Chemical Engineering Journal ( IF 15.1 ) Pub Date : 2022-07-22 , DOI: 10.1016/j.cej.2022.138244 Zhengwen Li , Jingpeng Zhang , Jiaming Tian , Kai Feng , Zhao Jiang , Binhang Yan
Ni-based bimetallic catalysts are widely explored for semi-hydrogenation of acetylene due to their enhanced catalytic performance. However, the comprehensive understanding of performance promoted by Ni-based alloy still remains elusive to date. Herein, supported NiCu/ZrO2 catalysts were fabricated to unveil the origin of improved selectivity and stability. Owing to the electronic and geometric modification of active Ni sites by Cu atoms, NiCu/ZrO2 ensures weak adsorption of key intermediates and easy desorption of ethylene, leading to an improved selectivity towards ethylene. DFT calculations indicate that both the activation barriers for the acetylene deep dehydrogenation pathway and the CC bond cleavage pathway on NiCu alloy are higher, suggesting that NiCu/ZrO2 would show superior stability over Ni/ZrO2. Therefore, the ID/IG ratio obtained via in-situ Raman, which represents the anti-coking ability of catalysts, can be employed as a descriptor of catalytic stability. These findings bring new insight for designing efficient heterogeneous catalysts for selective hydrogenation.
中文翻译:
揭示镍铜合金增强乙炔半加氢催化性能的起源
Ni基双金属催化剂由于其增强的催化性能而被广泛用于乙炔的半加氢。然而,迄今为止,对镍基合金所促进的性能的全面了解仍然难以捉摸。在此,制备了负载型 NiCu/ZrO 2催化剂,以揭示提高选择性和稳定性的原因。由于Cu原子对活性Ni位点的电子和几何修饰,NiCu/ZrO 2确保了关键中间体的弱吸附和乙烯的易解吸,从而提高了对乙烯的选择性。DFT 计算表明,NiCu 合金上乙炔深度脱氢途径和 C C 键裂解途径的活化势垒较高,表明 NiCu/ZrO图2将显示出优于Ni/ZrO 2的稳定性。因此,通过原位拉曼获得的 I D /I G比值代表了催化剂的抗结焦能力,可以作为催化剂稳定性的描述指标。这些发现为设计用于选择性加氢的高效多相催化剂带来了新的见解。