arXiv subjects

Shengcai Zhu

Publications and source records attributed to Shengcai Zhu.

2 recordsLinked to original sources

arXiv2024

Enhanced Hydrogen Evolution Catalysis of Pentlandite due to the Increases in Coordination Number and Sulfur Vacancy during Cubic-Hexagonal Phase Transition

The search for new phases is an important direction in materials science. The phase transition of sulfides results in significant changes in catalytic performance, such as MoS2 and WS2. Cubic pentlandite [cPn, (Fe, Ni)9S8] can be a functional material in batteries, solar cells, and catalytic fields. However, no report about the material properties of other phases of pentlandite exists. In this study, the unit-cell parameters of a new phase of pentlandite, sulfur-vacancy enriched hexagonal pentlandite (hPn), and the phase boundary between cPn and hPn were determined for the first time. Compared to cPn, the hPn shows a high coordination number, more sulfur vacancies, and high conductivity, which result in significantly higher hydrogen evolution performance of hPn than that of cPn and make the non-nano rock catalyst hPn superior to other most known nanosulfide catalysts. The increase of sulfur vacancies during phase transition provides a new approach to designing functional materials.

physics.chem-ph↗

arXiv2018

First-principles investigation of Sc-III/IV under High Pressure

Using ab initio evolutionary structure prediction method in conjunction with density functional theory, we performed a systematic investigation on the structural transition of elemental scandium under pressure up to 250 GPa. Our prediction successfully reproduced several allotropes which have been reported in the previous literature, including the Sc-I, Sc-II and Sc-V. Moreover, we observed a series of energetically degenerate and geometrically similar structures at 110-195 GPa, which are likely to explain the unsolved phases III and IV reported by Akahama [Phys. Rev. Lett.,94, 19, 195503, (2005)]. A detailed comparison on powder X-ray diffraction pattern (PXRD) suggested that the Ccca-20 phase may account for the observed Sc-III, while Sc-IV is likely to be explained by a mixture of multiple energetically competing structures. We also used the candidate Sc-III structure as the model system to explore its superconducting behavior under pressures between 80-130 GPa. The predicted superconducting transition temperature Tc values are in satisfactory agreement with previous experimental results.

cond-mat.mtrl-sci↗