等浓度的氯化铵和硫酸铵溶液哪个pH高

有中学化学参考资料题:0.10 mol/L的NH4Cl和(NH4)2SO4溶液哪个pH值高?这似乎是个中学生可做的简单题目,仔细考虑不是如此.如果简单地认为盐酸和硫酸都是强酸,而硫酸是二元酸,硫酸铵溶液中铵盐浓度为0.20 mol/L,那么NH4Cl溶液pH高,那是不妥的.硫酸是二元酸,第一个氢离子能完全电离,第二个氢离子部分电离,如此考虑情况怎么样呢?是不是答案发生变化?这要通过计算来说明.     

Enhanced efficiency and stability in Sn-based perovskite solar cells with secondary crystallization growth

The conversion efficiencies reported for Tin(Sn)halide-based perovskite solar cells(PSCs)fall a large gap behind those of lead halide-based PSCs,mainly because of poor film quality of the former.Here we report an efficient strategy based on a simple secondary crystallization growth(SCG)technique to improve film quality for tin halide-based PSCs by applying a series of functional amine chlorides on the perovskite surface.They were discovered to enhance the film crystallinity and suppress the oxidation of Sn²⁺remarkably,hence reduce trap state density and non-irradiative recombination in the absorber films.Furthermore,the SCG film holds the band levels matching better with carrier transport layers and herein favoring charge extraction at the device interfaces.Consequently,a champion device efficiency of 8.07% was achieved alo ng with significant enhancements in VOC and JSC,in contrast to 5.35% of the control device value.Moreover,the SCG film-based devices also exhibit superior stability comparing with the control one.This work explicitly paves a novel and general strategy for developing high performance lead-free PSCs.     

Energy level engineering of charge selective contact and halide perovskite by modulating band offset:Mechanistic insights

Mixed cation and anion based perovskites solar cells exhibited enhanced stability under outdoor conditions,however,it yielded limited power conversion efficiency when TiO₂ and Spiro-OMeTAD were employed as electron and hole transport layer(ETL/HTL)respectively.The inevitable interfacial recombination of charge carriers at ETL/perovskite and perovskite/HTL interface diminished the efficiency in planar(n-i-p)perovskite solar cells.By employing computational approach for uni-dimensional device simulator,the effect of band offset on charge recombination at both interfaces was investigated.We noted that it acquired cliff structure when the conduction band minimum of the ETL was lower than that of the perovskite,and thus maximized interfacial recombination.However,if the conduction band minimum of ETL is higher than perovskite,a spike structure is formed,which improve the performance of solar cell.An optimum value of conduction band offset allows to reach performance of 25.21%,with an open circuit voltage(VOC)of 1231 mV,a current density JSC of 24.57 mA/cm² and a fill factor of 83.28%.Additionally,we found that beyond the optimum offset value,large spike structure could decrease the performance.With an optimized energy level of Spiro-OMeTAD and the thickness of mixed-perovskite layer performance of 26.56% can be attained.Our results demonstrate a detailed understanding about the energy level tuning between the charge selective layers and perovskite and how the improvement in PV performance can be achieved by adjusting the energy level offset.     

Recent Advances of Pure Organic Room Temperature Phosphorescence Materials for Bioimaging Applications

Bioimaging,as a powerful and helpful tool,which allows people to investigate deeply within living organisms,has contributed a lot for both clinical theranostics and scientific research.Pure organic room temperature phosphorescence(RTP)materials with the unique features of ultralong luminescence lifetime and large Stokes shift,can efficiently avoid biological autofluorescence and scattered light through a time-resolved imaging modality,and thus are attracting increasing attention.This review classifies pure organic RTP materials into three categories,including small molecule RTP materials,polymer RTP materials and supramolecular RTP materials,and summarizes the recent advances of pure organic RTP materials for bioimaging applications.     

