Nowotny phase Mo3+2xSi3C0.6 dispersed in a porous SiC/C matrix: A novel catalyst for hydrogen evolution reaction

• Published in: Journal of the American Ceramic Society 2020-01, Vol.103 (1), p.508-519
• Main Authors: Feng, Yao, Yu, Zhaoju, Schuch, Jona, Tao, Shasha, Wiehl, Leonore, Fasel, Claudia, Jaegermann, Wolfram, Riedel, Ralf
• Format: Article
• Language: English
• Subjects: ceramic nanocomposites; Controlled atmospheres; Electrocatalysts; electrocatalytic activity; Heat treatment; hydrogen evolution reaction; Hydrogen evolution reactions; Molybdenum oxides; Nanocomposites; Nowotny phase; Polystyrene resins; Porosity; Porous media; Precursors; single‐source‐precursor; Ternary systems; Water splitting
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/jace.16731

The ternary Nowotny phase (NP), with a composition Mo3+2xSi3C0.6 (x = 0.9‐0.764), is found to be catalytically active in the field of electrochemical water splitting. The NP embedded in a porous SiC/C nanocomposite matrix is synthesized via a single‐source‐precursor approach which involves the reaction of allylhydridopolycarbosilane with MoO2(acac)2. Thermal treatment of the single‐source‐precursor up to 1400°C in a protective atmosphere results in the in situ formation of nanocrystalline Mo3+2xSi3C0.6 immobilized in a thermally and corrosion‐stable SiC/C matrix. The weight fractions of the observed crystalline phases Mo3+2xSi3C0.6 and SiC amount to ca. 28 (26) and 72 (74) wt%, respectively, when prepared at 1400°C (1350°C). The porosity of the formed nanocomposite is adjusted by the addition of polystyrene (PS) as a pore former to the single‐source‐precursor resulting in a specific surface area up to 206 m2/g. The electrocatalytic activity of the Mo3+2xSi3C0.6/C/SiC nanocomposite with respect to the hydrogen evolution reaction (HER) is characterized by low over potentials of 22 and 138 mV vs reversible hydrogen electrode (RHE) for applying 1 and 10 mA cm−2 of current density, respectively. The analyzed electrocatalytic performance exceeds that of most Mo‐based electrocatalysts and shows high stability (over 90%) during 35 hours. The Nowotny phase Mo Si C (x = 0.9‐0.764) was found to be catalytically active in electrochemical water splitting. The electrocatalytic activity of the Mo Si C /C/SiC nanocomposite with respect to the hydrogen evolution reaction was characterized by low overpotentials of 22 and 138 mV vs reversible hydrogen electrode for applying 1 and 10 m A cm of current density, respectively, which exceeds that of most Mo‐based electrocatalysts and shows a high stability (over 90 %) during 35 h.