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Exploiting Energy Flow in Plasmonic-Catalytic Colloids

Periodic Reporting for period 2 - CATALIGHT (Exploiting Energy Flow in Plasmonic-Catalytic Colloids)

Reporting period: 2020-07-01 to 2021-12-31

More than 85% of the energy that we daily use for our mobiles, washing machines and cars saw a catalyst before reaching us. Some of the fundamental reactions that are taking place right now in our cells would require temperatures higher than 1000 K to proceed if not having enzymes to catalyze them. As such, catalysis does not only make our life easier but in fact possible.
The aim of CATALIGHT is to use sunlight as a sustainable source of energy in order to trigger chemical reactions by harvesting photons with plasmonic nanoparticles and funneling the energy into catalytic materials. Plasmonic-catalytic devices would allow efficient harvesting, transport and injection of solar energy into molecules.
The project takes as its basis many of the currently most important open questions within the management of sustainable energy at the nanoscale:
- The exploration of routes for novel and efficient uses of sunlight energy.
- The realization of functional nanoscale architectures using colloids as building blocks.
- The marriage between harvesting, transport and injection of sunlight into molecules.
The outcomes of this work will not only yield a substantial amount of new fundamental knowledge also directly exploitable results for the applied sciences, particularly photocatalysis and fuel cells.
One of the initial tasks of the project consisted on assembling an interdisciplinary team able to carry out the different research lines involved in the project: physicists, chemists and material scientists. This - together with the installation of new facilities and equipment - build up solid grounds for the development of the rest of the project. Three main aspects were covered initially: a) the synthesis of new plasmonic catalysts; b) the mechanisms behind energy transfer at plasmonic interfaces and 3) new techniques capable of exploring and exploiting sunlight energy conversion at the nanoscale.

On one side, we have mastered the synthesis of novel and complex plasmonic catalysts - either mono or bimetallic ones – and tested them towards sunlight-driven redox reactions, including hydrogen generation. As such, we have exploited and enhanced different properties by designing and synthetizing colloidal structures with internal hotspots, multiple hotspots or fractal character – among others - improving the light absorption and energy conversion capabilities of standard colloidal architectures.

Furthermore, we have explored different nanoscale phenomena taking place across the plasmonic metal – molecule interface. We described a new type of charge transfer process mediated by the electric double layer that surround plasmonic colloids. Moreover, by combining plasmonic colloids and electrochemical measurements, we reveled the energy of photoexcited electrons and holes in these systems.

Finally, we developed new techniques for both: mapping nanoscale temperature at plasmonic interfaces and producing large-scale patterning of plasmonic colloidal catalysts. These techniques constitute a fundamental step towards optimizing and scaling-up our experimental results.
The new nanomaterials, mechanisms and techniques developed in CATALIGHT helped us so far to narrow the parameters space towards exploring and optimizing novel routes for converting sunlight into chemical energy. We envision that further progress in this direction could lead to efficient and selective routes towards sustainable production of solar fuels.
Novel plasmonic catalysts and routes for sunlight into chemical energy conversion.