The highly selective catalytic hydrogenation of CO2 to CO over transition metal nitrides

• 作者: Yichao Wu Zhiwei Xie Xiaofeng Gao Xian Zhou Yangzhi Xu Shurui Fan Siyu Yao Xiaonian Li Lili Lin
• 来源期刊: 中国化学工程学报（英文版）
• 年，卷（期）: 2022,（3）
• 页码范围: 248-254
• 页数: 7页
• 语种: 英文

摘要

Three transition metal-like facet centered cubic structured transition metal nitrides,γ-Mo2N,β-W2N andδ-NbN,are synthesized and applied in the reaction of CO2 hydrogenation to CO.Among the three nitride catalysts,the γ-Mo2N exhibits superior activity to target product CO,which is 4.6 and 76 times higher than the other two counterparts of β-W2N and δ-NbN at 600℃,respectively.Additionally,γ-Mo2N exhi-bits excellent stability on both cyclic heating-cooling and high space velocity steady state operation.The deactivation degree of cyclic heating-cooling evaluation after 5 cycles and long-term stability perfor-mance at 773 and 873 K in 50 h are all less than 10％.In-situ XRD and kinetic studies suggest that theγ-Mo2N itself is able to activate both of the reactants CO2 and H2.Below 400℃,the reaction mainly occurs at the surface of γ-Mo2N catalyst.CO2 and H2 competitively adsorbe on the surface of catalyst and CO2 is the relatively stronger surface adsorbate.At a higher temperature,the interstitial vacancies of the γ-Mo2N can be reversibly filled with the oxygen from CO2 dissociation.Both of the surface and bulk phase sites of γ-Mo2N participate in the high temperature CO2 hydrogenation pathway.