Periodic Reporting for period 2 - QuantumSolarFuels (Photoelectrochemical Solar Light Conversion into Fuels on Colloidal Quantum Dots Based Photoanodes)
Periodo di rendicontazione: 2021-11-01 al 2022-10-31
Technologies that produce carbon-neutral fuels and chemical feedstocks are needed to meet European and Global objectives toward a green economy and climate neutrality, specifically prioritized within the EU policy targets on Energy, Climate Change, and Environment. Solar energy is the most abundant renewable energy source and provides our planet with energy, largely exceeding our current demand. However, the intermittency of solar light and other renewable energy sources is the most significant barrier to their extensive utilization to displace fossil fuels. Electrocatalysis offers ways to convert electricity from renewable sources into energy-rich chemicals, including hydrogen and hydrocarbons, that can replace petrochemicals and fossil fuels. Addressing the storage of elusive renewable energies by identifying selective and energy-efficient catalysts and processes are the objectives of the QuantumSolarFuels project.
The three-year project joins two research groups: Professor Selli (Department of Chemistry at the Universià di Milano, Italy) and Professor Sargent (Department of Electrical and Computer Engineering of the University of Toronto, Canada). Dr. Grigioni, the researcher involved in the project, spent the first two years in the Sargent group. The group is field-leading in electrocatalysis to convert carbon dioxide (CO2) or carbon monoxide (CO), water, and renewable electricity into chemicals such as hydrogen, ethylene, ethanol, and propanol. The Selli group primarily focuses on direct solar light conversion to value-added molecules via photocatalysis and photoelectrocatalysis and hosted Dr. Grigioni during the last year of the project.
If successful, the QuantumSolarFuels project will enable the displacement of fossils with renewable-derived chemicals, nurturing new industrial processes and economic and social opportunities. To widely deploy electrolyzers at scale, we investigate efficient catalysts to produce specific products and devices that maximize energy efficiency to target industrial requirements.
The three-year project joins two research groups: Professor Selli (Department of Chemistry at the Universià di Milano, Italy) and Professor Sargent (Department of Electrical and Computer Engineering of the University of Toronto, Canada). Dr. Grigioni, the researcher involved in the project, spent the first two years in the Sargent group. The group is field-leading in electrocatalysis to convert carbon dioxide (CO2) or carbon monoxide (CO), water, and renewable electricity into chemicals such as hydrogen, ethylene, ethanol, and propanol. The Selli group primarily focuses on direct solar light conversion to value-added molecules via photocatalysis and photoelectrocatalysis and hosted Dr. Grigioni during the last year of the project.
If successful, the QuantumSolarFuels project will enable the displacement of fossils with renewable-derived chemicals, nurturing new industrial processes and economic and social opportunities. To widely deploy electrolyzers at scale, we investigate efficient catalysts to produce specific products and devices that maximize energy efficiency to target industrial requirements.
During the first two years at the University of Toronto, the project progressed toward the development of environmentally friendly catalysts liquid products from carbon dioxide electrocatalytic reduction. Indeed, liquid chemicals offer advantages compared to gaseous compounds, such as more straightforward storage and transportability, higher energy density, and lower separation costs.
During the third year, Dr. Grigioni transferred the acquired knowledge to the Università di Milano, setting up an electrocatalytic research line in the laboratories of Prof. Selli.
In the lab, we conducted CO2 reduction by assembling the catalytic nanomaterials in gas diffusion electrodes to favor CO2 availability to the active catalytic sites; ionomers in the catalytic layer tweaked the CO2 diffusion further. These approaches allowed industry-relevant production rates (above 200 mA cm-2, the lower threshold for commercial devices) at compelling cell voltages. Because CO2 can be lost through dissolution into alkaline electrolyte solutions, we achieved high CO2 utilization by using neutral or acid electrolytes or employing carbon monoxide (CO) electrocatalytic reduction. Indeed, CO can be produced from CO2 with complete selectivity through already consolidated electrocatalytic methods and then upgraded to more valuable chemicals. Upgrading CO to higher hydrocarbons allows high rates and efficient production of ethanol and propanol, two energy-dense alcohols that can be used as a reactant and as fuels. We characterized the materials with ex-situ and in-situ techniques to check their chemical composition, morphology, and electronic state. We also studied the reactivity of the intermediates with operando experiments and computational simulations.
Throughout the action, Dr. Grigioni became an expert in electrocatalysis for renewable energy conversion and storage. He now masters advanced characterization techniques, material synthesis at the atomic scale, and the use of a variety of gas diffusion electrode-based electrolyzers (flow cells, membrane electrode assemblies, gap-less flow cells) with cation, anion, and bipolar membranes. Furthermore, he improved his communication skills with the industry during recurring engagement opportunities with industrial partners and experienced methods and tools to meld academic and industrial research.
During the third year, Dr. Grigioni transferred the acquired knowledge to the Università di Milano, setting up an electrocatalytic research line in the laboratories of Prof. Selli.
