Abstract
Since hydrogen fuel involves the highest energy density among all fuels, production of this gas through the solar water splitting approach has been suggested as a green remedy for greenhouse environmental issues due to extensive consumption of fossil fuels. Low-dimensional materials possessing a large surface-to-volume ratio can be a promising candidate to be used for the photocatalytic approach. Here, we used extensive first-principles calculations to investigate the application of newly fabricated members of two-dimensional carbon nitrides including tg-C3N4, hg-C3N4, C2N, and C3N for water splitting. Band engineering via N-type, P-type, and isoelectronic doping agents such as B, N, P, Si, and Ge was demonstrated for tuning the electronic structure, optimizing solar absorption and band alignment for photocatalysis. Pristine tg-C3N4, hg-C3N4, and C2N crystals involve bandgaps of 3.190, 2.772, and 2.465 eV, respectively, which are not proper for water splitting. Among the dopants, Si and Ge dopants can narrow the band gap of carbon nitrides about 0.5-1.0 eV and also increase their optical absorption in the visible spectrum. This study presents the potential for doping with isoelectronic elements to greatly improve the photocatalytic characteristics of carbon nitride nanostructures.
| Original language | English |
|---|---|
| Pages (from-to) | 11143-11151 |
| Number of pages | 9 |
| Journal | ACS Applied Materials and Interfaces |
| Volume | 10 |
| Issue number | 13 |
| Early online date | 19 Mar 2018 |
| DOIs | |
| Publication status | Published - 4 Apr 2018 |
Funding
The authors gratefully acknowledge their financial support in parts by the Natural Sciences and Engineering Council of Canada (NSERC), University of Toronto, Connaught Global Challenge Award, and Hart Professorship. The computations were carried out through Compute Canada facilities, particularly SciNet and Calcul-Quebec. SciNet is funded by the Canada Foundation for Innovation, NSERC, the Government of Ontario, Fed Dev Ontario, and the University of Toronto, and we gratefully acknowledge the continued support of these supercomputing facilities.
Keywords
- band edge position
- band structure
- carbon nitride
- density functional theory
- solar absorption spectrum
- water splitting
ASJC Scopus subject areas
- General Materials Science
Access to Document
- CN_Doping_Manuscript
This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials and Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsami.8b01729.