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Experimental Identification of Ultrafast Reverse Hole Transfer at the Interface of the Photoexcited Methanol/Graphitic Carbon Nitride System
Author(s) -
Chen Zongwei,
Zhang Qun,
Luo Yi
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201713102
Subject(s) - photoexcitation , femtosecond , picosecond , ultrafast laser spectroscopy , graphitic carbon nitride , substrate (aquarium) , chemical physics , chemistry , carbon nitride , ultrashort pulse , absorption (acoustics) , photochemistry , methanol , electron transfer , carbon fibers , materials science , analytical chemistry (journal) , spectroscopy , atomic physics , optics , photocatalysis , physics , catalysis , organic chemistry , laser , oceanography , quantum mechanics , composite material , excited state , geology , composite number
An experimental scrutiny of the photoexcited hole dynamics in a prototypical system is presented in which hole‐scavenging methanol molecules are chemisorbed on a graphitic carbon nitride (g‐C 3 N 4 ) substrate. A set of comparison and control experiments by means of femtosecond time‐resolved transient absorption (fs‐TA) spectroscopy were conducted. The elusive reverse hole transfer (RHT) process was identified, which occurs on a timescale of a few hundred picoseconds. The critical role of interfacially chemisorbed methoxy (instead of methanol) as the dominant species responsible for hole scavenging was confirmed by a control experiment using protonated g‐C 3 N 4 as the substrate. A hot‐hole transfer effect was revealed by implementing different interband photoexcitation scenarios. The RHT rate is the key factor governing the hole‐scavenging ability of different hole scavengers.