Improvement of photocatalytic hydrogen evolution of La5Ti2AgS5O7by flash sintering method.

Impact Factor:

3.791

DOI number:

10.1063/5.0060840

Journal:

Appl. Phys. Lett.

Key Words:

Crystallinity, Density functional theory, Electric fields, Hydrogen, Lanthanum compounds, Light absorption, Photocatalytic activity, Sintering, Solid state reactions, Sulfur, Titanium compounds, Built-in electric fields, Charge separations, Electronic band structure, Photocatalytic H2 evolution, Photocatalytic hydrogen evolution, Preparation process, Small particle size, Visible light absorption, Silver compounds

Abstract:

La5Ti2AgS5O7 (LTA) is a long-wavelength-responsive oxysulfide photocatalyst that exhibits considerable photocatalytic H-2 evolution activity with an intense visible light absorption up to 570 nm. However, suppression of oxide impurities and sulfur defects when preparing LTA remains a big challenge. In this study, LTA was prepared by using a flash sintering (FS) method that allows for the synthesis of LTA (LTA-FS) with a significantly short heating period (a few seconds). The approach allowed a formation of high degree crystallinity with relatively small particle sizes without adding excessive sulfur that was employed in conventional solid-state reactions during the preparation process. Moreover, well-defined sulfur defects on the surface of LTA-FS were favorable for constructing the self-organized homojunction between the bulk and surface phases with a local built-in electric field, which is beneficial for charge separation and transfer, thus improving H-2 evolution activity. The corresponding structure-to-performance relationship was further investigated by combining with the density functional theory of the electronic band structures and charge densities. This work suggests that FS may be very useful for the preparation of oxysulfide photocatalysts.

Co-author:

Xue Wang, Jiawei Xue, Yong Jiang, Yuxue Wei, Qin Cheng, Jingshuai Chen

First Author:

Mengdie Cai

Correspondence Author:

Song Sun

Document Type:

SCI

Volume:

119

Issue:

7

Page Number:

071903

Translation or Not:

no

Date of Publication:

2021-08-18

Links to published journals:

https://aip.scitation.org/doi/abs/10.1063/5.0060840