Hybrid Photocatalyst for Hydrogen Production: The Effect of Fluorine on Optoelectronic Properties of Conjugated Porous Polymers

Abstract

Phenanthrenequinone (PhQ) based Conjugated Porous Polymers (CPPs) are synthetized without and with the presence of fluorine atoms in the trisubstituted core benzene unit (CPP‐FPA and CPP‐PA). Furthermore, organic‐inorganic hybrid heterojunctions based on these CPPs and TiO2 as inorganic semiconductor are prepared (CPP‐FPA@T‐10 and CPP‐PA@T‐10, with the polymer loading ≈10 wt.%). The photonic efficiency for H2 photoproduction is 33% higher when the CPP has fluorine atoms. This enhancement is even higher in presence of 1 wt.% platinum as co‐catalyst. Thus, the Pt/CPP‐FPA@T‐10 hybrid (≈31.7 mmol g–1 h–1 and 11.7% of photonic efficiency) presents H2 production nearly twice than that of the nonfluorinated hybrid Pt/CPP‐PA@T‐10 (≈16.6 mmol g–1 h–1 and 6.1% of photonic efficiency) and 3.5‐times higher than that of the Pt/TiO2 (≈8.9 mmol g–1 h–1 and 3.29% of photonic efficiency) photocatalyst. Charge dynamics studies show that both hybrid heterojunctions exhibit a direct Z‐scheme charge transfer mechanism, and the presence of fluorine atoms in the CPP structure leads to an increasing charge separation lifetime which is in accordance with the better performance in H2 production. These findings on fluorine doping provide essential clues for the design of structure electronic engineered CPPs for energy conversion and storage technologies.

A covalent organic framework based on BOPHY/TiO2 hybrid photocatalysts for solar driven hydrogen production

“…7A). 54,55 Since methanol is a very efficient hole scavenger, 56–58 the measured TiO 2 signal under our conditions ( ca. between 400 and 650 nm) can be only attributed to photoelectrons.…”

“…This loading percentage was selected considering our previous experience. 48,49,54 The percentage weight of the COF was determined by thermogravimetric analyses (Fig. S10 †).…”

Design of Stable 2D Heterostructured Photocatalyst for Drastically Improved Hydrogen Generation and Unravelling the Underlying Charge Carrier Dynamics

“…The higher value of K sv for MS ‐ mpg ‐ CN ‐ 3 as compared to that of other photocatalysts signifies the higher density of excited electrons in the conduction band and eventually an efficient electron transfer from mpg ‐ CN to MoS 2 resulting in fluorescence quenching, as shown in Table 4 and Table 5. The increase of quenching with the increase in loading of MoS 2 in MS ‐ mpg ‐ CN is attributed to the conduction band of MoS 2 being highly populated with the excited electrons arriving from the conduction band of mpg ‐ CN , implying the formation of Type II heterojunction [50,51] …”

“…The increase of quenching with the increase in loading of MoS 2 in MS-mpg-CN is attributed to the conduction band of MoS 2 being highly populated with the excited electrons arriving from the conduction band of mpg-CN, implying the formation of Type II heterojunction. [50,51] MottÀ Schottky (MS) analysis was performed to examine the electrocatalysis at the electrode/electrolyte interface in alkaline media (0.1 M Na 2 SO 4 ). The given information was gathered using impedance spectroscopy performed at a frequency of [a] The quencher consists of either the electron acceptor 2,4-dinitrotoluene (DNT) or electron donor triethanolamine (TEOA) as an indicator.…”

Thienoacene‐Based Conjugated Porous Polymer/TiO2 Hybrids as Photocatalysts in Artificial Photosynthesis

“…The amount of polymer loading was selected considering previous results obtained with other polymer families. [6][7][8][9] The morphology of the hybrids consists in a core of polymer surrounded by TiO 2 nanocrystals (7.5 nm of particle size [21] ). Figure 2 depicts the FESEM images of one of the hybrids and the homogeneous distribution of both components in the composite is confirmed by its EDS images (Figure S18, Supporting Information).…”