Hybrids of Two-Dimensional Ti₃C₂ and TiO₂ Exposing {001} Facets toward Enhanced Photocatalytic Activity

TLDR

Effective light harvesting to generate long‑lived charge carriers and suppress electron–hole recombination, together with exposing highly active facets, is crucial for high‑performance photocatalysts. The study synthesizes a hybrid of TiO₂ {001} nanosheets and layered Ti₃C₂ via facile hydrothermal partial oxidation. TiO₂ nanosheets are in situ grown on Ti₃C₂, forming an interface with minimized defects confirmed by TEM and DFT calculations. The TiO₂ {001} facets efficiently generate electron–hole pairs, and the interfacial Schottky junction with Ti₃C₂ enhances hole trapping and charge separation, markedly improving photocatalytic degradation of methyl orange dye.

Abstract

Effectively harvesting light to generate long-lived charge carriers to suppress the recombination of electrons and holes is crucial for photocatalytic reactions. Exposing the highly active facets has been regarded as a powerful approach to high-performance photocatalysts. Herein, a hybrid comprised of {001} facets of TiO2 nanosheets and layered Ti3C2, an emerging 2D material, was synthesized by a facile hydrothermal partial oxidation of Ti3C2. The in situ growth of TiO2 nanosheets on Ti3C2 allows for the interface with minimized defects, which was demonstrated by high-resolution transmission electron microscopy and density functional theory calculations. The highly active {001} facets of TiO2 afford high-efficiency photogeneration of electron–hole pairs, meanwhile the carrier separation is substantially promoted by the hole trapping effect by the interfacial Schottky junction with 2D Ti3C2 acting as a reservoir of holes. The improved charge separation and exposed active facets dramatically boost the photocatalytic degradation of methyl orange dye, showing the promise of 2D transition metal carbide for fabricating functional catalytic materials.