提高光催化剂光解水制氢效率的方法概述

光解水制氢有望解决能源危机与环境问题,成为开发新能源的研究热点之一。目前将光催化制氢技术实用化仍然面临许多难题,其中最主要问题是光解水制氢效率很低,达不到工业化生产的要求。因此,提高光解水制氢效率很有必要。本文简单概述了提高光催化剂光解水制氢效率的方法。     

可见光催化分解水制氢的研究进展

阐述了近五年来可见光催化分解水制氢的国内外最新研究进展。重点介绍了离子掺杂型光催化剂、价带控制型光催化剂、固溶体催化剂、Z型体系光催化剂、复合型光催化剂以及一些新型可见光催化剂。对今后可见光催化分解水制氢的研究工作进行了展望。     

光催化水制氢

通过表面改性的方法,以聚偏氟乙烯(PVDF)电纺纤维为基材,制备氟碳聚合物电纺纤维毡(表面含有羧基基团);在水热条件下,用含有羧基基团的氟碳聚合物电纺纤维毡作为载体,通过羧基基团对金属离子的吸附络合作用,控制半导体粒子在纤维表面的增长和成核,制备2种半导体复合光催化材料;在光化学反应仪中用制得的催化剂催化水产生氢气,初见成效。     

CDots-(001)TiO2纳米片的制备及其光解水制氢性能

以钛酸四丁酯、氢氟酸和石墨棒为原料,采用简单的水热法将具有高催化活性的碳点负载在TiO_2纳米片的(001)晶面上,制得CDots-(001)TiO_2纳米片。通过TiO_2纳米片高催化活性的(001)晶面与碳点的协同作用,提高TiO 2纳米片的光吸收、载流子的传输和分离效率,从而有效提高材料的光催化产氢性能。紫外-可见漫反射吸收谱(UV-visDRS)、光致发光光谱(PL)、瞬态光响应分析结果表明,暴露(001)晶面的TiO_2纳米片负载碳点后,可见光吸收增强,光生载流子的分离和传输速率加快,在间歇模拟太阳光照射下,CDots-(001)TiO 2纳米片的光电流密度约为TiO 2的4倍,当碳点的负载量为2%时,CDots-(001)TiO 2纳米片的光催化产氢速率达5859μmol/(h·g),量子效率达9.6%。     

Hydrogen Production through Catalytic Water Splitting Using Liquid-Phase Plasma over Bismuth Ferrite Catalyst

This study examined the H₂ production characteristics from a decomposition reaction using liquid-phase plasma with a bismuth ferrite catalyst. The catalyst was prepared using a sol–gel reaction method. The physicochemical and optical properties of bismuth ferrite were analyzed. H₂ production was carried out from a distilled water and aqueous methanol solution by direct irradiation via liquid-phase plasma. The catalyst absorbed visible-light over 610 nm. The measured bandgap of the bismuth ferrite was approximately 2.0 eV. The liquid-phase plasma emitted UV and visible-light simultaneously according to optical emission spectrometry. Bismuth ferrite induced a higher H₂ production rate than the TiO₂ photocatalyst because it responds to both UV and visible light generated from the liquid-phase plasma.     

半导体SiC光催化分解水制氢研究进展

简单介绍了半导体光催化分解水制氢的原理,综述了改变Si C的尺寸形貌、负载石墨烯、负载贵金属、半导体复合等方法对Si C的光催化产氢性能的影响,重点讨论了复合半导体的光催化产氢机理及SiC与其他半导体复合的研究进展,并提出前景展望。     

Effect of Zr Substitution for Ti in KLaTiO4 for Photocatalytic Water Splitting

The effect of substitution of Zr for Ti in KLaTiO₄ with a layered perovskite structure has been studied on the photocatalytic decomposition of water under the UV light irradiation. Both the optical property and the crystallinity of KLaTiO₄ were varied by the substitution of Zr for Ti. As Zr content was increased, the crystallinity of KLaZr_xTi_1-xO₄ was increased, which had a positive effect on the photocatalytic activity in the water splitting reaction. However, the direct band gap property was lost gradually with increase of Zr content, which resulted in lowering the photocatalytic activity. As a result, the highest activity was obtained for KLaZr_0.3Ti_0.7O₄. Although the absorption coefficients of photons for KLaZr_0.1Ti_0.9O₄ and KLaTiO₄ were higher than those for KLaZr_0.3Ti_0.7O₄, the crystal structure was disordered, which resulted in lowering the activity. The nickel-loaded catalysts showed a higher activity than unloaded perovskites by a factor of greater than 2.     

用于光催化分解水制氢的含钛氧化物催化剂

综述了用于光催化分解水制氢的各种含钛氧化物催化剂的研究进展情况;重点介绍了TiO2、简单的钙钛矿型复合氧化物、层状钛酸盐和隧道结构钛酸盐的结构特征、制备方法、作用机理和光催化性能;对今后的研究方向进行了展望。     

Non-Metal-Doped Porous Carbon Nitride Nanostructures for Photocatalytic Green Hydrogen Production

