Photocatalytic reactor and method for enhancing photoelectron utilization efficiency based on reflection

Abstract

The invention discloses a photocatalytic reactor and method for enhancing light path circulation efficiency based on arc-shaped inner wall reflection, and relates to the technical field of advanced photocatalytic reaction, the reactor comprises a reactor main body, a light incident section and an external light source, and is characterized in that a continuous arc-shaped inner wall is adopted in a reaction cavity; and the surface of the inner wall is covered with a reflection enhancement region. The method comprises the steps that a reaction medium containing a photocatalyst is placed in a cavity, vertical incidence is achieved through an external parallel light source, light rays penetrate through the medium and then are directionally reflected through a reflection enhancement area of the arc-shaped inner wall, and a multi-stage convergence and circulation light path structure is formed in the cavity. By means of the design, photons which are not absorbed for the first time are forced to penetrate through the reaction medium again, the effective optical path is remarkably prolonged, the problem that the light energy escape rate of a traditional reactor is high is solved, and the quantum efficiency of photocatalytic reaction is greatly improved.

Description

A photocatalytic reactor and method based on reflection-enhanced photoelectron utilization efficiency Technical Field

[0001] This invention relates to the field of advanced photocatalytic reaction technology, specifically to a photocatalytic reactor and method based on reflection-enhanced photoelectron utilization efficiency. Background Technology

[0002] The essence of photocatalysis is the conversion of photon energy into chemical energy, and its efficiency bottleneck often lies in the energy loss along the "photon-catalyst-electron" pathway. In traditional reactors (such as flat-plate and cylindrical reactors), most incident photons only have one chance to interact with the catalyst, while unabsorbed photons escape directly, resulting in low photon efficiency. To improve light energy utilization, current technologies mainly focus on increasing the optical path length or light intensity. In the design of photocatalytic or photoelectrochemical reaction systems, improving light energy utilization efficiency is often achieved through several approaches: First, using curved internal reflection structures to extend the optical path through discrete plane reflections. However, this method easily induces light scattering and energy loss at the curved surface and may lead to uneven distribution of photogenerated carriers, thus affecting the effective separation and utilization of electron-hole pairs. Second, introducing suspended particles or fixed-bed scattering to increase the chance of random photon collisions. However, this method lacks directionality, resulting in limited improvement in energy utilization efficiency, and excessive scattering may lead to overall light intensity attenuation inside the reactor. Third, using external light collection systems (such as CPCs or parabolic mirrors) mainly optimizes the light collection process from the light source to the reactor, but fails to fully consider the photon circulation and recapture mechanism inside the reactor, resulting in insufficient efficient reuse of photons that have already entered the reactor. Therefore, existing methods still face significant challenges in achieving directional photon transmission, internal circulation, and uniform distribution. There is an urgent need to develop a novel reactor structure that can actively guide photons for efficient, low-loss circulation inside the reactor, ensuring that each incident photon has the maximum probability of exciting the catalyst to generate and utilize photoelectrons. Summary of the Invention

[0003] The main objective of this invention is to provide a photocatalytic reactor and method based on reflection-enhanced photoelectron utilization efficiency, in order to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides a photocatalytic reactor based on reflection-enhanced photoelectron utilization efficiency, comprising: a reactor body having an internally defined cylindrical cavity for containing a reaction medium; a continuous arc-shaped inner wall forming the sidewalls and bottom of the cylindrical cavity; a reflection enhancement zone located on the inner surface of the continuous arc-shaped inner wall, configured to have high reflectivity for incident light of a specific wavelength; an incident light section disposed at the top opening of the reactor body; and an external light source disposed above the incident light section, configured to project a parallel light beam into the cavity; wherein, the reflection enhancement zone utilizes the curvature characteristics of the continuous arc-shaped inner wall to reflect the incident light after passing through the reaction medium back to the central region of the reaction medium or the liquid surface direction, thereby forming a light path loop.

[0005] As a further improvement of the present invention, the cross-sectional shape of the continuous arc-shaped inner wall is selected from U-shaped, semi-circular or parabolic; the parallel light emitted by the external light source is reflected by the reflection enhancement area and forms a light converging area in the central axis region of the reaction cavity.

[0006] As a further improvement of the present invention, the reflection enhancement area is a continuous arc-shaped region located on the inner wall of the arc, opposite to the incident light section, and covering a central angle of 230°-250°.

[0007] As a further improvement of the present invention, the light-incident section is a sealed window made of light-transmitting material.

[0008] As a further improvement of the present invention, the light-incident section is a region located on the wall of the reactor body that extends axially and has a width corresponding to a central angle of approximately 50°-70°.

[0009] As a further improvement of the present invention, the light outlet of the external light source is optically coupled to the light incident section.

