1269 results about "Porous membrane" patented technology

A process for electrowinning a metal using a flow-through electrowinning apparatus can include the steps of: a) conveying an anolyte material and a metal chemical feedstock material along an anolyte flow path within an anolyte chamber; b) conveying catholyte material along a catholyte flow path within a catholyte chamber that has a cathode; c) applying an activation electric potential between the anode and a cathode that is sufficient to electrolyze and liberate metal ions from the metal chemical feedstock material in the anolyte chamber, thereby causing a flux of metal ions to migrate through a porous membrane from the anolyte chamber to the catholyte chamber and a metal product to be formed in the catholyte chamber; and while applying the activation electric potential, extracting a feedstock-depleted anolyte material from the anolyte chamber; and extracting an outlet material comprising the catholyte material and the metal product from the catholyte chamber via a catholyte outlet.

The invention belongs to the technical field of diaphragms, and particularly relates to an organic-inorganic composite spongy porous diaphragm as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing a polyarylether high polymer material, a pore-foaming agent, metal oxide nanoparticles and an organic solvent, and carrying out defoaming treatment to obtain a membrane casting solution; preparing the membrane casting solution into a liquid membrane; the liquid film is placed in a wet air atmosphere for pre-phase inversion, in the pre-phase inversion process, water vapor in wet air and an organic solvent in the liquid film are subjected to preliminary exchange, a through spongy porous structure is induced to be formed in the liquid film, and a spongy porous liquid film is obtained; and placing the spongy porous liquid membrane in an extracting agent for phase inversion to obtain the organic-inorganic composite spongy porous diaphragm. The preparation method provided by the invention not only overcomes the defects of the existing diaphragm in pore channel connectivity and pore diameter control, but also remarkably improves the hydrophilic performance of the diaphragm, and greatly reduces the resistance at the same time.

The invention provides an electrochemical biosensor based on a nanoparticle modified multilayer porous membrane and application of the electrochemical biosensor. The nano particle modified multilayer porous membrane is composed of a plurality of modified nano particles among membranes with nano pore channels. The electrochemical biosensor constructed based on the nanoparticle modified multilayer porous membrane has the following advantages: (1) good conductivity and stability; and (2) multiple capture probes are modified on the surfaces of the nano pore channels of the multi-layer porous membrane, so that multiple different targets can be respectively detected, and multiple different targets can also be detected at the same time. And (3) enzyme-free double-target sensitive normal-temperature amplification-free detection can be carried out. (4) preparation steps are simple, consumed time is short, and operability is high; and (5) the sensitivity and the specificity are high.

Porous membranes, and methods of making such porous membranes, that comprise staple or discrete fibers and nanoparticles dispersed throughout at least a portion of the membrane are provided. A filter media comprises a porous membrane comprising staple fibers and having a mean pore size of less than about 10 microns. The media further includes nanoparticles disposed within the porous membrane. The nanoparticles reduce the mean pore size of the membrane, while substantially maintaining the pressure drop (e.g., bubble point) across the membrane. The porous membranes may be configured for use as filter media and are particularly useful for gas or liquid filters, including, but not limited to, membrane filters, diesel filters, air filters, face masks, gas turbine and compressor air intake filters, panel filters, cartridge filters, bag filters, clean-in-place (CIP) filters and the like.

The invention discloses a gas dissolving device for generating micro-nano bubbles by using a gas-liquid double-high-pressure jet method, which comprises a venturi tube body for generating micro-nano bubbles, a water inlet pipe is mounted at one end of the venturi tube body, a gas inlet pipe capable of preventing liquid from flowing back is mounted at a throat pipe of the venturi tube body, and a gas outlet pipe capable of preventing liquid from flowing back is mounted at the other end of the venturi tube body. A cutting blade for crushing and refining micro-nano bubbles is mounted in the Venturi tube body, and a detachable porous membrane is also mounted in the Venturi tube body. When liquid flows through the contraction section of the venturi tube at a high speed, the flow speed is increased, the pressure is reduced, negative pressure is generated, external gas is sucked into the liquid under the suction of the negative pressure, then the liquid and the gas are fully mixed in a pipeline and broken into micro-nano bubbles, and the micro-nano bubble generator is simple in structure, low in cost, capable of continuously working and capable of effectively improving the production efficiency. And the generated micro-nano bubbles can meet the requirements of particularly fine occasions.

