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Nowadays, considerable attention has been directed towards the two-electron oxygen reduction for the photocatalytic H 2 O 2 production. However, the challenge of insufficient charge separation capacity markedly constrains the rate of H 2 O 2 production. Herein, we designed a donor-acceptor (D-A) interface characterized by rapid charge migration and separation to enhance the photocatalytic H 2 O 2 production. Specifically, naphthalenetetracarboxylic acid-diaminotriazole as an organic molecule has been judiciously chosen as the electron donor, while perylenetetracarboxylic acid serves as the electron acceptor. The novel semiconductor with D-A interface performs markedly strong internal electric field and demonstrates an excellent H 2 O 2 production rate of 3176 μM h−1. The pronounced internal electric field facilitated by the D-A interface effectively expedites charge separation and induces the migration of photogenerated carriers to the O 2 reduction sites. This study introduces a novel paradigm for the design of D-A interfacial organic materials aimed at realizing enhanced photocatalytic capabilities. [Display omitted] • A novel organic semiconductor with electron donor-acceptor (D-A) interface was designed. • The D-A interface results in a markedly strong internal electric field. • The giant internal electric field efficiently accelerates photogenerated carrier separation. • The photocatalytic H2O2 production reaches an apparent quantum yield of 15.9% at 550 nm. [ABSTRACT FROM AUTHOR]

Organic polymer photocatalysts are a promising material platform for photosynthetic hydrogen peroxide production from water and oxygen. However, limited by the controlled structural design and lack of effective active sites, their photocatalytic efficiency is unsatisfactory. To address these above issues, we precisely designed and prepared two alkyne-based porous polymers via the Sonogashira cross-coupling reaction (POP-DT and POP-DF). Acetylene served as the oxygen-reducing active site, tuning the thiophene or furan ring as the electron donor unit. They exhibited a large specific surface area and rich pore architecture. Under visible light irradiation, the H2O2 generation rate of POP-DT was as high as 2422.2 μmol g−1 h−1, which was 4.3 times higher than that of POP-DF, representing one of the best performances ever reported for polymeric photocatalysts. We found that the combination of acetylene and thiophene resulted in faster charge separation and transfer efficiency, significantly improving the kinetic behaviour of the oxygen reduction reaction. More importantly, combined with in situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations, we demonstrate that acetylene-connected thiophene is more beneficial to the electron enrichment of the acetylene active site, enhancing the adsorption and activation of oxygen, thus boosting the photocatalytic efficiency for the oxygen reduction reaction. Our work provides a novel strategy for designing advanced polymer photocatalysts for enhanced solar energy conversion efficiency. [ABSTRACT FROM AUTHOR]

Artificial photosynthetic production of hydrogen peroxide (H2O2) using conjugated organic polymer semiconductor photocatalysts is a promising approach. However, its application is limited mainly by the rapid rate of photogenerated carrier complexation. Here, we have prepared three novel porphyrin-based donor–acceptor conjugated organic polymers using porphyrin as a precursor and benzene–diamine ligands as basic blocks for the photocatalytic and efficient production of H2O2 under pure water. Density functional theory (DFT) calculations show that aniline ligands act as electron donors (D) and porphyrins act as electron acceptors (A). The TCFPP-TPD exhibits efficient photocatalytic H2O2 production with an initial rate of 1180 μmol g−1 h−1 under visible light (λ > 420 nm) irradiation without any additional sacrificial agents or co-catalysts. By increasing the number of benzene rings, the electron-donating ability of the benzene–diamine ligands was significantly enhanced, improving their electron-donor–acceptor (D–A) interactions with the porphyrins and facilitating the separation of the photogenerated electron–hole pairs. Moreover, the possible process for producing H2O2 through TCFPP-TPD photocatalysis was disclosed through in situ FT-IR and electron spin resonance (ESR). This study proposes novel design concepts for the rational construction of D–A structures with the aim of increasing the charge separation efficiency, which is crucial for the effective production of H2O2. [ABSTRACT FROM AUTHOR]

• A novel A1-D-A2 type photocatalyst is designed for H 2 O 2 evolution. • The photocatalytic H 2 O 2 evolution activity is obviously enhanced. • Asymmetric receptor units induced efficient charge separation. • Dual reduction sites are confirmed to promote O 2 reduction to H 2 O 2. The study of hydrogen peroxide production by O 2 reduction reaction using covalent organic framework (COF) photocatalysts has attracted extensive attention in recent years. However, there are still great challenges in accurately controlling their structures to achieve rapid carrier separation and efficient O 2 reduction. Based on this, we constructed the A1-D-A2 COF photocatalytic material (TT-DTDA-COF) with asymmetric dual acceptor sites by connecting thieno [3,2-b] thiophene, benzene, and triazine as the basic units through imine bonds. Under the synergistic effect of thieno [3,2-b] thiophene and triazine electron acceptors, the separation and transfer efficiency of TT-DTDA-COF photogenerated carriers was significantly enhanced. At the same time, according to the in-situ infrared and DFT calculation results, it was found that these two acceptor units served as O 2 reduction sites, which realized the multi-site adsorption reduction of O 2 , and effectively enhanced the efficiency of photocatalytic O 2 reduction to H 2 O 2. The experimental results showed that the H 2 O 2 generation rate of TT-DTDA-COF with A1-D-A2 dual receptor structure was 1302 μmol·g−1·h−1 under visible light irradiation, which was 3.4 times higher than that of TB-DTDA-COF with single receptor D-A structure and higher than that of most of the materials reported so far. This study provides a new idea for accurately designing COF-based photocatalysts to achieve efficient O 2 reduction to produce H 2 O 2. [ABSTRACT FROM AUTHOR]