In situ integration of cobalt diselenide nanoparticles on CNTs realizing durable hydrogen evolution.

Cobalt diselenide (CoSe2) is considered to be a promising economical and efficient electrocatalyst for the hydrogen evolution reaction (HER). Here carbon nanotubes (CNTs) were employed as a conductive skeleton to optimize the electrocatalytic performance of CoSe2 through a simple one-step hydrothermal method. Beyond the expected, the introduction of CNTs not only accelerates electron transportation and ion diffusion, but also improves the reaction kinetics for HER by forming a CoSe2/CNT heterointerface. Consequently, the CoSe2/CNTs composite exhibits an optimal overpotential of 153 mV with a weight ratio of 10 : 1, and sustains a long period of 48 hours with an negligible overpotential deterioration. In addition, a Faraday efficiency of 97.67% is achieved with a H2/O2 molar ratio of 2 : 1. Therefore, these results open up further opportunities for yielding efficient and durable hydrogen evolving electrocatalysts from low-cost transition metal compounds.

Synergistic effect of cocatalytic NiSe2 on stable 1T-MoS2 for hydrogen evolution.

Robust and economical catalysts are imperative to realize the versatile applications of hydrogen. Herein, a 1T-MoS2/N-doped NiSe2 composite was rationally synthesized via a solvothermal method, in which the MoS2 nanosheets have a stable 1T phase structure, and the NiSe2 nanoparticles serve as a cocatalytic support for MoS2. The nonnegligible electronic couplings between NiSe2 and MoS2 could facilitate the optimization of their electronic structure and then improve the hydrogen adsorption. What is more, the nitrogen dopants in the NiSe2 nanoparticles could intensify the intercalation of ammonium ions in the 1T-MoS2 nanosheets, and further enlarge their interlayer spacing, thus the electrolyte could infiltrate into the catalyst more easily and sufficiently. This work provides a new route for rationally designing highly active and low cost hydrogen evolution reaction (HER) catalysts, and enriches the study of transition metal chalcogenides toward HER.

[Experimental study on promotion of somato-visceral heterogenic reinnervation with nerve growth factor in rat phrenic-to-vagus anastomosis model].

OBJECTIVE: To investigate the influence of nerve growth factor (NGF) on neuronal regeneration of somato-visceral heterogenic reinnervation using a rat phrenic-to-vagus anastomosis model. METHODS: Forty male SD rats, aging 3 months and weighing 200 g, were selected and randomly divided into 3 groups. In group A (n = 10, control group), phrenic and vagus nerves were exposed and no neurography was performed. In group B (n = 15) and group C (n = 15), both nerves were transected and proximal stump of phrenic nerves were microsurgically anastomosed to the distal stump of vagus nerves. Postoperatively, group C was intraperitoneally injected with NGF (20 microg/kg x d), while groups A and B were given matching saline solution. Twelve weeks later, cardiac function was examined under electrical stimulation of the regenerated nerve. Light and electron microscopies were used to examine the heterogenic regenerated nerve, and the passing rate of axon and thickness of myelin sheath were calculated. RESULTS: Under electrical never stimulation in groups A, B, and C, the decreases of blood pressure were (20.12 +/- 2.57), (10.63 +/- 2.44), and (14.18 +/- 2.93) mmHg (1 mmHg = 0.133 kPa), respectively; and the decreases of heart rate were (66.77 +/- 9.96), (33.44 +/- 11.82), and (43.27 +/- 11.02)/minutes, respectively. In group B, the decrease amplitudes of blood pressure and heart rate were 52.83% and 50.08% of group A, respectively. Blood pressure and heart rate in group C also decreased dramatically; the decrease amplitudes of blood pressure and heart rate in group C were 70.48% and 64.80% of group A. There were significant differences in the decrease amplitudes of blood pressure and heart rate (P < 0.05) between group B and group C. Morphological observation showed that heterogenic nerve fibers had the structure of matured myelin sheath and their axons could regenerate into the vagus nerve. In group B and group C, the passing rates of axon were 66.83% +/- 4.46% and 81.63% +/- 3.56%, respectively; and the thicknesses of myelin sheath were (0.25 +/- 0.10) microm and (0.46 +/- 0.08) microm, respectively; showing significant differences (P < 0.05) between group B and group C. CONCLUSION: Heterogenic nerve is primarily a somatic motor nerve; NGF can promote the axons of heterogenic nerve to regenerate into the parasympathetic nerve.