Quantum Dot Photocatalysts for Organic Transformations

Abstract

Quantum dots (QDs) with tunable photo-optical properties and colloidal nature are ideal for a wide range of photocatalytic reactions. In particular, QD photocatalysts for organic transformations can provide new and effective synthetic routes to high value-added molecules under mild conditions. In this Perspective, we discuss the advances of employing QDs for visible-light-driven organic transformations categorized into net reductive reactions, net oxidative reactions, and redox neutral reactions. We then provide our outlook for potential future directions in the field: nanostructure engineering to improve charge separation efficiencies, ligand shell engineering to optimize overall catalyst performance, in situ comprehensive studies to delineate underlying reaction mechanisms, and laboratory automation with the assistance of modern computing techniques to revolutionize the reaction optimization process.

Diesel soot photooxidation enhances the heterogeneous formation of H2SO4

“…S1a and S11), the formation of photo-generated holes (h + ) on excited EC may abstract electrons from OC and subsequently donate electrons to other available acceptors such as adsorbed O 2 (Eq. ( 3)) [50][51][52][53] . To further verify this, the photo-induced electron-hole pairs in residual EC were analyzed using TEMPO spin-trapping ESR spectra.…”

Beyond Water Oxidation: Hybrid, Molecular-Based Photoanodes for the Production of Value-Added Organics

“…The vast majority of the systems reported so far both for photoreforming and photoredox catalysis are based on semiconductor nanoparticles, mostly used as suspensions. Several reviews have been recently published on this subject and will not be discussed here ( Kampouri and Stylianou, 2019 ; Qi et al, 2021 ; Yuan et al, 2021 ; Casadevall, 2022 ). Material-based systems, either used as suspensions or electrodes, usually yield better performing and easy-to-handle devices, although at the expense of a more challenging mechanistic investigation and component tailoring, which are typical properties of systems based on organic or coordination compounds ( Berardi et al, 2014 ; Zhou et al, 2015 ; Zhang and Sun, 2019 ; Qi et al, 2021 ).…”

CdS Quantum Dots as Potent Photoreductants for Organic Chemistry Enabled by Auger Recombination

“…Semiconductor quantum dots (QDs) combine advantageous aspects of both homogeneous (high surface-volume ratio, solubility in reaction media, light penetration) and heterogeneous (durability, substrate binding) catalysts, and therefore offer new opportunities for photoredox catalysis. 25,26 QDs have proven to be robust fluorophores and photocatalysts, generally exhibiting superior photostability to small-molecule dyes, [27][28][29][30][31][32][33] however applications of QDs to organic synthesis remain underexplored. To address the need for continued development of photoredox catalysts, our group and others have been interested in new applications of QDs in organic chemistry.…”

“…To address the need for continued development of photoredox catalysts, our group and others have been interested in new applications of QDs in organic chemistry. 26, In addition to their high photostability, QDs exhibit tunable, size-dependent optical and redox properties; are made in single-step syntheses with no chromatography from abundant precursors; 62 reversibly bind to many molecules at once (typically 1 -5 ligands/nm 2 of QD surface are found for closely related CdSe QDs [63][64][65] ) through common organic functional groups (-CO 2 H, -PO 3 H, -SH, -NH 2 ); can become charged with many electrons at once without decomposing; 66,67 and undergo many electronic processes with no direct analogue in smallmolecules. 68 Inspired by reports of conPET-type photoreduction mechanisms operative within commonly used photocatalyst systems, 12,24,69 we envisioned that QDs could achieve a similar mode of reactivity, while also addressing the catalyst stability and availability challenges of organocatalyst-mediated photoreductions.…”