生物乙醇作为平台分子通过催化转化的方法可以制备烯烃、乙醛、丁醇和芳香化学品等,其中乙醛是生产乙酸、季戊四醇、三氯乙醛、山梨酸等重要化学品的原料.随着乙醛的需求量逐年增加,发展以乙醇直接脱氢生成乙醛的工艺,具有联产氢气、原子经济性高、产物易分离的优点,符合国际绿色低碳发展战略要求,有望替代当前乙烯氧化法生产工艺.乙醇分子比较活泼,催化过程中通常伴随着脱水、羟醛缩合等副反应,导致乙醛的选择性降低.根据文献报道,Cu基催化剂可解离吸附乙醇,选择性断裂C-H键,是有效的乙醇直接脱氢催化剂.常规氧化物负载的铜基催化剂往往存在乙醛选择性低、Cu物种易团聚失活等问题.本文通过球磨方法处理商业六方氮化硼(h-BN),从而得到表面缺陷,使其边缘暴露一定的-OH和-NH2等极性官能团,进而增强金属与载体的相互作用,抑制Cu物种的团聚,提高Cu基催化剂在乙醇脱氢反应中的稳定性.考察了不同负载量下Cu物种的分散情况,发现当负载量高达5％ (5Cu/BNS)时,Cu物种仍然能够保持高分散.5Cu/BNS催化剂在280℃,WHSV=9.6h-1反应条件下,催化生成乙醛选择性达到98％,乙醇转化率为82％,且反应50 h后活性保持不变,Cu物种在BNS载体上仍保持高度分散.结合红外光谱和X射线光电子能谱(XPS)表征,证实BNS表面存在B-OH官能团,增强了Cu物种与载体的相互作用,提高了Cu催化剂在乙醇脱氢反应中的稳定性.通过原位红外实验对反应物在载体上的吸附行为研究,进一步理解5Cu/BNS表现出优异的乙醛选择性的原因.结果 表明,乙醛在BNS载体上不发生吸附.从结构化学的角度来说,BNS富π电子,与乙醇的羟基相互作用但是与乙醛的富电子的C=O官能团相互排斥,促进产物乙醛脱附,因此表现出优异的选择性.该方法为设计一种高分散Cu基催化剂提供了新策略,相比于文献报道的催化体系,该催化剂在乙醇脱氢方面表现出更好的催化性能.“,”Copper-based heterogeneous catalysts commonly exhibit uncontrolled growth of copper species under reaction conditions because of the low Hüttig temperature (surface mobility of atoms) and Tamman temperature (bulk mobility) for copper at just 134 and 405 ℃,respectively.Herein,we report the use of defect-enriched hexagonal boron nitride nanosheets (BNSs) as a support to anchor the Cu species,which resulted in superior dispersion of the Cu species.The obtained Cu/BNS cata-lyst was highly stable for ethanol dehydrogenation,with a high selectivity of 98％ for producing acetaldehyde and an exceptionally high acetaldehyde productivity of 7.33 gAcH gcat-1 h-1 under a weight hourly space velocity of 9.6 gEtOH gcat-1 h-1.The overall performance of our designed catalyst far exceeded that of most reported heterogeneous catalysts in terms of the stability of the Cu species and the yield of acetaldehyde in this reaction.The hydroxyl groups at the defect edges of BNS were responsible for the stabilization of the copper species,and the metal-support interaction was rein-forced through charge transfer,as evidenced by coupling atomic resolution images with probe mol-ecule infrared spectroscopy and X-ray photoelectron spectroscopy.A designed in situ diffuse reflec-tance infrared Fourier transform spectroscopy study of ethanol/acetaldehyde adsorption further revealed that Cu/BNS favored ethanol adsorption while suppressing acetaldehyde adsorption and further side reactions.This study demonstrates a new method for designing highly dispersed Cu-based catalysts with high durability.