Enhanced photocatalytic efficiency of Bi₂MoO₆ for water and p-nitroaniline reduction via iodate (I⁵⁺) substitution: Implications of small polaron formation

The wide range of potential applications for photocatalysis has made research on photocatalytic materials highly active. However, various limitations hinder large-scale applications of photocatalysis, making the search for novel and improved catalysts an ongoing pursuit. To achieve this, a detailed analysis of material characteristics and charge transfer behavior is crucial. This study investigates the enhancement of Bi₂MoO₆ (BMO) photocatalytic performance through iodate (I⁵⁺) substitution, focusing on its impact on charge transport and reaction efficiency. Employing experimental and computational methods, we propose that carrier migration in Bi₂MoO₆ follow a small polaron model. Substituting I⁵⁺ into Bi₂MoO₆ increase the exposure on {100} facets, where polaron hopping along the facet is easier than on the exposed {010} facet of pristine Bi₂MoO₆. Moreover, this substitution creates defects and increases charge carrier concentration by approximately threefold. The increased Fermi energy level enables I-doped Bi₂MoO₆ to generate H₂ and enhance p-nitroaniline reduction activity. As a result, the catalyst exhibits nearly 10 times higher efficiency in both reactions. This work highlights a defect-engineering strategy that potentially involves polaronic transport to improve photocatalyst design, offering a promising solution for sustainable energy applications, including water splitting and selective organic transformations.