A liquid-phase photocatalytic reaction in-situ monitoring system and method based on a micro-nano optical fiber micro-force probe

Abstract

The application discloses a liquid-phase photocatalytic reaction in-situ monitoring system and method based on a micro-nano optical fiber micro-force probe.The micro-nano optical fiber micro-force probe is integrated with a liquid reaction cavity, an excitation light source module, a photoelectric detection module and a signal demodulation module, and micro-bubble generation, growth, desorption and movement processes in the liquid-phase photocatalytic reaction exert buoyancy or drag force on the micro-nano optical fiber micro-force probe, so that the micro-nano optical fiber micro-force probe is slightly deformed and further causes optical transmission state change, and mechanical signals are obtained through optical signal change, thereby realizing in-situ mechanical monitoring of the liquid-phase photocatalytic process.The application can not only observe micro-bubble morphology, but also identify early nucleation, growth stages and desorption instants from real-time mechanical signals, realizes correlation analysis of optical images and mechanical signals, and provides a new mechanical dimension for evaluating reaction kinetics.

Description

Technical Field

[0001] This invention belongs to the technical fields of micro-nano fiber optic sensing, dynamic force detection in liquid environments, photocatalytic reaction monitoring, microbubble mechanics detection, in-situ characterization of liquid phase reactions, and micro-nano optical detection instruments. Specifically, it relates to an in-situ monitoring system and method for liquid phase photocatalytic reactions based on a micro-nano fiber optic microforce probe. Background Technology

[0002] Photocatalytic reactions, especially photocatalytic water splitting, photocatalytic hydrogen production, photocatalytic oxygen production, photocatalytic pollutant degradation, and photo-driven liquid-phase gas production, are crucial processes in energy conversion, environmental remediation, and chemical reaction engineering. In liquid-phase photocatalytic systems, reactions typically occur on the surface of catalyst particles, catalyst films, or catalyst-supported structures. These reactions may be accompanied by the generation of gaseous products, microbubble nucleation, growth, fusion, desorption, and localized fluid disturbances. These microscale events are closely related to catalyst activity, reaction initiation time, reaction kinetics, local mass transfer, interfacial states, and reaction stability.

[0003] Existing methods for characterizing photocatalytic processes mainly include gas yield detection, gas chromatography analysis, photocurrent measurement, absorption spectroscopy, fluorescent probes, chemical indicators, microscopic imaging, and post-reaction material characterization. While these methods can evaluate overall reaction efficiency or material properties, they still have limitations in capturing local dynamic events near individual catalytic regions. For example, gas yield and gas chromatography are more suitable for statistically analyzing macroscopic gas production and are less effective at reflecting transient processes such as microbubble nucleation and desorption; photocurrent and spectroscopy can reflect photogenerated carriers or light absorption characteristics but cannot directly provide information on local mechanical disturbances caused by microbubbles; microscopic imaging can observe bubble morphology but has limited ability to acquire invisible early nucleation, weak buoyancy changes, micro-perturbations in the liquid, and mechanical signals at the moment of bubble desorption.

[0004] For detecting weak dynamic forces in liquid environments, traditional electrical sensors, piezoelectric sensors, capacitive sensors, or mechanical probes face limitations in miniaturization, liquid encapsulation, electromagnetic interference immunity, spatial resolution, real-time response, and compatibility with microscopic observation. Particularly in photocatalytic reactions, excitation light irradiation, the liquid environment, electrolytes or reaction media, microbubble disturbances, and catalyst particles can all interfere with traditional detection systems, making in-situ quantitative monitoring of localized reaction processes even more difficult.

[0005] Micro- and nano-fibers possess advantages such as small size, light weight, high evanescent field ratio, high optical readout sensitivity, resistance to electromagnetic interference, long-distance transmission capability, and the ability to operate in liquid environments. When constructed into micro-force probes, these fibers can convert weak buoyancy, dragging forces, disturbance forces, pressure disturbances, or fluid disturbances in liquid environments into changes in light intensity or wavelength. Furthermore, by placing photocatalytic particles or other reactants on or near the surface of the micro- and nano-fiber micro-force probe, it becomes possible to directly detect the mechanical signals caused by the generation, growth, and desorption of microbubbles near the reaction site, thereby achieving in-situ, real-time, and dynamic monitoring of liquid-phase photocatalytic reactions.

