No abstract

High performance multifunctional electrocatalysts are attracting significant importance for application in energy storage, energy conversion and various other electrochemical reactions. In this prospect, we report on the effective trifunctional electrocatalytic properties of nitrogen (N) doped graphitic carbon nanofibers (CNFs). The CNFs were synthesized on a nichrome (NiCr) foil by chemical vapor deposition (CVD) process. Incorporation of Ni and Cr was observed in the N doped CNFs sample from microscopic and spectroscopic analysis. The metal nanoparticles can be significant in boosting the trifunctional electrocatalytic behavior. The effective oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activities were obtained for the CNFs sample with relatively good overpotential values. The electron transfer number per O2 molecule calculated from Koutecky‐Levich (K‐L) plot was found to be 2e− for the ORR reaction. The OER activity of the CNFs is comparable to commercially available iridium oxide (IrO2), signifying the effectiveness of the developed catalyst. Our study revealed that N doped CNFs with incorporation of metal particles synthesized on a binary metal substrate can be significant as ORR, OER, HER trifunctional electrocatalyst.

2D materials such as molybdenum sulfide (MoS2) integrated with conventional semiconductors lead to the fabrication of novel heterojunctions with pivotal electrical and optoelectronic properties. Herein, an approach is reported which addresses the growth of MoS2 crystals on the lattice‐matched Ga–polar gallium nitride (GaN) wafer using ammonium tetrathiomolybdate (ATM) as a precursor in a chemical vapor deposition (CVD) process, instead of using the molybdenum‐oxide‐based precursors. Unidirectional triangular MoS2 crystals and continuous film are obtained on the free‐standing Ga–polar GaN substrate. Further, the interface quality of the as‐synthesized MoS2 crystals and GaN wafer is explored by X‐ray photoelectron spectroscopy. It is observed that a good quality interface can be obtained by using the ammonia‐containing ATM precursor, where the surface oxygen at the interface is significantly less. A heterojunction device is fabricated with the synthesized MoS2 layer on GaN, showing excellent rectifying diode characteristics and a photovoltaic action with light illumination. This study reveals the suitability of the ammonia‐containing ATM precursor for the growth of MoS2 crystals on GaN in the CVD process to obtain a suitable heterostructure for device applications.

No abstract

The charge collective electrode with faradaic redox reactor consisting of carbon nanocomposite including Ni nanoparticles is promising for the supercapacitor electrode.