Ultrathin organic polymer with p-πconjugated structure for simultaneous photocatalytic disulfide bond generation and CO_(2)reduction

Combining photocatalytic organic reactions with CO_(2)reduction is an efficient solar energy utilization mode,but it is still limited by the organic species that can be matched and the low conversion.Herein,ultrathin organic polymer with p-πconjugated structure(TPP)was rationally designed and prepared,and showed a high yield of CO(15.2 mmol g^(-1))and conversion of SAS coupled products(100%),far exceeding the organic polymer with P=O structure.The enhanced photoredox activity of TPP is ascribed to the orbital interaction between the p-orbital on phosphorus and theπ-orbitals of aromatic,which can accelerate the photoinduced charge carrier separation and improve the CO_(2)adsorption capacity.TPP can also be used for the dehydrocoupling of various benzyl mercaptans to the corresponding SAS bond products.This work provides a new concept for the efficient synthesis of disulfide bonds combined with CO_(2)reduction in a photoreaction system.

The incorporation of cocatalyst cobalt sulfide into graphitic carbon nitride:Boosted photocatalytic hydrogen evolution performance and mechanism exploration

2D-layered graphitic carbon nitride(g-C_(3)N_(4))is regarded as a great prospect as a photocatalyst for H_(2)generation.However,g-C_(3)N_(4)’s photocatalytic hydrogen evolution(HER)activity is significantly restricted by the recombination of photocarriers.We find that cobalt sulfide(CoS_(2))as a cocatalyst can promote g-C_(3)N_(4)nanosheets(NSs)to realize very efficient photocatalytic H_(2)generation.The prepared CoS_(2)/g-C_(3)N_(4)hybrids display highly boosted photocatalytic H_(2)generation performance and outstanding cycle stability.The optimized 7%-CoS_(2)/g-C_(3)N_(4)hybrids show a much improved photocatalytic H_(2)generation rate of 36.2μmol-1h-1,which is about 180 times as much as bare g-C_(3)N_(4)(0.2μmol-1h-1).In addition,the apparent quantum efficiency(AQE)of all the samples was computed under light atλ=370 nm,in which the AQE of 7%-CoS_(2)/g-C_(3)N_(4)hybrids is up to 5.72%.The experimental data and the DFT calculation suggest that the CoS_(2)/g-C_(3)N_(4)hybrid’s excellent HER activity is attributable to the lower overpotential and the smaller Co-H bond activation energy for HER.Accordingly,the CoS_(2)cocatalyst loading effectively boosts the photocatalytic performance of g-C_(3)N_(4)for H_(2)evolution.The project promotes fast development of high-efficiency photocatalysts and low-cost for photocatalytic H_(2)generation.

Photocatalytic degradation of dye effluent by titanium dioxide pillar pellets in aqueous solution

Photocatalytic oxidation(PCO) process is an effective way to deal with organic pollutants in wastewater which could be difficult to be degraded by conventional biological treatment methods. Normally the TiO 2 powder in nanometre size range was directly used as photocatalyst for dye degradation in wastewater. However the titanium dioxide powder was arduous to be recovered from the solution after treatment. In this application, a new form of TiO 2(i. e. pillar pellets ranging from 2 5 to 5 3 mm long and with a diameter of 3 7 mm) was used and investigated for photocatalytic degradation of textile dye effluent. A test system was built with a flat plate reactor(FPR) and UV light source(blacklight and solar simulator as light source respectively) for investigating the effectiveness of the new form of TiO 2. It was found that the photocatalytic process under this configuration could efficiently remove colours from textile dyeing effluent. Comparing with the TiO 2 powder, the pellet was very easy to recovered from the treated solution and can be reused in multiple times without the significant change on the photocatalytic property. The results also showed that to achieve the same photocatalytic performance, the FPR area by pellets was about 91% smaller than required by TiO 2 powder. At least TiO 2 pellet could be used as an alternative form of photocatalyst in applications for textile effluent treatment process, also other wastewater treatment processes.

