In-situ crystalline infiltrated Mo2C@C for efficient hydrogen evolution reaction. (13th November 2020) - Mei, Dexin
Abstract: Molybdenum carbide (Mo2 C) is a promising electrocatalyst for hydrogen evolution reaction (HER) due to the similar electron orbital structure to platinum. Preparing Mo2 C catalyst in nanoscale increases the exposure of active catalyst site and significantly enhances electrochemical reaction and improve HER performance. However, Mo2 C is not a good electron conductor which still requires a more sufficient contact between the catalyst and electrode to transfer electron current. Here, we proposed in-situ Mo2 C growth on carbon nanotubes (CNTs) by using wet impregnation of ammonium molybdate tetrahydrate as Mo source, which established a crystalline transition contact between Mo2 C and CNTs and significantly improved HER performance. Our results further showed the optimized HER performance of Mo2 C@Camt and achieved a lower Tafel slopes and low onset potential ( η onset ) of 46.7 mV dec −1, 51.3 mV dec −1 and 73 mV and 127 mV (vs. RHE) under alkaline and acidic condition, respectively. Furthermore, Mo2 C@Camt also shows less attenuation after 1000 times of cyclic voltammograms (CV) cycling stability test and 25 h continuous operation under alkaline and acidic condition. Graphical abstract: Image 1 Highlights: The HER properties of samples synthesized with different Mo sources were discussed. A special in-situ cementite on CNTs has larger SSA and more exposed active sites. The 3D network Mo2 C@Camt synthesized by modified wet impregnation method. The Mo2 C@Camt exhibits higher HER property and stability in 1 M KOH and 0.5 M H2 SO4 .