Visible Light-Induced Photocatalysis:Self-Fenton Degradation of p-CIPhOH Over Graphitic Carbon Nitride by a Polyethylenimine Bifunctional Catalyst

Deep degradation of organic pollutants by sunlight-induced coupled photocatalytic and Fenton (photo-Fenton) reactions is of immense importance for water purification. In this work, we report a novel bifunctional catalyst (Fe-PEI-CN) by codoping graphitic carbon nitride (CN) with polyethyleneimine ethoxylated (PEI) and Fe species, which demonstrated high activity during p-chlorophenol (p-ClPhOH) degradation via H_(2)O_(2) from the photocatalytic process. The relationship between the catalytic efficiency and the structure was explored using diff erent characterization methods. The Fe modification of CN was achieved through Fe-N coordination, which ensured high dispersion of Fe species and strong stability against leaching during liquid- phase reactions. The Fe modification initiated the Fenton reaction by activating H_(2)O_(2) into ·OH radicals for deep degradation of p-ClPhOH. In addition, it eff ectively promoted light absorption and photoelectron-hole (e-h ^(+) ) separation, corresponding to improved photocatalytic activity. On the other hand, PEI could significantly improve the ability of CN to generate H_(2)O_(2) through visible light photocatalysis. The maximum H_(2)O_(2) yield reached up to 102.6 μmol/L, which was 22 times higher than that of primitive CN. The cooperation of photocatalysis and the self-Fenton reaction has led to high-activity mineralizing organic pollutants with strong durability, indicating good potential for practical application in wastewater treatment.

Three‐dimensional(3D)‐printed MXene high‐voltage aqueous micro‐supercapacitors with ultrahigh areal energy density and low‐temperature tolerance

The rapid advancement in the miniaturization,integration,and intelligence of electronic devices has escalated the demand for customizable microsupercapacitors(MSCs)with high energy density.However,efficient microfabrication of safe and high‐energy MXene MSCs for integrating microelectronics remains a significant challenge due to the low voltage window in aqueous electrolytes(typically≤0.6 V)and limited areal mass loading of MXene microelectrodes.Here,we tackle these challenges by developing a highconcentration(18mol kg^(−1))“water‐in‐LiBr”(WiB)gel electrolyte for MXene symmetric MSCs(M‐SMSCs),demonstrating a record high voltage window of 1.8 V.Subsequently,additive‐free aqueous MXene ink with excellent rheological behavior is developed for three‐dimensional(3D)printing customizable all‐MXene microelectrodes on various substrates.Leveraging the synergy of a highvoltage WiB gel electrolyte and 3D‐printed microelectrodes,quasi‐solid‐state MSMSCs operating stably at 1.8 V are constructed,and achieve an ultrahigh areal energy density of 1772μWhcm^(−2)and excellent low‐temperature tolerance,with a long‐term operation at−40℃.Finally,by extending the 3D printing protocol,M‐SMSCs are integrated with humidity sensors on a single planar substrate,demonstrating their reliability in miniaturized integrated microsystems.

Preparation and catalytic properties of mesoporous nV ‐MCM‐41 for propane oxidative dehydrogenation in the presence of CO_2

The nV‐MCM‐41 catalysts were prepared by one‐step hydrothermal synthesis and applied to the oxidative dehydrogenation of propane（ODHP） in the presence of CO2. Several state‐of‐the‐art char‐acterization methods were performed to explore the correlation between catalytic performance and the physicochemical characterizations of the catalysts. Because moderate amounts of V species were introduced into the framework of MCM‐41, the catalyst maintained a large specific surface area, a highly ordered mesoporous structure, and highly dispersed V active sites（monomeric and dimeric V oxide species）, while the high‐vanadium‐doping catalysts caused an enhancement in the number of acidic sites and V2O5 crystallites. The ODHP reaction showed that the 6.8 V‐MCM‐41（V content 6.8 wt%） catalyst exhibits high activity and stability, and the C3H8/CO2 molar ratio（1：4） was suitable. The promoting effect of CO2 on the oxidative dehydrogenation of ODHP was demonstrated as the reaction coupling mechanism and ＂lattice oxygen＂ mechanism.

