Preparation of Few-Layer Graphene/Carbon Nanotube Hybrids Using Oxide Spinel Catalysts

• Type: Article in International Scientific Journal
• Date: 2019

Authors

Bruno F. Machado (Author) FEUP; Revathi R. Bacsa (Author) Other; Camila Rivera-Cárcamo (Author) Other; Philippe Serp (Author) Other

Journal

The Journal is awaiting validation by the Administrative Services.

Title: C-JOURNAL OF CARBON RESEARCH

Vol. 5 No. 2

Pages: 1-10

ISSN: 2311-5629

Indexing

ISI Web of Knowledge - 0 Citations

Other information

Authenticus ID: P-00Q-HGE

DOI: 10.3390/c5020028

Abstract (EN): Functional 3D materials can be developed from graphene-based hybrids by introducing other nanomaterials, with multi-walled carbon nanotubes (CNTs) being the most studied additive. For large-scale applications, few-layer graphene (FLG)-CNT hybrids are produced by catalytic chemical vapor deposition (c-CVD) starting from a mixture of catalysts (one for FLG and one for CNTs) in the required proportions. Due to the difference in growth kinetics between CNTs and FLG, the composition of such hybrids is not well controlled. In this study, we report the single-step preparation of FLG-CNT hybrid materials by a fixed-bed c-CVD process using a single catalyst with the formula AlxCo1-xFe2O4 (x = 0.025-0.10). Different catalysts (with varying x) were prepared by the citrate-nitrate gel combustion method. Then, c-CVD synthesis was carried out at 650 degrees C in a horizontal fixed-bed reactor using ethylene as the carbon source. Only FLG was obtained when using CoFe2O4. However, the introduction of small amounts of Al (x < 0.05) induced the simultaneous production of CNTs, leading to the formation of uniform FLG-CNT hybrids. For catalysts with higher Al content (e.g., AlCoFeO4), CNTs were selectively produced. Thus, we observed the existence of a narrow Al-doping window, where CNTs and FLG can be obtained simultaneously. Our results can pave the way to developing high-yield single catalyst-based CVD synthesis of FLG-CNT hybrid materials.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10