A new strategy to access Co/N co-doped carbon nanotubes as oxygen reduction reaction catalysts

Carbon nanotubes(CNTs),as one-dimensional nanomaterials,show great potential in energy conversion and storage due to their efficient electrical conductivity and mass transfer.However,the security risks,time-consuming and high cost of the preparation process hinder its further application.Here,we develop that a negative pressure rather than a following gas environment can promote the generation of cobalt and nitrogen co-doped CNTs(Co/N-CNTs) by using cobalt zeolitic imidazolate framework(ZIF-67) as a precursor,in which the negative pressure plays a key role in adjusting the size of cobalt nanoparticles and stimulating the rearragement of carbon atoms for forming CNTs.Importantly,the obtained Co/N-CNTs,with high content of pyridinic nitrogen and abundant graphitized structure,exhibit superior catalytic activity for oxygen reduction reaction(ORR) with half-wave potential(E_1/2) of 0.85 V and durability in terms of the minimum current loss(2%) after the 30,000 s test.Our development provides a new pathway for large-scale and cost-effective preparation of metal-doped CNTs for various applications.     

Stabilizing High-voltage Cathode Materials for Next-generation Li-ion Batteries

The pressing demand for high-energy/power lithium-ion batteries requires the deployment of cathode materials with higher capacity and output voltage.Despite more than ten years of research,high-voltage cathode mate-rials,such as high-voltage layered oxides,spinel LiNi0.5Mn1.5O4,and high-voltage polyanionic compounds still cannot be commercially viable due to the instabilities of standard electrolytes,cathode materials,and cathode electrolyte interphases under high-voltage operation.This paper summarizes the recent advances in addressing the surface and interface issues haunting the application of high-voltage cathode materials.The understanding of the limitations and advantages of different modification protocols will direct the future endeavours on advancing high-energy/power lithium-ion batteries.     

Suppressing trap states and energy loss by optimizing vertical phase distribution through ternary strategy in organic solar cells

Suppressing the trap-state density and the energy loss via ternary strategy was demonstrated.Favorable vertical phase distribution with donors(acceptors)accumulated(depleted)at the interface of active layer and charge extraction layer can be obtained by introducing appropriate amount of polymer acceptor N2200 into the systems of PBDB-T:IT-M and PBDB-TF:Y6.In addition,N2200 is gradiently distributed in the vertical direction in the ternary blend film.Various measurements were carried out to study the effects of N2200 on the binary systems.It was found that the optimized morphology especially in vertical direction can significantly decrease the trap state density of the binary blend films,which is beneficial for the charge transport and collection.All these features enable an obvious decrease in charge recombination in both PBDB-T:IT-M and PBDB-TF:Y6 based organic solar cells(OSCs),and power conversion efficiencies(PCEs)of 12.5%and 16.42%were obtained for the ternary OSCs,respectively.This work indicates that it is an effective method to suppress the trap state density and thus improve the device performance through ternary strategy.     

Conformational Properties of Comb-shaped Polyelectrolytes with Negatively Charged Backbone and Neutral Side Chains Studied by a Generic Coarse-grained Bead-and-Spring Model

A generic coarse-grained bead-and-spring model,mapped onto comb-shaped polycarboxylate-based(PCE)superplasticizers,is developed and studied by Langevin molecular dynamics simulations with implicit solvent and explicit counterions.The agreement on the radius of gyration of the PCEs with experiments shows that our model can be useful in studying the equilibrium sizes of PCEs in solution.The effects of ionic strength,side-chain number,and side-chain length on the conformational behavior of PCEs in solution are explored.Single-chain equilibrium properties,including the radius of gyration,end-to-end distance and persistenee length of the polymer backbone,shape-asphericity parameter,and the mean span dimension,are determined.It is found that with the increase of ionic strength,the equilibrium sizes of the polymers decrease only slightly,and a linear dependenew of the persistence length of backbone on the Debye screening length is found,in good agreement with the theory developed by Dobrynin.Increasing side-chain numbers and/or side-chain lengths increases not only the equilibrium sizes(radius of gyration and mean span)of the polymer as a whole,but also the persistence length of the backbone due to excluded volume interactions.     

Three-dimensionalization via control of laser-structuring parameters for high energy and high power lithium-ion battery under various operating conditions

