The replacement of platinum with non-precious-metal electrocatalysts with high efficiency and superior stability for the hydrogen-evolution reaction (HER) remains a great challenge. Herein, we report the one-step synthesis of uniform, ultrafine molybdenum carbide (Mo2C) nanoparticles (NPs) within a carbon matrix from inexpensive starting materials (dicyanamide and ammonium molybdate). The optimized catalyst consisting of Mo2C NPs with sizes lower than 3 nm encapsulated by ultrathin graphene shells (ca. 1-3 layers) showed superior HER activity in acidic media, with a very low onset potential of -6 mV, a small Tafel slope of 41 mV dec(-1), and a large exchange current density of 0.179 mA cm(-2), as well as good stability during operation for 12 h. These excellent properties are similar to those of state-of-the-art 20% Pt/C and make the catalyst one of the most active acid-stable electrocatalysts ever reported for HER.

Phosphorus (P) /sulfur (S) co-doped porous carbon derived from resorcinol and furaldehyde are synthesized through one-step sol-gel processing with the addition of phosphorus pentasulfide as P and S source followed with freeze-drying and pyrolysis in nitrogen. The P/S co-doping strategy facilitates the pore size widening both in micropore and mesopore regions, together with the positive effect on the degree of graphitization of porous carbon through elimination of amorphous carbon through the formation and evaporation of carbon disulfide. As an electrode for supercapacitor application, P/S co-doped porous carbon demonstrates 43.5% improvement on specific capacitance of the single electrode compared to pristine porous carbon in organic electrolyte at a current of 0.5 mA due to the P-induced pseudocapacitive reactions. As for electrocatalytic use, promoted electrocatalytic activity and high resistance to crossover effects of oxygen reduction reaction (ORR) in alkaline media are observed after the introduction of P and S into porous carbon. After air activation, the specific capacitance of the single electrode of sample PS-pC reaches up to 103.5 F g-1 and an improved oxygen reduction current density.

The lack of efficient electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) has been a fatal issue for the development of metal-air batteries in large-scale commercialization. In this paper, spinel CoFe 2 O 4 (CFO) nanoparticles were successfully in situ grown onto rod-like ordered mesoporous carbon (RC) by a facile, scalable hydrothermal method, followed by annealing at different temperatures. The as-acquired CFO/RC nanohybrid pyrolyzed at 400 C (CFO/RC-400) has a high specific surface area (150.3 m 2 g À1 ) and two sets of uniform mesopore systems (3.38 and 19.1 nm), all of which are favorable for the improvement of the electrocatalytic activity. The hybridization of CFO nanoparticles and the RC matrix results in increased ORR and OER electrocatalytic activity of the CFO/ RC nanohybrids, which is significantly superior to that of unsupported CFO nanoparticles and pure RC.CFO/RC-400 shows better catalytic activity for the ORR with a direct four-electron reaction pathway than those prepared at other temperatures in terms of the onset potential and limiting current density.Furthermore, the CFO/RC-400 nanohybrid exhibits outstanding durability for both the ORR and OER, and can outperform commercial Pt/C. The excellent bifunctional electrocatalytic activities of the CFO/ RC nanohybrids are mainly owing to the hierarchical mesoporous structures of the nanohybrids and strong coupling between the CFO nanoparticles and the RC matrix.