机构地区:[1]大连民族大学国家民委新能源与稀土资源利用重点实验室,辽宁省光敏材料与器件重点实验室,物理与材料工程学院,辽宁大连116600
出 处:《物理化学学报》2023年第4期85-95,共11页Acta Physico-Chimica Sinica
基 金:国家自然科学基金(62005036,12074055,11904046);辽宁省优秀青年科学基金(2022-YQ-13);辽宁省“百千万人才工程”,辽宁省自然科学基金(2020-MZLH-15);大连市青年科技之星(2020RQ131)。
摘 要:利用半导体作为催化剂,将水光催化还原为H_(2),为缓解全球能源危机以及环境污染问题提供了一种经济环保的途径。优化调控载流子动力学行为对提高半导体光催化分解水还原为绿色燃料-H_(2)的活性具有十分重要的意义。目前,基于半导体异质结效应或局域表面等离激元共振的敏化过程来设计和调控半导体基异质结构体系已成为调控载流子动力学行为的一种经典策略。然而,通过精细设计异质结构,合理耦合上述敏化过程,实现载流子动力学的级联调制,从而获得高效的光催化产H_(2)活性仍然任重道远。在本文中,我们通过原位氧化(g-C_(3)N_(4)的剥离和Ag_(2)S)和还原(Ag)反应,将等离激元Ag纳米颗粒(NPs)和两种不同的半导体Ag_(2)SNPs和g-C_(3)N_(4)纳米片(NSs)组装在电纺TiO_(2)纳米纤维(NFs)中,形成了一种新型四元异质组分纳米纤维(HNFs)体系。结合时间分辨光致发光光谱,3D时域有限差分模拟以及对照实验,我们证明了等离激元AgNPs和g-C_(3)N_(4)NSs由于吸收光谱重叠可以诱导从AgNPs到与其相邻的g-C_(3)N_(4)NSs上的等离激元共振能量转移,从而促进上述四元HNFs体系中g-C_(3)N_(4)上光生载流子的产生。同时,由Ag NPs产生的等离激元热电子能够进一步转移到与其相接触的TiO_(2)、g-C_(3)N_(4)、以及Ag_(2)S组分上,促进体系中光生载流子的产生和分离。而且,g-C_(3)N_(4)/TiO_(2)异质界面处的能带结构属于“II型”异质结,而TiO_(2)/Ag_(2)S异质界面处的能带结构属于“I型”异质结。这样可以在gC_(3)N_(4)/TiO_(2)/Ag_(2)S异质界面构建连续的“能带阶梯”,使光生电子从g-C_(3)N_(4)跨越TiO_(2)转移到Ag_(2)S上,从而促进光生电荷-载流子的分离和迁移。因此,将等离激元共振能量转移,热电子转移过程和连续的“能带阶梯”诱导的载流子分离过程合理地整合在所制备的四元Ag/Ag_(2)S/g-C_(3)N_(4)/TiO_(2)HNFs中,从而实现了The photocatalytic reduction of water to hydrogen(H_(2))over semiconductors potentially offers an economic way to alleviate the global energy crisis and environmental pollution.Optimal modulation of charge-carrier kinetics is of great importance for enhancing the photocatalytic activity of semiconductors for reducing water to green H_(2).The design and manufacture of semiconductor-based heterostructure systems have emerged as promising tactics for modulating charge-carrier kinetics based on sensitization either via the semiconductor heterojunction effect or localized surface plasmon resonance.However,the cascade modulation of charge-carrier kinetics is still difficult to achieve through rationally coupling the abovementioned sensitization processes in well-designed heterostructures for highly-efficient photocatalytic H_(2) generation.In this study,we developed a novel quaternary hetero-component nanofibers(HNFs)system by assembling plasmonic Ag nanoparticles(NPs)and two different semiconductors of Ag_(2)S NPs and g-C_(3)N_(4) nanosheets(NSs)into the electrospun TiO_(2) nanofibers(NFs)via in situ oxidation(for g-C_(3)N_(4) exfoliation and Ag_(2)S)and reduction(for Ag)reactions.By combining time-resolved photoluminescence spectroscopy,three-dimensional finite-difference-time-domain simulation,and control experiments,we found that the overlapping absorption peak of plasmonic Ag NPs and g-C_(3)N_(4) NSs could induce plasmonic resonant energy transfer from the Ag NPs to the neighboring g-C_(3)N_(4),thereby improving the generation of photoinduced charge carriers of g-C_(3)N_(4) in the quaternary HNFs system.Simultaneously,plasmonic hot electrons could be generated on the Ag NPs and transferred to the near-by hetero-components of TiO_(2),g-C_(3)N_(4),and Ag_(2)S,to boost the generation and separation of photoinduced charge carriers in the system.Furthermore,the energy band structure at the g-C_(3)N_(4)/TiO_(2) hetero-interface belongs to the"type II"heterojunction,while the energy band structure at the TiO_(2)/Ag_(2)S
关 键 词:级联调制 载流子动力学 Ag/Ag_(2)S/g-C_(3)N_(4)/TiO_(2)异质结复合纳米纤维 宽光谱响应 光催化产氢
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