Laser-structuring is an effective method to promote ion diffusion and improve the performance of lithium-ion battery(LIB)electrodes.In this work,the effects of laser structuring parameters(groove pitch and depth)on the fundamental characteristics of LIB electrode,such as interfacial area,internal resistances,material loss and electrochemical performance,are investigated,LiNi_0.5Co_0.2Mn_0.3O₂ cathodes were structured by a femtosecond laser by varying groove depth and pitch,which resulted in a material loss of 5%-14%and an increase of 140%-260%in the in terfacial area between electrode surface and electrolyte.It is shown that the importance of groove depth and pitch on the electrochemical performance(specific capacity and areal discharge capacity)of laser-structured electrode varies with current rates.Groove pitch is more im porta nt at low current rate but groove depth is at high curre nt rate.From the mapping of lithium concentration within the electrodes of varying groove depth and pitch by laser-induced breakdown spectroscopy,it is verified that the groove functions as a diffusion path for lithium ions.The ionic,electronic,and charge transfer resistances measured with symmetric and half cells showed that these internal resistances are differently affected by laser structuring parameters and the changes in porosity,ionic diffusion and electronic pathways.It is demonstrated that the laser structuring parameters for maximum electrode performance and minimum capacity loss should be determined in consideration of the main operating conditions of LIBs.     

Mesh-like vertical structures enable both high areal capacity and excellent rate capability

In order to balance electrochemical kinetics with loading level for achieving efficient energy storage with high areal capacity and good rate capability simultaneously for wearable electronics,herein,2 D meshlike vertical structures(NiCo_2 S_4@Ni(OH)_2) with a high mass loading of 2.17 mg cm^-2 and combined merits of both 1 D nanowires and 2 D nanosheets are designed for fabricating flexible hybrid supercapacitors.Particularly,the seamlessly interconnected NiCo_2 S_4 core not only provides high capacity of 287.5 μAh cm^-2 but also functions as conductive skeleton for fast electron transport;Ni(OH)_2 sheath occupying the voids in NiCo_2 S_4 meshes contributes extra capacity of 248.4 μAh cm^-2;the holey features guarantee rapid ion diffusion along and across NiCO_2 S_4@Ni(OH)_2 meshes.The resultant flexible electrode exhibits a high areal capacity of 535.9 μAh cm^-2(246.9 mAh g^-1) at 3 mA cm^-2 and outstanding rate performance with 84.7% retention at 30 mA cm^-2,suggesting efficient utilization of both NiCo_2 S_4 and Ni(OH)_2 with specific capacities approaching to their theoretical values.The flexible solid-state hybrid device based on NiCo_2 S_4@Ni(OH)_2 cathode and Fe_2 O_3 anode delivers a high energy density of 315 μWh cm^-2 at the power density of 2.14 mW cm^-2 with excellent electrochemical cycling stability.     

Ni_2P/Zr-MCM-41催化剂的制备及其对麻风树油加氢脱氧的催化性能

采用水热法合成MCM-41和Zr-MCM-41,由Ni(NO_3)_2和(NH_4)2HPO_4溶液共浸渍、高温焙烧、氢气还原和钝化制备了负载型Ni_2P/Zr-M CM-41催化剂。采用XRD、TEM、氮气吸附、CO吸附、吡啶吸附红外和XPS等方法对催化剂进行了表征,并在高压反应釜中研究了其对麻风树油加氢脱氧(HDO)的催化性能。结果表明,氢气还原温度为650℃、Ni2P负载量为20%(质量分数)、Ni2P物相呈晶型时,Ni_2P/Zr-M CM-41催化剂的活性最佳;较低的Ni2P负载量有利于其在Zr-M CM-41载体表面均匀分散,而负载量高于25%(质量分数)时,活性组分少量团聚,易导致孔道堵塞。催化剂表面存在部分因钝化而形成的Ni O。对于麻风树油加氢脱氧,Ni2P负载量为20%(质量分数)Ni_2P/Zr-M CM-41表现出优异的催化性能;脱氧率高达93.90%,直链烷烃含量高达85.36%,其中柴油组分产率较高,C15~20组分占直连烷烃组分50%以上。     

Ni2P-NiS双助剂促进g-C3N4光催化产氢动力学

本文通过简单的一步水热法得到Ni₂P-NiS双助催化剂,之后采用溶剂蒸发法将Ni₂P-NiS与g-C₃N₄纳米片结合构建获得无贵金属的Ni₂P-NiS/g-C₃N₄异质结。研究结果表明,优化后的复合材料具有良好的光催化产氢活性,其产氢速率最高可到6892.7 μmol·g^-1·h^-1,分别为g-C₃N₄ (150 μmol·g^-1·h^-1)、15%NiS/g-C₃N₄ (914.5 μmol·g^-1·h^-1)和15%Ni₂P/g-C₃N₄ (1565.9 μmol·g^-1·h^-1)的46.1、7.5和4.4倍。这主要归因于Ni₂P-NiS相比Ni₂P和NiS单体具有更好的载流子转移能力,其与g-C₃N₄形成的肖特基势垒能有效促进光生载流子在二者界面上的分离,同时Ni₂P-NiS能进一步降低析氢过电势,进而显著增强了表面析氢反应动力学。本研究为开发稳定、高效的非贵金属产氢助剂提供了实验基础。     

