reaction apparatus, thereby solving the problem of insufficient activation of the reaction interface in the liquid metal ammonia decomposition reaction in the prior art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This application provides a light-coupled enhanced liquid metal ammonia decomposition method, which introduces a light field into the interface region between liquid metal and ammonia gas.

[0007] Based on the characteristic that the decomposition reaction of ammonia in liquid metal mainly occurs at the gas-liquid interface, this application introduces a light field into the interface region between the liquid metal and ammonia, making the interface a preferential region for light energy. When the light field acts on the liquid metal interface, the free electrons at the interface respond rapidly to the light energy, forming transient electronic energy perturbations or local electron-rich regions, causing the electrons at the interface to exhibit a higher activation state. Simultaneously, the absorption of light energy by the liquid metal creates local energy deposition regions with short time and small spatial scales near the interface, causing slight but rapid temperature gradient changes, increasing the local energy density at the interface, and altering the energy state of ammonia molecules near the interface, thus making it easier for ammonia molecules to enter the initial dissociation step of the reaction. The photoinduced surface tension difference also causes subtle morphological perturbations at the interface, thereby changing the interface microstructure and the residence and approach paths of ammonia molecules at the interface. The aforementioned electronic state response, local energy redistribution, and interface morphological perturbation constitute the coupling process between the light field and the liquid metal-ammonia interface, providing more favorable interface conditions for the ammonia decomposition process.

[0008] Furthermore, the wavelength of the light field is 200-450 nm. This wavelength range makes it easier for free electrons at the liquid metal interface to be excited, thereby improving the absorption and excitation efficiency of light energy at the interface.

[0009] Furthermore, the liquid metal is one of gallium, gallium-indium alloy, gallium-tin alloy, or gallium-indium-tin alloy. Gallium and its gallium-based alloys have high free electron density and good light absorption characteristics, making them more prone to interfacial electron energy perturbation under the influence of a light field, which is conducive to the effective coupling of light energy to the interfacial reaction process.

[0010] This application also proposes a light-coupled enhanced liquid metal ammonia decomposition reaction device, including a reaction chamber, an inlet pipe, and an outlet pipe. The reaction chamber contains liquid metal. The inlet pipe is fixed at the center of the upper cover of the reaction chamber and extends into the reaction chamber. The outlet pipe is located on the side wall of the reaction chamber near the upper cover. The inlet pipe has multiple through holes on its wall below the liquid metal surface. Multiple optical fibers are connected to a light source and extend into the liquid metal through the through holes.

[0011] This application utilizes a through-hole in the wall of the inlet pipe below the liquid surface, through which an optical fiber extends into the liquid metal. This allows light energy to act directly on the interface region where the liquid metal and ammonia gas meet at a defined position and direction. Since the ammonia gas releases at the end of the inlet pipe and forms a local gas-liquid interface within the liquid metal, the light field introduced at the end of the optical fiber is concentrated near the bubble generation region, making the illumination position adjacent to the interface reaction region. This structural arrangement enables positionally controllable interface coupling of light energy within the reaction chamber, ensuring that the light field can be reliably introduced into the interface region, providing directional energy input for the subsequent interface excitation process.

[0012] Furthermore, the bottom of the intake pipe is a closed structure, with through holes arranged in an array along the axial and circumferential directions of the intake pipe. The closed bottom allows ammonia gas to enter the liquid metal only through the through holes, while the array of through holes in the axial and circumferential directions can form a more uniform bubble dispersion area, providing a controllable geometric basis for the spatial coupling of the light field and the bubble interface.

[0013] Furthermore, the through-hole is an elliptical hole with its main axis angled to the axial direction of the inlet pipe. The elliptical through-hole with its inclined main axis gives the ammonia jet directionality when it enters the liquid metal, bringing the bubble path closer to the light-emitting area at the end of the optical fiber. The slight fluid disturbance generated when the bubble exits along this path helps the interface to continuously renew itself, thereby enhancing the stability of the interaction between the light field and the interface.

[0014] Furthermore, the through-holes are densely arranged near the bottom of the intake pipe and sparsely arranged further away. This dense-to-sparse arrangement of the through-holes creates a gradient distribution for bubble generation at different heights of the intake pipe, allowing more bubbles to react in the liquid metal for a longer time, and enhancing the effective volume of the light field inside the liquid metal, thus improving the consistency of the interface illumination distribution.

