Enhanced hydrogen evolution reaction catalyzed by carbon‐rich Mo 4.8 Si 3 C 0.6 /C/SiC nanocomposites via a PDC approach

In this study, mesoporous carbon‐rich Mo 4.8 Si 3 C 0.6 /C/SiC ceramic nanocomposites were successfully prepared via a single‐source precursor route, starting from allylhydridopolycarbosilane (AHPCS, SMP‐10), bis(acetylacetonato) dioxomolybdenum (VI) [MoO 2 (acac) 2 ], and divinylbenzene (DVB). Besides, polystyrene (PS) was used as a pore former. The obtained carbon‐rich single‐source precursor/PS mixtures were pyrolyzed at 1100°C, and then annealed at 1350°C‐1600°C to fabricate a series of carbon‐rich Mo 4.8 Si 3 C 0.6 /C/SiC ceramics comprised of high carbon content above 50 wt%. In comparison to the carbon‐poor materials, the carbon‐rich samples retain the higher specific surface area up to 214.6‐304 m 2 /g at higher annealing temperatures (1350°C‐1600°C) due to the enhancement of carbothermal reaction. The carbon‐rich samples synthesized at 1500°C, denoted as SM/Mo/PS/DVB 2‐1‐4‐2 1500 exhibit enhanced electrocatalytic performance with ultra‐low overpotentials of 119 mV vs reversible hydrogen electrode at a current density of 10 mA cm −2 in acidic media, which is superior to that of the Mo 4.8 Si 3 C 0.6 /C/SiC ceramic (138 mV) with lower carbon content reported in our previous study. Therefore, our porous materials comprised of high carbon content and Nowotny phase (Mo 4.8 Si 3 C 0.6 , NP) are considered as promising catalysts for the hydrogen evolution reaction (HER).