Task 1
Task title: Engineering of new double perovskites with high visible light photoactivity
Start date: 1
End date: 12
Objective: (1) Fabricating of new double perovskite nanocrystals with narrow band and a CB edge appropriate for CO2 photoconversion; (2) Correlation of DNPs composition, morphology (1D to 3D) and stability with synthesis route
Task description:
According to recent literature data, the following double perovskites have been predicted theoretically (using DFT theory), but not synthesized yet: Cs2CuSbBr6; Rb2CuSbCl6; Rb2CuSbBr6; Rb2AgBiCl6; Rb2AgBiBr6; Cs2CuBiX6; Rb2CuBiX6; Rb2AgSbX6; Cs2AuSbX6; Rb2AuSbX6; Cs2AuBiX6; Rb2AuSbX6; Cs2InSbX6; Rb2InSbX6; Cs2InBiX6; Rb2InBiX6; (where X= Br, Cl, I). Thus, it is widely expected that new double perovskites will possess higher stability, visible light activity (due to narrow band gap) and high efficiency in CO2 photoconversion into useful hydrocarbons. Use of available theoretical modelling (solving stable structures and prediction of electronic structure related properties) for experimental studies should result in reduction of necessary experiment number and costs. Going beyond current knowledge, a new group of double perovskite nanocrystals will be synthesized. Rare and toxic elements (such as lead in double perovskites nanocrystals) will be excluded.
Task 2
Task title: Design and engineering of DPNs-MOFs hybrids with high visible light activity
Start date: 6
End date: 20
Objectives: (1) Enhancement stability of double perovskites (especially in aqueous environment) and enhancement of efficiency of CO2 photoconversion through encapsulation of DPNs in MOFs cages. (2) To find an effective way to encapsulate DPNs with MOFs (guest-host system); (3) Correlation of composition and structure of DPNs-MOFs hybrids with their stability and surface properties
Task description:
To enhance the yield of CO2 photoconversion over DPNs/MOFs hybrids, two types of MOFs will considered: (i) Cu-based MOFs; and (ii) MOFs showing high adsorption capacity towards CO2. Based on the literature, it could be hypothesized that copper-based MOFs should be especially interesting group of MOFs, due to it high affinity for CO2 conversion. Among all metal, Cu is the only one that exhibits high selectivity for CO2 electrochemical reduction to hydrocarbons (CH4 and C2H4). Also theoretical calculation of the overpotential of CO2 reduction to CH4 indicated that Cu is the closest to the volcano’s peak among all metal electrode materials. Thus, Cu ions/clusters included in MOFs structure could show additional catalytic activity, enhancing overall efficiency of hybrid system. On the other hand, maturing the CO2 conversion TRL requires lowering the barriers. Application of MOFs possessing high sorption capacity towards CO2 should solve this problem. Combining of MOFs with DPNs will be realized using two different approaches: (i) synthesis of DPNs in the first step, following by synthesis of MOFs; (ii) synthesis of MOFs structure in the first stage, followed by adsorption of B-site cations of DPNs and finally by sinking in solution containing A-site cations of DPNs (double perovskite nanocrystals will be synthesized in-situ in porous structure of MOFs).
Task 3
Task title: Efficiency of CO2 photoconversion into valuable hydrocarbons
Start date: 6
End date: 24
Objectives: (1) Correlate hybrid materials composition with their photoactivity and selectivity in CO2 photoconversion reaction; (2) To clarify excitation mechanism of hybrids and pathway of CO2 phototransformation in the presence of hybrid materials.
Task description:
Rational design of novel photocatalysts requires trustworthy information on dependence between material structure and its activity, which could be obtained only under relevant reaction conditions. A combination of advanced experimental techniques (reaction kinetics, identification of by-products, action spectra analysis and 13C-labelled experiments) – carried out under relevant reaction conditions – will give a deep insight mechanism of new material excitation and mechanism of CO2 phototransformation. Main product identification, yield and rate of CO2 conversion into valuable hydrocarbon will be measured for all samples, while action spectra analysis and 13CO2-labeled experiments will be done for selected, most promising samples (DPNs-MOFs and unit components as reference samples) to understand: (i) which wavelength is responsible for excitation of exact photocatalytic system, (ii) what intermediates are created during CO2 irradiation in the presence of hybrid systems; (iii) what is a pathway of CO2 to hydrocarbon transformation.
Task 4
Task title: Scaling up of DPNs-MOFs hybrid synthesis
Start date: 20
End date: 24
Objectives: (1) developing a method of obtaining selected hybrid material in the form of powder in the amount of at least 200 g from one batch; (2) To optimize synthesis condition in pilot scale (to reduce cost and energy consumption)
Task description:
Future application of hybrids materials requires the development production method in larger scale (switch from a few grams production to a few hundred grams or kilograms production. It requires optimizing: (i) parameters of synthesis (temperature and pressure in the case of solvothermal reaction, reaction duration, stirring rate, reagents feeding, etc.,); (ii) type of raw materials (cheap, available, non toxic, etc.); (iii) optimization of unit processes and operations. Based on WP1-WP3 results, the most promising material will be selected for production scaling-up. Selection will be done based on activity, stability and complexity of synthesis route.