[0015] Furthermore, the optical fibers are fixed in a bundle inside the air intake tube. This bundling of the optical fibers within the air intake tube maintains a stable relative position of the fibers at the through-hole; the bundled arrangement ensures that the ends of the optical fibers extending from the through-hole do not point in a single direction, but rather present a natural dispersion angle, thereby expanding the light coverage area and preventing the light area from becoming too concentrated.

[0016] Furthermore, the optical fiber is a multimode fiber. Multimode fiber has a larger numerical aperture and higher optical coupling capability, which can form a wider light spot or scattered light field inside the liquid metal, making it easier for light energy to cover the bubble generation area and improving the illumination uniformity of the interface area.

[0017] Furthermore, the optical fibers are of inconsistent lengths, with the fibers near the bottom of the intake pipe being relatively longer; and the multiple fibers within each through-hole are of varying lengths. This difference in fiber length creates a multi-depth spatial distribution at the fiber ends within the liquid metal, allowing the light field to act on interface regions at different heights. Configuring fibers of different lengths within a single through-hole helps to create a three-dimensional illumination volume, thereby expanding the coverage of the light field over the interface reaction region and improving the spatial continuity of light energy input.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The method of this application directly applies the light field to the interface between liquid metal and ammonia, so that the interface can obtain an additional energy source during the reaction process, reducing the energy requirement of the ammonia decomposition reaction at the interface and the dependence on simple temperature conditions, thereby making it easier for the interface to reach the activated state of ammonia decomposition, improving the problem of insufficient interface excitation caused by the reliance on single thermal excitation in traditional liquid metal systems, and improving the efficiency of ammonia decomposition reaction.

[0019] (2) The reaction device of this application adopts a structure in which a through hole is set on the wall of the gas inlet pipe and an optical fiber is passed through the through hole to introduce the light field into the liquid metal. The through hole not only enables ammonia gas to be dispersed into the liquid metal, but also serves as a channel for the light field to be introduced, so that the light energy can be stably introduced into the interface area between the liquid metal and ammonia gas at a certain position and direction, thereby reducing the loss of light energy during transmission, avoiding the drift of the illuminated area due to liquid surface fluctuations or fluid disturbances, realizing the coupling precision control of the light field and the interface reaction area, and improving the stability and targeting of the light energy input. Attached Figure Description

[0020] Figure 1 A schematic diagram of a light-coupled enhanced liquid metal ammonia decomposition reaction device provided by the present invention; Figure 2 A schematic diagram of the inlet pipe of a light-coupled enhanced liquid metal ammonia decomposition reaction device provided by the present invention; Figure 3 This is a cross-sectional schematic diagram of the optical fiber bundle of a liquid metal ammonia decomposition reaction device with enhanced optical coupling provided by the present invention.

[0021] Icons: 1-Reaction chamber; 2-Inlet pipe; 3-Outlet pipe; 4-Through hole; 5-Fiber optic cable; 6-Ammonia bubble; 7-Limiting ring. Detailed Implementation

[0022] To make the implementation process of this invention clearer, a detailed description will be provided below in conjunction with the accompanying drawings. Example 1:

[0023] This invention provides a light-coupled enhanced method for the decomposition of liquid metal ammonia, which involves introducing a light field into the interface region between the liquid metal and ammonia gas. This embodiment does not limit the specific structure of the reaction apparatus, but only focuses on the implementation of the method itself.

[0024] First, any one of the following liquid metals—gallium, gallium-indium alloy, gallium-tin alloy, or gallium-indium-tin alloy—is placed inside the reaction chamber and heated to the preset operating temperature by a heating belt or electric heating jacket surrounding the outer wall of the reaction chamber. Once the liquid metal is in a stable molten state, ammonia gas is introduced into it, causing the ammonia gas to form continuously rising bubbles inside the liquid metal, thereby naturally creating multiple gas-liquid contact interfaces within the liquid metal.

[0025] During the process of ammonia gas entering liquid metal and forming an interface, a light field generated by an external light source is introduced into the liquid metal, causing this light field to act on the interface region surrounding the bubble. In this embodiment, the preferred light field is ultraviolet light with a wavelength of 200-450 nm, so that the light energy is more easily absorbed or generates energy disturbance at the interface, which is more conducive to the excitation of the interface region. The method of introducing the light field is not limited and can be achieved through the end of an optical fiber, irradiation through a high-temperature resistant window, or other means that allow light to reach the interface region.