[0006] Therefore, it is necessary to provide an in-situ monitoring system and method for liquid-phase photocatalytic reactions based on micro-nano fiber optic micro-force probes, which can detect weak mechanical disturbances induced by photocatalytic reactions in real time in a liquid environment using micro-nano fiber optic micro-force probes, and extract information such as reaction start time, microbubble nucleation, bubble growth, bubble desorption, reaction activity and stability from the mechanical signals, so as to make up for the shortcomings of existing photocatalytic characterization methods that cannot directly obtain local dynamic mechanical information. Summary of the Invention

[0007] In view of the above, the purpose of this invention is to address the shortcomings of the prior art by providing an in-situ monitoring system and method for liquid-phase photocatalytic reactions based on micro-nano fiber optic micro-force probes. This system and method solve the problems of existing photocatalytic process characterization methods, such as difficulty in directly detecting local weak dynamic mechanical signals, difficulty in identifying individual bubble events, difficulty in in-situ evaluation of microscale reaction kinetics, and difficulty in achieving highly sensitive and stable monitoring under liquid and light conditions.

[0008] Furthermore, by integrating the micro-nano fiber optic micro-force probe with the liquid reaction chamber, excitation light source module, photoelectric detection module and signal demodulation module, the present invention enables the generation, growth, desorption and movement of microbubbles in the liquid-phase photocatalytic reaction to be converted into real-time optical signals, thereby obtaining mechanical signals through optical signals and realizing in-situ mechanical monitoring of the liquid-phase photocatalytic process.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides an in-situ monitoring system for liquid-phase photocatalytic reactions based on a micro / nano fiber optic micro-force probe, comprising a liquid reaction chamber, a micro / nano fiber optic micro-force probe with a reactant carrying area, a detection light source module, a photoelectric detection module, a signal demodulation module, an excitation light source module, and a microscopic observation module.

[0010] The liquid reaction chamber is used to contain the liquid-phase reaction system. The liquid-phase reaction system can be water, an aqueous solution containing a sacrificial agent, an electrolyte solution, an aqueous solution of organic matter, a pollutant degradation solution, a photocatalytic reaction solution, a photothermal reaction solution, a microfluidic reaction solution, or other systems capable of undergoing a liquid-phase physicochemical reaction under excitation conditions. The liquid reaction chamber is preferably a transparent liquid pool, a glass liquid pool, a microfluidic chip cavity, or a reaction chamber with an optical window to facilitate excitation light irradiation and microscopic observation.

[0011] The micro / nano fiber optic microforce probe is located at least partially within the liquid reaction chamber, and is used to sense weak dynamic mechanical disturbances in the liquid environment and convert them into changes in optical signals. The micro / nano fiber optic microforce probe is not limited to a single structure and can be an intensity modulation type, a phase interference type, a wavelength drift type, a micro / nano fiber optic microcantilever type, a ring probe, a U-shaped probe, or other micro / nano fiber optic probes capable of converting weak mechanical disturbances in the liquid environment into changes in optical signals.

[0012] Preferably, the micro / nano fiber optic microforce probe is a micro / nano fiber optic microcantilever with a reactant-bearing region. The micro / nano fiber optic microforce probe includes a micro / nano fiber, with both ends twisted to form a twisted-pair coupling region and an annular sensing region at the end. The twisted-pair coupling region and the annular sensing region are encapsulated by a transparent flexible thin film to form an optical microcantilever structure. The flexible thin film forms a protective layer on the fiber surface of the twisted-pair coupling region and the annular sensing region, and the reactant-bearing region is formed in the spatial region surrounded by the fiber in the annular sensing region. Input light excites even and odd modes in the twisted-pair coupling region. The two modes generate a phase difference due to their different effective refractive indices, forming an interference signal. When a liquid-phase photocatalytic reaction occurs in the reactant-bearing region, the resulting microbubble generation, growth, desorption, and movement cause microdeformation of the optical microcantilever structure, leading to changes in the output spectrum, light intensity at a fixed wavelength, or frequency domain components, thereby achieving in-situ mechanical monitoring of the liquid-phase photocatalytic process.

[0013] The detection light source module is used to input detection light into the micro / nano fiber optic microforce probe. The detection light can be broadband light or laser light. The photoelectric detection module is used to acquire the spectrum, intensity, or phase of the output of the micro / nano fiber optic microforce probe. The signal demodulation module is used to perform interference peak or valley tracking, fixed wavelength intensity readout, or frequency domain analysis on the output signal to obtain signals related to the dynamic forces in the liquid environment.