Zr改性Ni2P/SBA-15催化剂的制备及其加氢脱氧性能

以正丙醇锆（n）和Zr（SO₄）₂（m）为锆源制备了Zr改性的Ni₂P/ZrO₂-SBA-15（n）和Ni₂P/ZrO₂-SBA-15（m）催化剂,并采用XRD、BET、CO吸附、XPS、NH₃程序升温脱附等手段对催化剂进行了表征。以苯并呋喃（BF）为模型化合物,研究了催化剂加氢脱氧（HDO）性能。结果表明,Zr改性后,形成了新的层状结构的ZrP;Zr的引入有助于生成更多、更小粒径的Ni₂P活性相,催化剂的酸强度和酸量均提高。与正丙醇锆相比,Zr（SO₄）₂为锆源能够获得比表面积大、酸性强、酸量大的催化剂,得到更多的ZrP相、更小粒径的Ni₂P晶粒,暴露更多的Ni活性位点。Ni₂P/ZrO₂-SBA-15（n）和Ni₂P/ZrO₂-SBA-15（m）的BF HDO产率分别为71.5%和85.9%,较Ni₂P/SBA-15分别提高了14.0%和28.4%。催化剂HDO活性、脱氧产物选择性和产率大小顺序为：Ni₂P/ZrO₂-SBA-15（m） > Ni₂P/ZrO₂-SBA-15（n） > Ni₂P/SBA-15。     

非贵金属助剂Ni2P修饰类石墨碳氮化物光催化剂增强可见光光催化产氢性能

Energy crisis has become a serious global issue due to the increasing depletion of fossil fuels; therefore, it is crucial to develop environmentally friendly and renewable energy resources, such as hydrogen (H₂), to replace fossil fuels. From this viewpoint, photocatalytic H₂ production is considered as one of the most promising technologies. Noble metal platinum (Pt) can be applied as an efficient cocatalyst for improving the H₂ production performance of photocatalytic systems; however, its high cost limits its further application. Thus, the development of novel, high-activity, and low-cost cocatalysts for replacing noble metal cocatalysts is of great significance for use in photocatalytic H₂ evolution techniques. Herein, we successfully synthesized a Ni₂P/graphite-like carbonitride photocatalyst (Ni₂P/CN) using a conjugated polymer (SCN)_n as precursor for enhanced photocatalytic H₂ production under visible light illumination. Various characterization techniques, including optical and photoelectronic chemical tests, were used to investigate the structural composition, morphology, and light adsorption ability of these materials. X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy results showed that Ni₂P/CN nanocomposites with good crystal structure were obtained. Scanning electron microscopy and transmission electron microscopy results revealed that the Ni₂P/CN samples had a typical two-dimensional layered structure, and the Ni₂P nanoparticles were uniformly loaded on the surface of the CN to form a non-noble metal promoter. UV-Vis diffuse reflectance spectra results demonstrated that the loading of Ni₂P nanoparticles effectively enhances the adsorption capacity of CN to visible light. Photoluminescence spectroscopy and photocurrent (PL) results suggested that Ni₂P loading to CN is beneficial for promoting the migration and separation efficiency of photogenerated carriers. Photocatalytic H₂ production was conducted under visible light irradiation with triethanolamine as a sacrificial agent. The results suggest that the Ni₂P/CN composite photocatalysts exhibit excellent photocatalytic reduction performance. In particular, the H₂ evolution rate of the optimal Ni₂P/CN nanocomposite is 623.77 μmol·h^-1·g^-1, which is higher than that of CN modified by noble metal Pt, i.e., 524.63 μmol·h^-1·g^-1. In conclusion, Ni₂P nanoparticles are homogeneously attached to the surface of CN, and a strong interfacial effect exists between them, thereby forming an electron transfer tunnel that greatly inhibits the recombination of photoinduced carriers and promotes the migration of electrons from CN to Ni₂P. In addition, a possible photocatalytic mechanism is proposed based on the experiments and characterizations. This work has profound significance for developing non-noble metal cocatalysts for the substitution of noble metal cocatalysts for high-efficiency photocatalytic H₂ evolution.      