[0026] Liquid metal interfaces possess atomically smooth, self-reconfigurable, and weakly adsorbed properties, enabling... When molecules undergo dissociation reactions at the interface, the interfacial electron density and the ability to form active centers are relatively limited, leading to... The high interfacial energy barrier at the stepwise fracture process makes interfacial activation the main bottleneck limiting the ammonia decomposition rate. When a light field continuously acts on the gas-liquid interface, the interfacial electrons receive transient energy compensation under photoexcitation, increasing the probability of NH bond breaking. The electrons at the interface exhibit a higher activation state, leading to a more rapid ammonia decomposition reaction. The generated gas escapes from the liquid metal surface and is discharged through the exhaust end to an external collection or analysis device. Throughout the reaction, parameters such as light source power, reaction temperature, and ammonia flow rate can be flexibly adjusted as needed without affecting the fundamental characteristics of light-interface interaction. This method requires no additional treatment of the liquid metal surface and does not rely on special structural conditions of the reaction apparatus; it only requires ensuring that the light field reaches the interfacial region to achieve the effect of light coupling enhancing interfacial excitation. Example 2:

[0027] This invention also provides a light-coupled enhanced liquid metal ammonia decomposition reaction device, such as... Figure 1 As shown, the device includes a reaction chamber 1, an inlet pipe 2, and an outlet pipe 3. The reaction chamber 1 contains liquid metal. The inlet pipe 2 is fixed to the center of the top cover of the reaction chamber 1 and extends into the reaction chamber 1. The outlet pipe 3 is located on the side wall of the reaction chamber 1 near the top cover. The inlet pipe 2 has multiple through holes 4 on its wall below the liquid metal surface. Multiple optical fibers 5 are connected to the light source and extend into the liquid metal through the through holes 4.

[0028] The reaction chamber 1 is a cylindrical structure made of corrosion-resistant and high-temperature-resistant stainless steel or nickel-based materials to adapt to the liquid metal environment and reaction temperature requirements. The reaction chamber 1 contains a container for holding the liquid metal; its size can be selected according to the reaction scale, with a preferred diameter of 100-200 mm and an internal height of 80-150 mm to facilitate easier distribution of the light field in the lateral direction. The liquid metal is filled to a position 5-20 mm from the top of the reaction chamber 1 to facilitate the discharge of the generated product gases.

[0029] The inlet pipe 2 is fixedly positioned at the center of the upper cover of the reaction chamber 1 and connected to the upper cover in a sealed manner. The inlet pipe 2 extends into the reaction chamber 1, has a straight tubular shape, and is made of corrosion-resistant stainless steel or nickel-based material to adapt to the liquid metal environment. The upper end of the inlet pipe 2 is an opening structure connected to an external gas source, allowing ammonia gas to be stably introduced into the reaction chamber 1. The size of the inlet pipe 2 is set according to the size of the reaction chamber 1, with a pipe diameter ranging from 10-30 mm. The length inserted into the reaction chamber 1 is preferably 60-120 mm, so that the lower end of the inlet pipe 2 is located below the liquid metal surface. The outlet pipe 3 is fixedly positioned on the side wall of the reaction chamber 1 near the upper cover and connected to an external exhaust channel for discharging the product gas generated in the reaction. The outlet pipe 3 is welded or threaded to the side wall of the reaction chamber 1 in a sealed manner. Its pipe diameter is preferably 8-15 mm, and the opening position is slightly higher than the highest liquid level of the liquid metal to ensure that the gas can be smoothly discharged without being blocked by the liquid during device operation. As needed, the exhaust pipe 3 can also be connected to an external condensation, filtration, or analysis module to collect or measure the product gas. In this embodiment, the reaction chamber 1, the inlet pipe 2, and the exhaust pipe 3 together constitute the basic device structure for the decomposition reaction of liquid metal ammonia, providing a stable reaction space for subsequent light field introduction and interfacial interactions.

