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

Abstract

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 Bi<inf>2</inf>MoO<inf>6</inf> (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 Bi<inf>2</inf>MoO<inf>6</inf> follow a small polaron model. Substituting I⁵⁺ into Bi<inf>2</inf>MoO<inf>6</inf> increase the exposure on {100} facets, where polaron hopping along the facet is easier than on the exposed {010} facet of pristine Bi<inf>2</inf>MoO<inf>6</inf>. Moreover, this substitution creates defects and increases charge carrier concentration by approximately threefold. The increased Fermi energy level enables I-doped Bi<inf>2</inf>MoO<inf>6</inf> to generate H<inf>2</inf> 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.