Ag3PO4 Microcrystals Synthesized by Room-Temperature Solid State Reaction:Enhanced Photocatalytic Activity and Photoelectronchemistry Performance

Ag3PO4 microcrystals with highly enhanced visible light photocatalytic activity are prepared by a facile and simple solid state reaction at room temperature. The composition, morphology and optical properties of the asprepared Ag3PO4 microcrystMs are characterized by x-ray diffraction, scanning electron microscopy and UV-vis diffuse reflectance spectra. The photocatalytie properties of Ag3PO4 are investigated by the degradation of both methylene blue and methyl orange dyes under visible light irradiation. The as-prepared Ag3PO4 microcrystals possess high photocatalytic oxygen production with the rate of 673μmolh-1g-1. Moreover, the as-prepared Ag3PO4 microcrystals show an enhanced photoelectrochemistry performance under irradiation of visible light.

General approach for atomically dispersed precious metal catalysts toward hydrogen reaction

As a carbon-free energy carrier,hydrogen has become the pivot for future clean energy,while efficient hydrogen production and combustion still require precious metal-based catalysts.Single-atom catalysts(SACs)with high atomic utilization open up a desirable perspective for the scale applications of precious metals,but the general and facile preparation of various precious metal-based SACs remains challenging.Herein,a general movable printing method has been developed to synthesize various precious metal-based SACs,such as Pd,Pt,Rh,Ir,and Ru,and the features of highly dispersed single atoms with nitrogen coordination have been identified by comprehensive characterizations.More importantly,the synthesized Pt-and Ru-based SACs exhibit much higher activities than their corresponding nanoparticle counterparts for hydrogen oxidation reaction and hydrogen evolution reaction(HER).In addition,the Pd-based SAC delivers an excellent activity for photocatalytic hydrogen evolution.Especially for the superior mass activity of Ru-based SACs toward HER,density functional theory calculations confirmed that the adsorption of the hydrogen atom has a significant effect on the spin state and electronic structure of the catalysts.

Prospective life cycle assessment of CO_(2)conversion by photocatalytic reaction

CO_(2)conversion is gradually seen as a better way for society to effectively use carbon sources and avoid climate crisis associated with fossil CO_(2)emissions.And the decision to deploy CO_(2)technology scale should be relied on its environmental impact.In this work,life cycle assessment model evaluates the environmental performance of CO_(2)conversion by photocatalytic reaction process with two different catalysts(NiAl-LDH and Co-ZIF-9).Six impact categories considered in this analysis,including climate change,acidification potential,depletion of abiotic resources,eutrophication potential,ozone layer depletion potential,and photochemical oxidation potential.Results indicated that CO_(2)conversion with Co-ZIF-9 photocatalyst has a better environmental impact than the NiAl-LDH photocatalyst route.Moreover,the Co-ZIF-9 catalyst scenario also has a lower total environmental burden than the conventional CO production route.Sensitivity analysis shows that recycle performance of the catalyst is highly sensitive to the production process in two scenarios.This study could provide a framework for robust decisions in CO_(2)conversion by photocatalytic reaction,which is useful for policymakers to decide the feasibility of industrialization.

Experimental and theoretical investigation of sulfur-doped g-C_(3)N_(4)nanosheets/FeCo_(2)O_(4)nanorods S-scheme heterojunction for photocatalytic H_(2)evolution

