One-pot synthesis of three-dimensional Pt nanodendrites with enhanced methanol oxidation reaction and oxygen reduction reaction activities.

The high cost of Pt-based catalysts impedes the practical large-scale commercial application of fuel cells. Controlling the morphology of Pt nanostructure is one of the most promising approaches to promote the electrocatalytical activity and stability toward methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR). Herein, we report a facile method for the synthesis of Pt nanodendrites consisting a dense array of dendrites using K2PtCl4 as metal resource, L-ascorbic acid as reducing agent and hexadecyltrimethylammonium chloride as capping agent in aqueous solution at 96 °C for 30 min. Owing to the novel structure, the obtained Pt nanodendritic electrocatalyst exhibites superior MOR catalytic performance and particularly long-term stability both in acid and alkaline conditions. the Pt nanodendrites also exhibited a higher half wave potential of 0.86 V and lower tafel slope of 51.69 mV dec-1 when compared with 20% Pt/C (0.83 V, 93.55 mV dec-1) in acid conditions toward ORR. This work provides a promising way for the rational design of efficient and robust catalysts for sustainable energy conversion.

In situ-generated NiCo@NiS nanoparticle anchored s-doped carbon nanotubes as dual electrocatalysts for oxygen reduction reaction and hydrogen evolution reaction.

Developing low cost and highly robust electrocatalysts for oxygen evolution reaction, hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR) is of great importance for the efficient conversion of sustainable energy sources. Herein, we report a facile pyrolysis strategy for the controllable synthesis of NiCo@NiS/S-CNTs with NiCo@NiS nanoparticles anchored on sulfur-doped carbon nanotubes (CNTs). The obtained NiCo@NiS/S-CNT electrocatalyst exhibits excellent dual-functional catalytic activities under an alkaline condition, an ORR performance with an onset potential of -30 mV, and a half-wave potential of -150 mV (versus Ag/AgCl) while the overpotential for the HER is -1.16 V (versus Ag/AgCl) at a current density of 10 mA cm-2. It was found that the incorporation of sulfur can regulate the electronic structure of CNTs to accelerate the electron transfer performance and generate new catalytic sites, thus contributing to greatly enhancing both the activity and stability of the catalytic process. This work provides a promising way for the rational design of efficient and robust catalysts for sustainable energy conversion.