Photosensitizers used in homogeneous photocatalytic systems for artificial photosynthesis, such as hydrogen production, are typically based on expensive transition metal complexes such as d 6 ruthenium(II) or iridium(III). In this work, we demonstrate efficient H 2 production in acidic water by using an organic dye derived from the triazatriangulenium (TATA + ) family as a visible-light-absorbing photosensitizer (PS). By associat ing the hydrosoluble t ris(ethoxyet hanol)triazatriangulenium with an efficient H 2 -evolving cobalt catalyst and ascorbic acid as sacrificial electron donor (SD), remarkable photocatalytic performances were reached in aqueous solution at pH 4.5, under visible-light irradiation, with up to 8950 catalytic cycles versus catalyst. The performances of this dye largely exceed those of the benchmark Ru tris-bipyridine in the same experimental conditions when low concentrations of catalyst are used. This higher efficiency has been clearly ascribed to the remarkable robustness of the reduced form of the organic dye, TATA • . Indeed, the combination of the planar structure of TATA + together with the presence of the three electron-donating nitrogen atoms promotes the stabilization of TATA • by delocalization of the radical, thereby preventing its degradation in the course of photocatalysis. By contrast, the reduced form of the Ru photosensitizer, [Ru II (bpy) 2 (bpy •− )] + ("Ru − "), is much less stable. Nanosecond transient absorption experiments confirm the formation of TATA • in the course of the photocatalytic process in accordance with the mechanism initiated by the reductive quenching of the singlet excited state of TATA + by ascorbate. The second electron transfer from TATA • to the catalyst has also been evidenced by this technique with the detection of the signature of the reduced Co(I) form of the catalyst. The present study establishes that certain organic dyes are to be considered as relevant alternatives to expensive metal-based PSs insofar as they can exhibit a high stability under prolonged irradiation, even in acidic water, thereby providing valuable insights for the development of robust molecular systems only based on earth-abundant elements for solar fuel generation.

A bio-derived polyester has been crosslinked into flexible films for solid polymer electrolyte applications in Li+-ion batteries, with ionic conductivity around 10−5 S cm−1 at 60 °C, high Li+ transference number (0.84), and hydrolytic degradability.

This report describes the synthesis and characterization of organogels by reaction of a diol-containing polyether, derived from the sugar d-xylose, with 1,4-phenylenediboronic acid (PDBA). The cross-linked materials were analyzed by infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), scanning electron microscopy (FE-SEM), and rheology. The rheological material properties could be tuned: gel or viscoelastic behavior depended on the concentration of polymer, and mechanical stiffness increased with the amount of PDBA cross-linker. Organogels demonstrated self-healing capabilities and recovered their storage and loss moduli instantaneously after application and subsequent strain release. Lithiated organogels were synthesized through incorporation of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) into the cross-linked matrix. These lithium–borate polymer gels showed a high ionic conductivity value of up to 3.71 × 10–3 S cm–1 at 25 °C, high lithium transference numbers (t + = 0.88–0.92), and electrochemical stability (4.51 V). The gels were compatible with lithium-metal electrodes, showing stable polarization profiles in plating/stripping tests. This system provides a promising platform for the production of self-healing gel polymer electrolytes (GPEs) derived from renewable feedstocks for battery applications.