g-C_(3)N_(4)emerges as a promising metal-free semiconductor photocatalyst due to its cost-effectiveness,facile synthesis,suitable visible light response,and robust thermal stability.However,its practical application in photocatalytic hydrogen evolution reaction(HER)is impeded by rapid carrier recombination and limited light absorption capacity.In this study,we successfully develop a novel g-C_(3)N_(4)-based step-scheme(S-scheme)heterojunction comprising two-dimensional(2D)sulfur-doped g-C_(3)N_(4)nanosheets(SCN)and one-dimensional(1D)FeCo_(2)O_(4)nanorods(FeCo_(2)O_(4)),demonstrating enhanced photocatalytic HER activity.The engineered SCN/FeCo_(2)O_(4)S-scheme heterojunction features a well-defined 2D/1D heterogeneous interface facilitating directed interfacial electron transfer from FeCo_(2)O_(4)to SCN,driven by the lower Fermi level of SCN compared to FeCo_(2)O_(4).This establishment of electron-interacting 2D/1D S-scheme heterojunction not only facilitates the separation and migration of photogenerated carriers,but also enhances visible-light absorption and mitigates electron-hole pair recombination.Band structure analysis and density functional theory calculations corroborate that the carrier migration in the SCN/FeCo_(2)O_(4)photocatalyst adheres to a typical S-scheme heterojunction mechanism,effectively retaining highly reactive photogenerated electrons.Consequently,the optimized SCN/FeCo_(2)O_(4)heterojunction exhibits a substantially high hydrogen production rate of 6303.5μmol·g^(-1)·h^(-1)under visible light excitation,which is 2.4 times higher than that of the SCN.Furthermore,the conjecture of the S-scheme mechanism is confirmed by in situ XPS measurement.The 2D/1D S-scheme heterojunction established in this study provides valuable insights into the development of high-efficiency carbon-based catalysts for diverse energy conversion and storage applications.

Enhanced Photoactivity of Layered Nanocomposite Materials Containing Rare Earths,Titanium Dioxide and Clay

The nanocomposite materials containing rare earths, titanium dioxide and clay (RE/TiO2/Clay) were characterized and tested for the photocatalytic decomposition of formaldehyde. The results show that nanocomposite materials prepared by doping appropriate rare earth elements have better photocatalytic properties than that prepared by doping excessive rare earth elements. The photocatalytic mechanism of composite materials was studied by integrating the theory of pho-tocatalysis with experiment results. Because the site of photocatalytic reaction was limited in the interspace of clay, photocatalytic reaction occurred by two steps: firstly, organic molecules dispersed into the interlayers of clay; secondly, organic molecules and photocatalyst of RE/TiO2 occurred photocatalytic reaction, resulting in forming carbon dioxide.

Solar-harvesting lead halide perovskite for artificial photosynthesis

Facing the upcoming energy and environmental crisis, artificial photosynthesis for producing various solar fuels (e.g., hydrogen or carbon products) via a solar-to-chemical energy conversion is receiving increasing attention;however, its low conversion efficiency is a challenge for commercialization. To resolve low-efficiency issues, lead halide perovskite (LHP) with outstanding optoelectronic properties compared to conventional semiconductors can be a promising approach to improve the solar-to-fuel conversion reactions and solar fuel production efficiency. The tunable energy band structure and charge transport properties of LHP have promoted their extensive use in the production of solar fuels. This study summarizes the recent advancements of LHP-mediated solar-to-fuel conversions, classified by their redox reactions, namely solar water splitting, hydrohalic acid splitting, and CO_(2) reduction. Advanced approaches for achieving high conversion efficiency and long-term durability are discussed, including the configuration of devices, the composition of LHP, and the protection strategy of LHP. Moreover, the reaction mechanisms of LHP-mediated solar-to-chemical energy conversions and obstacles for enhancing the conversion efficiency are discussed. Finally, we present the perspectives on the development of LHP-incorporated solar-to-fuel conversion systems, which might open a new era of energy harvesting and storage.

锆/铪氧簇中硫原子导向的金属-配体协同高效催化胺氧化反应

The performance applications(e.g.,photocatalysis)of zirconium(Zr)and hafnium(Hf)based complexes are greatly hindered by the limited development of their structures and the relatively inert metal reactivity.In this work,we constructed two ultrastable Zr/Hf-based clusters(Zr_(9)-TC4A and Hf_(9)-TC4A)using hydrophobic 4-tert-butylthiacalix[4]arene(H4TC4A)ligands,in which unsaturated coordinated sulfur(S)atoms on the TC4A^(4-)ligand can generate strong metal–ligand synergy with nearby active metal Zr/Hf sites.As a result,these two functionalized H4TC4A ligands modified Zr/Hf-oxo clusters,as catalysts for the amine oxidation reaction,exhibited excellent catalytic activity,achieving very high substrate conversion(>99%)and product selectivity(>90%).Combining comparative experiments and theoretical calculations,we found that these Zr/Hf-based cluster catalysts accomplish efficient amine oxidation reactions through synergistic effect between metals and ligands:(i)The photocatalytic benzylamine(BA)oxidation reaction was achieved by the synergistic effect of the dual active sites,in which,the naked S sites on the TC4A^(4-)ligand oxidize the BA by photogenerated hole and oxygen molecules are reduced by photogenerated electrons on the metal active sites;(ii)in the aniline oxidation reaction,aniline was adsorbed by the bare S sites on ligands to be closer to metal active sites and then oxidized by the oxygen-containing radicals activated by the metal sites,thus completing the catalytic reaction under the synergistic catalytic effect of the proximity metal–ligand.In this work,the Zr/Hf-based complexes applied in the oxidation of organic amines have been realized using active S atom-directed metal–ligand synergistic catalysis and have demonstrated very high reactivity.

