Periodic Reporting for period 1 - CO2-CAT-ALOG (Surface and sub-surface modified nano-electrocatalysts for the conversion of CO2 to value-added products: A structure-selectivity-mechanism-stability catalog)
Période du rapport: 2020-12-01 au 2022-11-30
Anthropocene, the age in which human intervention with nature is highest in affecting the global weather patterns as well as the pollution of entire ecosystem. The major role in increasing the global temperature is attributed to the increase in the concentration of greenhouse gases, especially fossil fuels-based CO2. Concerning this, electrochemical and photo-electrochemical based technologies offer promising solutions if provided with the renewable electrical energy sources to make the mission energy efficient. With this background, the strategic goals of the Marie Skłodowska-Curie Actions (MSCA) entitled “Surface and sub-surface modified nano-electrocatalysts for the conversion of CO2 to value-added products: A structure-selectivity-mechanism-stability catalog” is to address and tackle the contemporary challenges in the field of electrocatalytic conversion of CO2 to value-added products (VAPs).
Four grand objectives: a). activity, b). selectivity, c). mechanism and d). stability of surface and sub-surface modified copper-based nanostructures. In order to comprehend the structure-activity-selectivity-stability relationships for these objectives, four shape and size selective copper nanostructures are prepared viz., copper-based nanospheres, nanocubes, nano-octahedras and nanowires. Facility for online-gas chromatography for electrochemical CO2 reduction is established and NMR protocols for liquid products are also standardized at the host institute. With the appropriate electrochemical protocol, we were able to produce selectively methane over copper nanocubes. Furthermore, with the modified nanowires we were able to produce selectively ethylene as a major product.
Four grand objectives: a). activity, b). selectivity, c). mechanism and d). stability of surface and sub-surface modified copper-based nanostructures. In order to comprehend the structure-activity-selectivity-stability relationships for these objectives, four shape and size selective copper nanostructures are prepared viz., copper-based nanospheres, nanocubes, nano-octahedras and nanowires. Facility for online-gas chromatography for electrochemical CO2 reduction is established and NMR protocols for liquid products are also standardized at the host institute. With the appropriate electrochemical protocol, we were able to produce selectively methane over copper nanocubes. Furthermore, with the modified nanowires we were able to produce selectively ethylene as a major product.
We derive fundamental understanding of the incorporation of IIIA group elements (viz, B, Al and Ga) in the pristine copper nanoclusters and their reactivity towards CO2 and CO activation with the aid of DFT based methodologies. Further, we established the electrochemical CO2 reduction facility equipped with real-time gas chromatography to measure hydrocarbons and also established the standard protocols for NMR measurements to quantify the liquid-oxygenates at the host institute. Experimentally, shape and size selective chloride-free nanocubes were produced on various substrates such as glassy carbon, Au, TiN/TiON surfaces by employing pulse-electrodeposition. These nanocubes on glassy carbon exhibited selective methane formation (Faradaic efficiency of 31.7%) by appropriate electrochemical protocols (become part of the PhD thesis of one student). Whereas, FE of 20% was achieved without any appropriate electrochemical protocol on Cu octahedras, owing to geometry corresponding to (111) surfaces. Furthermore, by using temperature programmed solid-state decomposition methodology we produced quasi-spherical and nanowires of copper. These nanowires, unique ternary heterointerface of C-Cu2O-Cu, demonstrated selective ethylene (major product) formation (FE of 25%) owing to the heterointerfacial effect. All the nanostructures were fully characterized with the aid of XRPD, Raman, HR-TEM, STEM, XPS, XAES and IL-SEM.
To describe and corroborate our findings we have used conceptual DFT based reactivity descriptors such as Fukui functions, chemical hardness and potential, global electrophilicity index, electronegativity, spin density distribution, electrostatic potential mapping, change in enthalpy of adsorption and free energy along with binding energies and relative energies wherever necessary. The activation of CO is further confirmed by IR stretching frequency, bond length, and extent of charge transfer. Moreover, to better understand the proton coupled electron transfer (PCET) at the electrochemical interface we have also considered few reactive intermediates (RIs) such as *COOH, *H, *COH, and *CHO (to name a few). All these RIs are selected to better understand the interfacial phenomena where product selectivity, HER suppression, and bifurcation pathways for liquid oxygenates and hydrocarbons. In summary, IIIA group elements-doped copper nanoclusters are better in activating CO2/CO, and in stabilizing RIs compared to pristine nanoclusters. Thus, we can design better electrocatalysts by fine-tuning the electronic structure of copper for efficient, selective and stable electrocatalysis in near future.