[0014] The excitation light source module is used to provide excitation light to the reactant-supporting region to trigger or regulate the liquid-phase photocatalytic reaction. The excitation light source module can be an ultraviolet light source, a visible light source, a near-infrared light source, a laser, an LED, or a fiber-coupled light source. The wavelength and intensity of the excitation light are selected according to the absorption characteristics of the reactant. Preferably, the excitation light wavelength is 200-1100 nm; when the reactant is SrTiO3, the excitation light is preferably 300-370 nm ultraviolet light, more preferably about 360 nm ultraviolet light.

[0015] The reactant-bearing region is used to support reactants, which include photocatalytic particles, catalyst particles, gas-generating reaction materials, photothermal materials, or combinations thereof. The reactant-bearing region is located on the flexible thin film surface of the annular sensing area of ​​the micro / nano fiber optic microforce probe. The reactants can be deposited in the reactant-bearing region through physical adsorption, electrostatic adsorption, dip coating, surface chemical modification, polydopamine modification, or micromanipulation.

[0016] The reactants can be SrTiO3, TiO2, ZnO, CdS, Fe2O3, composite semiconductor photocatalytic materials, photothermal conversion materials, enzyme catalytic particles, visible light responsive catalytic materials, or other materials that can induce liquid-phase photocatalytic reactions under light irradiation or other triggering conditions.

[0017] The microscopic observation module is used to observe local reaction processes in reactants, microbubbles, micro / nano fiber optic microforce probes, and liquid reaction chambers. The microscopic observation module may include an optical microscope, an inverted microscope, a CCD camera, a CMOS camera, a high-speed camera, a fluorescence microscopy module, or a combination thereof.

[0018] During operation, after the reactants are irradiated with excitation light, a liquid-phase photocatalytic reaction occurs on the surface of the reactants. When the reaction generates microbubbles, the generation, growth, desorption, and movement of these microbubbles exert buoyancy or dragging forces on the micro / nano fiber optic micro-force probe, causing minute deformations in the probe and resulting in changes in the optical transmission state. These changes are further manifested as shifts in interference peaks or valleys or variations in light intensity at a fixed wavelength.

[0019] This invention also provides a method for in-situ monitoring of liquid-phase photocatalytic reactions based on micro / nano fiber optic micro-force probes, comprising the following steps: S1 provides a liquid reaction chamber, a micro / nano fiber optic micro-force probe, a detection light source module, a photoelectric detection module, a signal demodulation module, and an excitation light source module; S2, the reactant is placed in the reactant-bearing area of ​​the micro-nano fiber optic micro-force probe; S3, the micro-nano fiber optic micro-force probe carrying the reactant is placed into the liquid reaction chamber, the detection light is input to the micro-nano fiber optic micro-force probe through the detection light source module, and the baseline signal under non-reaction conditions is collected through the photoelectric detection module; S4, turn on the excitation light source module to irradiate the reactants, causing them to undergo a liquid-phase photocatalytic reaction; S5 acquires the output optical signal of the micro-nano fiber optic micro-force probe in real time and simultaneously acquires microscopic images through the microscopic observation module; S6, the output optical signal is converted into a real-time mechanical signal through the signal demodulation module to identify the microbubble generation, growth, desorption and movement processes.

[0020] In some implementations, the optical signal changes of the micro-nano fiber optic micro-force probe can be converted into force values ​​through pre-calibration, specifically the buoyancy or drag force of the microbubbles acting on the probe.

[0021] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention converts the weak buoyancy or drag force in the liquid phase photocatalytic reaction into changes in light signals, thereby realizing in-situ monitoring of local dynamic mechanical events in the liquid environment.

[0022] (2) This invention can not only observe the morphology of microbubbles, but also identify the early nucleation, growth stage and desorption moment from real-time mechanical signals, providing a new mechanical dimension for evaluating reaction kinetics.

[0023] (3) The present invention uses a micro-nano fiber optic micro-force probe, which has the advantages of small size, low weight, compatibility with liquid environment, sensitive optical readout, anti-electromagnetic interference and suitability for long-distance transmission.

[0024] (4) This invention does not limit specific photocatalytic materials and reaction systems, and can be applied to various photocatalytic particles such as SrTiO3 and TiO2, as well as other gas-producing or liquid-phase physicochemical reaction systems.

