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Abstract:The hydroalkoxylation of dicyclopentadiene (DCPD) and norbornene (NB) with 2-hy-A C H T U N G T R E N N U N G droxyethyl methacrylate (HEMA) for the synthesis of industrially relevant monomers has been investigated with various metal-based Lewis acids and strong Brønsted acids. In the absence of other additives, copper(II) triflate is the most efficient catalyst system. Kinetics, electron spin resonance (ESR), catalyst poisoning and cross experiments indicate that triflic acid (TfOH) is the true active catalyst in these reactions. This in situ generation of TfOH occurs via reduction of CuA C H T U N G T R E N N U N G (OTf) 2 by the olefin reagent (DCPD, NB). The copper ions present in the reaction mixture act as radical polymerization retardants, preventing polymerization of HEMA (which is observed with most other metal salts and strong Brønsted acids investigated), thus improving the selectivity and yield (up to 95%) for the desired products. These observations have led to the development of a highly effective green process, using bulk reagents (no solvent) and a cheap, metal-free catalyst system, based on TfOH and a phenolic radical inhibitor (2,5-di-tert-butylhydroxytoluene, BHT).

Mesoporous WO3 thin film exhibits a higher photocurrent compared to the dense thin film obtained in the same conditions.

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The generation of hydrogen from water and sunlight offers a promising approach for producing scalable and sustainable carbon free fuels. One of the challenges of solar-to-fuel technology is the design of efficient, long-lasting and low-cost photocathodes, which are responsible for absorbing sunlight and driving catalytic hydrogen evolution. We report on the protection of a Cu/CuO/CuO photoelectrode against photocorrosion by a 200-300 nm-thick BaTiO perovskite layer, deposited using the sol-gel method. This photoelectrode mediates H production with a current density of ∼3.1 mA cm at 0 V versus RHE under 3 Sun irradiation and in a pH = 6 aqueous electrolyte. While the unprotected Cu/CuO/CuO photoelectrodes show a rapid decay of activity, the BaTiO-protected photoelectrodes exhibit ∼10% current decay over 20 min.

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