Abstract Phase-selective synthesis of stable metallic 1T transition metal dichalcogenides (TMDs) is challenging. Herein, we in-situ synthesis of stable 1T cobalt-doped tungsten selenide/carbon nanotubes (Co-WSe2/CNTs) by synergistic effect of mechanical strain and interfacial-chemical interaction by CNTs and Co. Our experimental results indicate that Co-doping is pivotal for conformal coating of 1T Co-WSe2 nanosheets around the CNTs due to their strong interfacial-chemical interaction between Co and CNTs, which is prerequisite for 1T phase engineering with high-stability by mechanical curvature strain. More importantly, for the first time we can easily regulate the concentrations of 1T Co-WSe2 from 67.2% to 82.9% by varying the CNTs curvatures due to the tunable mechanical strains. The single-walled CNTs (SWNTs) with the largest curvature strain induces the highest content of 1T phase in Co-WSe2 (82.9%), and moreover the 1T phase still remains even after high temperature annealing. Further benefiting from the improved electronic properties, the 1T Co-WSe2/SWNTs exhibits enhanced electrocatalytic hydrogen evolution reaction (HER) activity in both acidic and alkaline electrolytes. The present work highlights the important role of strain in the 1T phase formation, also sheds lights on how the 1T phase occurs and stabilizes.

中文翻译：

---

碳纳米管和钴稳定 1T-WSe2 的机械应变和界面化学相互作用的协同效应

摘要 稳定的金属 1T 过渡金属二硫属元素化物 (TMD) 的相选择性合成具有挑战性。在此，我们通过 CNTs 和 Co 的机械应变和界面化学相互作用的协同作用原位合成了稳定的 1T 钴掺杂硒化钨/碳纳米管（Co-WSe2/CNTs）。我们的实验结果表明 Co-doping 是由于 Co 和 CNT 之间的强界面化学相互作用，因此 1T Co-WSe2 纳米片在 CNT 周围保形涂层的关键，这是通过机械曲率应变实现具有高稳定性的 1T 相工程的先决条件。更重要的是，我们第一次可以通过可调机械应变改变碳纳米管曲率，轻松地将 1T Co-WSe2 的浓度从 67.2% 调节到 82.9%。具有最大曲率应变的单壁碳纳米管（SWNTs）在 Co-WSe2 中诱导了最高含量的 1T 相（82.9%），而且即使在高温退火后 1T 相仍然存在。进一步受益于改进的电子性能，1T Co-WSe2/SWNTs 在酸性和碱性电解质中都表现出增强的电催化析氢反应（HER）活性。目前的工作强调了应变在 1T 相形成中的重要作用，也阐明了 1T 相如何发生和稳定。1T Co-WSe2/SWNTs 在酸性和碱性电解质中均表现出增强的电催化析氢反应（HER）活性。目前的工作强调了应变在 1T 相形成中的重要作用，也阐明了 1T 相如何发生和稳定。1T Co-WSe2/SWNTs 在酸性和碱性电解质中均表现出增强的电催化析氢反应（HER）活性。目前的工作强调了应变在 1T 相形成中的重要作用，也阐明了 1T 相如何发生和稳定。