Carbonization of a Molybdenum Substrate Surface and Nanoparticles by a One-Step Method of Femtosecond Laser Ablation in a Hexane Solution

Yoshiki Tanaka; Xi Yu; Shusaku Terakawa; Takafumi Ishida; Koh Saitoh; Hongwei Zhang; Toru Asaka; Fumihiro Itoigawa; Makoto Kuwahara; Shingo Ono

doi:10.1021/acsomega.2c07697

Carbonization of a Molybdenum Substrate Surface and Nanoparticles by a One-Step Method of Femtosecond Laser Ablation in a Hexane Solution

ACS Omega. 2023 Feb 13;8(8):7932-7939. doi: 10.1021/acsomega.2c07697. eCollection 2023 Feb 28.

Authors

Yoshiki Tanaka¹, Xi Yu², Shusaku Terakawa¹, Takafumi Ishida^{2

3}, Koh Saitoh^{2

3}, Hongwei Zhang⁴, Toru Asaka⁵, Fumihiro Itoigawa⁶, Makoto Kuwahara³, Shingo Ono¹

Affiliations

¹ Department of Physical Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
² Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8601, Japan.
³ Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan.
⁴ Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610042, China.
⁵ Life Science and Applied Chemistry Advanced Ceramics, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
⁶ Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.

Abstract

Molybdenum carbides (MoC and Mo₂C) are being reported for various applications, for example, catalysts for sustainable energies, nonlinear materials for laser applications, protective coatings for improving tribological performance, and so on. A one-step method for simultaneously fabricating molybdenum monocarbide (MoC) nanoparticles (NPs) and MoC surfaces with a laser-induced periodic surface structure (LIPSS) was developed by using pulsed laser ablation of a molybdenum (Mo) substrate in hexane. Spherical NPs with an average diameter of 61 nm were observed by scanning electron microscopy. The X-ray diffraction pattern and electron diffraction (ED) pattern results indicate that a face-centered cubic MoC was successfully synthesized for the NPs and on the laser-irradiated area. Notably, the ED pattern suggests that the observed NPs are nanosized single crystals, and a carbon shell was observed on the surface of MoC NPs. The X-ray diffraction pattern of both MoC NPs and LIPSS surface indicates the formation of FCC MoC, agreeing with the results of ED. The results of X-ray photoelectron spectroscopy also showed the bonding energy attributed to Mo-C, and the sp²-sp³ transition was confirmed on the LIPSS surface. The results of Raman spectroscopy have also supported the formation of MoC and amorphous carbon structures. This simple synthesis method for MoC may provide new possibilities for preparing Mo _x C-based devices and nanomaterials, which may contribute to the development of catalytic, photonic, and tribological fields.