A newly designed porous oxynitride photoanode with enhanced charge carrier mobility

作者：Mao, Liang; Cai, Xiaoyan; Gao, Hong; Diao, Xungang; Zhang, Junying^*

来源：Nano Energy, 2017, 39: 172-182.

DOI：10.1016/j.nanoen.2017.06.026

• Oxynitride
• Solid solution
• Photoanode
• Porous
• Charge mobility

Visible-light-driven (oxy)nitride photoanode materials have received extensive attention for photoelectrocatalytic (PEC) water splitting due to the unique photoelectric properties. However, developing efficient and earth-abundant (oxy) nitrides with favorable band edge alignments and high charge carrier mobility remains a great challenge. In this study, a practical strategy is proposed to fine-tune the energy band structure of a newly designed porous oxynitride by forming a series of solid solutions between two perovskite-type materials. Taking advantage of the Na/La and O/N compensated substitution in LaTiO2N, the Na0.5xLa1-0.5xTiO2+xN1-x (x = 0-0.3) solid solutions exhibited a constant small band gap of ca. 2.0 eV (corresponding to a ca. 620 nm absorption edge), while the positively shifted valence band potential improved the water oxidation activity. Among various oxynitride photoanodes, Co3O4/Na0.1La0.9TiO2.2N0.8 photoanode exhibited the largest photocurrent density of 4.02 mA/cm(2) at 1.23 V vs. RHE under AM 1.5 G solar irradiation (100 mW/cm(2)). First-principle calculations and photoelectrochemical measurements separately provided theoretical and experimental evidences for the efficient charge transfer from the bulk of the solid solution photoanodes to the surface, resulting from the enhanced charge carrier mobility.

• 出版日期2017-9
• 单位北京航空航天大学