二维/一维BiOBr0.5Cl0.5/WO3 S型异质结助力光催化CO2还原

S型异质结不但可以提高载流子的分离效率,还可以维持较强的氧化还原能力。因此,构建S型异质是提高光催化二氧化碳还原反应的有效途径。本研究通过静电自组装法构建了具有近红外光响应(> 780 nm)的二维BiOBr_0.5Cl_0.5纳米片和一维WO₃纳米棒S型异质结光催化剂,并用于高效还原二氧化碳。能带位置和界面电子相互作用的综合分析表明：在光催化二氧化碳还原反应过程中,BiOBr_0.5Cl_0.5/WO₃遵循S型电子转移路径;不仅提高了载流子的高效分离,还维持了两相(BiOBr_0.5Cl_0.5和WO₃)较高的氧化还原能力。此外,二维纳米片/一维纳米棒的结构使得半导体之间具备良好的界面接触,有利于载流子的分离,且暴露更多的活性位点,最终提高催化效率。结果显示,BiOBr_0.5Cl_0.5/WO₃异质结催化剂表现出较高的CO₂还原能力和CO选择性,CO的产率高达16.68 μmol∙g^-1∙h^-1,分别是BiOBr_0.5Cl_0.5的1.7倍和WO₃的9.8倍。本工作为构建S型二维/一维异质结光催化剂高效还原二氧化碳提供了新的思路。     

还原温度对低温还原法制备的Ni_2P/Ti-MCM-41催化剂加氢脱硫性能的影响

以氯化镍(Ni Cl_2·6H_2O)为镍源、次磷酸铵(NH_4H_2PO_2)为磷源、Ti-MCM-41为载体,通过程序升温还原法制备了Ni_2P/Ti-M CM-41催化剂,并采用H_2-TPR、XRD、BET、XPS、TEM等手段对其结构和性质进行了表征。以二苯并噻吩(DBT)为模型化合物,考察了还原温度对Ni_2P/Ti-M CM-41催化剂的加氢脱硫(HDS)性能的影响。结果表明,程序升温还原法制备的Ni_2P/Ti-M CM-41催化剂前驱体的还原温度为318℃,比传统程序升温还原制备的Ni_2P低200℃。在350-500℃下还原得到的催化剂活性相为单一的Ni_2P相,较低的还原温度有利于形成更小粒径的磷化镍晶粒。还原温度为400℃时,制得的Ni_2P/Ti-M CM-41催化剂比表面积高、分散性最好、表面P富集少,具有最高的HDS活性;在340℃、3.0 M Pa、H_2/油体积比500、质量空速(WHSV)为2.0 h~(-1)的条件下,二苯并噻吩HDS转化率达到99.4%。     

Ni_2P催化剂的低温还原法合成及其HDS性能

在低还原温度下程序升温还原法制备了Ni2P/MCM-41催化剂,并采用H2-TPR、TG-DTG、XRD、BET、XPS等手段对制备的催化剂进行了表征,考察了还原温度对活性相Ni2P形成以及催化剂二苯并噻吩HDS性能的影响。结果表明,在210~390℃下还原得到的催化剂活性相为单一的Ni2P相;在390℃下还原得到的催化剂具有最高的二苯并噻吩HDS活性,在反应温度340℃、反应压力3.0 MPa、氢/油体积比500、质量空速(WHSV)2.0 h-1的条件下二苯并噻吩HDS转化率达到99.0%。     

不同半导体体系中磷化镍光催化甲酸分解的助催化作用

研究了在不同的半导体体系(TiO₂, CdS和C₃N₄)中, Ni₂P光催化甲酸(HCOOH)分解制氢的助催化效应. 作为助催化剂, Ni₂P与3种半导体形成的复合光催化剂均表现出良好的HCOOH分解制氢活性. Ni₂P/TiO₂, Ni₂P/CdS, Ni₂P/C₃N₄ 3种光催化剂最优的产氢活性分别为41.69, 22.45和47.67 μmol·mg^-1·h^-1, 分别为纯TiO₂, CdS和C₃N₄的3.8倍、 10倍和210倍, 表明Ni₂P在光催化HCOOH分解制氢体系中具有普适性. 研究了光催化HCOOH分解制氢的机理, Ni₂P的加入使光生电子从半导体转移至Ni₂P, 提高了光生电子-空穴对的分离效率; Ni₂P还促进了活性物种·OH的生成, 提高了光催化HCOOH分解的产氢速率.     