In the lab, we conducted CO2 reduction by assembling the catalytic nanomaterials in gas diffusion electrodes to favor CO2 availability to the active catalytic sites; ionomers in the catalytic layer tweaked the CO2 diffusion further. These approaches allowed industry-relevant production rates (above 200 mA cm-2, the lower threshold for commercial devices) at compelling cell voltages. Because CO2 can be lost through dissolution into alkaline electrolyte solutions, we achieved high CO2 utilization by using neutral or acid electrolytes or employing carbon monoxide (CO) electrocatalytic reduction. Indeed, CO can be produced from CO2 with complete selectivity through already consolidated electrocatalytic methods and then upgraded to more valuable chemicals. Upgrading CO to higher hydrocarbons allows high rates and efficient production of ethanol and propanol, two energy-dense alcohols that can be used as a reactant and as fuels. We characterized the materials with ex-situ and in-situ techniques to check their chemical composition, morphology, and electronic state. We also studied the reactivity of the intermediates with operando experiments and computational simulations.
Throughout the action, Dr. Grigioni became an expert in electrocatalysis for renewable energy conversion and storage. He now masters advanced characterization techniques, material synthesis at the atomic scale, and the use of a variety of gas diffusion electrode-based electrolyzers (flow cells, membrane electrode assemblies, gap-less flow cells) with cation, anion, and bipolar membranes. Furthermore, he improved his communication skills with the industry during recurring engagement opportunities with industrial partners and experienced methods and tools to meld academic and industrial research.
The research performed advanced the field by discovering catalytic nanomaterials that outperform those reported in the literature on the electrocatalytic conversion of renewable electricity and carbon dioxide to solar fuels. In particular, we optimized colloidal quantum dots of InP (a non-toxic semiconductor). We integrated them in electrodes for selective CO2-to-formate production at high rates (selectivity above 90%, rate above 1 A cm-2). In addition, we demonstrated high selectivity in the 8-electron reduction of carbon monoxide to acetate by controlling the adsorption of the intermediates via surface atomic modification of copper oxide. Finally, cooperative catalysis between copper and nitrogen-doped carbon nanoparticles achieved high selectivity in the 12- and 8-electron reduction toward propanol and ethanol, respectively.
In the last year of the project, we studied the effects of catalysts' oxidation state on the reactivity in different local environments with in-situ XAS at the European Synchrotron Radiation Facility (ESRF). Advanced in-situ XAS is one of the few techniques that enables observing the oxidation state during the reaction, which has crucial impacts on the catalytic reaction and the catalyst's long-term stability. Lastly, we developed a shielding strategy to avoid undesired charge recombination in heterojunction systems, such as WO3/BiVO4 for water splitting.
The results of this project were disseminated through five papers in high-impact journals: one on CO2 reduction to formate in ACS Energy Letters, four papers on solar light-driven water splitting for hydrogen production (on ACS Applied Energy Materials, Applied Surface Science, and The Journal of Physical Chemistry C). Furthermore, one article has been recently accepted on Nature Synthesis.
The research carried out during the project directly addresses issues related to climate change and industrial and societal needs. Using renewable electricity to produce fuels and chemicals from CO2 and water will be essential to achieve carbon neutrality by still increasing the current welfare standards and manufacturing commodity chemicals and materials such as polymers, cosmetics, and highly energy-dense fuels without employing fossil resources.
Modular electrolyzes can be stacked in series to build facilities with size on demand. They can be deployed close to CO2 emitting points (cement factories, bio-refineries, bio-treatment plants, bio-alcohol production sites as the most common CO2 emitters) in plants that can adapt to regional conditions, for example, the abundance of renewable energies and CO2 point sources. Advances in this field can open technical, industrial, societal, and economic opportunities in a 10-year timescale. Looking ahead, progresses in the circular carbon economy will reduce the reliance on foreign resources and stimulate the job market by designing new highly-skilled job positions: for example, in the infrastructure sectors for energy distribution and storage, in the automotive and net-zero emission plastics and polymers industry.
In the last year of the project, we studied the effects of catalysts' oxidation state on the reactivity in different local environments with in-situ XAS at the European Synchrotron Radiation Facility (ESRF). Advanced in-situ XAS is one of the few techniques that enables observing the oxidation state during the reaction, which has crucial impacts on the catalytic reaction and the catalyst's long-term stability. Lastly, we developed a shielding strategy to avoid undesired charge recombination in heterojunction systems, such as WO3/BiVO4 for water splitting.
The results of this project were disseminated through five papers in high-impact journals: one on CO2 reduction to formate in ACS Energy Letters, four papers on solar light-driven water splitting for hydrogen production (on ACS Applied Energy Materials, Applied Surface Science, and The Journal of Physical Chemistry C). Furthermore, one article has been recently accepted on Nature Synthesis.
The research carried out during the project directly addresses issues related to climate change and industrial and societal needs. Using renewable electricity to produce fuels and chemicals from CO2 and water will be essential to achieve carbon neutrality by still increasing the current welfare standards and manufacturing commodity chemicals and materials such as polymers, cosmetics, and highly energy-dense fuels without employing fossil resources.
Modular electrolyzes can be stacked in series to build facilities with size on demand. They can be deployed close to CO2 emitting points (cement factories, bio-refineries, bio-treatment plants, bio-alcohol production sites as the most common CO2 emitters) in plants that can adapt to regional conditions, for example, the abundance of renewable energies and CO2 point sources. Advances in this field can open technical, industrial, societal, and economic opportunities in a 10-year timescale. Looking ahead, progresses in the circular carbon economy will reduce the reliance on foreign resources and stimulate the job market by designing new highly-skilled job positions: for example, in the infrastructure sectors for energy distribution and storage, in the automotive and net-zero emission plastics and polymers industry.