The embodiment of the invention relates to electrochemical enhanced biological integrated intelligent regulation and control equipment for treating organic wastewater. The electrochemical enhanced biological integrated intelligent regulation and control equipment comprises an electrochemical enhanced biodegradation module and an intelligent control system, the electrochemical enhanced biodegradation module comprises a porous membrane electrode assembly, a power supply control system, an electrolyte adding system, a fixed bed biological membrane, an aeration system and a carbon source adding system; the intelligent control system comprises a data acquisition and remote monitoring module and a PLC (Programmable Logic Controller); the data acquisition and remote monitoring module acquires parameters such as COD (Chemical Oxygen Demand), dissolved oxygen concentration, ammonia nitrogen, total nitrogen and conductivity of the electrochemical enhanced biodegradation module and transmits the parameters to the PLC; and the PLC receives the parameters, and automatically adjusts one or more of voltage, current density, aeration rate and carbon source dosage based on a preset model established by a support vector regression and neural network machine learning algorithm. The intelligent regulation and control equipment can keep an optimal treatment state under different wastewater characteristics and load conditions, and has strong adaptability to environment or load fluctuation.

The invention discloses a method for preparing a polymer anti-pollution membrane, which is characterized in that a'fluorine-containing polymer / styrene-maleic anhydride 'porous membrane is prepared by taking a styrene-maleic anhydride copolymer and a fluorine-containing polymer as base materials and adopting a thermally induced phase separation technology. And loading chitosan on the surface of the porous membrane by utilizing a chemical reaction between anhydride on the surface of the membrane and a small part of amino groups in a chitosan chain. The chitosan molecular chain with pH responsiveness not only improves the hydrophilicity of the membrane and slows down the deposition of inorganic scales on the surface of the membrane, but also has the conformation subjected to'curl-stretch 'reversible transformation (similar to'curl-stretch' motion of earthworms in soil so as to soften the soil) in the'acid washing-alkali washing 'cleaning process of the membrane; hardened inorganic scale deposited on the surface of the membrane becomes loose, the binding force between the inorganic scale and the surface of the membrane becomes weak, and the inorganic scale can be effectively removed through surface water cleaning in the follow-up process. The prepared cleaning agent has the advantages of being high in pollution resistance, good in inorganic dirt removal effect after cleaning and the like.

The invention belongs to the technical field of preparation of diaphragm materials, and particularly relates to a preparation method of a polymer porous membrane, the polymer porous membrane and application. The method comprises the following steps: (1) obtaining a film containing a polymer and a plasticizer; (2) extracting the plasticizer in the thin film by adopting an extracting solution to obtain a wet film; and (3) the wet film is dried, and in the drying process, the size shrinkage rate of the wet film in the TD direction ranges from 5% to 20%. The polymer porous membrane prepared by the method has high-temperature dimensional stability and good air permeability and thickness uniformity.

The present invention discloses a method for preparing a composite solid electrolyte membrane, the composite solid electrolyte membrane comprises three layers, the first layer is a composite solid electrolyte layer containing oxide-polymer, the second layer is a sulfide solid electrolyte layer, and the third layer is a polysiloxane solid electrolyte layer; the preparation method comprises the following steps: S1, preparation of the first layer: immersing a polymer porous membrane as a substrate into the first layer slurry, coordinating ultrasound to make the first layer slurry fully fill the pores, and drying to obtain; S2, preparation of the second layer: coating the second layer slurry on the basis of the first layer, drying to obtain; S3, preparation of the third layer: coating the third layer slurry on the basis of the second layer, drying to obtain; S4, pressing: the first, second and third layers are hot-pressed by rollers to obtain. The composite solid electrolyte membrane of the present invention can effectively improve the interface contact between the solid electrolyte and the positive and negative electrodes, reduce the interface impedance, and has the characteristics of high mechanical strength, high ionic conductivity, good thermal stability, etc.