[0010] As a further improvement of the present invention, it also includes an online detection component; the online detection component has a tubular structure, is inserted longitudinally into the interior of the reaction medium, and its arrangement avoids the main optical path area where light reflection and convergence occur.

[0011] As a further improvement of the present invention, it also includes a mass transfer device connected to the reactor for driving the reaction medium to flow in the cavity to maintain the suspension state of the photocatalyst; a rotor is provided at the bottom of the reactor and is driven to rotate by an external magnetic field to form a vortex in the reaction medium.

[0012] This invention discloses a method for improving the photocatalytic light path circulation efficiency of a photocatalytic reactor based on reflection-enhanced photoelectron utilization efficiency, comprising the following steps: Step 1: Injecting a fluid containing a photocatalyst as the reaction medium into the cavity of the reactor body; Step 2: Activating the mass transfer device to ensure the photocatalyst is uniformly dispersed and suspended in the reaction medium; Step 3: Activating an external light source to emit a parallel beam that passes through the incident light section at the top and enters the reaction medium; Step 4: Establishing the light path circulation: Photons in the incident beam that are not initially absorbed by the photocatalyst penetrate to the bottom of the cavity and are reflected by the reflection enhancement zone on the continuous arc-shaped inner wall; The reflected light passes through the reaction medium again according to the curvature path of the inner wall, propagating towards the center of the cavity or the liquid surface, thereby increasing the probability of secondary collisions between photons and the photocatalyst; Step 5: Monitoring the reaction process in real time using an online detection component inserted inside the medium.

[0013] The present invention relates to the application of a photocatalytic reactor based on reflection-enhanced photoelectron utilization efficiency, comprising: photocatalytic reaction for pollutant photodegradation, photocatalytic hydrolysis to produce hydrogen, photocatalytic carbon dioxide reduction, or photocatalytic synthesis reaction.

[0014] The beneficial effects of this invention are mainly reflected in the improvement of photoelectron utilization efficiency: 1. Photon recycling rate is doubled: The continuous arc-shaped reflective surface minimizes the diffuse scattering loss and beam divergence caused by traditional discrete reflective surfaces (such as prism edges), allowing reflected photons to return to the reaction region more concentratedly and effectively for the next excitation. Experimental calculations show that the average number of effective photon interactions can be increased by 2-5 times.

[0015] 2. Significantly improved photogenerated carrier yield: The increased photon recycling rate directly translates into an increase in the number of times the catalyst is excited per unit time. Under the premise of unchanged catalyst performance, the steady-state concentrations of photogenerated electrons and holes are significantly improved, providing a stronger driving force for surface redox reactions.

[0016] 3. Improved reaction kinetics and quantum efficiency: Higher photogenerated carrier concentration helps overcome the energy barrier of the rate-determining step, accelerating surface reaction speed. Simultaneously, since photoexcitation is the initial step of the reaction, its efficiency directly leads to a significant improvement in apparent quantum efficiency (AQE).

[0017] 4. Excellent synergy between light field and mass transport: The smooth, arc-shaped inner wall has no dead corners, which is conducive to the uniform suspension of catalyst particles and the mass transfer of reactants / products. It avoids the problem of local carrier recombination aggravation caused by the support structure and ensures that the generated photoelectrons can be effectively captured and utilized by the reactants. Attached Figure Description

[0018] Figure 1 is a schematic diagram of the overall photocatalytic reactor based on reflection-enhanced photoelectron utilization efficiency according to the present invention; the reference numerals are as follows: 1. Reactor body; 2. Continuous arc-shaped inner wall; 3. Reaction medium; 4. External light source; 5. Light incident section; 6. Online detection component; 7. Mass transfer device; 8. Reflection enhancement zone; 9. Rotor. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are merely some, not all, of the embodiments of this invention. Unless otherwise specified, the embodiments and features described in this application can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0020] In one embodiment, referring to Figure 1, a photocatalytic reactor based on reflection-enhanced photoelectron utilization efficiency according to the present invention includes a reactor body 1, which internally defines a columnar cavity for containing a reaction medium 3; a continuous arc-shaped inner wall 2, which forms the sidewalls and bottom of the columnar cavity; a reflection enhancement zone 8, located on the inner surface of the continuous arc-shaped inner wall 2, configured to have high reflectivity for incident light of a specific wavelength; an incident light section 5, disposed at the top opening of the reactor body 1; and an external light source 4, disposed above the incident light section 5, configured to project a parallel light beam into the cavity; wherein, the reflection enhancement zone 8 utilizes the curvature characteristics of the continuous arc-shaped inner wall 2 to reflect the incident light after passing through the reaction medium 3 back to the central region or liquid surface direction of the reaction medium 3, thereby forming a light path loop.

