Premium
Noble Metal Free, Visible Light Driven Photocatalysis Using TiO 2 Nanotube Arrays Sensitized by P‐Doped C 3 N 4 Quantum Dots
Author(s) -
Kumar Pawan,
Kar Piyush,
Manuel Ajay P.,
Zeng Sheng,
Thakur Ujwal K.,
Alam Kazi M.,
Zhang Yun,
Kisslinger Ryan,
Cui Kai,
Bernard Guy M.,
Michaelis Vladimir K.,
Shankar Karthik
Publication year - 2020
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201901275
Subject(s) - materials science , photocatalysis , anatase , visible spectrum , rutile , water splitting , band gap , nanotube , photocurrent , nanotechnology , heterojunction , doping , nanoparticle , carbon nanotube , chemical engineering , optoelectronics , catalysis , biochemistry , chemistry , engineering
Abstract Bulk g‐C 3 N 4 is an earth‐abundant, easily synthesizable, and exceptionally stable photocatalyst with an electronic bandgap of 2.7 eV. Herein, the concepts of P‐doping and size quantization are combined to synthesize highly fluorescent P‐doped carbon nitride quantum dots (CNPQDs) with a bandgap of 2.1 eV. CNPQDs are hosted on anatase‐phase and rutile‐phase TiO 2 nanotube array scaffolds, and examined as photoanodes for sunlight‐driven water‐splitting and as photocatalysts for surface catalytic reactions. Square‐shaped rutile phase TiO 2 nanotube arrays (STNAs) decorated with CNPQDs (CNPQD‐STNA) generate 2.54 mA cm −2 photocurrent under AM1.5 G simulated sunlight. A champion hydrogen evolution rate of 22 µmol h −1 corresponds to a Faradaic efficiency of 93.2%. In conjunction with Ag nanoparticles (NPs), the CNPQD‐STNA hybrid is also found to be an excellent plexcitonic photocatalyst for the visible light‐driven transformation of 4‐nitrobenzenethiol (4‐NBT) to dimercaptoazobenzene (DMAB), producing reaction completion at a laser power of 1 mW (532 nm) while Ag NP/TNA and Ag NP/STNA photocatalysts cannot complete this transformation even at 10 mW laser power. The results point the way forward for photochemically robust, noble metal free, visible light harvesting photoacatalysts based on nanostructured heterojunctions of graphenic frameworks with TiO 2 .