The invention discloses a natural polysaccharide assisted MXene porous membrane electrode and a preparation method thereof, and relates to the technical field of electrodes. According to the technical scheme, hydrochloric acid and lithium fluoride are used for carrying out etching and intercalation on an MAX raw material, and MXene dispersion liquid is obtained; mixing the MXene dispersion liquid with a metal ion solution to obtain a metal ion doped MXene solution; mixing the metal ion doped MXene solution with a natural polysaccharide dispersion liquid to obtain a natural polysaccharide modified MXene dispersion liquid; mixing the natural polysaccharide modified MXene dispersion liquid with a template substance, performing vacuum filtration, and performing vacuum drying to obtain a flexible MXene film; and carrying out template substance removal treatment on the flexible MXene film to obtain the natural polysaccharide-assisted MXene porous film electrode. According to the invention, the stacking problem of the MXene material is solved, and the electrochemical performance of the natural polysaccharide-assisted MXene porous membrane electrode is obviously improved.

The invention discloses a preparation method of a PVDF composite ultrafiltration membrane with underwater piezoelectric activity, and belongs to the technical field of water treatment. The preparation method of the PVDF composite ultrafiltration membrane with underwater piezoelectric activity comprises the following steps: dispersing graphene oxide in an organic solvent, then adding a pore-foaming agent and PVDF, heating and stirring until complete dissolution, and defoaming to obtain a membrane casting solution; a flat plate is coated with the membrane casting solution and then immersed in a pure water coagulating bath arranged in a negative electrode direct-current electric field for phase separation and synchronous polarization, and a PVDF porous membrane is obtained; and carrying out hydrophobic modification on the PVDF porous membrane to obtain the PVDF composite ultrafiltration membrane. GO is introduced in the PVDF separation membrane forming process, the negative electrode electric field polarization effect is synchronously applied, and then a hydrophobic modification method is combined, so that the PVDF composite ultrafiltration membrane with remarkable underwater piezoelectric activity and anti-pollution capacity is finally prepared.

The present invention belongs to the field of electrochemistry, and specifically relates to an anion membrane electrode and a preparation method thereof, and a device for preparing synthesis gas by gas-phase electrolysis of carbon dioxide. The preparation method is as follows: a porous membrane protective layer is covered on the surface of a vacuum heating plate, and then an anion membrane is covered; then an anion exchange ionomer solution and a cathode catalyst anion exchange ionomer solution are sprayed on the surface in sequence. The present invention can reduce the structural damage to the anion membrane caused by the temperature fluctuation of the metal plate surface during the heating process of the vacuum heating plate by introducing a porous membrane protective layer between the anion membrane and the vacuum heating plate; the anion exchange ionomer layer is introduced between the catalyst layer and the anion membrane to increase the bonding strength between the catalyst layer and the anion membrane and increase the stability of the membrane electrode; during the volatilization process of the heating solvent, the solvent can be promoted to volatilize at low temperature by blowing dry, thereby accelerating the membrane electrode preparation process and improving the stability of the membrane electrode, thereby extending the service life of the device.

