Enhanced visible light photocatalytic activity of Cu₂O via cationic–anionic passivated codoping

Abstract

To improve the photocatalytic activity of Cu2O for hydrogen production through water splitting, the band edges of Cu2O should be modified to meet the electronic transition of angular momentum selection rules (Δl = ±1) and match with the hydrogen or oxygen production levels. Upon analyzing the band structure of Cu2O and the chemical potentials of the dopants, we show that passivated codopants such as (Sn + B) can induce superior modification in the band edges of Cu2O: the conduction band edge is changed from the d band character of Cu atoms to the p band character of the Sn atom and shifted slightly downwards, while the valence band edge keeps the d band character of the Cu atoms and energy unchanged, indicating that the stringent requirements get satisfied. Moreover, the optical absorption spectrum of (Sn + B) codoped Cu2O shows a greatly improved absorption of visible light. The calculated defect formation energy shows that the codoping is energetically more favorable than mono-doping due to the Coulomb interactions and charge compensation effects.

Understanding the synergistic effects, optical and electronic properties of ternary Fe/C/S‐doped TiO2 anatase within the DFT + U approach

“…The stability of co‐ and ternary‐doped systems is investigated by calculating their defect binding energies according to Equations : where , , and represent the total energy of Fe/C/S ternary‐doped TiO 2 , C/S co‐doped TiO 2 , un‐doped TiO 2 , C, S, and Fe mono‐doped TiO 2 , respectively. Positive defect binding energy signifies strong tendency for the impure atoms to bind to each other …”

Hybrid Density Functional Study on Mono‐ and Codoped NaNbO3 for Visible‐Light Photocatalysis

“…[49][50][51][52][53][54][55] Such ac odopinga pproachi sa lso effective to enhance the visible-light photocatalytic activity of Cu 2 Ob y changing the even-parity symmetry of the CBM to odd-parity symmetry to meet the angular selection rule of electronic transitions. [56] Erünale tal. investigated the interplay between aliovalent CuO doping and nonstoichiometry on the development of defect structuresa nd the formation of secondary phases of antiferroelectric NaNbO 3 ceramics.…”

Investigation of visible‐light absorption in Cu2O/TiO2 heterojunctions with an interstitial at the interface

“…We first built 2 × 1 × 2 supercells ( a = 9.188 Å, b = 4.594 Å, c = 5.918 Å) as an initial structure model of a defect‐free TiO 2 layer through a primitive cell of rutile TiO 2 ( a = b = 4.594 Å, c = 2.959 Å), as Fig. a shows . Then, other 2 × 1 × 2 supercells of defect‐free Cu 2 O layer ( a = 8.5392 Å, b = 4.2696 Å, c = 8.5392 Å) were built on a primitive cell of Cu 2 O ( a = b = c = 4.2696 Å), as Fig.…”

“…Robert and coworkers investigated the impact of different amounts of Cu 2 O on the photocatalytic activity of Cu x O/TiO 2 heterojunctions and found the high efficiency for photodecomposition of Orange II . About the visible‐light photocatalytic activity of Cu 2 O, Jiang et al concluded that it could be enhanced by changing the odd–even property of the conduction‐band edge of Cu 2 O via Sn + B passivated codoping. Following these studies, we here carry out first‐principles calculations to investigate the impact of dopants at the interface of Cu x O/TiO 2 heterojunctions on the visible‐light absorption.…”