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Wang, Zhenhai

Publications and source records attributed to Wang, Zhenhai.

6 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Ternary inorganic electrides with mixed bonding

A high-throughput screening based on first-principles calculations was performed to search for new ternary inorganic electrides. From the available materials database, we identified three new thermodynamically stable materials (Li 12 Mg 3 Si 4 , NaBa 2 O, and Ca 5 Ga 2 N 4 ) as potential electrides made by main group elements, in addition to the well known mayenite based electride (C12A7:e – ). Different from those conventional inorganic electrides in which the excess electrons play only the role of anions, the three new materials, resembling the electrides found in simple metals under high pressure, possess mixed ionic and metallic bonding. The interplay between two competing mechanisms, together with the different crystal packing motifs, gives rise to a variety of geometries in anionic electrons and rich physical phenomena such as ferromagnetism, superconductivity, and metal-insulator transition. Furthermore, our finding here bridges the gap between electrides found at ambient and high-pressure conditions.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Enhanced hydrogen production from water on Pt/g-C3N4 by room temperature electron reduction

Highlights: • A novel way to get efficient Pt/g-C{sub 3}N{sub 4} through glow discharge plasma reduction. • Plasma treatment can be applied to prepare catalyst used for visible light driven reaction. • An alkaline reduction environment can promote the Pt reduction process. - Abstract: An efficient Pt/g-C{sub 3}N{sub 4} photocatalyst was prepared via glow discharge plasma reduction. Based on the hydrogen evolution from water splitting under visible light irradiation, the Pt/g-C{sub 3}N{sub 4} obtained through plasma reduction exhibited enhanced photocatalytic performance with a H{sub 2} evolution rate of 33.9 μmol/h. Among the samples obtained through plasma reduction under different environments, the Pt/g-C{sub 3}N{sub 4} photocatalyst with Pt reduced in NaOH alkaline environment exhibited a markedly increased H{sub 2} evolution rate of 40 μmol/h. The enhanced photocatalytic performance could be attributed to plasma reduction controlling the size of Pt particles and the alkaline environment promoting Pt reduction.

08 HYDROGEN↗
DOE OSTI2016

Prediction of a new ground state of superhard compound B6O at ambient conditions

Boron suboxide B 6 O), the hardest known oxide, has an Rm crystal structure (α-B 6 O) that can be described as an oxygen-stuffed structure of α-boron, or, equivalently, as a cubic close packing of B 12 icosahedra with two oxygen atoms occupying all octahedral voids in it. Here we show a new ground state of this compound at ambient conditions, Cmcm-B 6 O) (β-B 6 O)), which in all quantum-mechanical treatments that we tested comes out to be slightly but consistently more stable. Increasing pressure and temperature further stabilizes it with respect to the known α-B 6 O) structure. β-B 6 O) also has a slightly higher hardness and may be synthesized using different experimental protocols. We suggest that β-B 6 O) is present in mixture with α-B 6 O), and its presence accounts for previously unexplained bands in the experimental Raman spectrum.

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