合金纳米颗粒原子级分散制备的双位点催化剂中单点Ag1对Pd1在炔烃双烷氧羰基化反应中的促进作用  

Promotional role of Ag_(1) on Pd_(1) in dual-site configurations from atomic dispersion of alloy nanoparticles for alkyne dialkoxycarbonylation

作　　者：李星局 李峥 冯四全[1] 宋宪根[1] 严丽[1] 母佳利 袁乔 宁丽丽[1] 陈维苗[1] 韩仲康 丁云杰[1,3,4] Xingju Li;Zheng Li;Siquan Feng;Xiangen Song;Li Yan;Jiali Mu;Qiao Yuan;Lili Ning;Weimiao Chen;Zhongkang Han;Yunjie Ding(Dalian National Laboratory for Clean Energy,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,Liaoning,China;School of Materials Science and Engineering,Zhejiang University,Hangzhou 310027,Zhejiang,China;Department of Chemical Physics,University of Science and Technology of Chin,Hefei 230026,Anhui,China;State Key Laboratory of Catalysis,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,Liaoning,China)

机构地区：[1]中国科学院大连化学物理研究所,洁净能源国家实验室(筹),辽宁大连116023 [2]浙江大学材料科学与工程学院,浙江杭州310027 [3]中国科学技术大学化学物理系,安徽合肥230026 [4]中国科学院大连化学物理研究所,催化基础国家重点实验室,辽宁大连116023

出　　处：《Chinese Journal of Catalysis》2024年第4期282-292,共11页催化学报（英文）

基　　金：中国科学院稳定支持基础研究领域青年团队计划(YSBR-022);国家自然科学基金(22372161);国家自然科学基金(22108275);国家自然科学基金(22108276);国家自然科学基金(22102147);中国科学院战略性先导科技专项(XDA29040400);中国科学院青年创新促进会(2022179);中国科学院青年创新促进会(2021181);浙江省自然科学基金(LQ21B030009)。

摘　　要：炔烃烷氧羰基化反应是一种原子经济反应,可以生成α,β-不饱和羧酸、二羧羧酸酯及其衍生物.其中,乙炔的双烷氧羰基化产物(丁烯二酸二酯)可通过两段加氢制备1,4-丁二醇,该反应路径对于生产生物可降解材料聚丁二酸丁二醇酯(PBS)具有重要意义.然而,目前广泛应用的均相Pd基催化体系存在催化剂分离困难、金属流失以及需要添加有机膦配体或各种磺酸助剂等问题,这不仅增加了制备成本,还可能引入不必要的杂质.此外,尽管纳米催化剂在催化领域有着广泛的应用,但大多数纳米催化剂在炔烃双烷氧基羰基化反应中仍表现出反应活性低和稳定性差的问题,这限制了其在工业生产中的应用.相比之下,多相单金属点催化剂因其100%的原子利用率和较好的催化活性而备受关注.然而,由于多相单金属点催化剂具有相对简单的结构和配位环境,其应用仍受到一定的限制.为了克服这一难题,合成具有不同金属的双位点催化剂成为了一个研究热点.双位点催化剂有望进一步释放单金属位点催化剂的潜力,提高反应活性和稳定性.然而,尽管双位点催化剂具有巨大的应用前景,但目前仍面临着制备方法的挑战.如何设计并实用可行地制备出具有高效催化性能的双位点催化剂,是当前科研领域亟待解决的问题.本文提出一种由CO/CH3I混合物诱导分散Pd-Ag合金纳米颗粒的处理方法,用于制备Pd1-Ag1/AC双位点催化剂.利用X射线衍射、X射线光电子能谱和高角环形暗场扫描透射电子显微镜等方法对分散过程进行表征.结果表明,在分散过程中,CO和CH3I与金属发生协同作用,通过配位生成一种独特的双核络合物(PdI2(CO)-I2-AgI)结构.这种络合物结构逐一从合金纳米颗粒上剥落,直至完成原子级的分散.乙炔双烷氧羰基化反应结果表明,与单金属Pd1/AC相比,在相同反应条件下,双位点Pd1-Ag1/AC催化剂上的乙炔转Heterogeneous single-metal-site catalysts frequently encounter issues related to the poor stability of their coordination structures,hindering their industrial applications.Synthesizing bimetallic single-metal-site catalysts with two closely connected single sites may realize the full potential of single-site catalysts.Herein,we present a“top-down”dispersion process to prepare bimetallic single-metal-site catalysts from Pd-Ag alloy nanoparticles induced by CO and CH3I mixture,with the unique binuclear complex structure of Pd1-Ag1 established as PdI2(CO)-I2-AgI by combined characterization.The Pd1-Ag1/activated carbon(AC)catalyst showed a three times increase in conversion for acetylene dialkoxycarbonylation compared to Pd1/AC,owing to the promotive effect of the single-Ag-site via the binuclear complex configuration.Moreover,Pd1-Ag1/AC showed 98%selectivity for 1,4-unsaturated dicarboxylic acid esters over ten cycles without apparent decay,with the activated adsorption amount of acetylene doubled and the reduction of active Pd1δ+species partially inhibited.According to density functional theory calculations,the Pd1-Ag1/AC catalyst exhibited a substantially lower reaction energy barrier of 0.45 eV for the rate-determining step compared with that of the Pd1/AC catalyst(1.06 eV).This study provides insight into the preparation and synergetic catalysis of bimetallic single-metal-site catalysts.

关 键 词：协同促进作用 双位点催化剂 原子级分散 合金纳米颗粒 炔烃双烷氧羰基化 稳定性 

分 类 号：TQ426[化学工程]