Provided is a porous separator selected from (a) to (c). (a) Porous membranes containing hydrophilic inorganic particles, an aromatic porous support, and an organic polymer including a hydrophilic organic polymer that has a sulfo group and / or a carboxy group and has an acid value of 0.3 mmol / g or higher; (b) porous membranes containing no porous support and containing hydrophilic inorganic particles and an organic polymer including a hydrophilic organic polymer that has a sulfo group and / or a carboxy group and has an acid value of 0.3 mmol / g or higher, the hydrophilic inorganic particle content of said porous membranes being 10 mass% or greater; (c) porous membranes containing no hydrophilic inorganic particles and containing an aromatic porous support and an organic polymer including a hydrophilic organic polymer that has a sulfo group and / or a carboxy group and has an acid value of 0.3 mmol / g or higher.

The invention discloses a screen cloth enhanced polybenzimidazole porous membrane as well as a preparation method and application thereof. The preparation method comprises the following steps: fully mixing polybenzimidazole, a polar solvent and a template to obtain a mixed solution, coating a base material with the mixed solution, placing a polymer mesh on the previous base material, and carrying out in-situ compounding, polar solvent removal and film formation to obtain a compact mesh reinforced polybenzimidazole film; and then carrying out in-situ etching treatment to prepare the screen cloth enhanced polybenzimidazole porous membrane. The size and connectivity of ion channels in the membrane can be regulated and controlled by regulating and controlling the type and content of templates in the membrane casting process, and the polybenzimidazole porous layer can be ultrathin by combining the effect of enhancing the mechanical property of the polymer mesh cloth, so that the mass transfer resistance of the polybenzimidazole porous separation layer is remarkably reduced, and the performance of the membrane is improved. The mesh-reinforced polybenzimidazole porous membrane has good dimensional stability and pore uniformity, and has the characteristics of high ion selectivity, high ion conductivity and high stability.

The preparation method comprises the following steps: fully mixing a good solvent and a poor solvent of a polymer, adding a film-forming polymer while stirring at room temperature, fully dissolving to form a homogeneous solution, and then coating or spinning the homogeneous solution to form a primary membrane; immersing the primary membrane into a coagulating bath of which the temperature is higher than the low critical solution temperature of the homogeneous solution for phase separation; according to the invention, heat transfer is adopted as driving force, so that a polymer composition change route rapidly passes through a bisection line area, and spiral section line phase splitting is carried out, so that a complex mass transfer rate regulation process is avoided. And meanwhile, by utilizing the characteristic of low critical solution temperature of a polymer system, the inconvenience conditions of high-temperature operation environment, extraction agent recovery and the like in a thermally induced phase separation process are overcome.

Filter media for use in liquid filters and liquid filters are provided that include a substrate, such as a porous membrane, and nanoparticles incorporated into the substrate. The nanoparticles may comprise nanoparticles, nanofibers or mini fibers that have at least one dimension less than about 20 microns. The nanoparticles are bonded to the fibers within the substrate and are dispersed "in depth" within the substrate, which improves the performance characteristics of the material for a number of different applications. For example, the nanoparticles increase the overall surface area within the substrate, which may increase its filtration efficiency and allow for the capture of submicron contaminants without significantly compromising other factors, such as bubble point or through-put across the filter.

The invention provides an electrochemical biosensor for detecting mycoplasma pneumoniae, the core of the electrochemical biosensor comprises a specific capture probe, and the nucleotide sequence of the specific capture probe is a complementary sequence of a 23S-5S rDNA spacer sequence (ITS) of the mycoplasma pneumoniae. In the preparation link, the porous membrane is used as a high-efficiency electron transmission channel, the process is remarkably simplified, and the reaction efficiency is improved. By virtue of a capture probe taking 23S-5S rDNA ITS as a target, the sensor is endowed with excellent specificity and high sensitivity, so that the sensor has excellent performance in complex biological sample detection, can accurately and efficiently recognize a target object and effectively avoids interference of other substances. The electrochemical biosensor is easy and convenient to operate and high in response speed, has wide application prospects in the fields of clinical diagnosis and rapid disease screening, can provide key technical support for timely diagnosis of mycoplasma pneumoniae infection, greatly meets the urgent requirements for rapid and accurate detection in clinical and practical application, and has good application prospects. The development process of a biological detection technology in the mycoplasma pneumoniae detection direction is powerfully promoted.