[0030] like Figure 2 As shown, the inlet pipe 2 has multiple through holes 4 on its wall below the liquid metal surface. After entering the reaction chamber 1, ammonia gas enters the liquid metal in a dispersed form through these through holes 4, forming continuously rising ammonia bubbles. The number and size of the through holes 4 are selected according to the size of the inlet pipe 2 and the required gas flow rate. To introduce the light field into the reaction area, multiple optical fibers 5 connected to an external light source are installed in the reaction device. The optical fibers 5 pass through the corresponding through holes 4 from inside the inlet pipe 2 and extend into the liquid metal, with their ends located at a predetermined depth in the liquid metal, for directly irradiating the interface area formed by the bubbles and the liquid metal. The optical fibers 5 are preferably made of quartz material to accommodate ultraviolet light transmission, thereby ensuring that the light energy is effectively coupled to the interface position inside the liquid metal.

[0031] The bottom of the intake pipe 2 is a closed structure, preventing ammonia gas from directly escaping from the bottom of the pipe. Instead, it enters the liquid metal through the through-holes 4 on the pipe wall. The through-holes 4 are arranged in an array along the axial and circumferential directions of the intake pipe 2, allowing ammonia gas to form dispersed bubbles from different heights and angles when entering the liquid metal. The size and spacing of the through-holes 4 can be selected based on the diameter of the intake pipe 2, the required ammonia flow rate, and the number of optical fibers 5. For example, the diameter of the through-holes 4 is 0.4-0.6 mm, the spacing between adjacent axial through-holes 4 is 1-5 mm, and the spacing between adjacent circumferential through-holes 4 at the same height is 3-8 mm. The shape of the through-holes 4 is preferably an elliptical or oblong structure with a difference between its major and minor axes, which provides more usable space along the major axis for the same opening area compared to a circular hole. In this embodiment, the through-hole 4 is elliptical. Its major axis provides a large passage space, facilitating the insertion of the optical fiber 5 within the through-hole 4 and maintaining a stable posture. The minor axis restricts the flow cross-section of ammonia gas, causing the generated bubbles to exhibit a more uniform flat or stretched interface when exiting the orifice, which is beneficial for creating a more sufficient disturbance effect in liquid metal. The wall of the through-hole 4 remains smooth and continuous, avoiding sharp edges that could affect the durability of the optical fiber 5, thereby improving the structural stability under long-term immersion and airflow impact conditions.

[0032] Furthermore, the major axis of the elliptical through-hole 4 is rotated at a preset angle relative to the axial direction of the air inlet pipe 2 within the vertical plane where the through-hole 4 is located, so that the elliptical hole has a tilted orientation on the pipe wall. The tilt angle is preferably 15°-45°, and can be selected according to the arrangement of the optical fiber 5, the control of the bubble interface morphology, and processing requirements. In this embodiment, the tilt angle of the elliptical through-hole is alternately set at 20° and -20°. The elliptical hole has directional geometric constraints, so that the interface morphology of the bubble when it leaves the through-hole 4 is asymmetrically flattened or stretched, thereby generating a slight oscillation, twisting, or rotational tendency during the floating process, enhancing the degree of disturbance at the gas-liquid interface. The tilt direction of the major axis of the elliptical hole can also make the light emission direction of the end of the optical fiber 5 inserted in the through-hole 4 closer to the main development direction of the bubble interface, improving the matching of the light field effect in the interface region. The elliptical through-hole 4 structure can be formed by laser processing, five-axis micro-milling, or electrical discharge machining, etc., and has good processing feasibility and stability.

[0033] In the axial direction of the inlet pipe 2, the arrangement density of the through holes 4 is differentiated according to their distance from the bottom: the region near the bottom of the inlet pipe 2 uses a denser arrangement of through holes 4, so that ammonia gas forms a continuous and uniform dispersion band at the initial position of entering the liquid metal; along the axial direction upward, the arrangement of through holes 4 gradually becomes sparser, forming a more discrete upper air intake path. Based on the same structural control principle, the aperture of the through holes 4 is also designed to vary according to the height position. The through holes 4 near the bottom use a relatively large aperture to meet the initial gas flux requirements; the upper through holes 4 far from the bottom are set with a smaller aperture to maintain a finer and more stable high-level bubble distribution. Through the combined adjustment of arrangement density and aperture, the air intake, bubble formation characteristics and interface distribution in each height region are better coordinated, allowing bubbles to stay in the liquid metal for a longer time, which is beneficial to improving the stability of the light field and interface interaction.