[0025] (5) The present invention supports various structures such as reactants being directly loaded onto the probe surface, placed near the probe, or integrated into the microfluidic channel, and has strong experimental adaptability and system integration capability.

[0026] (6) This invention can work synchronously with microscopic observation, high-speed imaging, spectral detection and data processing modules to realize the correlation analysis of optical images and mechanical signals.

[0027] (7) This invention can be used for catalyst activity evaluation, catalyst stability analysis, microbubble kinetics research, photocatalytic reaction mechanism analysis, microfluidic reaction monitoring and in-situ characterization of liquid phase reaction processes. Attached Figure Description

[0028] To more clearly illustrate the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings. The accompanying drawings are only used to illustrate the system structure, working principle, monitoring process, and typical experimental results of the present invention, and should not be construed as limiting the scope of protection of the present invention.

[0029] Figure 1 This is a schematic diagram of the overall structure of the in-situ monitoring system for liquid-phase photocatalytic reaction based on a micro / nano fiber optic micro-force probe of the present invention; in the figure: 1-liquid reaction chamber, 2-micro / nano fiber optic micro-force probe, 3-detection light source module, 4-photoelectric detection module, 5-signal demodulation module, 6-excitation light source module, 7-reactant carrying area, 8-microscopic observation module.

[0030] Figure 2 This is a schematic diagram of the reactant placement method of the present invention, showing the reactant placed on the flexible thin film surface of the annular sensing area of ​​the micro-nano fiber optic micro-force probe.

[0031] Figure 3 This is a schematic diagram of the photocatalytic reaction principle of the present invention, showing the process of generating photogenerated electrons and holes under excitation light irradiation using semiconductor photocatalytic particles as an example, and inducing liquid-phase reaction to generate gaseous products or other reaction products.

[0032] Figure 4 This is a flowchart of the in-situ monitoring method for liquid-phase photocatalytic reaction of the present invention, showing the steps of particle setting, liquid placement, baseline acquisition, excitation light irradiation, and signal acquisition.

[0033] Figure 5 The figure shows the experimental results of in-situ detection of bubble growth in photocatalysis according to the present invention. It corresponds to the changes in the output signal and equivalent buoyancy signal of the micro-nano fiber optic micro-force probe over time when microbubbles are gradually generated and grow during the photocatalysis process.

[0034] Figure 6 The diagram shows the experimental results of the microbubble desorption process of this invention, corresponding to the process in which the probe output signal rapidly decreases or undergoes transient changes when microbubbles desorb from the surface or reaction area of ​​the micro / nano fiber optic micro-force probe. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the following embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Equivalent substitutions or conventional improvements made by those skilled in the art to the structure, materials, dimensions, detection methods, reaction systems, or data processing methods without departing from the concept of the present invention should all fall within the scope of protection of the present invention.

[0036] The core of this invention lies in using a micro-nano fiber optic micro-force probe to sense the weak mechanical disturbances induced by photocatalytic reactions in a liquid environment, and converting the microbubble generation, growth, desorption and movement processes into optical signals that can be acquired in real time, thereby obtaining mechanical signals through optical signals and realizing in-situ mechanical monitoring of the liquid-phase photocatalytic process.

[0037] Example 1: In-situ monitoring system for liquid-phase photocatalytic reaction like Figure 1 As shown, this embodiment provides an in-situ monitoring system for liquid-phase photocatalytic reactions based on a micro / nano fiber optic micro-force probe, including a liquid reaction chamber 1, a micro / nano fiber optic micro-force probe 2 with a reactant carrying area 7, a detection light source module 3, a photoelectric detection module 4, a signal demodulation module 5, an excitation light source module 6, and a microscopic observation module 8. The liquid reaction chamber 1 is used to contain the liquid-phase reaction system, which can be water, an aqueous solution containing a sacrificial agent, an electrolyte solution, an aqueous solution of organic matter, a pollutant degradation solution, a photocatalytic reaction liquid, a photothermal reaction liquid, a microfluidic reaction liquid, or other systems capable of undergoing liquid-phase physicochemical reactions under excitation conditions. The liquid reaction chamber 1 can be a transparent liquid pool, a glass liquid pool, a microfluidic chip cavity, or a reaction chamber with an optical window.

