Nitrogen (N 2 ) reduction to produce ammonia (NH 3 ) is one of the most important chemical processes globally. Nowadays, the Haber−Bosch process is the main industrial procedure for artificial N 2 fixation, which requires extremely harsh synthetic conditions and large energy consumption resulting in massive emission of greenhouse gas. Hence, an alternative photosynthesis of NH 3 under mild condition, which is sustainable and less energy consuming, would be highly desirable. In this study, Au nanoparticles modified (BiO) 2 CO 3 nanodisks were fabricated through a facile hydrothermal method followed by chemical bath deposition and investigated for the photocatalytic reduction of N 2 in a pure water system at atmospheric pressure and room temperature. The induction of Au nanoparticles can dramatically enhance the light trapping as well as charge separation in the Au/(BiO) 2 CO 3 hybrid, thereby promoting overall energy conversion efficiency. The synergetic effect of the nanostructured gold/bismutite hybrid results in high catalytic activity and exhibits high performance for artificial photosynthesis of ammonia.

Although Fe 3 O 4 particles have exhibited excellent microwave absorbing capacity and widely used in practical application due to the synergistic effect of magnetic loss and dielectric loss, their applications are still limited for the required high mass fraction in absorbers. To overcome this problem, the development of Fe 3 O 4 materials with low dimensional structures is necessary. In this study, the shape anisotropic Fe 3 O 4 nanotubes (NTs) with low mass ratios were applied to realize efficient microwave absorption. The NTs with different aspect ratios were prepared through facile electrospinning followed by two-step thermal treatments and mechanical shearing. The cross-linked nanotubular structure enabled the absorbers to have much higher electrical conductivity, multiple scattering, polarization relaxation and better anti-reflection surface, while the shape anisotropic NTs maintained significant multiple resonances with stronger coercivity. These all were beneficial to microwave absorption with enhanced dielectric loss, magnetic loss and sterling impedance matching. Results showed that the absorber with 33.3 wt.% of short Fe 3 O 4 NTs had minimum reflection loss of −58.36 dB at 17.32 GHz with a thickness of 1.27 mm, and had the maximum effective absorbing bandwidth (EAB) of 5.27 GHz when the thickness was 1.53 mm. The absorber with 14.3 wt.% of long Fe 3 O 4 NTs presented the widest EAB in certain radar band with attenuated 80.75% X band and 85% Ku band energy bellow −10 dB at the thickness of 2.65 and 1.53 mm, respectively. This study provided an approach for the development of shape anisotropic magnetic absorbing materials, and broadened their practical applications as magnetic absorbers.

Two-dimensional (2D) layered semiconductors have shown great application potential in next generation nanoelectronic devices. The ferroelectric and piezoelectric properties of 2D semiconductors are also highly desirable in many applications, such as ferroelectric nonvolatile memory and switch. In the present work, we experimentally demonstrate the simultaneous out-of-plane and in-plane ferroelectricity of β-indium selenide (β-InSe) nanoflakes at room temperature. The polarization switching in the as-prepared β-InSe with the P63/mmc symmetry is studied by piezoresponse force microscopy. Out-of-plane polarization hysteresis loops are observed in a 7-nm-thick sample, and the in-plane and out-of-plane ferroelectric switching under the forward and reverse direct current bias are obtained in a 10-nm-thick sample at room temperature. These results indicate that β-InSe is a promising intrinsic 2D van der Waals ferroelectric material. Our work has connected the 2D materials with ferroelectric materials and inspired their applications in electronic devices.