[0034] In this embodiment, the light source is located outside the reaction device, or it can be arranged in the upper region of the air inlet pipe 2. The light source is connected to the optical fiber 5 through a high-temperature resistant optical fiber interface, so that the light energy can be stably coupled into the interior of the optical fiber 5. The light source type is a continuous or pulsed light source, preferably with a center wavelength in the range of 200-450nm, and the light source power is adjustable in the range of 1-50W according to the interface excitation requirements.

[0035] The portion of optical fiber 5 inside the air intake pipe 2 is gathered, organized, and fixed into a bundle, such as... Figure 3 As shown, the fiber optic cable 5 is fixed to the positioning area on the inner wall of the air inlet pipe 2 by an annular limiting ring 7, radial clamping parts, or high-temperature resistant slots, ensuring that the fiber optic cable 5 maintains a relatively stable arrangement under fluid disturbance and temperature changes. The light source of the structure in the figure is an external light source and is not shown in the figure. The bundled structure ensures that the fiber optic cable 5 has a clear arrangement path before entering the through hole 4, so that the corresponding position of each fiber optic cable 5 at the through hole 4 will not be offset or tangled. At the same time, the free section extending outward from the bundled section outside the through hole 4 will naturally disperse slightly in different directions after the restricted bundle diameter relaxes, so that the ends of the fiber optic cable 5 are not pointing in a single direction, but forming a certain dispersion angle distribution inside the liquid metal, thereby expanding the illumination coverage and avoiding excessive concentration of the light focus in a single area. In addition, since the free end of the fiber optic cable 5 is located inside the liquid metal, the formation and detachment of bubbles at the through hole 4 will cause slight vibration of the fiber optic cable 5, causing slight changes in the position of the end of the fiber optic cable 5, thus causing slight fluctuations in the illumination area over time, avoiding continuous concentration of the light field at a fixed interface point, and making the illumination coverage more uniform.

[0036] Fiber 5 is preferably made of multimode fiber, which has a large numerical aperture, a wide cone angle for emitted light, and a large spot area, thus forming a wider illumination coverage area near the liquid metal interface. Simultaneously, multimode fiber has a high tolerance for bending, end-face processing, and installation position deviations, making it suitable for applications where fiber 5 passes through the elliptical through-hole 4 and maintains stable light output inside the liquid metal. The outer diameter of fiber 5 is preferably 0.05-0.2 mm, allowing it to pass smoothly through the elliptical through-hole 4 without causing significant shaking or compression within the hole, and providing sufficient flow space for gas to enter the liquid metal from the through-hole 4. The multimode fiber forms a stable, continuous, and large-coverage illumination area at the bubble interface at different heights, providing a reliable foundation for light energy input at the interface. The end of the optical fiber 5 is preferably processed into a beveled end, a tapered end, or a scattering end after being tapered. The beveled end forms an inclination angle of 5°-30° on the end face of the optical fiber 5, which causes the emitted beam to be deflected and expands the illumination range. The tapered end can make the light form a gradually diverging illumination cone in the axial direction of the optical fiber 5. The scattering end after being tapered produces microstructure scattering at the end, which makes the light diffuse to the surroundings at a larger angle.

[0037] With a large number of optical fibers 5 and a wide distribution range of through-holes 4, the length of each optical fiber 5 is not uniformly set, but is differentiated according to the height of the through-hole 4 it passes through, the desired illumination depth, the size of the reaction chamber 1, and the position of the interface reaction. The optical fibers 5 corresponding to the through-holes 4 near the bottom of the air inlet pipe 2 are relatively long, allowing the ends of the optical fibers 5 to penetrate deeper into the liquid metal, providing stronger optical coupling in the lower bubble initiation zone; the lengths of the optical fibers 5 located in the middle and upper through-holes 4 gradually shorten, allowing the ends of the optical fibers 5 to cover the interface distribution in the middle and upper parts. At the same time, multiple optical fibers 5 can be configured inside a single through-hole 4, and the lengths of these optical fibers 5 are different, so that the ends of the optical fibers 5 extending into the liquid metal from the same through-hole 4 form a staggered three-dimensional distribution. This structure makes the illumination area corresponding to a single through-hole 4 exhibit volumetric expansion, rather than forming local illumination at a single depth, which is beneficial to improving the spatial continuity of the light field near the interface, reducing illumination dead zones, and ensuring that the bubble remains within the range of the light field during its ascent.

