Lignin is an abundant renewable source of bio-aromatics and its valorization is of great importance. In this work, an efficient non-precious carbon based metal-Mo 2 C catalytic system for selective production of phenolic monomers (PMs) from organosolv lignin depolymerization is proposed. With the optimized catalyst of Ni-Fe-Mo 2 C, 89.56% of liquefaction and 35.53% of PMs yields were achieved under 260 ℃ for 4 h with water-methanol (4:1 v/v) solvent. Characterization of the catalysts shows that the induction of Ni-Fe species was favor for the formation of β-Mo 2 C, and efficiently promoted the lignin liquefaction. The decoration of Ni/Fe can also change the side chain hydrogenolysis ability of the catalyst and exhibite high yield for 4-ethylphenol (14.77%) production. Methanol, used as co-solvent, was found to play an important role in PMs production and lignin depolymerization. These results demonstrated that the Ni-Fe-Mo 2 C catalytic system has potential to produce valuable phenolic monomers from lignin under mild conditions.
Qingshan Rong,Wei Ding,Guogang Liu,Xiangyu Fu,Yan Shi,Zhiqiang Zhang,Zhiwei Yao
In this study, we found that β-Mo2C prepared at different carbonization temperatures exhibited significantly different catalytic activities for the reverse water gas shift (RWGS) reaction. The β-Mo2C synthesized at 600 °C demonstrated notably higher activity compared to those prepared at 700 °C and 800 °C. This enhanced activity was likely attributed to its improved redox properties, which were primarily driven by a smaller crystallite size and the presence of MoxOCy species. Therefore, we proposed that the crystallite size and MoxOCy content were the key factors governing the RWGS activity of β-Mo2C. Clearly, both factors were strongly influenced by the carbonization temperature. Notably, the β-Mo2C prepared at 600 °C even outperformed Cu-doped β-Mo2C prepared at 700 °C under similar reaction conditions.
Sihui He,Hao Qu,Jiadong Liu,Jian Sun,Yue Su,Ruijue Hu,Yulong Zhang,Haiquan Su
Higher alcohols synthesis (HAS) is an important branch of syngas conversion, and Mo 2 C-based catalyst is a promising system for this reaction. However, the CO conversion and alcohols selectivity of current Mo 2 C-based catalysts are still low, which hinders their industrial application. Here, a series of Mo 2 C with three-dimensional hierarchically porous (3DHP) structures were prepared via a hard template method and their catalytic performance in HAS was investigated. The CO conversion and higher alcohols proportion of the optimal 3DHP catalyst were increased from 5.1 % and 60.4 % to 17.6 % and 70.5 %, respectively, compared with that of bulk Mo 2 C under similar total alcohols selectivity. The enhancement of the catalytic performance could be related to the increased number of active sites and the synergistic effect between multivalent Mo species. Additionally, the optimal 3DHP catalyst demonstrated good stability over a period of 200 h. This study provides a potential application for 3DHP materials and an alternative for designing efficient Mo 2 C catalysts for the HAS reactions.
Meixuan Li,Yun Zhu,Huiyuan Wang,Ce Wang,Nicola Pinna,Xiaofeng Lu
It is urgently required to develop highly efficient and stable bifunctional non-noble metal electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) for water splitting. In this study, a facile electrospinning followed by a post-carbonization treatment to synthesize nitrogen-doped carbon nanofibers (NCNFs) integrated with Ni and Mo 2 C nanoparticles (Ni/Mo 2 C-NCNFs) as water splitting electrocatalysts is developed. Owing to the strong hydrogen binding energy on Mo 2 C and high electrical conductivity of Ni, synergetic effect between Ni and Mo 2 C nanoparticles significantly promote both HER and OER activities. The optimized hybrid (Ni/Mo 2 C(1:2)-NCNFs) delivers low overpotentials of 143 mV for HER and 288 mV for OER at a current density of 10 mA cm −2 . An alkaline electrolyzer with Ni/Mo 2 C(1:2)-NCNFs as catalysts for both anode and cathode exhibits a current density of 10 mA cm −2 at a voltage of 1.64 V, which is only 0.07 V larger than the benchmark of Pt/C-RuO 2 electrodes. In addition, an outstanding long-term durability during 100 h testing without obvious degradation is achieved, which is superior to most of the noble-metal-free electrocatalysts reported to date. This work provides a simple and effective approach for the preparation of low-cost and high-performance bifunctional electrocatalysts for efficient overall water splitting.
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