Polymer compositions are disclosed containing at least one high molecular weight polyethylene polymer for producing gel extruded articles. In one embodiment, porous membranes are produced that have an excellent balance of properties including high porosity and high strength characteristics. In one aspect, very thin membranes can be formed having high strength characteristics.

The invention belongs to the technical field of organoid chips of biological medicine, and particularly relates to a multi-organoid chip and a preparation method thereof. The multi-class organ chip comprises an upper-layer chip and a lower-layer chip which are detachably arranged; 2-10 organ-like chambers are embedded in the upper-layer chip, and 2-5 porous membranes are arranged at the bottoms of the organ-like chambers; the lower-layer chip is provided with a flow channel, and the flow channel is communicated with the organ-like chamber. Compared with the existing multi-class organ chip technology, the multi-barrier construction in the independent cavity is realized, and meanwhile, the multi-class organ chip is combined with a transwell component for use, so that the personalized combination of the multi-class organ chips is realized. The method is economical and fast, can play an important role in promoting the fields of precise medicine, medicine evaluation, disease models, especially in-vitro evaluation and simulation of traditional Chinese medicine and the like, and is suitable for popularization and application.

The invention provides an electrochemical biosensor based on ultrasonic bidirectional driving and a detection method, and belongs to the technical field of biosensing. The sensor comprises a porous membrane and an ultrasonic bidirectional driving unit, and a probe capable of specifically capturing a target object is fixed in a pore channel of the porous membrane; the ultrasonic bidirectional driving unit is composed of a first ultrasonic transducer and a second ultrasonic transducer which are symmetrically arranged on the two sides of the porous membrane, and can synchronously execute reverse power gradient change to form alternately changing pressure difference on the two sides of the membrane so as to drive liquid to repeatedly penetrate through the porous membrane. The detection method comprises the steps of to-be-detected liquid injection and ultrasonic bidirectional driving, ultrasonic auxiliary cleaning and electrochemical detection. The problems of insufficient probe utilization rate, low mass transfer efficiency and non-specific adsorption of a traditional passive diffusion mechanism are solved by utilizing bidirectional ultrasonic active driving force, the detection sensitivity, speed and signal-to-noise ratio are remarkably improved, and the method is suitable for rapid and high-sensitivity quantitative analysis of various analytes.

The invention belongs to the technical field of water purification materials, and particularly relates to a multifunctional water purification gel material and a preparation method thereof. The composite material consists of an outer-layer film, a middle-layer framework and an inner-layer carbon core, the outer-layer film is prepared from the following raw materials: sodium alginate, carboxymethyl starch, NaCl and Tween-20; the middle-layer framework is prepared from the following raw materials: chitosan, modified sodium bentonite and Fe-P nano powder; the inner-layer carbon core is prepared from the following raw materials: rice hull biochar, nano CaCO3, FeCl3. 6H2O and FeSO4. 7H2O. Efficient water purification is achieved through a three-layer synergistic structure, and the outer layer Ca < 2 + > cross-linked sodium alginate / carboxymethyl starch porous membrane intercepts particles and buffers metal ions; the middle layer is integrated with chitosan to chelate heavy metals, CTAB-bentonite electrostatically adsorbs anions and Fe-P nanoparticles to precipitate phosphate / arsenate; and the biochar-Fe3O4 complex on the inner layer provides deep adsorption and catalytic oxidation functions.