[0038] In actual operation, the light field emitted from the end of fiber 5 can directly illuminate the interface region formed by the liquid metal and ammonia bubbles, providing additional energy input near the interface. The light disturbs the electronic state distribution at the interface, which helps reduce the local excitation conditions required for the interface reaction, making it easier to trigger the ammonia decomposition process at the interface. As the ammonia bubbles rise to different heights, the multi-layered illumination area composed of fiber 5 of different lengths can form a continuous light field coverage along the bubble's rising path, ensuring a relatively stable photoexcitation environment in the interface region throughout the reaction process. Simultaneously, the different geometric structures at the ends of fiber 5 allow the light field to cover a wider interface area within the liquid metal, reducing local shadow areas and further improving the spatial uniformity of light energy distribution in the interface region. This embodiment's optical coupling structure provides a more easily triggered interface excitation environment for the liquid metal ammonia decomposition reaction without significantly increasing the overall temperature. Example 3:

[0039] In this embodiment, to further enhance the excitation effect of the optical coupling interface, based on embodiment 2, an ultrasonic transducer is installed on the inner wall of the region below the liquid metal surface of the air inlet pipe 2.

[0040] In this embodiment, the ultrasonic transducer adopts a wall-mounted fixed structure, ensuring a tight connection between the transducer and the inner wall of the inlet pipe 2. Its vibrational energy is preferentially radiated into the cavity, thereby reducing lateral stress on the pipe wall and the through-hole 4 area, and preventing fatigue of the inlet pipe 2 structure. Simultaneously, the ultrasonic transducer is positioned separately from the light field introduction area, ensuring that the end of the optical fiber 5 or the illumination window does not experience light angle jitter due to acoustic vibration during operation, allowing the light field to stably irradiate the interface region inside the liquid metal. The ultrasonic transducer preferably uses a high-frequency sound field of 20-80kHz. This frequency range allows for precise control of bubble size, placing the bubble at a more favorable scale and morphology for the optical coupling reaction. Furthermore, it avoids the severe cavitation, structural vibration, and large-amplitude interface disturbances caused by low-frequency sound fields, concentrating the sound field's effect more on the bubble generation region inside the inlet pipe 2 without disrupting the optical environment inside the liquid metal body.

[0041] Before ammonia gas enters the liquid metal through inlet pipe 2, it passes through the area where the ultrasonic transducer is located. During operation, the ultrasonic transducer generates a high-frequency sound field in this area, dispersing the ammonia gas into smaller, more uniform microbubbles at through-hole 4, and creating periodic interface disturbances at the moment of bubble formation. Subsequently, these pre-controlled bubbles enter the liquid metal, maintaining high interface dynamics during their ascent. This synergistic effect with the excitation mechanism of the optical field makes the interface more easily placed in a highly activated state. Through this arrangement, the ultrasonic transducer can provide precise interface control during the bubble formation stage, resulting in smaller, more uniform ammonia bubbles with higher deformation frequencies, thereby enhancing the excitation efficiency of the optical field on the interface. Example 4:

[0042] Based on the optically coupled enhanced liquid metal ammonia decomposition reactor in Example 2, this example describes its usage and explains the operation process of the device in actual operation.

[0043] During use, first place the reaction chamber 1 on the heating device and check the inner wall and the sealing surface of the top cover to ensure that there are no residues or oxide layers, so as to ensure the sealing effect after the liquid metal is added. Open the top cover of the reaction chamber 1 and add the liquid metal into the reaction chamber 1, so that the liquid level covers the lower end of the air inlet pipe 2 and does not exceed the air outlet pipe 3.

[0044] Before installing the air inlet pipe 2 into the liquid metal, the optical fibers 5 are arranged. Multiple optical fibers 5 are bundled and fixed inside the air inlet pipe 2 within the limiting ring 7. Then, each optical fiber 5 is sequentially inserted into the corresponding elliptical through-hole 4 on the wall of the air inlet pipe 2, so that the end of the optical fiber 5 extends out of the pipe wall at a predetermined length. This process is carried out in an air environment to avoid bending or damage to the optical fibers 5 when operating in the liquid metal.