[0038] The reactant-bearing region 7 of the micro / nano fiber optic microforce probe 2 extends into the liquid reaction chamber 1. The detection light source module 3 is connected to the input end of the micro / nano fiber optic microforce probe 2 to input broadband light or laser light. The photoelectric detection module 4 is connected to the output end of the micro / nano fiber optic microforce probe 2 to acquire the output spectrum, output light intensity, or phase signal. The signal demodulation module 5 is connected to the photoelectric detection module 4 to track interference peaks or valleys and read out fixed-wavelength light intensity from the acquired light signal, thereby obtaining real-time signals related to the dynamic forces of the liquid environment.

[0039] The excitation light source module 6 provides ultraviolet, visible, near-infrared, or other trigger light to the reactant support area 7. The excitation light source module 6 can be positioned to one side, above, or below the liquid reaction chamber 1, with its illumination direction aligned with the reactant support area 7. The microscopic observation module 8 is used to observe the micro / nano fiber optic microforce probe 2, the reactants, microbubbles, and localized reaction processes within the liquid reaction chamber 1. The microscopic observation module 8 can be coaxially arranged with the excitation light source module 6 or at a certain angle to reduce the influence of stray light on the detection optical path.

[0040] Example 2: Micro / Nano Fiber Optic Microforce Probe and Optical Readout Method In this embodiment, the micro / nano fiber optic microforce probe 2 is preferably a micro / nano fiber optic cantilever with a reactant-carrying region. The micro / nano fiber of the micro / nano fiber optic microforce probe 2 can be made from standard silica fiber through flame heating and mechanical stretching, or from polymer fiber, fluoride glass fiber, chalcogenide glass fiber, or other materials capable of forming micro / nano-scale optical waveguides. The two ends of the micro / nano fiber are twisted to form a twisted-pair coupling region and an annular sensing region at the end. The twisted-pair coupling region and the annular sensing region are encapsulated by a transparent flexible thin film to form an optical microcantilever structure. The flexible thin film forms a protective layer on the fiber surface of the twisted-pair coupling region and the annular sensing region, and forms a reactant-carrying region in the spatial area surrounded by the fiber in the annular sensing region. The flexible thin film can be a polydimethylsiloxane film, a hydrogel film, a silicone rubber film, a polyimide film, a Nafion film, or other transparent flexible polymer films.

[0041] When the detection light enters the micro-nano fiber micro-force probe 2, it excites even and odd modes in the torsional coupling region. The two modes generate a phase difference due to their different effective refractive indices and form an interference signal. When the liquid-phase photocatalytic reaction occurs in the reactant-bearing region, the microbubble generation, growth, desorption and movement processes it triggers cause micro-deformation of the optical microcantilever structure, resulting in changes in the output spectrum, light intensity at a fixed wavelength or frequency domain components, thereby realizing in-situ mechanical monitoring of the liquid-phase photocatalytic process.

[0042] When static monitoring is required, the photoelectric detection module 4 can employ a spectrometer and obtain mechanical changes by tracking the wavelength drift of interference peaks or valleys. When rapid dynamic monitoring is required, the photoelectric detection module 4 can employ a photodetector and record changes in output light intensity at a fixed wavelength, which are then acquired and analyzed at high speed by the signal demodulation module 5. The above readout methods can be used individually or in combination.

[0043] Example 3: Reactant Setup like Figure 2 As shown, the flexible thin film surface of the annular sensing area of ​​the micro-nano fiber optic micro-force probe 2 is used as the reactant carrying area 7, so that microbubbles are generated and grow in the reactant carrying area 7, thereby improving the mechanical coupling efficiency.

[0044] The reactants can be placed in the reactant-bearing region through physical adsorption, electrostatic adsorption, dip coating, surface chemical modification, polydopamine modification, or micromanipulation. Preferably, the reactant loading is controlled within a range that can generate a detectable reaction signal without significantly reducing the sensitivity of the micro / nano fiber optic microforce probe 2.

[0045] Example 4: Photocatalytic reaction principle and in-situ monitoring process like Figure 3As shown, taking SrTiO3 semiconductor photocatalytic particles as an example, when the excitation light provided by the excitation light source module 6 irradiates the reactants, the semiconductor material absorbs photons and generates photogenerated electrons and holes. Photogenerated electrons can participate in reduction reactions, and photogenerated holes can participate in oxidation reactions, thereby generating hydrogen, oxygen, or other reaction products in the liquid-phase reaction system; when the gaseous products reach local supersaturation, microbubbles can be formed on or near the particle surface.

