Enhancing Carrier Transport via σ‐Linkage Length Modulation in D‐σ‐A Semiconductors for Photocatalytic Oxidation

Abstract

Carrier transport is an equally decisive factor as carrier separation for elevating photocatalytic efficiency. However, limited by indefinite structures and low crystallinities, studies on enhancing carrier transport of organic photocatalysts are still in their infancy. Here, we develop an σ-linkage length modulation strategy to enhance carrier transport in imidazole-alkyl-perylene diimide (IMZ-alkyl-PDI, corresponding to D-σ-A) photocatalysts by controlling π-π stacking distance. Ethyllinkage can shorten π-π stacking distance (3.19 Å) the most among IMZ-alkyl-PDIs (where alkyl = none, ethyl, and n-propyl) via minimizing steric hindrance between D and A moieties, which leads to the fastest carrier transport rates. Thereby, IMZ-ethyl-PDI exhibits remarkable enhancement in phenol degradation with 32fold higher rates than IMZ-PDI, as well as the oxygen evolution rate (271-fold increased). In microchannel reactors, IMZ-ethyl-PDI also presents 81.5 % phenol removal with high-flux surface hydraulic loading (44.73 L m À 2 h À 1 ). Our findings provide a promising molecular design guideline for high-performance photocatalysts and elucidate crucial internal carrier transport mechanisms.

Recent Progress in Nonsacrificial H2O2 Generation Using Organic Photocatalysts and In Situ Applications for Environmental Remediation

“…Not limited to the introduction of active sites, the nonsacrificial H 2 O 2 generation can be also enhanced by promoting the charge separation in the photocatalysts. The construction of donor–acceptor (D-A) structure like imidazole-alkyl-PDI and tetraphenylporphinesulfonate/fullerene reported by our group has been illustrated to effectively promote the charge separation, and thus enhance the photocatalytic activity. In 2022, such a D–A structure was used for H 2 O 2 generation.…”

Organic Donor‐Acceptor Systems for Photocatalysis

“…Constructing polymer heterojunctions has become a pervasive solution in the pursuit of superior photocatalytic steriliza- [63] Copyright 2023, Wiley-VCH. b) The structure and electrostatic potential distribution of PCN-5B2T.…”

Promoted Photocatalytic Hydrogen Evolution by Tuning the Electronic State of Copper Sites in Metal‐Organic Supramolecular Assemblies

“…However, the construction of metal‐organic supramolecular assembly based on π⋅⋅⋅π stacking has received less attention. The π⋅⋅⋅π stacking could provide a pathway for the transport of photoexcited carriers, which promotes the charge separation and transportation efficiency of the photocatalysts [41–43] . Ideally, metal‐organic supramolecular assembly formed by π⋅⋅⋅π stacking have great potentials for photocatalytic hydrogen production because i) The π⋅⋅⋅π stacking enhances the long‐distance delocalization and electron coupling effect of π‐electrons, which is beneficial to the separation and transport of charge carriers; ii) The supramolecular network provides diffusion paths for reactants and products, thereby improving photocatalytic hydrogen production activity; iii) intrinsic metal‐based active sites can be evenly dispersed on the skeleton and fine‐tuned by the coordination environments, to enhance the photocatalytic activity.…”