DFT calculations for single-atom confinement effects of noble metals on monolayer g-C3N4 for photocatalytic applications

• Published in: RSC advances Vol. 11; no. 7; pp. 4276 - 4285
• Main Authors: Cheng, Yang, Zong-Yan, Zhao, Hai-Tang, Wei, Xi-Yu, Deng, Qing-Ju, Liu
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 29.01.2021; The Royal Society of Chemistry
• Subjects: Carbon nitride; Catalytic activity; Charge transport; Chemistry; Conduction bands; Confinement; Electronic structure; Mathematical analysis; Monolayers; Noble metals; Photocatalysis; Synergistic effect
• ISSN: 2046-2069
• DOI: 10.1039/d0ra09815a

Graphitic carbon nitride, as a very promising two-dimensional structure host for single atom catalysts (SACs), has been studied extensively due to its significant confinement effects of single atoms for photocatalytic applications. In this work, a systematic investigation of g-C3N4 confining noble metal single atoms (NM1@g-C3N4) will be performed by using DFT calculations. The geometric structure calculations indicate that the most favorable anchored sites for the NM1 is located in the six-fold cavity, and the deformed wrinkle space of g-C3N4 helps the NM1 to be stabilized in the six-fold cavity. The electronic structure calculations show that the conduction band of NM1@g-C3N4 moved down and crossed through the Fermi level, resulting in narrowing the band gap of the NM1@g-C3N4. Moreover, the confined NM1 provide a new channel of charge transport between adjacent heptazine units, resulting in a longer lifetime of photo-generated carriers except Ru, Rh, Os and Ir atoms. Furthermore, the d-band centres of NM1 in NM1@g-C3N4 show that Rh1@, Pd1@, Ir1@ and Pt1@g-C3N4 SACs may have better photocatalytic performance than other NM1@g-C3N4 SACs. Finally, Pt1@g-C3N4 SACs are considered to have higher photocatalytic activity than other NM1@g-C3N4 SACs. These results demonstrate that the confinement effects of noble metals on monolayer g-C3N4 not only makes the single atom more stable to be anchored on g-C3N4, but also enhances the photocatalytic activity of the system through the synergistic effect between the confined NM1 and the monolayer g-C3N4. These detailed research may provide theoretical support for engineers to prepare photocatalysts with higher activity.