ABSTRACT
The design and synthesis of oxygen evolution reaction (OER) electrocatalysts that operate efficiently and stably under acidic conditions are important for the preparation of green hydrogen energy. The low intrinsic catalytic activity and poor acid resistance of commercial RuO2 limit its further development, and the construction of heterointerface structures is the most promising strategy to break through the intrinsic activity limitation of electrocatalysts. Herein, we synthesized spherical and oxygen vacancy-rich heterointerface MnO2/RuO2 using morphology control, which promoted the kinetics of the oxygen evolution reaction with the interaction between oxygen vacancies and the oxide heterointerface. MnO2/RuO2 was reported to be an acidic OER catalyst with excellent performance and stability, requiring only an ultra-low overpotential of 181 mV in 0.5 M H2SO4 to achieve a current density of 10 mA cm-2. The catalyst activity remained essentially unchanged in a 140 h stability test with an ultra-high mass activity (858.9 A g-1@ 1.5 V), which was far superior to commercial RuO2 and most previously reported noble metal-based acidic OER catalysts. The experimental results showed that the effect of more oxygen vacancies and the heterointerfaces of manganese ruthenium oxides broke the intrinsic activity limitation, provided more active sites for the OER, accelerated reaction kinetics, and improved the stability of the catalyst. The excellent performance of the catalyst suggests that MnO2/RuO2 provides a new idea for the design and study of heterointerfaces in metal oxide nanomaterials.
ABSTRACT
Objective: General anesthesia is commonly performed with tracheal intubation. We aimed to evaluate the effects of right stellate ganglion block combined with topical anesthesia on the heart rate variability in awake patients receiving tracheal intubation. Methods: A total of 120 eligible patients were equally divided into observation and control groups using a random number table. The observation group underwent right stellate ganglion block combined with topical anesthesia. The excellent and good rate of anesthesia, indicators of vital signs and heart rate variability, incidence rate of adverse reactions, success rate and time consumption of tracheal intubation, postoperative resuscitation and cognitive function score of the two groups were compared. Results: The systolic pressure, diastolic pressure and heart rate significantly increased in both groups during tracheal intubation compared with those before tracheal intubation, which they were lower in the observation group than those in the control group during tracheal intubation (P<0.05). Low-frequency power, ratio of low-frequency power to high-frequency power and heart rate variability index significantly decreased in both groups during tracheal intubation compared with those before tracheal intubation (P<0.05). Conclusion: Right stellate ganglion block combined with topical anesthesia can work well for awake patients during tracheal intubation.