The invention belongs to the technical field of biological culture, and particularly relates to a three-dimensional dynamic biological culture device and method. The three-dimensional dynamic biological culture device comprises: a culture chamber unit, which comprises a porous membrane and a chamber body with a first opening, the porous membrane and the chamber body are detachably enclosed to form a first chamber, and the first chamber can accommodate a curable culture medium for providing a growth space for culturing cells; the flow path plate unit comprises a base part, the base part is provided with a circulation groove and a liquid storage opening matched with a liquid storage device storing a culture solution, and the liquid storage opening is communicated with the circulation groove; a plurality of mounting ports which can be matched with the culture room units are formed in the circulating groove and are used for communicating the first chamber with the circulating groove through the porous membrane; and the driving unit and the circulating groove form a circulating loop so as to drive the culture solution in the circulating groove to flow in the plurality of culture room units. According to the invention, dynamic culture of three-dimensional cells, cell spheres and organoid cells can be better realized.

The invention discloses a composite solid electrolyte layer, a preparation method and application, the composite solid electrolyte layer comprises a porous membrane laminated on a negative pole piece, and pores in the porous membrane and gaps between the porous membrane and the negative pole piece are filled with in-situ generated polymers. Inorganic solid electrolyte is also dispersed in the porous membrane, and lithium salt is dispersed in the polymer and the porous membrane. The composite solid electrolyte layer is obtained through in-situ polymerization of a polymer in pores in the porous membrane and gaps between the porous membrane and the negative electrode plate, and a novel interface structure with the electrode-electrolyte integration characteristic is constructed. By adopting a collaborative optimization strategy of a polymer matrix and inorganic filler double-crosslinking network system and an interface stable layer, the volume effect problem of a silicon-based negative electrode, the electrolyte interface impedance problem and the battery safety problem can be solved at the same time, so that the cycling stability and the rate capability of the lithium ion battery are remarkably improved.

The invention relates to the field of enhanced intrinsic safety in a gas-liquid phase mixing process, and discloses a gas-liquid mixing device and a gas-liquid mixing vaporization method. The device comprises a shell, a Venturi gas-phase turbulent mixing section, a liquid-phase atomizing mixing section and a static mixing section are sequentially arranged in the shell in the flowing direction of material flow, the Venturi gas-phase turbulent mixing section comprises a reducing structure and an expanding structure, a liquid inlet component is arranged at the position, close to the reducing structure, of the expanding structure, and the static mixing section is connected with the liquid inlet component. The liquid phase atomization mixing section is provided with a membrane tube base body, the membrane tube base body is provided with a plurality of inner holes in the axial direction, the surfaces of the inner holes are coated with nanometer materials, and the static mixing section is provided with filler. According to the device, the liquid-phase oxidizing agent and the gas-phase oxidizing agent are subjected to multi-stage mixing vaporization, the atomization degree of the liquid phase is increased, the uniformity degree of the obtained mixed gas phase is improved, meanwhile, the device can be quenched after burning explosion by coupling a porous membrane pipe and filler, and the burning explosion risk in the mixing vaporization process is reduced.

The invention belongs to the technical field of lithium metal batteries, and relates to preparation of an ultrathin polymer electrolyte with a wide electrochemical window and application of the ultrathin polymer electrolyte in a solid-state lithium metal battery, a preparation method comprises the following steps: firstly, coating a substrate with polymer slurry, and then soaking, stripping and drying to obtain a porous membrane matrix; the preparation method comprises the following steps: mixing an electrolyte, a conductive lithium salt, a cross-linking agent, 4-fluorine-alpha-methyl styrene and an initiator to obtain an electrolyte precursor solution; and then supporting the electrolyte precursor liquid on the porous membrane substrate, and carrying out in-situ polymerization and curing to obtain the polymer electrolyte. Compared with the prior art, the thickness of the polycarbonate solid electrolyte is 7.8 microns, and the polycarbonate solid electrolyte shows high room-temperature ionic conductivity, a wide electrochemical window and excellent dendritic crystal resistance. And the corresponding 4.5 V high-voltage LiLCO solid-state battery can stably circulate for 1500 circles at room temperature. The electrolyte is ultrathin, the preparation process is simple, the scale is easy to enlarge, and the electrolyte shows a good practical application prospect.

