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

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

Enhancing Solar Hydrogen Production Via Modified Photochemical Treatment Of Pt/Cds Photocatalyst

A modified photoetching process is found to significantly improve the photocatalytic activity of Pt/CdS photocatalyst for solar hydrogen production. The photoetching process was carried out by dispersing Pt/CdS photocatalyst particles in an aqueous ammonium sulfite ((NH4)2SO 3) solution under a vacuum-degassed condition. The Pt/CdS particles were then exposed to photo-radiation (350-800 nm) for 20 h. The rate of hydrogen production via visible light photooxidation of aqueous (NH4) 2SO3 solution over the photochemically treated Pt/CdS is about 130 times higher than that of untreated Pt/CdS samples. Effects of platinum loading technologies on the photocatalytic activity of Pt/CdS photocatalyst for hydrogen production are also investigated in this paper. Photochemically deposited Pt/CdS photocatalyst in an aqueous ammonium sulfite solution has shown a 100% increase in hydrogen production rate over that of photocatalysts traditionally photo-platinized in an aqueous glacial acetic acid solution. The prepared catalysts are characterized using XRD, FESEM, TEM, BET and XPS techniques and the changes of Pt particle size and surface elementary states of Cd and S are observed before and after the photoetching process. © 2012 Elsevier B.V

Synthesis And Characterization Of High Efficiency And Stable Ag 3Po 4/Tio 2 Visible Light Photocatalyst For The Degradation Of Methylene Blue And Rhodamine B Solutions

A Fabry-Perot etalon, consisting of two π phase shifted reflecting volume Bragg gratings, is presented. These gratings are obtained as a moiré pattern resulting from sequential recording of interference patterns with different periods in photo-thermo-refractive glass and called moiré volume Bragg gratings (MVBGs). A detailed investigation of the fundamental operating principles and measurement techniques for phase shifted gratings is shown. Experimental results demonstrating a MVBG with a 15 pm bandwidth and 90% transmission at resonance are presented. The use of the MVBG for longitudinal mode selection in a laser resonator is shown. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE)

Optimizing the guiding sign system to improve drivers’ lane-changing behavior at freeway exit ramp

A high incidence of traffic accidents is often observed in freeway exit ramp areas. Slowing down, wandering, and changing lanes suddenly and continually in a short interval near the exit ramp are important reasons for accidents. Helping drivers start changing lanes sooner and more efficiently in freeway exit ramp areas is a feasible solution to vehicle interweaving. This paper aims to optimize the current guiding sign system and improve drivers’ lane-changing behavior before the exit ramp. Three guiding sign optimization measures (sign symbols, ground signs and voice prompts) had been considered before five guiding sign plans were made for driving simulation experiments: original sign (OS) plan, new type sign (NTS) plan, ground guiding sign (GOS) plan, voice prompt (VOS) plan, and voice-ground sign (VGOS) plan. The decisions, reactions, and operation processes of 43 Chinese drivers were compared to confirm the optimal guiding sign plan. The results showed that updating sign symbols, adding ground signs and voice prompts all contributed to the drivers’ shorter response time, earlier arrival at the lane-changing location, higher average speed and greater longitudinal distance of lane-changing. These findings can help freeway designers optimize the guiding sign system for freeway exit ramps.</p

Ternary N, S, and P-Doped Hollow Carbon Spheres Derived from Polyphosphazene as Pd Supports for Ethanol Oxidation Reaction

Ethanol oxidation reaction (EOR) is an important electrode reaction in ethanol fuel cells. However, there are many problems with commercial ethanol oxidation electrocatalysts today, such as poor durability, poor anti-CO poisoning ability, and low selectivity for C&#8315;C bond cleavage. Therefore, it is very meaningful to develop a high-performance EOR catalyst. Herein, we designed ternary N, S, and P-doped hollow carbon spheres (C&#8315;N,P,S) from polyphosphazene (PCCP) as Pd supports for EOR. Using SiO2 spheres as the templates, the PCCP was first coated on the surfaces of SiO2 spheres by in situ polymerization. Through high-temperature pyrolysis and hydrofluoric acid-etching, the hollow PCCP has a large surface area and porous structure. After loading Pd nanoparticles (NPs), the Pd/C&#8315;N, P, S catalysts with Pd NPs decorated on the surfaces of C&#8315;N, P, S can achieve a high mass peak current density of 1686 mA mgPd&#8722;1, which was 2.8 times greater than that of Pd/C. Meanwhile, the Pd/C&#8315;N, P, S catalyst also shows a better stability than that of Pd/C after a durability test of 3600s

Mucus-penetrating nonviral gene vaccine processed in the epithelium for inducing advanced vaginal mucosal immune responses

Establishment of vaginal immune defenses at the mucosal interface layer through gene vaccines promise to prevent infectious diseases among females. Mucosal barriers composed of a flowing mucus hydrogel and tightly conjugated epithelial cells (ECs), which represent the main technical difficulties for vaccine development, reside in the harsh, acidic human vaginal environment. Different from frequently employed viral vectors, two types of nonviral nanocarriers were designed to concurrently overcome the barriers and induce immune responses. Differing design concepts include the charge-reversal property (DRLS) to mimic a virus that uses any cells as factories, as well as the addition of a hyaluronic acid coating (HA/RLS) to directly target dendritic cells (DCs). With a suitable size and electrostatic neutrality, these two nanoparticles penetrate a mucus hydrogel with similar diffusivity. The DRLS system expressed a higher level of the carried human papillomavirus type 16 L1 gene compared to HA/RLS in vivo. Therefore it induced more robust mucosal, cellular, and humoral immune responses. Moreover, the DLRS applied to intravaginal immunization induced high IgA levels compared with intramuscularly injected DNA (naked), indicating timely protection against pathogens at the mucus layer. These findings also offer important approaches for the design and fabrication of nonviral gene vaccines in other mucosal systems

Temperature dependence of the Rayleigh Brillouin spectrum linewidth in air and nitrogen

The relation between spontaneous Rayleigh Brillouin (SRB) spectrum linewidth, gas temperature, and pressure are analyzed at the temperature range from 220 to 340 K and the pressure range from 0.1 to 1 bar, covering the stratosphere and troposphere relevant for the Earth’s atmosphere and for atmospheric Lidar missions. Based on the analysis, a model retrieving gas temperature from directly measured linewidth is established and the accuracy limitations are estimated. Furthermore, some experimental data of air and nitrogen are used to verify the accuracy of the model. As the results show, the retrieved temperature shows good agreement with the reference temperature, and the absolute difference is less than 3 K, which indicates that this method provides a fruitful tool in satellite retrieval to extract the gaseous properties of atmospheres on-line by directly measuring the SRB spectrum linewidth