Periodic Reporting for period 1 - CATART (Reaction robot with intimate photocatalytic and separation functions in a 3-D network driven by artificial intelligence)
Período documentado: 2022-09-01 hasta 2023-08-31
Mimicking the chemical production of nature is a well pursued dream in the scientific community. Scientific progress is limited by the lack of efficient synergies among complex functions and by a much smaller research library than nature. CATART will explore new synergies in reaction robots that mimic nature in a much faster way. This will be achieved using H2O and CO2 as model substrates. We propose systems containing 3-D quantum dot networks with the ability to simultaneously harvest sun-light by luminescence, photocatalyze substrates and separate products. These phenomena will be managed by artificial intelligence, leading to reaction robots that autonomously learn and instantly maximize productivity. The envisioned system will revolutionize the way chemicals are produced. The combination of expertise in photonics, machine learning, catalysis, organic chemistry and engineering from 5 academic, 1 research center, 1 SME and 1 industrial partner will enable a successful pathway into feasible reaction robots. CATART will contribute to a game-changing chemical technology, placing EU industry and society in a privileged situation to face future economic and environmental constraints.
CATART has worked on developing LSC reactors, tuning the absorption & Re-emission, shift in wavelength, down conversion, total internal reflection, matrix and light concentration. The mode of operation allows certain flexibility to test the different catalytic conditions. This optimized the operating conditions (temperature, photo-features, combination within the LSC reactor). This led to a process with gas-reactant feed, LSC reactor and product analysis. A critical part in the design of LSC reactors is the choice of the luminescent dye, which leads to different absorption/emission spectra.
Given the multitude of available approaches for synthesizing ionic CNs, it is important to examine how the synthesis influences the bulk material properties, setting precise design goals and potential of various synthesis procedures. The results achieved so far represent a significant milestone in the design of defect-free M+PHIs and pave the way for further refinement. To build on this progress, the subsequent steps will involve a detailed study of the modification of the synthesis procedure, including CN variations.
Significant development of the modular closed loop synthesis / optimisation platform has enabled the solvothermal or ionothermal synthesis of the M+PHI materials along with their subsequent metal modification. Investigations into technologies to be implemented into the currently platform framework such as induction heating elements or conventional high temperature heating. Priority is being given to safety and robustness, continuous and autonomous operation of the resultant robotic platform in conjunction with the ML and AI based learning algorithms for optimisation.
The photocatalysts have been tested in a double-emission photoreactor. The initial photocatalytic experiments used graphitic carbon nitrides (gCN) for different metals (Pd, Pt, Co) impregnated through wet-contact. When comparing the ratio of H2 to CO2, increasing the ratio to 1:3 lowers catalytic activity in Pt, while increasing activity in Pd- and Co. Specificity for CO is surprisingly high with a rate of 90%-99% conversion into CO over CH4. When excited by light, all catalysts show an immediate reaction, often reaching a plateau after about 2 h.
Operando-XAS data at HE-APE beamline (ELETTRA synchrotron facility) were adopted to suit the photocatalyst sample with an external light source for: i) Na-PHI and Mg PHI, upon irradiation and H2O; ii) Mn-PHI and Fe-PHI, in the presence of H2O + O2. Irradiation with H2O causes a shift of the band toward lower energies, which is maintained after stopping the feed. Only upon switching off the light source, recovery of the original situation is attained.
The relevant synthesis parameters involving C-membranes led to performance as a function of porous size distribution and functional groups. We designed hydrophobic membranes for such separation. The approach is thus to work on the hydrophobization for the elimination/removal of –OH groups in the carbon structure: i) increasing the Carbonization Temperature: the OH decrease leads to a hydrophobicity increase as well as a increase in selectivity H2/H2O, but pores size and vacuum volume in the carbon layer decreases and permeance decreases; ii) modification of the polymeric precursor: reducing the amount of -OH groups present in the initial reactants.
Given the multitude of available approaches for synthesizing ionic CNs, it is important to examine how the synthesis influences the bulk material properties, setting precise design goals and potential of various synthesis procedures. The results achieved so far represent a significant milestone in the design of defect-free M+PHIs and pave the way for further refinement. To build on this progress, the subsequent steps will involve a detailed study of the modification of the synthesis procedure, including CN variations.
Significant development of the modular closed loop synthesis / optimisation platform has enabled the solvothermal or ionothermal synthesis of the M+PHI materials along with their subsequent metal modification. Investigations into technologies to be implemented into the currently platform framework such as induction heating elements or conventional high temperature heating. Priority is being given to safety and robustness, continuous and autonomous operation of the resultant robotic platform in conjunction with the ML and AI based learning algorithms for optimisation.
