MXene-Derived 3D Defect-Rich TiO2@Reduced Graphene Oxide Aerogel with Ultrafast Carrier Separation for Photo-Assisted Uranium Extraction: A Combined Batch, X-ray Absorption Spectroscopy, and Density Functional Theory Calculations

Tao Chen; Pan He; Tong Liu; Li Zhou; Mingxin Li; Kaifu Yu; Qi Meng; Jie Lian; Wenkun Zhu

doi:10.1021/acs.inorgchem.2c01850

MXene-Derived 3D Defect-Rich TiO₂@Reduced Graphene Oxide Aerogel with Ultrafast Carrier Separation for Photo-Assisted Uranium Extraction: A Combined Batch, X-ray Absorption Spectroscopy, and Density Functional Theory Calculations

Inorg Chem. 2022 Aug 15;61(32):12759-12771. doi: 10.1021/acs.inorgchem.2c01850. Epub 2022 Aug 1.

Authors

Tao Chen^{1

2}, Pan He¹, Tong Liu², Li Zhou¹, Mingxin Li¹, Kaifu Yu¹, Qi Meng¹, Jie Lian¹, Wenkun Zhu¹

Affiliations

¹ State Key Laboratory of Environmentally Friendly Energy Materials, National Collaborative Innovation Center for Nuclear Waste and Environmental Safety, School of National Defence, Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory, Sichuan Civil-military Integration Institute, Southwest University of Science and Technology, Mianyang 621010, China.
² National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China.

PMID: 35914187
DOI: 10.1021/acs.inorgchem.2c01850

Abstract

Encapsulation of nano-semiconductor materials in three-dimensional (3D) adsorbents to build a typical semiconductor-adsorbent heterostructure is a forward-looking strategy for photo-assisted uranium extraction. Here, we develop 3D MXene-derived TiO₂(M)@reduced graphene oxide (RGO) aerogel for photo-assisted uranium extraction. Theoretical simulations demonstrate that oxygen vacancies on TiO₂(M) tailor the energy level structure and enhance the electron accumulation at gap states of TiO₂(M), thereby further realizing the spatial separation efficiency of electron-hole pairs by the Schottky junction. By virtue of the in situ X-ray photoelectron spectroscopy spectrum, we identify that photogenerated electrons generated over TiO₂(M) were transferred to graphene oxide aerogel by the Schottky junction. Accordingly, TiO₂ (M)@RGO aerogel presents a considerable removal efficiency for U(VI) with a removal ratio of 95.7%. Relying on the X-ray absorption spectroscopy technique, we distinguish the evolution of 2H₂O-2O_ax-U-5O_eq into H₂O-2O_ax-U-3O_eq from dark to light conditions, further confirming the reduction of high-valent uranium. This strategy may open a paradigm for developing novel heterojunctions as photocatalysts for selective U(VI) extraction.