Nanjing Tech University

About: Nanjing Tech University is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Catalysis & Membrane. The organization has 21827 authors who have published 21794 publications receiving 364050 citations. The organization is also known as: Nangongda & Nánjīng Gōngyè Dàxúe.

Controllable Design of MoS2 Nanosheets Anchored on Nitrogen-Doped Graphene: Toward Fast Sodium Storage by Tunable Pseudocapacitance

Abstract: Transition-metal disulfide with its layered structure is regarded as a kind of promising host material for sodium insertion, and intensely investigated for sodium-ion batteries. In this work, a simple solvothermal method to synthesize a series of MoS2 nanosheets@nitrogen-doped graphene composites is developed. This newly designed recipe of raw materials and solvents leads the success of tuning size, number of layers, and interplanar spacing of the as-prepared MoS2 nanosheets. Under cut-off voltage and based on an intercalation mechanism, the ultrasmall MoS2 nanosheets@nitrogen-doped graphene composite exhibits more preferable cycling and rate performance compared to few-/dozens-layered MoS2 nanosheets@nitrogen-doped graphene, as well as many other reported insertion-type anode materials. Last, detailed kinetics analysis and density functional theory calculation are also employed to explain the Na+ - storage behavior, thus proving the significance in surface-controlled pseudocapacitance contribution at the high rate. Furthermore, this work offers some meaningful preparation and investigation experiences for designing electrode materials for commercial sodium-ion batteries with favorable performance.

Direct evidence of boosted oxygen evolution over perovskite by enhanced lattice oxygen participation.

Abstract: The development of oxygen evolution reaction (OER) electrocatalysts remains a major challenge that requires significant advances in both mechanistic understanding and material design. Recent studies show that oxygen from the perovskite oxide lattice could participate in the OER via a lattice oxygen-mediated mechanism, providing possibilities for the development of alternative electrocatalysts that could overcome the scaling relations-induced limitations found in conventional catalysts utilizing the adsorbate evolution mechanism. Here we distinguish the extent to which the participation of lattice oxygen can contribute to the OER through the rational design of a model system of silicon-incorporated strontium cobaltite perovskite electrocatalysts with similar surface transition metal properties yet different oxygen diffusion rates. The as-derived silicon-incorporated perovskite exhibits a 12.8-fold increase in oxygen diffusivity, which matches well with the 10-fold improvement of intrinsic OER activity, suggesting that the observed activity increase is dominantly a result of the enhanced lattice oxygen participation.

Two-dimensional Ruddlesden–Popper layered perovskite solar cells based on phase-pure thin films

Abstract: Two-dimensional Ruddlesden–Popper layered metal-halide perovskites have attracted increasing attention for their desirable optoelectronic properties and improved stability compared to their three-dimensional counterparts. However, such perovskites typically consist of multiple quantum wells with a random well width distribution. Here, we report phase-pure quantum wells with a single well width by introducing molten salt spacer n-butylamine acetate, instead of the traditional halide spacer n-butylamine iodide. Due to the strong ionic coordination between n-butylamine acetate and the perovskite framework, a gel of a uniformly distributed intermediate phase can be formed. This allows phase-pure quantum well films with microscale vertically aligned grains to crystallize from their respective intermediate phases. The resultant solar cells achieve a power conversion efficiency of 16.25% and a high open voltage of 1.31 V. After keeping them in 65 ± 10% humidity for 4,680 h, under operation at 85 °C for 558 h, or continuous light illumination for 1,100 h, the cells show <10% efficiency degradation. Two-dimensional Ruddlesden–Popper layered metal-halide perovskites show better performance over three-dimensional versions, but are typically based on quantum wells with random width distribution. Liang et al. show that introducing molten salt spacers gives phase-pure quantum wells and improved solar cell performance.