Photocatalytic green hydrogen (H₂) production through water electrolysis is deemed as green, efficient, and renewable fuel or energy carrier due to its great energy density and zero greenhouse emissions. However, developing efficient and low-cost noble-metal-free photocatalysts remains one of the daunting challenges in low-cost H₂ production. Porous graphitic carbon nitride (gCN) nanostructures have drawn broad multidisciplinary attention as metal-free photocatalysts in the arena of H₂ production and other environmental remediation. This is due to their impressive catalytic/photocatalytic properties (i.e., high surface area, narrow bandgap, and visible light absorption), unique physicochemical durability, tunable electronic properties, and feasibility to synthesize in high yield from inexpensive and earth-abundant resources. The physicochemical and photocatalytic properties of porous gCNs can be easily optimized via the integration of earth-abundant heteroatoms. Although there are various reviews on porous gCN-based photocatalysts for various applications, to the best of our knowledge, there are no reviews on heteroatom-doped porous gCN nanostructures for the photocatalytic H₂ evolution reaction (HER). It is essential to provide timely updates in this research area to highlight the research related to fabrication of novel gCNs for large-scale applications and address the current barriers in this field. This review emphasizes a panorama of recent advances in the rational design of heteroatom (i.e., P, O, S, N, and B)-doped porous gCN nanostructures including mono, binary, and ternary dopants for photocatalytic HERs and their optimized parameters. This is in addition to H₂ energy storage, non-metal configuration, HER fundamental, mechanism, and calculations. This review is expected to inspire a new research entryway to the fabrication of porous gCN-based photocatalysts with ameliorated activity and durability for practical H₂ production.     

Nanosized Au Particles as an Efficient Cocatalyst for Photocatalytic Overall Water Splitting

The effect of the photodeposition of gold particles onto several photocatalysts on the photocatalytic activities was studied. The photocatalytic activities of K₄Nb₆O₁₇, Sr₂Nb₂O₇, KTaO₃ NaTaO₃, and NaTaO₃ doped with La for water splitting were improved when gold particles were deposited. The latter were nanoparticles, consistent with their surface plasmon absorption. The nanosized gold particle functioned as an efficient cocatalyst for photocatalytic water splitting by assisting H₂ evolution.     

三维WO3/rGO复合物的制备及光解水制氢性能研究

通过水热法制备出WO₃/rGO复合物用于可见光下光解水制氢。采用XRD和SEM表征手段对复合物组成、形貌进行研究,同时进行光解水制氢性能测试并对其机理进行探讨。研究结果表明,WO₃样品呈海草状,具有丰富的空隙,可以更大程度上提升光解水制氢性能,WO₃/rGO复合物与未复合石墨烯的WO₃样品比较,其形貌没有明显变化。并且还原氧化石墨烯(rGO)的导电性在提高光感应电荷载流子分离效率中也起着关键作用。WO₃/rGO复合物产氢速率为236μmol/h,而WO₃样品的产氢速率为212μmol/h,氧化石墨与WO₃复合后样品对光解水制氢性能得到提升。增强的光解水制氢性能归因于rGO的优异电导率和WO₃/rGO复合物纳米结构的协同作用。     

Visible-light-responding Bi0.5Dy0.5VO4 Solid Solution for Photocatalytic Water Splitting

Bi_0.5Dy_0.5VO₄ (BDV) oxide solid solution was synthesized by a solid state reaction method and was characterized by XRD, UV–visible DRS, BET, SEM and TEM. It has an appropriate band gap energy of ca. 2.76 eV to absorb visible light, corresponding to an absorption edge of 450 nm. When Pt-Cr₂O₃ was co-loaded, BDV could split water under UV light and visible light. The amounts of the produced hydrogen and oxygen were about 7.27 and 3.82 μmol respectively under the irradiation of visible light (λ > 420 nm) for 2 h. This study indicated that the suitable band gap of BDV for overall water splitting might be attributed to the formation of new VB due to Bi6s participating in the electronic structure.     

金属有机配合物在光解水制氢体系中的应用

实现可见光光解水制氢一直被认为是最终解决能源和环境问题的最佳途径,有效地实现可见光光解水制氢技术的关键在于光敏剂材料的制备及其改性。综述了贵金属钌Ru(Ⅱ)、铂Pt(Ⅱ)、铱Ir(Ⅲ)和铼Re(Ⅰ)的配合物、金属卟啉配合物作为光敏剂在光解水制氢体系中的应用。最后,对金属有机配合物光敏剂未来的发展趋势进行了展望。     

Photocatalytic Production of Hydrogen Peroxide over Modified Semiconductor Materials: A Minireview

Topics in Catalysis - Hydrogen peroxide (H2O2) has exhibited huge application value in many fields including chemical synthesis, medicine, environmental remediation, and fuel cells. Traditional...     

占顿染料敏化光催化制氢的影响因素探讨

分别测试了pH、载Pt、占顿染料上溴的个数等不同条件下的染料敏化光催化制氢行为。结果发现:pH为中性、载Pt的TiO_2的催化下制氢性能较好;占顿染料上溴的个数越多,制氢性能越高,特别是在载Pt的条件下,四溴荧光素(曙红Y)染料敏化的氢气产生量在2 h内可达75.2μmol,但由于脱溴导致稳定性偏差。     

水分解制氢中的电解液调控机制

氢气因能量密度高和燃烧产物无污染得到了广泛的关注，如何以清洁高效的方式制备氢能成为研究中的重点。光伏-电解、光催化、光电催化分解水可以利用储量丰富的太阳能和水产生氢气，是很有前景的氢气制备技术。其中，电化学反应是水分解工艺的关键环节，直接决定整个系统能量转换效率的高低。而以往研究多集中于催化材料的开发，往往忽略了电解液的性质对电解性能的影响。因此本文综述了电解质对电催化分解水的影响和意义，根据水分解的基本理论和反应机理，讨论了电化学步骤中电解质pH、离子成分对表面催化过程和物质传输的影响。通过调控电解质来影响固液界面反应，达到在各种水分解系统中提高能量转化效率和稳定性的目的，这有助于开发高效的电催化体系，并为大规模应用提供参考。