A confined micro-reactor with a movable Fe_(3) O_(4) core and a mesoporous TiO_(2) shell for a photocatalytic Fenton-like degradation of bisphenol A

Photocatalysis and Fenton process are two primary and promising advanced oxidation processes to degrade organic pollutants.However,the practical applications of single photocatalysis and Fenton process are still limited.Introducing one of them into another to form a combined photocatalytic Fentonlike system has shown great potential but still faces challenges in designing a well-tailored catalyst.Herein,a confined photocatalytic Fenton-like micro-reactor catalyst with a movable Fe_(3) O_(4) core and a mesoporous TiO_(2) shell has been constructed via a successive Stober coating strategy,followed by an ultrasound assisted etching method.The resulting micro-reactor possesses well-defined yolk-shell structures with unifo rm mesopores(~4 nm),a large Brunauer-Emmett-Teller(BET) surface area(~166.7 m^(2)/g),a high pore volume(~0.56 cm^(3)/g) and a strong magnetization(~51 emu/g),as well as tunable reactor sizes(20-90 nm).When evaluated for degrading bisphenol A under solar light in the presence of peroxymo no sulfate,the micro-reactor exhibits a superior catalytic degradation perfo rmance with a high magnetic separation efficiency and an excellent recycle ability.The outstanding performance can be attributed to its unique textual structure,which leads to a great syne rgistic effect from the photocatalytic and Fenton-like process.This study gives an important insight into the design and synthesis of an advanced micro-reactor for a combined advanced oxidation processes(AOPs).

A Review on Crystalline Porous MOFs Materials in Photocatalytic Transformations of Organic Compounds in Recent Three Years

Metal-organic frameworks(MOFs)have always been the focus of chemists due to their diverse structures,adjustable pore size and high stability since they came into being.In recent years,as one of the most significant applications of MOFs porous materials,photocatalytic organic compounds transformation has made full-grown progress both in the preparation of the catalysts themselves and in the scope of specific applications.Herein,we summarize the research progress of MOFs catalysts for photocatalytic transformations of organic compounds in recent three years.Some outstanding works on the preparation and synthesis strategies of photocatalysts are introduced firstly,including internal optimization and modification of MOFs,POM@MOF composite and core-shell MOF@COF hybrids.The second part is about the application of diverse types of organic reactions,including dual-function organic reactions,catalytic oxidation reactions,comprehensive utilization of CO_(2) and degradation of organic pollutants.Besides,the development opportunities and some problems to be solved in this field are proposed.

In situ construction of oxygen-vacancy-rich Bi^(0)@Bi_(2)WO_(6)-x microspheres with enhanced visible light photocatalytic for NO removal

Surface oxygen vacancy defects and metal deposition on semiconductor photocatalysts play a critical role in photocatalytic reactions.In this work,oxygen-deficient Bi_(2)WO_(6)microspheres have been prepared by a facile ethylene glycol-assisted solvothermal method.Bi0 nanoparticles were reduced by in situ thermaltreatment on Bi_(2)WO_(6)microspheres to obtain Bi^(0)@Bi_(2)WO_(6)-x as well as maintaining the oxygen vacancies(OVs)under N_(2)atmosphere.Afterwards,photocatalytic NO oxidation removal activities of these photocatalysts were investigated under visible light irradiation and Bi^(0)@Bi_(2)WO_(6)-x shows the best NO removal activity than other samples.The photogenerated cha rge separation and trans fe r are promoted by Bi0 nanoparticles deposited on the surface of semiconductor catalysts.OVs defects promote the activation of reactants(H_(2)O and O_(2)),thereby enhancing the formation of the active substance.Moreover,both OVs defects and Bi0 metal have the characteristics of extending light absorption and enhancing the efficient utilization of solar energy.Besides,the photocatalytic NO oxidation mechanism of Bi^(0)@Bi_(2)WO_(6)-xwas investigated by in situ FTIR spectroscopy for reaction intermediates and final products.This work furnishes insight into the synthesis strategy and the underlying photocatalytic mecha nism of the surfacemodified Bi^(0)@Bi_(2)WO_(6)-x composite for pollutants removal.

