MOF-Derived Mesoporous g-C 3 N 4 /TiO 2 Heterojunction with Enhanced Photocatalytic Activity
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MOF‑Derived Mesoporous g‑C3N4/TiO2 Heterojunction with Enhanced Photocatalytic Activity Congcong Wei1 · Wei Zhang1 · Xinpeng Wang1 · Aihong Li1 · Jianping Guo2 · Bo Liu1 Received: 10 July 2020 / Accepted: 11 November 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Here, g-C3N4/TiO2 photocatalysts with mesoporous structure and intimate interfacial connection were synthesized via the facile pyrolysis of g-C3N4/MIL-125 composites. The photocatalytic H 2 evolution reaction was performed to examine the photocatalytic activity of obtained photocatalysts. Under the UV–vis light irradiation, the average H 2 evolution rate of g-C3N4/TiO2 sample with optimal g-C3N4 loading content (4.12wt%) was most increased by up to 0.606 mmol·g−1·h−1, a value which transcended that of as-prepared g-C3N4 (0.138 mmol·g−1·h−1) and mesoporous T iO2 (0.244 mmol·g−1·h−1) by a factor of 4.41 and 2.48, respectively. The improvement in photocatalytic activity of g-C 3N4/TiO2 composites was explained by the synergistic effect between large specific surface area, decreased energy band gap and intimate interface contact. This study demonstrated a new approach for the preparation of binary mesoporous heterojunction photocatalysts. Graphical Abstract
Keywords Titanium dioxide · Graphitic carbon nitride · Heterojunction · Mesoporous structure · Photocatalysis
* Jianping Guo [email protected] * Bo Liu [email protected] Extended author information available on the last page of the article
1 Introduction Nowadays, hydrogen as clean energy source has been paid more and more attention by researchers from all over the world as the aggravation of fossil fuels depletion and
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ecological pollution [1, 2]. Recently, photocatalytic water splitting has been considered a potentially renewable way to realize the environmental and economical production of hydrogen, and this approach can be implemented using photocatalysts [2]. Among all the photocatalysts, TiO2 was one of the most extensively studied material for its low–cost, non-toxic, and outstanding catalytic properties [3]. Nevertheless, the inherent limitations of TiO2 for photocatalytic hydrogen evolution embodying in low specific surface area, high overpotential and high photo–induced electron–hole pairs recombination rate, are the chronic bottlenecks for application in photocatalytic hydrogen evolution [4, 5]. For the moment, various effective strategies have been dedicated to overcome these bottlenecks, including element–doping, semiconductor coupling, noble metal depositing, etc. [6–8]. Among them, coupling TiO2 with narrow band gap semiconductors has been a dramatically feasible method to expand the optical response range and form heterojunction which can efficiently stimulate the separation of photo–generated carriers. Especially, recent studies show that the metal free g-C3N4 semiconductor has been regarded as an ideal candidate to integrate with T iO2, which exhibits excellent thermal and chemical stability profiting from
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