Nickel Nitride Particles Supported on 2D Activated Graphene–Black Phosphorus Heterostructure: An Efficient Electrocatalyst for the Oxygen Evolution Reaction

Hydrogen is regarded as the most promising green clean energy in the 21st century. Developing the highly efficient and low‐cost electrocatalysts for oxygen evolution reaction (OER) is of great concern for the hydrogen industry. In the water electrolyzed reaction, the overpotential and the kinetics are the main hurdles for OER. Therefore, an efficient and durable oxygen evolution reaction electrocatalyst is required. In this study, an activated graphene (AG)–black phosphorus (BP) nanosheets hybrid is fabricated for supporting Ni3N particles (Ni3N/BP‐AG) in the application of OER. The Ni3N particles are combined with the BP‐AG heterostructure via facile mechanical ball milling under argon protection. The synthesized Ni3N/BP‐AG shows excellent catalytic performance toward the OER, demanding the overpotential of 233 mV for a current density of 10 mA cm−2 with a Tafel slope of 42 mV dec−1. The Ni3N/BP‐AG catalysts also show remarkable stability with a retention rate of the current density of about 86.4% after measuring for 10 000 s in potentiostatic mode.A black phosphorus (BP)–activated graphene (AG) heterostructure is designed for supporting nickel nitride (Ni3N) to enhance the performance of oxygen evolution reaction (OER). The Ni3N/BP‐AG exhibits excellent electrocatalytic performance toward OER with low overpotential and small Tafel slope. It also shows remarkable stability with a retention rate of ≈86.4% OER activity after 10 000 s.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152804/1/smll201901530.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152804/2/smll201901530_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152804/3/smll201901530-sup-0001-S1.pd

H2O2 can Increase Lignin Disintegration and Decrease Cellulose Decomposition in the Process of Solid-State Fermentation (SSF) by Aspergillus oryzae Using Corn Stalk as Raw Materials

H2O2 is both bactericidal and the main oxidant responsible for lignin degradation reaction catalyzed by manganese peroxidase (MnP) and lignin peroxidase (LiP). Thus, H2O2 treatment of corn stalk and the implementation of solid-substrate fermentation (SSF) is possible to increase the removal rate of lignin from stalk in the process of SSF and after SSF, while avoiding the need to sterilize the raw materials. To demonstrate this approach, SSF was initially carried out using corn stalk pretreated with different concentrations of H2O2 as a substrate. A. oryzae was found to grow well in the 3% H2O2-pretreated corn stalk. H2O2-pretreated corn stalk showed increased MnP and LiP synthesis and disintegration of lignin, but inhibited cellulase synthesis and cellulose degradation. Production of the SSF (200 g) on the 10th day was hydrolyzed in the presence of additional 600 mL different concentration of H2O2 aqueous solution. The total removal of lignin (73.15%) of hydrolysis for 10 h at 3% H2O2 solution was highest and far higher than that at the 12th day, as achieved by conventional SSF. Applying this strategy in practice may shorten the time of lignin degradation, increase the removal of lignin, and decrease the loss of cellulose. Thus, this study has provided a foundation for further study saccharification of corn stalk

Preparation and Electrocatalytic Characteristics of PdW/C Catalyst for Ethanol Oxidation

A series of PdW alloy supported on Vulcan XC-72 Carbon (PdW/C) with total 20 wt. % as electrocatalyst are prepared for ethanol oxidation by an ethylene glycol assisted method. Transmission electron microscopy (TEM) characterization shows that PdW nanoparticles with an average size of 3.6 nm are well dispersed on the surface of Vulcan XC-72 Carbon. It is found that the catalytic activity and stability of the PdW/C catalysts are strongly dependent on Pd/W ratios, an optimal Pd/W composition at 1/1 ratio revealed the highest catalytic activity toward ethanol oxidation, which is much better than commercial Pd/C catalysts

Gibberellins are required for dimorphic flower development in Viola philippica

Photoperiod is a major determinant of chasmogamous (CH)-cleistogamous (CL) dimorphic flower development in Viola philippica, and only long-day (LD) conditions induce CL flowers. In this study, it was found that the active gibberellin (GA) content in CL floral buds was higher than in CH floral buds formed under short-day (SD) conditions, suggesting that the biosynthesis of active GAs is enhanced by a longer photoperiod and may be associated with dimorphic flower development. Thus, the next step was to molecularly characterize the key V. philippica GA synthesis genes GA 20-oxidase (VpGA20ox) and GA 3-oxidase (VpGA3ox). In terms of the expression of VpGA20ox and VpGA3ox, it was found that the active GAs could be upregulated in developing pistils under both LD and SD conditions to develop functional pistils, and GAs could also accumulate in the stamens under SD conditions. The anthers and the adjacent petals were well developed under SD conditions. In contrast, the above-mentioned floral organs displayed low GA contents under LD conditions and were poorly developed. Although the application of paclobutrazol, an inhibitor of GA synthesis, did not reverse CL development under LD conditions, exogenous GAs could partially trigger the transition from CH to CL flowers under relative SD conditions (<= 12 h daylight). This was coupled with the downregulation of B-class MADS-box genes, thereby restraining stamen and petal development. Both VpGA20ox and VpGA3ox exhibited similar expression profiles with B-class MADS-box genes in the development of the stamens and petals. Therefore, in response to photoperiod, GA signaling could affect the expression of B-class homeotic genes and regulate dimorphic flower development in Viola. As a compensation for poorly-developed nectaries, anthers, and petals, filament elongation, style shortness, and inward bending could ensure self-pollination in CL flowers. This work provides new insights into the regulation of CH-CL floral development and the evolutionary significance of the formation of dimorphic flowers

Deformation mechanisms of a NiTi alloy under high cycle fatigue

In this paper, high-cycle fatigue mechanisms of a pseudoelastic NiTi shape memory alloy (SMA) under different mean strains are investigated. The uni-axial cyclic tensile tests with small amplitude of 0.25% are operated at three different states, i.e. austenite/elastic region, austenite and martensite coexisted region and martensite/elastic region with a pre-strain. Mechanical results indicate that the cyclic deformation strain is mainly in the inhomogeneous deformation band when the sample cycling in the B2 + B19′ phase coexist status. Cyclic deformation in the B2 + B19’ phase showed cyclic hardening effect. With increasing of the mean strain, the saturation stress is decreased, and saturation rate is reduced. The mean strain effect on the high-cycle fatigue life of NiTi is attributed to the inhomogeneous transformation of martensite. High resolution electron microscopy (HREM) observations and atomic simulations showed that partial dislocations with the Burgers vectors of 1/2 are induced on (001)M twin planes, the interaction of dislocations and edge dislocations in martensite results in cyclic hardening in martensite. While cyclic softening in martensite at the upper plateau of stress–strain (S–S) curve is attributed to the grain reorientation/rotation phenomenon. It suggests that newly generated stress-induced martensite at the interface of martensite and austenite could increase the high-cycle fatigue of NiTi SMA