[0021] In this embodiment, the reactor body 1 is an axially extending cylindrical cavity with at least one section of a smooth, arc-shaped inner wall. On this arc-shaped inner wall, at least one light-transmitting incident light section 5 is defined for introducing initial photons; and at least one reflection-enhancing section 8 with an inner wall covered by a high-reflectivity film. Crucially, the reflection-enhancing section 8 is a continuous arc surface with a designed geometry that reflects photons arriving at its surface in a direction conforming to the laws of optical reflection and with a continuously changing tangential component. This forms a closed or spiral-progressing circular optical path within the cavity's cross-section, rather than a simple deflection. This significantly increases the number of collisions between a single photon and the catalyst particles before escape.

[0022] This structure can reflect undissipated photons (including initial transmitted light and scattered light) after penetrating the reaction medium 3 back to the reaction region in a smooth, continuous manner with minimal energy loss, thus achieving the "recycling" of photons. This controlled multiple excitation directly increases the yield of photogenerated electron-hole pairs per unit time and per unit catalyst, and provides a more abundant source of charge carriers for surface catalytic reactions.

[0023] Furthermore, the cross-sectional shape of the continuous arc-shaped inner wall 2 is selected from U-shaped, semi-circular or parabolic; the parallel light emitted by the external light source 4 is reflected by the reflection enhancement area 8 and forms a light convergence area in the central axis region of the reaction cavity; the light-incident section 5 is a sealed window made of light-transmitting material.

[0024] Furthermore, it also includes an online detection component 6 and a mass transfer device 7; the online detection component 6 has a tubular structure, with a spectral probe installed inside, inserted longitudinally into the reaction medium 3, and its arrangement avoids the main optical path area where light reflection and convergence occur; the mass transfer device 7 can be a circulating pump or a stirrer, connected to the reactor, used to drive the reaction medium 3 to flow in the cavity to maintain the suspension state of the photocatalyst.

[0025] Furthermore, a rotor 9 is installed at the bottom of the reactor, which is driven to rotate by an external magnetic field, causing the reaction medium 3 to form a vortex. This enables efficient mixing without the introduction of a mechanical seal, avoids the entry of contaminants, and ensures that the photocatalyst is uniformly dispersed in the reaction system.

[0026] A method for improving the photocatalytic light path circulation efficiency of a photocatalytic reactor based on reflection-enhanced photoelectron utilization efficiency includes the following steps: Step 1: Injecting a fluid containing a photocatalyst as the reaction medium 3 into the cavity of the reactor body 1; Step 2: Turning on the mass transfer device 7 to make the photocatalyst uniformly dispersed and suspended in the reaction medium 3; Step 3: Turning on the external light source 4 to emit a parallel beam of light that passes through the incident light section 5 at the top and enters the reaction medium 3; Step 4: Establishing the light path circulation: Photons in the incident beam that are not initially absorbed by the photocatalyst penetrate to the bottom of the cavity and are reflected by the reflection enhancement area 8 on the continuous arc-shaped inner wall 2. The reflected light passes through the reaction medium 3 again according to the curvature path of the inner wall and propagates towards the center of the cavity or the liquid surface, thereby increasing the probability of secondary collisions between photons and the photocatalyst, causing photons to repeatedly collide with catalyst particles, continuously exciting the catalyst to generate photoelectrons and holes, and using the efficiently generated photoelectrons and holes to drive the target catalytic reaction. The reflected light passes through the reaction medium 3 again according to the curvature path of the inner wall and propagates towards the center of the cavity or the liquid surface, thereby increasing the probability of secondary collision between photons and photocatalyst; Step 5: Use the online detection component 6 inserted inside the medium to monitor the reaction process in real time.

[0027] Referring to Figure 1, this embodiment provides a reactor structure designed to maximize photon residence time. The reactor body 1 is a high-purity quartz tube, with a continuous arc-shaped inner wall 2 defined inside, having a standard circular cross-section. On the wall of the reactor body 1, an axially extending region with a width corresponding to a central angle of 50°-70° is defined as the light-incident section 5. This section maintains the original high light transmittance of the quartz and is used to transmit external light. On the arc-shaped inner wall, opposite to the light-incident section 5, within a continuous arc-shaped region covering 230°-250°, a reflection enhancement region 8 is provided. This reflection enhancement region 8 is a layer of Al2O3 / Ag nanolayered reflective film with a reflectivity greater than 95% for the target wavelength (such as 365 nm ultraviolet light) uniformly deposited using atomic layer deposition (ALD) technology.

