High efficiency photocatalytic hydrogen production over ternary Cu/TiO2@Ti3C2Tx enabled by low-work-function 2D titanium carbide. (November 2018)

• Record Type: Journal Article
• Authors: Peng, Chao; Wei, Ping; Li, Xiaoyao; Liu, Yunpeng; Cao, Yonghai; Wang, Hongjuan; Yu, Hao; Peng, Feng; Zhang, Liyun; Zhang, Bingsen; Lv, Kangle
• Is Part Of: Nano energy. Volume 53(2018)
• Page Start: 97
• Page End: 107
• Publication Date: 2018-11
• Subjects: MXenes -- Titanium carbides -- Hole mediators -- Copper cocatalysts -- Photocatalytic water splitting -- Hydrogen evolution reaction; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2018.08.040
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: It is of prime importance to harness the transfer and flow of photogenerated electrons and holes to elongate the lifetimes of charge carriers and enhance the activity of semiconductor photocatalyst, which can be achieved by hybridizing the photocatalyst with appropriate cocatalysts with right electronic properties and placement. Herein, MXenes, a young family of two-dimensional transition metal carbides, are exploited as a hole mediator to enhance the photocatalytic activity of TiO2 . We grow TiO2 sheets exposing (001) surfaces on layered Ti3 C2 Tx, and then photodeposited Cu2 O nanodots on TiO2 . We experimentally prove that the Ti3 C2 Tx MXene from the wet HF etching method behaves as a low work function material ( ϕ = 3.4 eV). Thanks to this unique electronic property, the photogenerated electrons on TiO2 hybridized with Ti3 C2 Tx accumulate and tunnel to Cu2 O to reduce it to elemental Cu as a reduction cocatalyst. The resulting Cu/TiO2 @Ti3 C2 Tx photocatalyst efficiently split water to produce hydrogen at 860 μmol g −1 h −1 . The results presented here demonstrate the promise of MXene materials in photocatalytic solar energy utilization. The insight into the electronic property of MXene sheds light on the new approach to the rational design of high-efficiency photocatalysts composed of MXenes. Graphical abstract: fx1 Highlights: Cu2 O nanoparticles are photodeposited on TiO2 nanosheets hybridized with 2D Ti3 C2 . The work function of –OH terminated 2D Ti3 C2 is determined as 3.4 eV. 2D Ti3 C2 as hole mediator enables the in-situ reduction of Cu2 O to Cu as reduction cocatalyst. The Cu/TiO2 @Ti3 C2 photocatalyst is highly active for water splitting to produce hydrogen at 860 μmol g −1 h −1 .