Measurable surface d charge of Pd as a descriptor for the selective hydrogenation activity of quinoline

Au Pd nanoalloys with tunable Pd concentrations have been synthesized and used as model catalysts. They have been directly imaged by high-angle annular dark-field scanning transmission electron microscopy and investigated by thorough analyses of their extended X-ray absorption fine structure, X-ray absorption near-edge structure, X-ray diffraction and X-ray photoelectron spectroscopy measurements. The bimetallic nanoparticles are embedded in a carbonaceous matrix and have almost an identical structure at the atomic level and the same electronic properties as Au Pd bulk alloys with the same compositions. The d-electron increase at surface Pd sites is determined by the Pd concentration of the alloy. Similarly, their activation entropy and catalytic activity for the hydrogenation of quinoline is related to the Pd concentration, with Au50 Pd50 the most active of the alloys investigated. An almost 11 times higher activity was achieved compared to a pure Pd catalyst. The experimentally measurable surface d charge at the Pd sites in the Au Pd was found to linearly correlate with the activation entropy and catalytic activity for the hydrogenation of quinoline. The alloy structure is stable, showing negligible metal segregation, dissolution-redeposition and aggregation during the hydrogenation process which involves strong adsorption.

Microwave-assisted ionothermal synthesis of hierarchical microcube-like BiOBr with enhanced photocatalytic activity

Bismuth oxybromide（BiOBr） with a hierarchical microcube morphology was successfully synthesized via microwave-assisted ionothermal self-assembly method. The as-obtained BiOBr was composed of regular multi-layered nanosheets, which were formed by selective adsorption of ionic liquids on the Br-terminated surface, followed by the formation of hydrogen bond-co-π-π stacking.The synthesized BiOBr exhibited high activity, excellent stability, and superior mineralization ability in the photocatalytic degradation of organic dyes under visible light owing to its enhanced light absorbance and narrow bandgap. Furthermore, photo-generated electrons were determined to be the main active species by comparison with different trapping agents used in the photocatalytic reactions.

Radiation-induced cross-linking:a novel avenue to permanent 3D modification of polymeric membranes

Membrane fouling is always the biggest problem in the practice of membrane separation technologies,which strongly impacts their applicability,separation efficiency,cost effectiveness,and service lifespan.Herein,a simple but effective 3D modification approach was designed for permanently functionalizing polymeric membranes by directly cross-linking polyvinyl alcohol(PVA)under gamma-ray irradiation at room temperature without any additives.After the modification,a PVA layer was constructed on the membrane surface and the pore inner surface of polyvinylidene fluoride(PVDF)membranes.This endowed them with good hydrophilicity,low adsorption of protein model foulants,and easy recoverability properties.In addition,the pore size and distribution were customized by controlling the PVA concentration,which enhanced the rejection ability of the resultant membranes and converted them from microfiltration to ultrafiltration.The crosslinked PVA layer was equipped with the resultant membranes with good resistance to chemical cleaning by acidic,alkaline,and oxidative reagents,which could greatly prolong the membrane service lifetime.Furthermore,this approach was demonstrated as a universal method to modify PVDF membranes with other hydrophilic macromolecular modifiers,including polyethylene glycol,sodium alginate,and polyvinyl pyrrolidone.This modification of the membranes effectively endowed them with good hydrophilicity and antifouling properties,as expected.

Enhancing Photocatalytic Performance of NH 2-UIO66 by Defective Structural Engineering

NH_(2)-UIO66(NU)is a promising photocatalyst for the reduction of Cr(VI)to low-toxic Cr(III)driven by visible light under ambient conditions.However,the main limitation in this process is the ineffi cient ligand to metal charge transfer(LMCT)of photo-excited electrons,which is caused by inherent energy gap(ΔE_(LMCT)).This study synthesized the defective NU(NUXH,where X is the molar equivalent of the modulator)with reducedΔE_(LMCT)through linkers removal via acid treatment.The electronic structure of NUX-H was systematically investigated,and the results indicated that the structural defects in NUX-H strongly altered the environment of the Zr atoms.Furthermore,they substantially lowered the energy of the unoccupied d orbitals(LUMO),which was benefi cial to effi cient LMCT,resulting in an improved photocatalytic activity of NUX-H toward high-concentration(100 mg/L)Cr(VI)reduction.Compared to NU with defect-free structure,the reducing rate of Cr(VI)was increased by 47 times.This work introduced an alternative strategy in terms of designing effi cient photocatalysts for reducing Cr(VI)under ambient conditions.

The self-assembly of gold nanoparticles in large-pore ordered mesoporous carbons

Simple encapsulation of 3 nm gold nanoparticles in ordered mesoporous carbon with large pores of 17 nm and thick pore walls of 16 nm was achieved by a metal–ligand coordination assisted-selfassembly approach.Polystyrene-block-polyethylene-oxide(PS-b-PEO)diblock copolymer with a large molecular weight of the PS chain and mercaptopropyltrimethoxysilane were used as the template and the metal ligand,respectively.Small-angle X-ray scattering,X-ray diffraction,transmission electron microscopy,and X-ray photoelectron spectroscopy showed that monodispersed aggregation-free gold nanoparticles approximately 3 nm in size were partially embedded in the large open pore structure of the ordered mesoporous carbon.The strong coordination between the gold species and the mercapto groups and the thick porous walls increased the dispersion of the gold nanoparticles and essentially inhibited particle aggregation at 600℃.The gold nanoparticles in the ordered mesoporous carbon are active and stable in the reduction of nitroarenes involving bulky molecules using sodium borohydride as a reducing agent under ambient conditions(30℃)in water.The large interconnected pore structure facilitates the mass transfer of bulky molecules.

