Non-noble metal based and earth-abundant electrocatalysts with high hydrogen evolution reaction (HER) activities are highly desirable as replacements for the scarce and expensive platinum-based catalysts. Cobalt phosphides (CoxP) have been recently demonstrated as one of the most promising HER candidates in acidic electrolytes. However, the fabrication methods are normally tedious and produce only a small amount (few milligrams) of catalyst. In this paper, we report a one-pot, large-scale (tens of grams), simple synthesis of cobalt phosphide nanoparticles with impressive HER activities. The CoxP catalyst, when obtained using suitable reaction conditions, shows a high cathodic current density at a low overpotential and a small Tafel slope (approximately 58 mV dec−1). Thus, this study provides a practically promising approach to fabricate cost effective catalysts at a large scale for electrochemical hydrogen production.

Thermal decomposition of single-crystal SiC is one of the popular methods for growing graphene. However, the mechanism of graphene formation on the SiC surface is poorly understood, and the application of this method is also hampered by its high growth temperature. In this study, based on the ab initio calculations, we propose a vacancy assisted Si–C bond flipping model for the dynamic process of graphene growth on SiC. The fact that the critical stages during growth take place at different energy costs allows us to propose an energetic-beam controlled growth method that not only significantly lowers the growth temperature but also makes it possible to grow high-quality graphene with the desired size and patterns directly on the SiC substrate.

Electromagnetic interactions in the microelectronvolt (μeV) or microwave region have numerous important applications in both civil and military fields, such as electronic communications, signal protection, and antireflective coatings on airplanes against microwave detection. Traditionally, nonmagnetic wide-bandgap metal oxide semiconductors lack these μeV electronic transitions and applications. Here, we demonstrate that these metal oxides can be fabricated as good microwave absorbers using a 2D electron gas plasma resonance at the disorder/order interface generated by a hydrogenation process. Using ZnO and TiO2 nanoparticles as examples, we show that large absorption with reflection loss values as large as −49.0 dB (99.99999%) is obtained in the microwave region. The frequency of absorption can be tuned with the particle size and hydrogenation condition. These results may pave the way for new applications for wide bandgap semiconductors, especially in the μeV regime.Keywords: 2D electron gas; electromagnetic absorption; nanoparticles; plasmon; semiconductors; wide bandgap;

A facile pulse laser ablation approach for preparing black titanium oxide nanospheres, which could be used as photocatalysts under visible light, is proposed. The black titanium oxide nanospheres are prepared by pulsed-laser irradiation of pure titanium oxide in suspended aqueous solution. The crystalline phases, morphology, and optical properties of the obtained nanospheres are characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), and UV–vis–NIR diffuse reflectance spectroscopy. It is shown that high-energy laser ablation of titanium oxide suspended solution benefited the formation of Ti3+ species and surface disorder on the surface of the titanium oxide nanospheres. The laser-modified black titanium oxide nanospheres could absorb the full spectrum of visible light, thus exhibiting good photocatalytic performance under visible light.Keywords: laser; nanospheres; photocatalytic; titanium oxides; visible light;

Understanding the single-molecule switching mechanism in densely packed, rationally designed, and highly organized nanostructures is crucial for practical applications such as high-density data storage devices. In this article, we report an in situ low-temperature scanning tunneling microscopy (LT-STM) investigation of reversible switching of a single-dipole molecule (chloroaluminium phthalocyanine, ClAlPc) imbedded in two-dimensional (2D) hydrogen-bonded binary molecular networks on graphite. The single-molecule switching is highly localized and reversible and leaves the neighboring molecular network unaffected. The switching direction can be controlled by the polarity of the voltage pulse applied to the STM tip. On the basis of experimental results and theoretical calculations, the reversible switching is proposed to be caused by the “shuttling” of the Cl atom between two sides of the ClAlPc molecular plane.

Non-noble metal based and earth-abundant electrocatalysts with high hydrogen evolution reaction (HER) activities are highly desirable as replacements for the scarce and expensive platinum-based catalysts. Cobalt phosphides (CoxP) have been recently demonstrated as one of the most promising HER candidates in acidic electrolytes. However, the fabrication methods are normally tedious and produce only a small amount (few milligrams) of catalyst. In this paper, we report a one-pot, large-scale (tens of grams), simple synthesis of cobalt phosphide nanoparticles with impressive HER activities. The CoxP catalyst, when obtained using suitable reaction conditions, shows a high cathodic current density at a low overpotential and a small Tafel slope (approximately 58 mV dec−1). Thus, this study provides a practically promising approach to fabricate cost effective catalysts at a large scale for electrochemical hydrogen production.