In this work, density functional theory (DFT), catalytic activity tests, and in-situ X-ray absorption spectroscopy (XAS) was performed to gain detailed insights into the activity and stability of MoS₂, Ni-MoS₂, and Co-MoS₂ catalysts used for hydrodeoxygenation (HDO) of ethylene glycol upon variation of the partial pressures of H₂O and H₂S. The results show high water tolerance of the catalysts and highlight the importance of promotion and H₂S level during HDO.

DFT calculations unraveled that the active edge of MoS₂ could be stabilized against SO exchanges by increasing the partial pressure of H₂S or by promotion with either Ni or Co. The Mo, NiMo, and CoMo catalysts of the present study were all active and fairly selective for ethylene glycol HDO at 400 °C, 27 bar H₂, and 550–2200 ppm H₂S, and conversions of ≈50–100%. The unpromoted Mo/MgAl₂O₄ catalyst had a lower stability and activity per gram catalyst than the promoted analogues. The NiMo and CoMo catalysts produced ethane, ethylene, and C₁ cracking products with a C₂/C₁ ratio of 1.5–2.0 at 550 ppm H₂S. This ratio of HDO to cracking could be increased to ≈2 at 2200 ppm H₂S which also stabilized the activity. Removing H₂S from the feed caused severe catalyst deactivation. Both DFT and catalytic activity tests indicated that increasing the H₂S concentration increased the concentration of SH groups on the catalyst, which correspondingly activated and stabilized the catalytic HDO performance. In-situ XAS further supported that the catalysts were tolerant towards water when exposed to increasing water concentration with H₂O/H₂S ratios up to 300 at 400–450 °C.

Raman spectroscopy and XAS showed that MoS₂ was present in the prepared catalysts as small and highly dispersed particles, probably owing to a strong interaction with the support. Linear combination fitting (LCF) analysis of the X-ray absorption near edge structure (XANES) spectra obtained during in-situ sulfidation showed that Ni was sulfided faster than Mo and CoMo, and that Mo was sulfided faster when promoted with Ni. Extended X-ray absorption fine structure (EXAFS) results showed the presence of MoS₂ in all sulfided catalysts. Sulfided CoMo was present as a mixture of CoMoS and Co₉S₈, whereas sulfided NiMo was present as NiMoS.

在这项工作中，进行了密度泛函理论（DFT），催化活性测试和原位X射线吸收光谱（XAS），以深入了解MoS ₂，Ni-MoS ₂和Co-的活性和稳定性。随H ₂ O和H ₂ S分压的变化而用于乙二醇加氢脱氧（HDO）的MoS ₂催化剂。结果表明，该催化剂具有很高的耐水性，并突出了在HDO过程中促进和H ₂ S含量的重要性。

DFT计算表明，通过增加H ₂ S的分压或通过Ni或Co的促进作用，可以使MoS ₂的活性边缘对S O交换稳定。本研究的Mo，NiMo和CoMo催化剂均具有活性在400°C，27 bar H ₂和550–2200 ppm H ₂ S的条件下对乙二醇HDO具有相当的选择性，转化率约为50–100％。未促进的Mo / MgAl ₂ O ₄催化剂的每克催化剂的稳定性和活性均低于促进的类似物。制得的乙烷，乙烯和的NiMo催化剂的CoMo，和C ₁裂解产物与C ₂ / C ₁在550 ppm H ₂ S时，比率为1.5–2.0。在2200 ppm H ₂ S时，HDO与开裂的比率可以增加到≈2，这也使活性稳定。从进料中除去H ₂ S会导致严重的催化剂失活。DFT和催化活性测试均表明，增加H ₂ S浓度会增加催化剂上SH基团的浓度，从而相应地活化和稳定了催化HDO性能。原位XAS进一步证明，当催化剂在400–450°C的H ₂ O / H ₂ S比高达300的不断增加的水浓度下暴露时，它们对水具有耐受性。

拉曼光谱法和XAS分析表明，所制得的催化剂中的MoS ₂以小的且高度分散的颗粒形式存在，这可能是由于与载体的强烈相互作用所致。在原位硫化过程中获得的X射线吸收近边缘结构（XANES）光谱的线性组合拟合（LCF）分析显示，Ni的硫化速度比Mo和CoMo快，而Mo则在被Ni促进时硫化得更快。扩展的X射线吸收精细结构（EXAFS）结果表明，所有硫化催化剂中均存在MoS ₂。硫化的CoMo以CoMoS和Co ₉ S ₈的混合物形式存在，而硫化的NiMo以NiMoS形式存在。