Photocatalytic Hydrogen Production by the Sensitization of Sn(IV)-Porphyrin Embedded in a Nafion Matrix Coated on TiO2

Abstract

Efficient utilization of visible light for photocatalytic hydrogen production is one of the most important issues to address. This report describes a facile approach to immobilize visible-light sensitizers on TiO2 surfaces. To effectively utilize the sensitization of Sn(IV) porphyrin species for photocatalytic hydrogen production, perfluorosulfonate polymer (Nafion) matrix coated-TiO2 was fabricated. Nafion coated-TiO2 readily adsorbed trans-diaqua[meso-tetrakis(4-pyridinium)porphyrinato]tin(IV) cation [(TPyHP)Sn(OH2)2]6+ via an ion-exchange process. The uptake of [(TPyHP)Sn(OH2)2]6+ in an aqueous solution completed within 30 min, as determined by UV-vis spectroscopy. The existence of Sn(IV) porphyrin species embedded in the Nafion matrix coated on TiO2 was confirmed by zeta potential measurements, UV-vis absorption spectroscopy, TEM combined with energy dispersive X-ray spectroscopy, and thermogravimetric analysis. Sn(IV)-porphyrin cationic species embedded in the Nafion matrix were successfully used as visible-light sensitizer for photochemical hydrogen generation. This photocatalytic system performed 45% better than the uncoated TiO2 system. In addition, the performance at pH 7 was superior to that at pH 3 or 9. This work revealed that Nafion matrix coated-TiO2 can efficiently produce hydrogen with a consistent performance by utilizing a freshly supplied cationic Sn(IV)-porphyrin sensitizer in a neutral solution.

Supramolecular squares of Sn(iv)porphyrins with Re(i)-corners for the fabrication of self-assembled nanostructures performing photocatalytic degradation of Eriochrome Black T dye

“…[27][28][29][30] Besides, attractive photophysical properties of Sn(IV)porphyrins with distinct absorption and emission have led to develop interesting optoelectronic supramolecular systems. [31][32][33][34][35] We have been devoting ourselves to studying the nanostructures based on the supramolecular Sn(IV)porphyrin assembly and their photocatalytic performances for watersplitting H 2 generation 36,37 and degradation of pollutant dyes. [38][39][40][41][42][43] Specifically, the complementary Zn(II)-Sn(IV)-Zn(II) porphyrin triads, [38][39][40][41] the coordination frameworks of Sn(IV) porphyrin with Ag(I) ions, 42 and the ionic assembly of cationic Sn(IV)porphyrin 43 were investigated, where we intensively explored important aspects such as the fabrication of nanostructures, the morphology control, and photocatalytic performances.…”

Hybrid Composite of Sn(IV)-Porphyrin and Mesoporous Structure for Enhanced Visible Light Photocatalytic Degradation of Organic Dyes

“…This advantageous tuning capability of Sn(IV)-porphyrins enables creation of coordination complexes [ 21 , 22 , 23 , 24 , 25 ], multiporphyrin arrays [ 26 , 27 , 28 ], and nanostructures [ 29 , 30 , 31 ], which exhibit characteristic functions. In particular, supramolecular nanostructures based on Sn(IV)-porphyrins have been intensively studied for the application of photocatalysis of AOPs for water remediation [ 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. Therefore, the combination of Sn(IV)-porphyrins with the mesoporous MCM−41 not only enables morphology fabrication of the surface but also enhances the photocatalytic degradation efficiencies of organic pollutants by manifold compared to the parent Sn(IV)-porphyrins ( Scheme 1 ).…”

Fabrication and properties of Sn(iv) porphyrin-linked porous organic polymer for environmental applications

“…Owing to the oxophilic nature of the Sn(IV) center, Sn(IV) porphyrin can readily form stable sixcoordinated complexes with two oxyanions (carboxylates or alkoxides) in the trans position. This advantageous tuning capability of SnPs makes them ideal scaffolds for constructing coordination complexes, [27][28][29][30][31][32][33][34][35] nanostructures, [36][37][38][39][40][41][42][43][44] and multiporphyrin arrays, [45][46][47] which exhibit characteristic functions. Sn(IV)-porphyrin-based supramolecular nanostructures have been extensively studied as photocatalysts for wastewater remediation.…”