g-C3N4/BiVO4复合催化剂的制备及应用于光催化还原CO2的性能

用简单的超声分散法合成了具有可见光响应的类石墨氮化碳(g-C₃N₄)/BiVO₄复合光催化剂. 采用X射线衍射(XRD), X射线光电子能谱(XPS), 扫描电子显微镜(SEM), 透射电子显微镜(TEM), 紫外-可见(UV-Vis)分光光谱, 傅里叶红外变换(FTIR)光谱, 荧光发射谱(PL)和光电流响应等技术对所制备催化剂进行相关表征. 通过可见光下(λ> 420 nm)光催化还原CO₂的性能来评价样品的光催化活性, 发现不同复合比的催化剂中, 含40% (w) g-C₃N₄的复合催化剂表现出最高的光催化活性, 其催化活性分别为纯g-C₃N₄纳米片和纯BiVO₄的催化活性的2倍和4倍.光催化活性增加的主要原因是g-C₃N₄和BiVO₄之间形成了异质结, 且相互间能级匹配, 有利于光生电子和空穴的分离.     

棒状金属有机框架结构PCN-222(Cu)/TiO2复合材料的制备及其高效光催化CO2还原性能

The photocatalytic reduction of CO₂ has attracted considerable attention owing to the dual suppression of environmental pollution and energy shortage. The technology uses solar energy to convert carbon dioxide into hydrocarbon fuel, which is of great significance for achieving the carbon cycle. The development of low-cost photocatalytic materials is critical to achieving efficient solar energy to fuels conversion. One of the most commonly employed photocatalysts is TiO₂. However, it suffers from broad band gap as well as the recombination of photo-excited holes and electron. Hence, in this work, we report the photochemical reduction of CO₂ using rod-like PCN-222(Cu)/TiO₂ composites as photocatalyst through a simple hydrothermal method, in which TiO₂ nanoparticles are anchored at the interface of the SiC rod PCN-222(Cu). Multiple characterization techniques were used to analyze the structure, morphology, and properties of the PCN-222(Cu)/TiO₂ composite. A series of characterizations including X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), Fourier-transform infrared spectroscopy, photo-electrochemical, and photoluminescence (PL) confirm the successful preparation of PCN-222(Cu)/TiO₂ composites. SEM reveals that the TiO₂ nanoparticles are uniformly distributed on the surface of the rod-shaped PCN-222(Cu)/TiO₂. XRD results show that PCN-222(Cu) and PCN-222(Cu)/TiO₂ composite photocatalysts with good crystal structure were successfully synthesized. According to the DRS results, the prepared PCN-222(Cu)/TiO₂ composite samples exhibit characteristic absorption peaks of metalloporphyrins in the visible region. PL spectroscopy, transient photocurrent response, and electrochemical impedance spectroscopy further confirm that the rod-like PCN-222(Cu)/TiO₂ samples have high electron-hole pair separation efficiency. By controlling the mass ratio of PCN-222(Cu) and TiO₂, the photocatalytic CO₂ reduction performance test shows that the 10% PCN-222(Cu)/TiO₂ composite achieves optimal catalytic performance, yielding 13.24 μmol·g⁻¹·h⁻¹ CO and 1.73 μmol·g⁻¹·h⁻¹ CH₄, respectively. All the rod-like PCN-222(Cu)/TiO₂ composites exhibit better photocatalytic CO₂ activity than that of TiO₂ nanoparticles or PCN-222(Cu) under the illumination of xenon lamps, which is attributed to charge transport and electron-hole separation capabilities. After three test cycles, the catalytic activity of PCN-222(Cu)/TiO₂ photocatalyst was virtually unchanged. The reduction yield of the catalyst increased for 8 h under continuous illumination, indicating that PCN-222(Cu)/TiO₂ composites have acceptable stability. The estimation of the band gap curve and the Mote-Schottky curve test show that the lowest unoccupied molecular orbital position of PCN-222(Cu) is more negative than the TiO₂ of the conduction band; hence, a possible photocatalytic reaction mechanism of the PCN-222(Cu)/TiO₂ composite is proposed. This study provides a new strategy for the integration of metal-organic frameworks and oxide semiconductors to construct efficient photocatalytic systems.