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<p>Transition metal dichalcogenides (TMDs) have widespread applications in the fields of optoelectronics and catalysis. Generally, 1T phase TMDs have more edge active sites than 2H phase TMDs and thus exhibit superior catalytic efficiency. However, it remains challenging to prepare 1T phase TMDs to date. In this study, we found that when two 2H phase tungsten disulfide (2H-WS<sub>2</sub>) grains with large crystallographic orientation differences (&gt;10°) come into contact at a temperature of 1000 °C, they can combine and further transform into one pure 1T phase tungsten disulfide (1T-WS<sub>2</sub>) grain without crystallographic orientation differences. The first-principles calculation showed that at a temperature lower than 280 K, the 2H-WS<sub>2</sub> is a stable phase and 1T-WS<sub>2</sub> is a metastable phase. But when the temperature is higher than 280 K, their relative stability turns. In the kinetic analysis of 2H to 1T phase nucleation, homogeneous nucleation needs to cross the energy barrier of 2.314 eV, while the heterogeneous nucleation of two nanosheets in contact only needs to cross the energy barrier of 0.005 eV, which is more prone to phase transformation. This work presents a novel approach for synthesizing 1T-WS<sub>2</sub> and may provide a strategy for synthesizing other 1T phase TMDs.</p>

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Large crystallographic orientation difference contacts induce phase transformation of WS2 nanosheets from 2H to 1T

  • 期刊论文

  • 发表日期：

    2025年10月9日

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  • Hantao Cui,
  • Yunna Guo,
  • Peng Jia,
  • Yanxian Li,
  • Zhangran Ye,
  • Lei Deng,
  • Chongchong Ma,
  • Chao Tai,
  • Liqiang Zhang,
  • Bin Wen

摘要

Transition metal dichalcogenides (TMDs) have widespread applications in the fields of optoelectronics and catalysis. Generally, 1T phase TMDs have more edge active sites than 2H phase TMDs and thus exhibit superior catalytic efficiency. However, it remains challenging to prepare 1T phase TMDs to date. In this study, we found that when two 2H phase tungsten disulfide (2H-WS2) grains with large crystallographic orientation differences (>10°) come into contact at a temperature of 1000 °C, they can combine and further transform into one pure 1T phase tungsten disulfide (1T-WS2) grain without crystallographic orientation differences. The first-principles calculation showed that at a temperature lower than 280 K, the 2H-WS2 is a stable phase and 1T-WS2 is a metastable phase. But when the temperature is higher than 280 K, their relative stability turns. In the kinetic analysis of 2H to 1T phase nucleation, homogeneous nucleation needs to cross the energy barrier of 2.314 eV, while the heterogeneous nucleation of two nanosheets in contact only needs to cross the energy barrier of 0.005 eV, which is more prone to phase transformation. This work presents a novel approach for synthesizing 1T-WS2 and may provide a strategy for synthesizing other 1T phase TMDs.