Tuning the Conduction Band Potential of Bi‐based Semiconductors Using a Combination of Organic Ligands

Abstract

Most Bi‐based semiconductors are incapable of photocatalytic reduction reaction from a thermodynamic view, owing to relatively positive conduction band potentials (ECB). Here, a novel Bi‐based metal–organic framework (Bi‐MBA, MBA=4‐mercaptobenzoic acid) with excellent photocatalytic reduction activities is developed. The ECB of Bi‐MBA locates at −1.38 eV, which is able to efficiently reduce O2, CrVI and CO2. Theoretical calculations reveal the significant contribution of organic ligand (MBA) to the conduction band. Our results provide an effective route to improve the photocatalytic reduction activities of Bi‐based photocatalysts.

A Bismuth-Based Metal–Organic Framework for Visible-Light-Driven Photocatalytic Decolorization of Dyes and Oxidation of Phenylboronic Acids

“…According to our previous results, the extension of light absorption is due to the formation of the Bi−S bond. 12,33 According to the formula 34 the band gap for can be determined to be 2.67 eV.…”

“…The experimental conditions for the photocatalytic decolorization of RhB were the same as those reported previously. 12 Specifically, to the RhB aqueous solution (50 mL, 10 mg L −1 ) was added the catalyst (25 mg), and the system was irradiated with visible light (λ > 420 nm). At given time intervals, a 1 mL suspension was taken out and centrifuged to obtain a clarified liquid, which was analyzed on an UV−vis spectrophotometer (TU-1810, PERSEE) to monitor the absorption intensity at 540 nm.…”

“…Besides that, the electron-withdrawing ability of the −COOH group on the organic ligand plays an important role in improving the charge transfer ability. 12 Our group also used 4,4′,4″-s-triazine-2,4,6-triyl-tribenzoic acid with a large amount of π-conjugation as the organic ligand to build MOFs, and the wide range of light absorption greatly enhanced the photocatalytic activity. 11 2-Mercapto-4-methyl-5-thiazoleacetic acid (MMTAA) is a biocompatible molecule that can be used as an intermediate for the antibiotic cefodizime.…”

“…Bismuth (Bi) is the largest nonradioactive element on the periodic table. Due to their nontoxic nature and flexible coordination, Bi-based metal–organic frameworks (MOFs) are attracting more and more attention. − Over the last few decades, an increased number of Bi-based MOFs have been developed and applied in the fields of fluorescence, biomedicine, gas adsorption, catalysis, etc. − Particularly, the semiconducting behavior of some Bi-based MOFs has sparked research into photocatalytic degradation, water splitting, carbon dioxide reduction, and organic synthesis. − …”

“…In our previous work, we used a thiophenol-containing ligand (4-mercaptobenzoic acid) to construct Bi-based MOFs, and the formation of the Bi–S bond significantly extended the light absorption. Besides that, the electron-withdrawing ability of the −COOH group on the organic ligand plays an important role in improving the charge transfer ability . Our group also used 4,4′,4″- s -triazine-2,4,6-triyl-tribenzoic acid with a large amount of π-conjugation as the organic ligand to build MOFs, and the wide range of light absorption greatly enhanced the photocatalytic activity …”