Mott-Schottky异质结对金属电子态持续调控促进乙醇氧化C-C断裂  

Continuous electronic state regulation by tunable Mott-Schottky Heterojunction potential boosting C-C cleavage for ethanol oxidation

作　　者：冯志浩 于丰收 攸杨 王亚恒 张鲁华 Zhihao Feng;Fengshou Yu;Yang You;Yaheng Wang;Lu-Hua Zhang(National-Local Joint Engineering Laboratory for Energy Conservation in Chemical Process Integration and Resources Utilization,School of Chemical Engineering and Technology,Hebei University of Technology,Tianjin 300130,China)

机构地区：[1]National-Local Joint Engineering Laboratory for Energy Conservation in Chemical Process Integration and Resources Utilization,School of Chemical Engineering and Technology,Hebei University of Technology,Tianjin 300130,China

出　　处：《Science China Materials》2023年第11期4403-4410,共8页中国科学（材料科学（英文版）

基　　金：supported by the National Natural Science Foundation of China(22278108,22008048);the Hundred Talents Project of Hebei Province(E2019050015);the Natural Science Foundation of Tianjin(22JCYBJC00250);the Natural Science Foundation for Outstanding Youth Scholars of Hebei Province(B2021202061);the Natural Science Foundation of Hebei Province(B2021202010);the State Key Laboratory of Fine Chemicals,Dalian University of Technology(KF 2108)。

摘　　要：直接乙醇燃料电池的效率与阳极乙醇氧化反应(EOR)C1路径选择性密切相关,然而C-C键断裂的能垒较高,使得C1路径产物选择性低,从而限制了直接乙醇燃料电池效率的提升.设计具有高C-C裂解效率的电催化剂,对于构建高效直接乙醇燃料电池具有重要意义.本文报道了一种Mott-Schottky异质结调节催化活性中心电子状态从而促进EOR过程中C-C裂解的新策略.我们以PdAu合金纳米颗粒(NPs)为模型催化剂,制备了PdAu@N_(x)C金属-碳Mott-Schottky异质结构.PdAu NPs(15.9±1.9 nm)均匀地分散在N掺杂的碳载体上.我们通过在宽范围内调节N掺杂量,调控异质结界面电势,形成了不同程度的电荷分离.通过催化剂结构与性能研究,建立了反应活性与催化剂功函数之间的线性关系,表明金属/碳界面电子转移可以有效促进EOR.优化的催化剂PdAu@N10.69C,显示出高C1产物选择性(FE=51.1%),质量活性(MA=9.7 A mg Pd^(-1))和比活性(SA=13.2 mA cm^(-2)),优于PdAu@C和大多数报道的Pd基EOR催化剂.实验结果和理论计算表明,N的引入促进了电子由碳层向PdAu转移,加强了对*CH_(3)CO的吸附,从而提高了C-C键的断裂效率.这项工作为整流策略提高EOR性能提供了一种新的研究思路.The efficiency of direct ethanol fuel cells has been limited by the low performance of ethanol oxidation reaction(EOR)due to the high energy barrier for C-C bond cleavage via the C1 pathway,and thus the design of electro-catalysts with high C-C cleavage efficiency is critical for the high-performance direct ethanol fuel cells.In this paper,we reported a novel strategy for electronic state regulation of catalytic sites by Mott-Schottky junction facilitating C-C cleavage during EOR.With PdAu alloy as a model catalyst,we fabricated PdAu@N_(x)C metal-carbon Mott-Schottky hetero-structures with PdAu nanoparticles(NPs,15.9±1.9 nm)evenly dispersed on the N-doped carbon supports.The tunable amount of N dopants with a wide range is highly capable of modifying the band gap of the carbon,where more N creates a higher degree of charge separation in the interface.A linear relationship was established by plotting the reactivity vs.the work function of the catalysts,indicating that the increase of electron transfer across the metal/carbon interfaces was ben-eficial for EOR.The optimal PdAu supported on N-doped carbon catalyst PdAu@N10.69C displays an impressive C1 se-lectivity of 51.1%and significant activity with a mass activity of 9.7 A mgPd−1 and specific activity of 13.2 mA cm^(−2),superior to the reference PdAu@C and most of reported Pd-based EOR catalysts.Experimental results and theoretical calculations reveal that the introduction of N enriches the electron density of PdAu NPs,which strengthens the adsorption of*CH_(3)CO,thus improving the efficiency of C-C bond cleavage.This work provides a new possibility for enhancing the EOR performance of electrocatalysts via the rectification strategy.

关 键 词：metal-carbon heterojunction ethanol oxidation re-action work function electronic state regulation 

分 类 号：O643.36[理学—物理化学] TM911.4[理学—化学]