A new series of bimetallic Ni-Co catalysts, prepared by step wise substitution of Ni by Co, in mono metallic
Ni (8%)/ CeO₂ -Al₂O₃, with the compositions of 6%Ni-2% Co, 4%Ni-4%Co, 2.5%Ni-5.5%Co and 8%Co, have been evaluated for conversion of ethanol to butanol and higher alcohols according to Guerbet alcohol chemistry. XRD, TPR and XPS studies reveal the formation of Ni-Co alloys at specific bimetallic compositions. Maximum reducibility is observed for the composition 4%Ni-4%Co, which also displays maximum ethanol conversion (55.1%) with C₄₊ alcohols selectivity of 50.2%, which are higher than those realized for mono metallic Ni and Co catalysts. Ni-Co alloys in bimetallic catalysts promote the crucial ethanol dehydrogenation and C₄ and C₄₊ aldehydes hydrogenation steps in the Guerbet process, thereby increasing ethanol conversion and C₄₊ alcohol selectivity. Selection of bimetallic catalysts with optimum compositions seems to be one of strategies to improve ethanol conversion and selectivity for higher alcohols.

中文翻译：

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在镍和钴修饰的CeO2-Al2O3混合氧化物催化剂上将乙醇缩合为丁醇和高级醇

通过在
Ni（8％）/ CeO ₂ -Al ₂ O ₃中以6％Ni-2％Co，4组成的单金属Ni逐步取代Co制备一系列新的双金属Ni-Co催化剂。根据Guerbet醇化学方法，已评估了％Ni-4％Co，2.5％Ni-5.5％Co和8％Co的乙醇转化为丁醇和高级醇的能力。XRD，TPR和XPS研究表明，在特定的双金属成分下会形成Ni-Co合金。观察到组成4％Ni-4％Co的最大还原度，在C _{4+的条件下，}乙醇的转化率也最高（55.1％）醇的选择性为50.2％，高于单金属Ni和Co催化剂所实现的。双金属催化剂中的Ni-Co合金促进了Guerbet工艺中至关重要的乙醇脱氢以及C ₄和C ₄₊醛加氢步骤，从而提高了乙醇转化率和C ₄₊醇的选择性。选择具有最佳组成的双金属催化剂似乎是提高乙醇转化率和对高级醇的选择性的策略之一。