高稳定性网状Ni/ZrO_(2)催化剂CO甲烷化性能研究

Robust Ni/ZrO^(2) Catalysts for Highly Efficient and Stable CO Methanation:Effect of Interwoven Structure

合成具有抗烧结和抗积碳性能的Ni基催化剂是CO甲烷化催化剂设计的难点,而利用催化剂载体特定的结构对活性金属纳米颗粒的空间限域效应是提高镍基催化剂活性和稳定性的有效策略。以一步法制备的Ni/UiO-66为前驱体,经焙烧和还原,获得了一系列具有网状结构的Ni/ZrO_(2)催化剂。针对反应强放热的特点,三维网状结构在稳定镍颗粒的同时,三维空隙结构能够有效移除反应中的局部热点,并且金属Ni与载体ZrO_(2)紧密的界面结构有效地提升了催化剂的活性和稳定性。结果表明,一步法制备的Ni/ZrO_(2)催化剂的反应活性和稳定性均优于浸渍法制备的Ni/t-ZrO_(2)催化剂,在压力1 MPa,t=325℃,WHSV=15000 mL·g^(-1)·min^(-1)条件下,Ni/ZrO_(2)-N催化剂的CO转化率达到86%,反应120 h后催化剂网状结构保留完好,反应活性和选择性保持稳定。CO甲烷化结果表明,网状结构催化剂的设计策略可以拓展至对其他活性金属进行限域以提升其反应活性和稳定性。

The design of Ni catalysts with anti-sintering and anti-coking properties remains challenging for CO methanation.The confinement of Ni nanoparticles by support is an effective method to achieve high activity and stability during the reaction.A series of Ni/ZrO_(2)catalysts with interwoven structure were designed and prepared by using Ni/UiO-66 composite as precursor after calcination and H2 reduction.The three-dimensional structures stabilize Ni nanoparticles and the voids in the interwoven structure on Ni/ZrO_(2)facilitates the removal of hot spot during the reaction.This interwoven structure on Ni/ZrO_(2)provides closer interface between Ni and ZrO_(2),contributing to an improved activity and stability for CO methanation.The results show that Ni/ZrO_(2)-N presents 86%of CO conversion at 325℃under 1 MPa with a space velocity of 15000 mL·g^(-1)·min^(-1) and stable activity and selectivity during 120 h test.The confinement effect through interwoven structure can be extended to anchor other metal nanoparticles for enhanced catalytic performance and stability.