MoS₂ is a promising non-noble metal electrocatalyst for hydrogen evolution reaction (HER). Transition metal doping (TM = Fe, Co, Ni, etc.) into the Mo site of MoS₂ is a simple and effective method to improve the catalytic activity of MoS₂. However, homogeneous TM-doping suffers from phase segregation due to the different coordination modes between TMS₆ and MoS₆. Here, we propose a solid-state reaction method with rapid heating and quenching to homogeneously dope TM atoms into the MoS₂ lattice. The electrical conductivity of a Co-doped sample (Co_xMo_1−xS₂) is ten times larger than that of pristine MoS₂. The Co_xMo_1−xS₂ is applied as an efficient electrocatalyst for the hydrogen evolution reaction, which has an onset potential of HER activity near −65 mV versus RHE and a Tafel slope of 120 mV dec⁻¹, compared with pristine MoS₂ (an onset potential of −240 mV versus. RHE, a Tafel slope of 133 mV dec⁻¹). The first-principles calculations reveal that half-filled intermediate bands (IBs) mainly consist of Co 3d orbitals present in the forbidden band of 2H-MoS₂ after Co doping. Half-filled IBs in Co_xMo_1−xS₂ account for better electrical conductivity and lower overpotential to promote rapid electron transfer to hydrogen ions, consequently resulting in efficient hydrogen evolution.

中文翻译：

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Co掺杂使MoS _2的中间能带增强了氢的释放

MoS ₂是用于氢气析出反应（HER）的有前途的非贵金属电催化剂。向MoS ₂的Mo位置掺杂过渡金属（TM = Fe，Co，Ni等）是提高MoS ₂催化活性的简单有效的方法。然而，由于TMS ₆和MoS ₆之间的不同协调模式，均匀的TM掺杂会发生相偏析。在这里，我们提出了一种固态反应方法，该方法具有快速加热和淬灭的功能，以将TM原子均匀地掺杂到MoS ₂晶格中。钴掺杂样品的电导率（Co _x Mo _{1- x} S ₂）是原始MoS _2的十倍。与原始MoS相比，Co _x Mo _{1- x} S ₂可作为氢释放反应的高效电催化剂，其相对于RHE的HER活性起始电位接近-65 mV ，Tafel斜率为120 mV dec ^-1。₂（相对于RHE的起始电位为-240 mV ，Tafel斜率为133 mV dec ^-1）。第一性原理计算表明，Co掺杂后，半填充中间带（IBs）主要由存在于2H-MoS ₂的禁带中的Co 3d轨道组成。Co _x中的半填充IBMo _{1- x} S ₂具有更好的电导率和更低的超电势，从而促进了电子快速转移到氢离子，从而有效地释放了氢。