Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, ON K7M 0A9, Canada.
Nanotechnology. 2018 Jan 12;29(2):025708. doi: 10.1088/1361-6528/aa981a.
Nickel hydroxide is a material composed of two-dimensional layers that can be rolled up to form cylindrical nanotubes belonging to a class of inorganic metal hydroxide nanotubes that are candidates for applications in catalysis, energy storage, and microelectronics. The stabilities and other properties of this class of inorganic nanotubes have not yet been investigated in detail. The present study uses self-consistent-charge density-functional tight-binding calculations to examine the stabilities, mechanical properties, and electronic properties of nickel hydroxide nanotubes along with the energetics associated with the adsorption of water by these systems. The tight-binding model was parametrized for this system based on the results of first-principles calculations. The stabilities of the nanotubes were examined by calculating strain energies and performing molecular dynamics simulations. The results indicate that single-walled nickel hydroxide nanotubes are stable at room temperature, which is consistent with experimental investigations. The nanotubes possess size-dependent mechanical properties that are similar in magnitude to those of other inorganic nanotubes. The electronic properties of the nanotubes were also found to be size-dependent and small nickel oxyhydroxide nanotubes are predicted to be semiconductors. Despite this size-dependence, both the mechanical and electronic properties were found to be almost independent of the helical structure of the nanotubes. The calculations also show that water molecules have higher adsorption energies when binding to the interior of the nickel hydroxide nanotubes when compared to adsorption in nanotubes formed from other two-dimensional materials such as graphene. The increased adsorption energy is due to the hydrophilic nature of nickel hydroxide. Due to the broad applications of nickel hydroxide, the nanotubes investigated here are also expected to be used in catalysis, electronics, and clean energy production.
氢氧化镍是一种由二维层组成的材料，可以卷成圆柱形纳米管，属于无机金属氢氧化物纳米管的一类，有望应用于催化、储能和微电子学领域。这类无机纳米管的稳定性和其他性质尚未得到详细研究。本研究使用自洽电荷密度泛函紧束缚计算方法，研究了氢氧化镍纳米管的稳定性、力学性能和电子性能，以及这些体系吸附水的能量学。该紧束缚模型是基于第一性原理计算的结果针对该体系进行参数化的。通过计算应变能和进行分子动力学模拟来研究纳米管的稳定性。结果表明，单壁氢氧化镍纳米管在室温下是稳定的，这与实验研究一致。纳米管具有与其他无机纳米管相似的尺寸依赖性力学性能。还发现纳米管的电子性质也具有尺寸依赖性，并且小的镍氧氢氧化物纳米管预计为半导体。尽管存在这种尺寸依赖性，但力学和电子性质几乎与纳米管的螺旋结构无关。计算还表明，与在石墨烯等二维材料形成的纳米管中吸附相比，水分子在吸附到氢氧化镍纳米管内部时具有更高的吸附能。吸附能的增加是由于氢氧化镍的亲水性。由于氢氧化镍的广泛应用，这里研究的纳米管也有望用于催化、电子学和清洁能源生产。