[0046] like Figure 4 As shown, the in-situ monitoring method for liquid-phase photocatalytic reaction of the present invention includes the following steps: First, the reactant is placed in the reactant-bearing area 7 of the micro-nano fiber optic micro-force probe; second, the micro-nano fiber optic micro-force probe carrying the reactant is placed into the liquid reaction chamber 1; third, the detection light source module 3 and the photodetector module 4 are turned on to collect the baseline signal of the micro-nano fiber optic micro-force probe under non-reaction conditions; subsequently, the excitation light source module 6 is turned on to irradiate the reactant and excite the liquid-phase photocatalytic reaction; finally, the output signal is collected in real time through the photodetector module 4 and the signal demodulation module 5, and the microbubble generation, growth, desorption and movement process is identified by combining the image obtained by the microscopic observation module 8.

[0047] During monitoring, the generation and growth of microbubbles cause gradual changes in the buoyancy or drag force acting on the micro-nano fiber optic micro-force probe 2; when the microbubbles detach and float, the mechanical conditions acting on the micro-nano fiber optic micro-force probe 2 undergo abrupt changes. By analyzing the corresponding changes in optical signals, parameters such as reaction start time, growth rate, desorption time, desorption frequency, mechanical amplitude, and reaction stability can be obtained.

[0048] Example 5: In-situ photocatalytic detection of bubble growth experiment like Figure 5 As shown, in one exemplary embodiment, SrTiO3 particles are used as reactants, water is used as the liquid-phase reaction system, and ultraviolet light with a wavelength of 360 nm is used as excitation light to perform in-situ mechanical monitoring of the photocatalytic water splitting process. The SrTiO3 particles are disposed on the flexible thin film surface of the annular sensing area of ​​the micro-nano fiber optic micro-force probe 2, ensuring full contact between the particles and the liquid-phase reaction system.

[0049] Specifically, a micro / nano fiber optic cantilever with a flexible thin film can be used as the micro / nano fiber optic microforce probe 2, and SrTiO3 particles are loaded onto the surface of the flexible thin film; the maximum outer diameter of the annular sensing area of ​​the micro / nano fiber optic microforce probe 2 is 0.5 mm; the detection light source module 3 inputs detection light to the micro / nano fiber optic microforce probe 2, and the photoelectric detection module 4 collects the output light intensity; the excitation light source module 6 provides approximately 360 nm ultraviolet light to irradiate the reactant-bearing area 7. It should be noted that the above-mentioned catalyst material, excitation wavelength, and probe size are only exemplary parameters and do not limit the present invention.

[0050] Without ultraviolet light, the output signal of the micro-nano fiber optic micro-force probe 2 maintains a stable baseline. After ultraviolet light is turned on, a photocatalytic water splitting reaction occurs on the surface of the SrTiO3 particles, and microbubbles gradually form and increase in size. As the volume of the microbubbles increases, the buoyancy or drag force they generate on the micro-nano fiber optic micro-force probe 2 gradually increases, which is manifested as a gradual increase in the output light intensity or the demodulated equivalent buoyancy signal over time.

[0051] In one example, after illumination, minute mechanical changes corresponding to the early growth of the bubble could be detected. Subsequently, the signal continued to rise as the microbubble gradually increased, corresponding to buoyancy changes on the nanonewton scale. The real-time microscopic images obtained through the microscopic observation module 8 can be correlated with the real-time mechanical signals to confirm the generation and growth process of the microbubble. This result demonstrates that the micro / nano fiber optic microforce probe 2 can detect the bubble growth process induced by photocatalytic reaction in situ and in real time in a liquid environment.

[0052] Example 6: Monitoring of Microbubble Desorption Process like Figure 6 As shown, when microbubbles detach from the surface of the micro-nano fiber optic micro-force probe 2, the surface of the reactant, or the vicinity of the reaction area, the buoyancy or drag force that originally acted on the probe will decrease or change rapidly, causing the output optical signal to drop rapidly, change abruptly, or experience transient disturbances.

[0053] In the specific detection, the microscopic observation module 8 records images before and after microbubble desorption, while the photoelectric detection module 4 simultaneously records the output signal of the micro-nano fiber optic micro-force probe 2. The signal demodulation module 5 determines the desorption time based on the abrupt change points in the output signal, and obtains the relative mechanical amplitude, desorption frequency, and reaction stability of a single bubble event based on the abrupt change amplitude, signal recovery time, and event interval.

