Molecular‐Level Regulation Strategies Toward Efficient Charge Separation in Donor−Acceptor Type Conjugated Polymers for Boosted Energy‐Related Photocatalysis

Abstract

The development of efficient photocatalysts for artificial photocatalytic energy conversion is an intriguing strategy. Promisingly, conjugated polymers (CPs) have been actively investigated as alternatives to traditional inorganic semiconductors for photocatalysis due to their molecularly tunable optoelectronic properties, thus providing a great platform for molecular design. Incorporating donor (D) and acceptor (A) units into the backbone of CPs ensures an adequate D−A interface, which is essential for facilitating charge separation. This approach also allows for tunable bandgaps and optoelectronic properties, leading to significant progress in photocatalytic energy conversions in recent years. Here, the fundamentals of D–A type CPs for photocatalysis are initially outlined, followed by advanced experimental methods and density functional theory (DFT) calculations for investigating carrier dynamics. Then, a detailed exposition of the synthetic strategies for D−A type CPs is carried out. Their extensive applications in diverse energy‐related photocatalytic conversions, such as hydrogen evolution, oxygen evolution, overall water splitting, CO2 reduction, N2 reduction, and H2O2 evolution are comprehensively presented. This review provides new and comprehensive insights into the molecular‐level design of D−A type CPs catalysts for boosted photocatalytic energy conversion, which is expected to further advance the development of CPs in photocatalysis.

Solution-Processable Polymer Donor-Small Molecule Acceptor Bulk Heterojunction Organocatalysts for Enhancing CO2-to-CO Photoconversion

“…Additionally, atmospheric N 2 within the needle edges during injection may contribute to the observed larger m/z = 28 peak compared to other products. As shown in Figure 4, another strong peak at m/z = 30 in the mass spectrograph indicates the presence of C 18 O product, strongly affirming the C 18 O products originated from C 18 O 2 photoreduction, 40 excluding other catalysts or catalysts degradation. Moreover, the C 18 O content observed in our isotope experiment exceeds that found in naturally occurring C 18 O in the atmosphere, providing strong evidence of BHJ's efficient generation of CO through CO 2 photoreduction.…”

“…Additionally, in the absence of a photocatalyst or light, no CO was generated, confirming the photocatalytic nature of the reported CO production. To confirm that the photocatalytic reduction of CO 2 led to the generation of CO products, an isotope experiment was conducted using C 18 O 2 and H 2 18 O as a reactant in lieu of normal C 16 O 2 under the same photocatalytic reaction conditions, and the gaseous products were detected by mass spectrometry. The oxygen isotope (m/z = 32) appears due to the possible presence of atmospheric oxygen inside the needle edges during the injection process (Figure 4).…”

“…Recently, organic semiconductors, favored by their cost-effectiveness, sustainability, broad light absorption spectrum, structural versatility, and adjustable physical and optoelectronic properties, have emerged as the forefront candidates for the succeeding generation of synthetic photocatalysts, evoking a crescendo of scientific attention . Graphitic carbon nitride (g-C 3 N 4 ) has been researched for CO 2 conversion, owing to its distinctive optoelectronic properties and finely conjugated stacking structure. − Simultaneously, alternative active materials, encompassing covalent organic frameworks (COFs), − covalent triazine-based frameworks (CTFs), , linear conjugated polymers (LCPs), conjugated microporous polymers (CMPs), , and metal–organic frameworks (MOFs), wherein molecular structures can be meticulously tailored through an abundance of building blocks, have emerged as potent photocatalysts for CO 2 conversion. Yet, akin to g-C 3 N 4 and its derivatives, most polymeric photocatalysts exhibit insolubility in organic solvents, posing a formidable challenge in achieving functional composites through solution processes .…”

Synthesis of borocarbonitride nanosheets from biomass for enhanced charge separation and hydrogen production

“…Recent years have seen the intentional design of conjugated polymers 12 , including covalent organic frameworks (COFs) 13 – 17 , conjugated triazine frameworks (CTFs) 18 – 22 , polymeric carbon nitrides (PCN) 23 – 30 , conjugated microporous polymers (CMPs) 31 – 34 , and BCN-based polymers 35 – 40 , as promising metal-free photocatalysts due to their semiconductive, electrochemical, and optical properties. Among these, BCN has emerged as a highly promising candidate, distinguished by its unique electronic and structural properties that facilitate both CO 2 fixation and water-splitting reactions 41 .…”

Leveraging phenazine and dihydrophenazine redox dynamics in conjugated microporous polymers for high-efficiency overall photosynthesis of hydrogen peroxide

“… 5 To address these limitations, research has ventured into incorporating diverse functional groups into CMPs, such as triazines, thiophenes, and furans, aiming to enhance photocatalytic performances of CMPs. 6 Unfortunately, CMP-based photocatalysts still tend to underperform when compared to other polymer photocatalysts such as resorcinol–formaldehyde resins, covalent organic frameworks, and g-C 3 N 4 derivatives. 7 Thus, enhancing the photocatalytic efficiency of CMPs through molecular engineering, particularly by introducing innovative redox-active groups that can improve charge transfer and lower the energy threshold for H 2 O 2 production, is highly desirable.…”