[0045] The top cover and air inlet pipe 2 are then installed and locked in place. During the process of inserting the liquid metal into the air inlet pipe 2, a small amount of inert gas is temporarily introduced to maintain a slight positive pressure inside the air inlet pipe 2. The air inlet pipe 2 is then slowly inserted, allowing its lower end to gradually enter the liquid metal. Due to the slight positive pressure at the through-hole 4, the liquid metal will not flow back into the air inlet pipe 2 through the through-hole 4, thus ensuring the stability of the optical fiber 5 and preventing it from being affected by liquid impact. Once the air inlet pipe 2 is inserted to the predetermined depth, it and the top cover of the reaction chamber 1 are sealed and secured.

[0046] The heating device is activated to raise the liquid metal to the target working temperature to establish suitable gas-liquid interface conditions. At the same time, the light source is activated, and the light signal output by the light source is introduced into the reaction chamber 1 through the optical fiber 5 located inside the air inlet pipe 2. The optical fiber 5 passes through the through holes 4 at different heights and extends into the liquid metal at different lengths, so that a multi-layered and continuously distributed light-emitting area is formed inside the reaction chamber 1.

[0047] After the temperature and light field stabilize, the inlet pipe 2 is connected to the ammonia source, and ammonia is introduced at a controllable flow rate, allowing the ammonia to enter the liquid metal through the through-hole 4 and form dispersed, floating bubbles. As the bubbles rise, they pass through different illuminated areas at varying heights, ensuring the interface receives continuous light energy input throughout its upward path, making it easier to achieve local excitation conditions. As the reaction continues, the generated product gas accumulates near the liquid surface and is discharged through the outlet pipe 3 on the upper sidewall of the reaction chamber 1, entering an external condenser or detection module for collection and analysis.

[0048] By adjusting the light source intensity, heating temperature, and ammonia flow rate, the reaction process is carried out under stable conditions. The light field is fully coupled with the gas-liquid interface in the reaction space, thereby achieving stable operation of the reaction device described in Example 2 and forming a continuous, stable, and controllable interface excitation environment.

[0049] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for optically coupled enhanced decomposition of liquid metal ammonia, characterized in that: An optical field is introduced into the interface region between liquid metal and ammonia.

2. The optically coupled enhanced liquid metal ammonia decomposition method according to claim 1, characterized in that: The wavelength of the light field is 200-450nm.

3. The optically coupled enhanced liquid metal ammonia decomposition method according to claim 2, characterized in that: The liquid metal is one of gallium, gallium-indium alloy, gallium-tin alloy, and gallium-indium-tin alloy.

4. A photocoupled enhanced liquid metal ammonia decomposition reaction device, comprising a reaction chamber, an inlet pipe, and an outlet pipe, wherein the reaction chamber contains liquid metal, the inlet pipe is fixed at the center of the upper cover of the reaction chamber and extends into the reaction chamber, and the outlet pipe is located on the side wall of the reaction chamber near the upper cover, characterized in that: The air inlet pipe has multiple through holes on its wall below the liquid metal surface; multiple optical fibers are connected to the light source and extend through the through holes into the liquid metal.

5. The optically coupled enhanced liquid metal ammonia decomposition reaction device according to claim 4, characterized in that: The bottom end of the intake pipe is a closed structure, and the through holes are arranged in an array along the axial and circumferential directions of the intake pipe.

6. The optically coupled enhanced liquid metal ammonia decomposition reaction apparatus according to claim 5, characterized in that: The through hole is an elliptical hole whose main axis is inclined at an angle to the axial direction of the intake pipe.

7. The optically coupled enhanced liquid metal ammonia decomposition reaction apparatus according to claim 6, characterized in that: The through holes are densely arranged near the bottom of the air intake pipe and sparsely arranged away from the bottom of the air intake pipe.

8. The optically coupled enhanced liquid metal ammonia decomposition reaction apparatus according to claim 4, characterized in that: The optical fibers are fixed in a bundle inside the air intake pipe.

9. The optically coupled enhanced liquid metal ammonia decomposition reaction apparatus according to claim 8, characterized in that: The optical fiber is a multimode optical fiber.

10. The optically coupled enhanced liquid metal ammonia decomposition reaction apparatus according to claim 9, characterized in that: The optical fibers are of different lengths, with the optical fiber near the bottom of the air inlet pipe being relatively longer; and the multiple optical fibers in each through hole are of different lengths.

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