Non-aqueous membrane emulsion methods for producing polymeric and polymer-coated microparticles are provided. Some embodiments provide methods for producing a sustained release or controlled release microparticle by combining micronized protein powder and a polymer into a hydrocarbon solvent to form a non-aqueous first solution, agitating the first non-aqueous solution to form a suspension, feeding the suspension into a dispersion pump, wherein the suspension is infused through a porous membrane into a continuous phase comprising a fluorocarbon liquid and a fluorosurfactant to form a hydrocarbon-in-fluorocarbon emulsion. The hydrocarbon solvent, the fluorocarbon liquid, and the fluorosurfactant are removed, and the microparticles are collected.

The invention discloses a double-layer piezoelectric sensor and an application and method of the double-layer piezoelectric sensor in representing beta-phase polyvinylidene fluoride membrane adsorptive pollution, a piezoelectric beta-phase polyvinylidene fluoride membrane is a porous membrane formed by a blending system of polyvinylidene fluoride and ionic liquid and has a beta-phase crystal structure and a piezoelectric response characteristic, and the piezoelectric beta-phase polyvinylidene fluoride membrane is prepared by spin-coating a PVDF solution on a chip. The double-layer piezoelectric sensor containing the beta-phase polyvinylidene fluoride membrane is obtained, and QCM-D detection is carried out to characterize the adsorptive pollution condition of the beta-phase polyvinylidene fluoride membrane. Adsorption and desorption behaviors of organic matters with different dissolvability and mixtures thereof on the beta-phase PVDF membrane layer are represented, the adsorption result is matched with the hole blocking resistance in the actual membrane pollution process, and the hole blocking resistance is calculated by monitoring the fifth overtone of the piezoelectric quartz sensor. And the quality of soluble organic matters adsorbed on the PVDF surface and the property of an adsorption layer can be evaluated by using a frequency change value and a dissipation value, and a scheme is provided for researching the pollution behavior of the beta-phase polyvinylidene fluoride membrane.

A device and method for assembling objects by generating an axial acoustic radiation force in order to position the objects on pressure nodes and / or antinodes and generating a transverse acoustic radiation force in order to move the thus positioned objects on a porous membrane contact structure.

A method for forming a pellicle for use in a lithographic apparatus is disclosed. The method includes: providing a porous membrane formed from a first material; applying at least one layer of two-dimensional material to at least one side of the porous membrane; and applying a capping layer to the at least one layer of two-dimensional material on at least one side of the porous membrane such that the at least one layer of two-dimensional material is disposed between the or each capping layer and the porous membrane. The at least one layer of two-dimensional material may act to close the adjacent side of the porous membrane and to form a smoother and flatter exterior surface of the pellicle. Advantageously, this may allow the porous membrane to be protected from etching while reducing EUV flare, regardless of the material used for the capping layer.

The invention discloses a method for producing formic acid by reducing carbon dioxide through a hydrogen-driven hollow fiber catalytic membrane reactor, and relates to the technical field of carbon dioxide resource utilization. In order to solve the problems of low formic acid product selectivity, low CO2 conversion efficiency and high cost in the prior art, hydrogen is used as the only energy source, and a hollow fiber non-porous membrane is utilized to realize bubble-free efficient mass transfer of H2 to form a compact hydrogen-rich layer on the surface; the nano-metal particle catalyst loaded on the surface of the membrane synergistically activates hydrogen at a gas-liquid-solid three-phase interface to generate active hydrogen atoms, and CO2 transferred in a dissolved state or a gas phase is subjected to directional catalytic reduction to form formic acid with high selectivity. The method is operated at normal temperature and normal pressure, so that the H2 utilization efficiency and the CO2 mass transfer efficiency are remarkably improved, and the byproduct separation cost and the operation energy consumption are effectively reduced; the produced formic acid can be used as an important chemical raw material and intermediate, an excellent liquid hydrogen storage carrier, a formic acid fuel cell fuel and a microbial carbon source, and has wide application value.