Developing new electrocatalysts is essentially important for efficient water splitting to produce hydrogen. Two-dimensional (2D) materials provide great potential for high-performance electrocatalysts because of their high specific surface area, abundant active edges, and tunable electronic structure. Here, we report few-layer NiPS nanosheet-graphene composites for high-performance electrocatalysts for oxygen evolution reaction (OER). The pure NiPS nanosheets show an overpotential of 343 mV for a current density of 10 mA cm, which is comparable to that for IrO and RuO catalysts. More importantly, the NiPS nanosheet-graphene composites show significantly improved OER activity due to the synergistic effect. The optimized composite shows a very low overpotential of 294 mV for a current density of 10 mA cm, 351 mV for a current density of 100 mA cm, a small Tafel slope of 42.6 mV dec, and excellent stability. These overall performances are far better than those of the reported 2D materials and even better than those of many traditional materials even at a much lower mass loading of NiPS.
The vibration characteristics of an axially moving vertical plate immersed in fluid and subjected to a pretension are investigated, with a special consideration to natural frequencies, complex mode functions and critical speeds of the system. The classical thin plate theory is adopted for the formulation of the governing equation of motion of the vibrating plates. The effects of free surface waves, compressibility and viscidity of the fluid are neglected in the analysis. The velocity potential and Bernoulli’s equation are used to describe the fluid pressure acting on the moving plate. The effect of fluid on the vibrations of the plate may be regarded as equivalent to an added mass on the plate. The formulation of added mass is obtained from kinematic boundary conditions of the plate–fluid interfaces. The effects of some system parameters such as the moving speed, stiffness ratios, location and aspect ratios of the plate and the fluid-plate density ratios on the above-mentioned vibration characteristics of the plate–fluid system are investigated in detail. Various different boundary conditions are considered in the study.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.