[0028] During operation, a parallel ultraviolet LED external light source 4 illuminates the incident light section 5, and photons enter the reaction medium 3 (e.g., a suspension containing carbon nitride g-C3N4) filled within the cavity. Photons that are not absorbed after penetrating the medium reach the reflection enhancement region 8 and are efficiently reflected along the normal direction of the circular surface. Because the reflection enhancement region 8 is a continuous, smooth surface, the direction of the reflected light changes continuously tangentially along the circumference, causing a large number of photons to be "confined" within the cavity and undergo multiple cycles, greatly increasing the probability of collisions between photons and the catalyst in the reaction medium 3. This design is particularly suitable for reactions requiring high-density photogenerated carriers, such as pollutant photodegradation, photocatalytic hydrolysis for hydrogen production, carbon dioxide photoreduction, or photocatalytic synthesis reactions.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A photocatalytic reactor based on reflection-enhanced photoelectron utilization efficiency, characterized in that, include: The reactor body (1) has a cylindrical cavity inside which a reaction medium (3) is contained. A continuous arc-shaped inner wall (2) forms the sidewall and bottom of the cylindrical cavity. A reflection enhancement zone (8) is located on the inner surface of the continuous arc-shaped inner wall (2) and is configured to have high reflectivity for incident light of a specific wavelength. An incident light section (5) is located at the top opening of the reactor body (1). An external light source (4) is located above the incident light section (5) and is configured to project a parallel light beam into the cavity. The reflection enhancement zone (8) utilizes the curvature characteristics of the continuous arc-shaped inner wall (2) to reflect the incident light after passing through the reaction medium (3) back to the central region or liquid surface of the reaction medium (3), thereby forming a light path loop.

2. The photocatalytic reactor based on reflection-enhanced photoelectron utilization efficiency according to claim 1, characterized in that: The cross-sectional shape of the continuous arc-shaped inner wall (2) is selected from U-shaped, semi-circular or parabolic; the parallel light emitted by the external light source (4) is reflected by the reflection enhancement area (8) and forms a light convergence area in the central axis region of the reaction cavity.

3. A photocatalytic reactor based on reflection-enhanced photoelectron utilization efficiency according to claim 2, characterized in that: The reflection enhancement area (8) is a continuous arc-shaped area located on the inner wall of the arc, opposite to the incident light section (5) and covering a central angle of 230°-250°.

4. A photocatalytic reactor based on reflection-enhanced photoelectron utilization efficiency according to claim 3, characterized in that: The light-receiving section (5) is a sealed window made of light-transmitting material.

5. A photocatalytic reactor and method based on reflection-enhanced photoelectron utilization efficiency according to claim 4, characterized in that: The light-incident section (5) is an area located on the wall of the reactor body (1) that extends axially and has a width corresponding to a central angle of about 60 degrees.

6. The photocatalytic reactor and method based on reflection-enhanced photoelectron utilization efficiency according to claim 5, characterized in that: The light outlet of the external light source (4) is optically coupled to the light inlet section (5).

7. A photocatalytic reactor and method based on reflection-enhanced photoelectron utilization efficiency according to claim 6, characterized in that: It also includes an online detection component (6); the online detection component (6) has a tubular structure, is inserted longitudinally into the reaction medium (3), and its arrangement avoids the main optical path area where light reflection and convergence occur.

8. A photocatalytic reactor and method based on reflection-enhanced photoelectron utilization efficiency according to claim 7, characterized in that: It also includes a mass transfer device (7) connected to the reactor, used to drive the reaction medium (3) to flow in the cavity to maintain the suspension state of the photocatalyst; the bottom of the reactor is provided with a rotor (9), which is driven to rotate by an external magnetic field to make the reaction medium (3) form a vortex.

9. A method for improving the photocatalytic light path circulation efficiency of a photocatalytic reactor based on reflection-enhanced photoelectron utilization efficiency according to claim 8, comprising the following steps: Step Step 1: Inject the fluid containing the photocatalyst as the reaction medium (3) into the cavity of the reactor body (1); Step 2: Turn on the mass transfer device (7) to make the photocatalyst uniformly dispersed and suspended in the reaction medium (3); Step 3: Turn on the external light source (4) to emit a parallel beam of light through the light incident section (5) at the top and into the reaction medium (3); Step 4: Establish the optical path circulation: the photons in the incident beam that are not initially absorbed by the photocatalyst penetrate to the bottom of the cavity and are reflected by the reflection enhancement area (8) on the continuous arc-shaped inner wall (2), so that the photons collide with the catalyst particles repeatedly, continuously exciting the catalyst to generate photoelectrons and holes, and using the efficiently generated photoelectrons and holes to drive the target catalytic reaction. The reflected light passes through the reaction medium (3) again according to the curvature path of the inner wall and propagates towards the center of the cavity or the liquid surface, thereby increasing the probability of secondary collision between the photons and the photocatalyst; Step 5: Use the online detection component (6) inserted inside the medium to monitor the reaction process in real time.

10. The application of a photocatalytic reactor based on reflection-enhanced photoelectron utilization efficiency according to claim 8, comprising: Photocatalytic reactions are used for the photodegradation of pollutants, photocatalytic hydrolysis to produce hydrogen, photocatalytic reduction of carbon dioxide, or photocatalytic synthesis reactions.

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