[0054] This embodiment demonstrates that the present invention can not only monitor the continuous growth process of microbubbles, but also capture the mechanical events at the moment of microbubble desorption. Compared with observation solely based on microscopic images, the mechanical signals from micro / nano optical fibers can provide information on the local mechanical changes caused by bubble desorption, which is beneficial for analyzing bubble desorption mechanisms, catalyst surface states, and reaction kinetics.

[0055] This invention can be used for in-situ mechanical characterization of photocatalytic water splitting, photocatalytic hydrogen production, photocatalytic oxygen production, photocatalytic pollutant degradation accompanied by gas generation reactions, microfluidic gas generation reactions, photothermal induced bubble processes, electrochemical gas generation-assisted monitoring, enzyme-catalyzed gas generation systems, and other liquid-phase physicochemical reactions. Any equivalent implementation of this invention is permitted as long as the bubbles, fluid disturbances, pressure disturbances, or acoustic disturbances generated by the liquid-phase reaction can be sensed by the micro / nano fiber optic microforce probe 2 and used for reaction process evaluation.

[0056] In summary, the in-situ monitoring system and method for liquid-phase photocatalytic reactions based on micro / nano fiber optic micro-force probes provided by this invention can utilize micro / nano fiber optic micro-force probes to detect weak dynamic mechanical signals induced by photocatalytic reactions in real time in a liquid environment, enabling in-situ monitoring of microbubble generation, growth, desorption, movement processes, and reaction stability. This system has advantages such as miniaturization, high sensitivity, compatibility with liquid environments, resistance to electromagnetic interference, synchronization with microscopic observation, and wide applicability to various reaction systems. It can be used for photocatalytic reaction research, catalyst screening, microbubble dynamics research, and monitoring of liquid-phase physicochemical reaction processes.

[0057] The above are preferred embodiments of the present invention and are not intended to limit the invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A system for in-situ monitoring of liquid-phase photocatalytic reactions based on micro / nano fiber optic micro-force probes, characterized in that, It includes a liquid reaction chamber, a micro / nano fiber optic micro-force probe, a detection light source module, a photoelectric detection module, a signal demodulation module, an excitation light source module, and a microscopic observation module; The liquid reaction chamber is used to contain the liquid-phase reaction system; the micro-nano fiber optic micro-force probe is a micro-nano fiber optic micro-cantilever with a reactant carrying area. The reactant carrying area of ​​the micro-nano fiber optic micro-force probe extends into the liquid reaction chamber to sense weak dynamic mechanical disturbances in the liquid environment and convert them into changes in optical signals. The detection light source module is used to input detection light into the micro-nano fiber optic micro-force probe; the photoelectric detection module is used to collect the spectrum, light intensity or phase signal output by the micro-nano fiber optic micro-force probe; the signal demodulation module is used to perform interference peak or interference valley tracking, fixed wavelength light intensity readout or frequency domain analysis on the output signal to obtain real-time signals related to the dynamic force of the liquid environment. The excitation light source module is used to provide excitation light to the reactant carrying area to trigger or regulate the liquid-phase photocatalytic reaction; the microscopic observation module is used to observe the reactants, microbubbles generated by the liquid-phase photocatalytic reaction, micro-nano fiber optic micro-force probes, and local reaction processes in the liquid reaction chamber.

2. The in-situ monitoring system for liquid-phase photocatalytic reaction based on a micro / nano fiber optic micro-force probe according to claim 1, characterized in that, After the excitation light irradiates the reactants, a liquid-phase photocatalytic reaction occurs on the surface of the reactants. When the reaction generates microbubbles, the generation, growth, desorption, and movement of the microbubbles exert buoyancy or drag force on the micro-nano fiber optic micro-force probe, causing the micro-nano fiber optic micro-force probe to undergo slight deformation, which in turn leads to changes in the optical transmission state. This manifests as a shift in the interference peak or valley or a change in light intensity at a fixed wavelength. The mechanical signal is obtained through the change in the optical signal, realizing in-situ mechanical monitoring of the liquid-phase photocatalytic process.

3. The in-situ monitoring system for liquid-phase photocatalytic reaction based on a micro / nano fiber optic micro-force probe according to claim 1, characterized in that, During monitoring, the generation and growth of microbubbles cause gradual changes in the buoyancy or drag force acting on the micro-nano fiber optic micro-force probe. When microbubbles detach and float, the mechanical conditions acting on the micro-nano fiber optic micro-force probe undergo abrupt changes, causing the output optical signal to drop rapidly, change abruptly, or experience transient disturbances. By analyzing the corresponding changes in optical signals, the reaction start time, growth rate, desorption time, desorption frequency, mechanical amplitude, and reaction stability parameters can be obtained.