The photocatalysts have been tested in a double-emission photoreactor. The initial photocatalytic experiments used graphitic carbon nitrides (gCN) for different metals (Pd, Pt, Co) impregnated through wet-contact. When comparing the ratio of H2 to CO2, increasing the ratio to 1:3 lowers catalytic activity in Pt, while increasing activity in Pd- and Co. Specificity for CO is surprisingly high with a rate of 90%-99% conversion into CO over CH4. When excited by light, all catalysts show an immediate reaction, often reaching a plateau after about 2 h.
Operando-XAS data at HE-APE beamline (ELETTRA synchrotron facility) were adopted to suit the photocatalyst sample with an external light source for: i) Na-PHI and Mg PHI, upon irradiation and H2O; ii) Mn-PHI and Fe-PHI, in the presence of H2O + O2. Irradiation with H2O causes a shift of the band toward lower energies, which is maintained after stopping the feed. Only upon switching off the light source, recovery of the original situation is attained.
The relevant synthesis parameters involving C-membranes led to performance as a function of porous size distribution and functional groups. We designed hydrophobic membranes for such separation. The approach is thus to work on the hydrophobization for the elimination/removal of –OH groups in the carbon structure: i) increasing the Carbonization Temperature: the OH decrease leads to a hydrophobicity increase as well as a increase in selectivity H2/H2O, but pores size and vacuum volume in the carbon layer decreases and permeance decreases; ii) modification of the polymeric precursor: reducing the amount of -OH groups present in the initial reactants.
In CATART a new type of LSC photo microreactor is developed, using silicon oil as matrix. The luminescent oil can withstand temperatures up to 250°C and the luminophore is shown to be stable at these temperatures. Automation is used to ease the operation of the photochemical system and reduce the degree of human interactions. This innovation includes the development of control systems for the light intensity and pressure. For the latter a variable back pressure regulator could be controlled via a stepper motor. Photocatalyst powder can be mixed with glass beads of various sizes to obtain an uniform coating of the catalyst on the glass beads. These beads can then be evenly distributed over the reactor to get a high irradiated surface area and a reproducible catalyst loading protocol. The method was found to be effective for different type of heterogeneous catalyst. Beads can be loaded in the reactor using compressed air and removed using liquid.
In addition we developed a method to coat cylindrical membranes of several cm height for selective small molecules separation, such as H2 and CO2, with a semiconductor active material, namely carbon nitride, for the selective conversion of these molecules upon illumination with visible light. In these regards, the as prepared composite membranes have been tested preliminarily in a home-made reactor to test the selective photocatalytic activity. Through the manipulation of the synthesis procedure, our objective is to obtain carbon nitrides semiconductors with a precisely controlled crystalline size using a straightforward synthesis methodology. This ability to fine-tune the synthesis process enables us to tailor the crystalline size of the desired materials to our exact specifications. By controlling the crystalline size, we expect to gain deeper insights into the relationship between particle dimensions and photocatalytic activity.
Based on the inputs on C3N4 synthesis, the recipe has been reproduced under lab conditions in an automated synthesis robot allowing the control of all synthesis parameters. The key photo-features of such carbon nitrides are in-situ characterized and such steps are converted into a chemical language that allows continuous improvement through computing and machine learning. A reaction cell with a double window has been designed, containing a reaction cell that allows the operation under two main modes: i) Photocatalyst testing using a two-sided beam and a flow-through reactor; ii) Photocatalytic membrane testing allowing the feeding of reactants and permeants. It has been tested for carbon-nitride photocatalytic performance using CO2 and/or H2O as reactant.
In addition we developed a method to coat cylindrical membranes of several cm height for selective small molecules separation, such as H2 and CO2, with a semiconductor active material, namely carbon nitride, for the selective conversion of these molecules upon illumination with visible light. In these regards, the as prepared composite membranes have been tested preliminarily in a home-made reactor to test the selective photocatalytic activity. Through the manipulation of the synthesis procedure, our objective is to obtain carbon nitrides semiconductors with a precisely controlled crystalline size using a straightforward synthesis methodology. This ability to fine-tune the synthesis process enables us to tailor the crystalline size of the desired materials to our exact specifications. By controlling the crystalline size, we expect to gain deeper insights into the relationship between particle dimensions and photocatalytic activity.
Based on the inputs on C3N4 synthesis, the recipe has been reproduced under lab conditions in an automated synthesis robot allowing the control of all synthesis parameters. The key photo-features of such carbon nitrides are in-situ characterized and such steps are converted into a chemical language that allows continuous improvement through computing and machine learning. A reaction cell with a double window has been designed, containing a reaction cell that allows the operation under two main modes: i) Photocatalyst testing using a two-sided beam and a flow-through reactor; ii) Photocatalytic membrane testing allowing the feeding of reactants and permeants. It has been tested for carbon-nitride photocatalytic performance using CO2 and/or H2O as reactant.