摘要：To harness abundant and clean solar energy along with relieving energy and environmental issues,photoca.alysis holds great ***-based photoca.alysts are crucial to its successful ***,the photoca.alytic efficiency based on a unitary semiconductor material falls short of expectations,mainly because of the rapid recombination of photogenerated electrons and *** originates in the extremely strong Columbic force between ***,it is impossible for a single photoca.alyst to achieve wide light absorption and ample redox ability concurrently.

摘要：Reducing CO_(2) to hydrocarbon fuels by solar irradiation provides a feasible channel for mitigating excessive CO_(2) emissions and addressing resource ***,severe charge recombi‐nation and the high energy barrier for CO_(2) photoreduction on the surface of photoca.alysts com‐promise the ca.alytic ***,a 2D/2D Bi_(2)MoO_(6)/BiOI composite was fabricated to achieve improved CO_(2) photoreduction *** transfer in the composite was facilitated by the van der Waals heterojunction with a large‐area *** function calculation demon‐strated that S‐scheme charge transfer is operative in the composite,and effective charge separation and strong redox capability were revealed by time‐resolved photoluminescence and electron para‐magnetic resonance ***,the intermediates of CO_(2) photoreduction were identi‐fied based on the in situ diffuse reflectance infrared Fourier‐transform *** functional theory calculations showed that CO_(2) hydrogenation is the rate‐determining step for yielding CH_(4) and *** Bi_(2)MoO_(6) into the composite further decreased the energy barrier for CO_(2) photoreduction on BiOI by 0.35 *** study verifies the synergistic effect of the S‐scheme heterojunction and van der Waals heterojunction in the 2D/2D composite.

摘要：光催化材料和技术可合理利用太阳能,完成能量转化与存储,并实现环境治理和双碳目标.光催化剂活性是影响其效率的关键,因此光催化剂的合理设计成为研究热点.为抑制光生电子和空穴的快速复合并拓展单一光催化剂的光吸收范围,可通过构建异质结特别是新兴的梯型(S型异质结)的策略.在保有体系最大氧化还原能力的同时,实现光生电荷的有效分离.可通过原位光照X射线光电子能谱和原位光照原子力显微镜等技术研究梯型异质结的电荷转移机制,然而,目前尚缺少对于异质结界面处瞬态动力学的深入研究.近期,中国地质大学(武汉)余家国教授、张留洋教授与湖北文理学院梁桂杰教授合作,通过原位生长策略,在芘基共轭聚合物(PDB)表面原位生长硫化镉(Cd S)纳米晶体,制备了一系列硫化镉/聚合物梯型异质结(CPDB),并系统地研究了异质结界面处的稳态电荷分布以及瞬态电荷转移动力学.密度泛函理论计算和开尔文探针测试结果表明,暗态下电子由PDB向Cd S转移,并在界面处形成内建电场和能带弯曲.原位光照X射线光电子能谱表明,在内建电场和能带弯曲的驱动下,Cd S的光生电子与PDB的光生空穴复合,而PDB的光生电子与Cd S的光生空穴得以保留.利用飞秒瞬态吸收技术揭示了异质结界面处的电荷转移演化过程.通过实验信号的拟合分析,Cd S的光生电子有三条衰减路径:晶格间的电子扩散、光生电子空穴对直接复合以及光生电子与捕获态空穴复合.对于CPDB复合物而言,除了上述三种衰减路径,还发现Cd S的光生电子与PDB的光生空穴复合路径.作者通过调控Cd S/PDB配比,阐述了异质结界面电荷转移过程动力学与其光催化性能的关系.结果表明,随着PDB含量的增加,Cd S与PDB之间界面电荷转移寿命越短(速度越快);然而,加入过量PDB会导致聚合物发生聚集,从而抑制界面电荷转移.该结论与CPDB复合物的光催化性能表现一致.综上,该工作通过使用飞秒瞬态吸收技术,对梯型异质结光催化剂的界面电荷转移过程进行了直接跟踪观测,为揭示光催化过程中的复杂机制提供了新思路.