4. The in-situ monitoring system for liquid-phase photocatalytic reaction based on a micro / nano fiber optic micro-force probe according to claim 1, characterized in that, The liquid-phase reaction system is a system capable of undergoing liquid-phase physicochemical reactions under excitation conditions; the reactant is a material capable of inducing liquid-phase photocatalytic reactions under excitation conditions, and the reactant is disposed in the reactant carrier area of ​​the micro-nano fiber optic micro-force probe by means of physical adsorption, electrostatic adsorption, dip coating, surface chemical modification, polydopamine modification or micromanipulation.

5. The in-situ monitoring system for liquid-phase photocatalytic reaction based on a micro / nano fiber optic micro-force probe according to claim 1, characterized in that, The excitation light source module is an ultraviolet light source, a visible light source, a near-infrared light source, a laser, an LED, or a fiber-coupled light source. It is located on one side, above, or below the liquid reaction chamber, and its irradiation direction is aligned with the reactant carrying area. The wavelength and intensity of the excitation light are selected according to the absorption characteristics of the reactants.

6. The in-situ monitoring system for liquid-phase photocatalytic reaction based on a micro / nano fiber optic micro-force probe according to claim 1, characterized in that, The microscopic observation module includes an optical microscope, an inverted microscope, a CCD camera, a CMOS camera, a high-speed camera, a fluorescence microscopy module, or a combination thereof. The microscopic observation module is coaxially arranged with the excitation light source module, or is arranged at a certain angle to the excitation light source module, so as to reduce the influence of stray light on the detection optical path.

7. The in-situ monitoring system for liquid-phase photocatalytic reaction based on a micro / nano fiber optic micro-force probe according to claim 1, characterized in that, The micro / nano fiber optic microforce probe includes a micro / nano fiber. The two ends of the micro / nano fiber are twisted to form a twisted coupling region in the shape of a twisted pair and an annular sensing region at the end. The twisted coupling region and the annular sensing region are encapsulated by a transparent flexible thin film to form an optical microcantilever structure. The flexible thin film forms a protective layer on the fiber surface of the twisted coupling region and the annular sensing region, and forms a reactant carrying region in the spatial region surrounded by the fiber in the annular sensing region.

8. The in-situ monitoring system for liquid-phase photocatalytic reaction based on a micro / nano fiber optic micro-force probe according to claim 7, characterized in that, When the detection light enters the micro-nano fiber micro-force probe, it excites even and odd modes in the torsional coupling region. The two modes generate a phase difference due to their different effective refractive indices and form an interference signal. When the liquid-phase photocatalytic reaction occurs in the reactant-bearing region, the microbubble generation, growth, desorption and movement processes it triggers cause micro-deformation of the optical microcantilever structure, resulting in changes in the output spectrum, light intensity at a fixed wavelength or frequency domain components, thereby realizing in-situ mechanical monitoring of the liquid-phase photocatalytic process.

9. A method for in-situ monitoring of liquid-phase photocatalytic reactions based on the system described in any one of claims 1-8, characterized in that, Includes the following steps: S1 provides a liquid reaction chamber, a micro / nano fiber optic micro-force probe, a detection light source module, a photoelectric detection module, a signal demodulation module, and an excitation light source module; S2, the reactant is placed in the reactant-bearing area of ​​the micro-nano fiber optic micro-force probe; S3, the micro-nano fiber optic micro-force probe carrying the reactant is placed into the liquid reaction chamber, the detection light is input to the micro-nano fiber optic micro-force probe through the detection light source module, and the baseline signal under non-reaction conditions is collected through the photoelectric detection module; S4, turn on the excitation light source module to irradiate the reactants, causing them to undergo a liquid-phase photocatalytic reaction; S5 collects the output optical signal of the micro-nano fiber optic micro-force probe and simultaneously acquires microscopic images through the microscopic observation module; S6, the output optical signal is converted into a real-time mechanical signal through the signal demodulation module to identify the microbubble generation, growth, desorption and movement processes.

10. The method for in-situ monitoring of liquid-phase photocatalytic reactions according to claim 9, characterized in that, By pre-calibrating, the optical signal changes of the micro-nano fiber optic micro-force probe are converted into the buoyancy or drag force of the microbubbles acting on the probe.

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