Dissemination plan for this MSC action included reports targeting at material scientists, specific to CO2 catalysis community and the broader audience from till schools to general public. Specifically, two scientific publications in peer-reviewed journals have been published. Three more publications are still underway from this project in high-impact peer-reviewed journals. Especially the work with nanowires, a unique ternary heterointerface is expected to be the game changer in the community of CO2 electrocatalysis. Moreover, I have participated in four international conferences and workshops (with two posters and two oral presentations). In addition, I have also given lectures at the various departments of the host institution.
To describe and corroborate our findings we have used conceptual DFT based reactivity descriptors such as Fukui functions, chemical hardness and potential, global electrophilicity index, electronegativity, spin density distribution, electrostatic potential mapping, change in enthalpy of adsorption and free energy along with binding energies and relative energies wherever necessary. The activation of CO is further confirmed by IR stretching frequency, bond length, and extent of charge transfer. Moreover, to better understand the proton coupled electron transfer (PCET) at the electrochemical interface we have also considered few reactive intermediates (RIs) such as *COOH, *H, *COH, and *CHO (to name a few). All these RIs are selected to better understand the interfacial phenomena where product selectivity, HER suppression, and bifurcation pathways for liquid oxygenates and hydrocarbons. In summary, IIIA group elements-doped copper nanoclusters are better in activating CO2/CO, and in stabilizing RIs compared to pristine nanoclusters. Thus, we can design better electrocatalysts by fine-tuning the electronic structure of copper for efficient, selective and stable electrocatalysis in near future.
Dissemination plan for this MSC action included reports targeting at material scientists, specific to CO2 catalysis community and the broader audience from till schools to general public. Specifically, two scientific publications in peer-reviewed journals have been published. Three more publications are still underway from this project in high-impact peer-reviewed journals. Especially the work with nanowires, a unique ternary heterointerface is expected to be the game changer in the community of CO2 electrocatalysis. Moreover, I have participated in four international conferences and workshops (with two posters and two oral presentations). In addition, I have also given lectures at the various departments of the host institution.
With respect to the progress beyond the state of the art, we have successfully designed a unique ternary heterointerface of C-Cu2O-Cu. Heterointerfacial effect of this ternary material for the selective formation of ethylene as well as to prevent the dissolution/loss of active copper during relevant electrochemical CO2RR is achieved, covering also the final grand challenge of the CO2-CAT-ALOG project. Work of this project led to the discovery of a unique ternary heterointerface with gram scale levels of this nanomaterial in one-step, one-pot, and solvent free methodology. This material will not only be active for CO2 conversion but also might be well suited for other electrocatalytic reactions such as HER/ORR in alkaline media. Moreover, this will also be useful in copper based electronic industries. In addition, we are most likely to file a patent for the synthesis and application of this novel heterointerface in the field of heterogenous catalysis.
Research conducted in this MSCA of CO2-CAT-ALOG project is directly related to EU climate action and the European Green Deal (https://ec.europa.eu/clima/policies/eu-climate-action_en); which signifies the gravity of environmental measures to be taken to reduce the greenhouse gas emissions, to have cutting-edge research and innovation to become the first climate-neutral continent. Work carried out in this MSC action is on the electrochemical reduction of CO2, a greenhouse gas, to circumvent global warming as well as to have chemical feed-stock (value-added liquid oxygenates) and production of hydrocarbons. Hence, it is expected that the outcome of this project work (soon after the publication/patent) will be landmark in the field of heterogenous electrocatalysis of CO2 and anticipated to receive high citations in the scientific community as well as will have industrial impact for the stable production of hydrocarbons and/or liquid oxygenates. Nevertheless, as this action is to curb the impact of greenhouse gases (CO2) on our environment to make it cleaner and greener, this CO2-CAT-ALOG project also has direct impact in upliftment of the socio-economic status of the common people with community participations.
Research conducted in this MSCA of CO2-CAT-ALOG project is directly related to EU climate action and the European Green Deal (https://ec.europa.eu/clima/policies/eu-climate-action_en); which signifies the gravity of environmental measures to be taken to reduce the greenhouse gas emissions, to have cutting-edge research and innovation to become the first climate-neutral continent. Work carried out in this MSC action is on the electrochemical reduction of CO2, a greenhouse gas, to circumvent global warming as well as to have chemical feed-stock (value-added liquid oxygenates) and production of hydrocarbons. Hence, it is expected that the outcome of this project work (soon after the publication/patent) will be landmark in the field of heterogenous electrocatalysis of CO2 and anticipated to receive high citations in the scientific community as well as will have industrial impact for the stable production of hydrocarbons and/or liquid oxygenates. Nevertheless, as this action is to curb the impact of greenhouse gases (CO2) on our environment to make it cleaner and greener, this CO2-CAT-ALOG project also has direct impact in upliftment of the socio-economic status of the common people with community participations.