Novel organically linked Zn II hydrogenselenite coordination polymers: synthesis, characterization, and efficient TiO 2 photosensitization for enhanced photocatalytic hydrogen production.

This study focused on the solvothermal synthesis, characterization, and photocatalytic activities of two novel coordination polymers, namely [Zn(μ-HSeO 3 ) 2 (bipy)] n (1) and [Zn(μ-HSeO 3 ) 2 (phen)] n (2). These compounds represent the first organically linked Zn II hydrogenselenite coordination polymers. The synthesis of compounds 1 and 2 involved the addition of 2,2'-bipyridine and 1,10-phenanthroline, respectively, to SeO 2 and ZnO in methanol as the solvent. The novel hydrogenselenite compounds were thoroughly characterized using spectroscopic and crystallographic methods. The photocatalytic solids (TiO 2 -1A and TiO 2 -2A) were prepared by immobilizing compounds 1-2 onto TiO 2 through the sol-gel approach. These photocatalysts were then evaluated for hydrogen evolution via water splitting using a 300 W Hg/Xe lamp as the irradiation source. Among the newly synthesized photocatalytic materials, TiO 2 -1A demonstrated auspicious photocatalytic performance for hydrogen gas production. Its catalytic activity overcame the observed for the pure solid support TiO 2 and Degussa P25 (commercial titania), making compound 1 a particularly attractive TiO 2 photosensitizer. Additionally, TiO 2 -1A exhibited superior photocatalytic activity compared to TiO 2 -2A. The latter performed better than freshly prepared TiO 2 , approaching that of Degussa P25. These findings highlight the potential of compound 1 as an effective photosensitizer for TiO 2 -based photocatalysis, making it a promising candidate for applications in clean energy generation, specifically in hydrogen production by water splitting.