摘要：Covalent organic frameworks(COFs)are promising materials for converting solar energy into green ***,limited charge separation and transport in COFs impede their application in the photocatalytic hydrogen evolution reaction(HER).In this study,the intrinsically tunable internal bond electric field(IBEF)at the imine bonds of COFs was manipulated to cooperate with the internal molecular electric field(IMEF)induced by the donor-acceptor(D-A)structure for an efficient *** aligned orientation of IBEF and IMEF resulted in a remarkable H_(2) evolution rate of 57.3 mmol·g^(-1)·h^(-1)on TNCA,which was approximately 520 times higher than that of TCNA(0.11 mmol·g^(-1)·h^(-1))with the opposing electric field *** superposition of the dual electric fields enables the IBEF to function as an accelerating field for electron transfer,kinetically facilitat-ing the migration of photogenerated electrons from D to ***,theoretical calculations indicate that the inhomogeneous charge distribution at the C and N atoms in TNCA not only pro-vides a strong driving force for carrier transfer but also effectively hinders the return of free elec-trons to the valence band,improving the utilization of *** strategy of fabricating dual electric fields in COFs offers a novel approach to designing photocatalysts for clean energy synthesis.

摘要：少教多学"的教学理念,是尝试将教学传统上以"教师为主体的多教"转换到"以学生为主体的多学",目的是激发学生对学习的兴趣,提供更具弹性的发挥空间,并强化学生的自学能力,从而培养学生积极主动的学习精神。"学生为主体,教师为主导

摘要：纳米片与空心球上之间的合理界面调控是开发高效太阳能制氢光催化剂的潜在策略。在各类光催化材料中,金属硫化物由于具有相对较窄的带隙和优越的可见光响应能力而被广泛研究。ZnIn_(2)S_(4)是一种层状的三元过渡金属半导体光催化剂,其带隙可控(约2.4 eV)。在众多金属硫化物光催化剂中,ZnIn_(2)S_(4)引起了广泛兴趣。然而,单纯的ZnIn_(2)S_(4)光催化活性仍然相对较差,主要是因为光生载流子的复合率较高、迁移速率较慢。在半导体光催化剂上负载助催化剂是提升光催化剂性能的一种有效方法,因为它不仅可以加速光生电子和空穴的分离,而且还可以降低质子还原反应的活化能。作为一种三元过渡金属硫化物,NiCo_(2)S_(4)表现出较高的导电性、较低的电负性、丰富的氧化还原特性以及优越的电催化活性。这些特性表明,NiCo_(2)S_(4)可以作为光催化制氢的助催化剂,以加速电荷分离和转移。此外,NiCo_(2)S_(4)和ZnIn_(2)S_(4)都属于三元尖晶石的晶体结构,这可能有助于构建具有紧密界面接触的NiCo_(2)S_(4)/ZnIn_(2)S_(4)复合物,从而提高光催化性能。本文中,将超薄ZnIn_(2)S_(4)纳米片原位生长到非贵金属助催化剂NiCo_(2)S_(4)空心球上,形成具有强耦合界面和可见光吸收的NiCo_(2)S_(4)@ZnIn_(2)S_(4)分级空心异质结构光催化剂。最优NiCo_(2)S_(4)@ZnIn_(2)S_(4)复合样品(NiCo_(2)S_(4)含量:ca.3.1%)的析氢速率高达78μmol·h−1,约是纳米片组装ZnIn_(2)S_(4)光催化剂析氢速率的9倍、约是1%(w,质量分数)Pt/ZnIn_(2)S_(4)样品析氢速率的3倍。此外,该复合光催化剂在反应中表现出良好的稳定性。荧光和电化学测试结果表明,NiCo_(2)S_(4)空心球是一种有效的助催化剂,可促进光生载流子的分离和传输,并降低析氢反应的活化能。最后,提出了NiCo_(2)S_(4)@ZnIn_(2)S_(4)光催化析氢的可能反应机理。在NiCo_(2)S_(4)@ZnIn_(2)S_(4)复合光催化剂中,具有高导电性的NiCo_(2)S_(4)助催化剂可快速接受ZnIn_(2)S_(4)上的光生电子,用以还原质子生成氢气,而电子牺牲剂TEOA捕获光生空穴,进而完成光催化氧化还原循环。该研究有望为基于纳米片为次级结构的分级空心异质结光催化剂的设计合成及其光催化制氢研究提供一定的指导。