Hydrogen energy is currently the most efficient and clean new energy technology with the most application prospects. Compared with the traditional methane steam reforming hydrogen production process and alkaline electrolysis water process, the proton exchange membrane water electrolysis device has significant advantages such as fast startup speed, high hydrogen purity, fast hydrogen production rate, large current density and high energy efficiency, etc. The next generation of advanced clean hydrogen production methods. However, non-platinum-based catalysts are generally unstable in acidic media, and active metal components are easily lost during the operation of the electrolytic cell. The current acidic electrolyzed water membrane electrode relies on platinum-based catalysts (Pt, Ir, Ru, etc.), resulting in excessively high hydrogen production components, which greatly limits the application and promotion of proton exchange membrane water electrolysis cells.

Recently, a team of academicians Yu Shuhong and Professor Gao Minrui from the University of Science and Technology of China proposed a "crystal phase mixing" strategy and successfully designed and developed a non-noble metal electrocatalyst that exhibits high stability in acid electrolytes. The researchers subjected the cubic phase cobalt diselenide (CoSe2) to a "rigorous" alkali heat treatment (5 M KOH, 200 ° C), which caused the cubic phase CoSe2 partial structure to be transformed into the orthogonal phase CoSe2, and successfully prepared a novel mixture The phase CoSe2 structure exhibits excellent water reduction electrochemical activity and stable performance in acidic media. The related research results were titled "Polymorphic cobalt diselenide as extremely stable electrocatalyst in acidic media via a phase-mixing strategy" and were published in "Nature Communications" (Nature Communications 2019, 10, 5338) on November 25. The co-first authors of the paper are Zhang Xiaolong, Hu Shaojin and postdoctoral Zheng Yarong, PhD students of the Chinese University of Science and Technology.

The researchers processed the cubic phase CoSe2 by alkali thermal method, so that part of the Co and Se atoms escaped from the perfect cubic phase CoSe2 crystal, generating atomic-level defects. The formation of these defects makes the Se-Se bond in the cubic phase structure rotate in its local part and transforms into the orthogonal phase structure, and finally obtains the homogeneous and uniformly distributed CoSe2 of the cubic phase and the orthogonal phase (Figure 1).

Figure 1. Preparation and structure of mixed-phase CoSe2 catalyst

Electrochemical tests showed that the polarization curve of the mixed-phase CoSe2 catalyst did not change significantly after 50,000 cycles. At the same time, after over 400 hours of operation, the overpotential at 10 mA cm-2 did not increase significantly. The excellent stability of the catalyst prepared by "crystal phase mixing" in acidic electrolytes is far superior to that of cubic and orthogonal phase CoSe2 catalysts (Figure 2).

Figure 2. Comparison of catalytic activity and stability performance of mixed phase, cubic phase and orthogonal phase catalysts for water reduction in acidic media

The study found that this new type of cubic phase-orthogonal CoSe2 catalyst greatly improves the covalence between Co and Se atoms, giving the lattice a stronger bonding energy, which makes this cheap material in The acidic medium not only exhibits high water reduction activity, but also exhibits excellent stability performance (Figure 3).

Figure 3. Understanding the excellent electrochemical stability of mixed-phase CoSe2 catalysts

This research will provide a strategy for the design of highly stable catalysts in acidic media through the crystalline phase control of materials in the future, and for the development of low-cost, high-activity and high-stability catalytic materials that can actually operate in acidic media. New ideas.

Related research was supported by the National Natural Science Foundation of China Innovation Research Group, the National Natural Science Foundation of China Key Projects, the Chinese Academy of Sciences Frontier Science Key Research Projects, Chinese Academy of Sciences Nanoscience Excellence Innovation Center, Suzhou Nanotechnology Collaborative Innovation Center, etc.

SWACO ALS II  Shaker Screen

Replacement SWACO ALS II Shale Shaker Screen– Hook Strip Flat Screens

SJ-ALS-2 shaker screen with dimension of 1141 × 1210 mm, is produced to meet the exact API specifications as a replacement screen for ALS series shale shakers from M-I SWACO. It is commonly compatible with the ALS-2 shaker. Banded steel hook edges prevent the screen from flattening and eliminating mesh pull-out caused by fine wire mesh or high tension screens. There are various mesh combinations available according to different drilling applications. XR or XL mesh range from API 18 to API 325.

Technical Parameter

• Mesh Material: stainless steel 304/316/316 L.
• Frame Material: Q235 steel.
• Screen Type: XL, XR.
• API RP 13C Designation: API 18 – API 325.
• Package: packed in paper carton, shipped by wooden case

Adaptable Shale Shaker Model

SJ-Swaco Als Ii Shaker Screen are used as the substitute screen for

• SWACO ALS II shale shaker.

Competitive Advantage

• 100% interchangeable with OEM brands screen panel size.
• SS 304/316 wire mesh cloth does not rust or delaminate.
• Hook strip soft screen with maximum non-blank areas.
• Manufactured according to the API RP 13C (ISO 13501).
• Scientific & reasonable cost control system for competitive price.
• Adequate inventory in the shortest time to meet customers' demand.

Remarks:

M-I SWACO, ALS II are marks of M-I L.L.C.

ShengJia only produces the replacement screens but not original from M-I SWACO

Swaco ALS II Shaker Screen

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