Perylene Diimide-Based Multicomponent Metallacages as Photosensitizers for Visible Light-Driven Photocatalytic Oxidation Reaction

Self-assembled supramolecular structures with efficient singlet oxygen(1O2)-generation ability are expected to enable photocatalytic oxidation reactions.Herein,we use two photosensitizers,perylene diimide and benzothiadiazole derivative,as the boards to prepare two barrel-shaped metallacages viametal-coordination-driven self-assembly.

通过锚定钯纳米颗粒在CsPbBr_(3)钙钛矿纳米晶体上从而增强光催化CO_(2)还原

最近,全无机铯铅溴(CsPbX_(3)(X=Cl,Br,I))钙钛矿纳米晶体被广泛应用于光催化CO_(2)还原(CO_(2)RR)领域.但是,由于纯CsPbX_(3)纳米晶体内部载流子辐射复合严重,所以精心设计基于CsPbX_(3)纳米晶体的异质结构对于分离载流子和实现高效的CO_(2)RR是非常重要的.本文中,我们介绍了利用光辅助的方法将Pd纳米颗粒锚定在CsPbX_(3)纳米晶体上.利用此方法所制备的CsPbBr_(3)@Pd纳米晶体通过在CsPbBr_(3)/Pd界面处构建肖特基结从而促进了载流子的分离并抑制了辐射复合.第一性原理计算表明:在CO_(2)RR过程中,CsPbBr_(3)@Pd纳米晶体比纯CsPbX_(3)纳米晶体具有更低的能量势垒.当CsPbBr_(3)@Pd纳米晶体被用作CO_(2)RR催化剂时,电子消耗速率高达46.2μmol g^(-1)h^(-1),是纯CsPbX_(3)纳米晶体作为光催化剂时电子消耗速率的4.8倍.这项工作不仅介绍了一种利用光辅助将钯纳米颗粒锚定在CsPbX_(3)纳米晶体上的方法,而且还证明了CsPbBr_(3)@Pd纳米晶体在光催化CO_(2)还原领域的巨大潜能.

Aromatic alcohols oxidation and hydrogen evolution over π-electron conjugated porous carbon nitride rods

Photocatalysis using polymeric carbon nitride(CN)materials is a constantly evolving field,where the variation of synthetic procedures allows the constant improvement of activity by tackling the intrinsic limitations of these materials(optical absorbance,specific surface area,charge migration,etc.).Amongst the possible photocatalytic reactions,the most popular application of CNs is the hydrogen evolution reaction(HER)from water.In this work,we design precisely-controlled carbon-doped porous CN rods with extended π-electron conjugation from supramolecular assemblies of melem and co-monomers,which partially substitute nitrogen for carbon atoms at the pyrimidine ring of the melem.Dense hydrogen bonds and good thermal stability of the melem-based supramolecular framework allow synthesizing a more ordered structure for improved charge migration;the control from the molecular level over the position of carbon-substituted nitrogen positions tailors the band alignment and photogenerated charge separation.The optimal photocatalyst shows an excellent HER rate(up to 10.16 mmol·h-1·g-1 under 100 W white light-emitting diode(LED)irradiation,with an apparent quantum efficiency of 20.0%at 405 nm,which is 23.2 times higher compared to a reference bulk CN).To fully harness the benefits of the developed metal-free CNs,selective oxidation reaction of aromatic alcohols is demonstrated with high conversion and selectivity.