Research Progress on Photocatalytic/Photoelectrocatalytic Oxidation of Nitrogen Oxides

The emission of nitrogen oxides(NO_(x))increases year by year,causing serious problems to our livelihoods.The photocatalytic oxidation of NO_(x)has attracted more attention recently because of its effi cient removal of NO_(x),especially for low concentra-tions of NO_(x).In this review,the mechanism of the photocatalytic oxidation of NO_(x)is described.Then,the recent progress on the development of photocatalysts is reviewed according to the categories of inorganic semiconductors,bismuth-based compounds,nitrogen carbide polymer,and metal organic frameworks(MOFs).In addition,the photoelectrocatalytic oxida-tion of NO_(x),a method involving the application of an external voltage on the photocatalytic system to further increase the removal effi ciency of NO_(x),and its progress are summarized.Finally,we outline the remaining challenges and provide our perspectives on the future directions for the photocatalytic oxidation of NO_(x).

Effect of catalyst on formation of poly(methyl methacrylate) brushes by surface initiated atom transfer radical polymerization

Poly （methyl methacrylate） （PMMA） brushes were synthesized from silicon wafers via surface initiated atom transfer radical polymerization （SI-ATRP）. Energy disperse spectroscopy （EDS） and atomic force microscopy （AFM） confirmed that PMMA brushes were successfully prepared on the silicon wafers, and the surface became more hydrophobic according to the contact angle of 69~. It is found that CuCI/1, 1, 4, 7, 10, 10-hexamethyl triethylenetetramine （HMTETA） system is more suitable than CuBr/N, N, N′, N″, N′″-pentamethyl diethylenetriamine （PMDETA） system to control the free radical polymerization of MMA in solution. Nevertheless, better control on the thickness of PMMA brushes was achieved in CuBr/PMDETA than in CuC1/HMTETA due to higher activity and better reversibility of the former system.

Two flowers per seed:Derivatives of CoG@F127/GO with enhanced catalytic performance of overall water splitting

In this work,cobalt glycerate(CoG@F127)nanosheets grown on the surface of graphene oxide(GO),i.e.CoG@F127/GO,have been synthesized with the assistance of nonionic surfactant Pluronic F127 via a hydrothermal method.After calcination,CoG@F127/GO is transformed into one derivative,Co nanoparticles coated with a trace amount of carbon(Co-C)on GO(Co-C/GO).The Co nanoparticles consist of an atypical core-shell structure,in which the core and the shell are both Co.Co-C anchored on GO can avoid the nanoparticles aggregation and expose more active sites for hydrogen evolution reaction(HER)to significantly improve the catalyst activity of HER.CoG@F127/GO is phosphatized to form the other derivate,cobalt pyrophosphate coated with a small amount of carbon(Co_(2)P_(2)O_(7)-C)on GO(Co_(2)P_(2)O_(7)-C/GO).Co_(2)P_(2)O_(7)-C/GO composite owns a large electrochemical active surface area(ECSA)and fast rate towards oxygen evolution reaction(OER).Furthermore,the two derivatives of CoG@F127/GO,i.e.Co-C/GO and Co_(2)P_(2)O_(7)-C/GO as twin flowers,are assembled into an overall water splitting electrolytic cell with a cell voltage of 1.56 V to deliver a current density of 10 mA cm^(-2).

Solar-assisted selective separation and recovery of precious group metals from deactivated air purification catalysts

The mitigation of environmental and energy crises could be advanced by reclaiming platinum group precious metals(PGMs) from decommissioned air purification catalysts. However, the complexity of catalyst composition and the high chemical inertness of PGMs significantly impede this process. Consequently,recovering PGMs from used industrial catalysts is crucial and challenging. This study delves into an environmentally friendly approach to selectively recover PGMs from commercial air purifiers using photocatalytic redox technology. Our investigation focuses on devising a comprehensive strategy for treating three-way catalysts employed in automotive exhaust treatment. By meticulously pretreating and modifying reaction conditions, we achieved noteworthy results, completely dissolving and separating rhodium(Rh), palladium(Pd), and platinum(Pt) within a 12-h time frame. Importantly, the solubility selectivity persists despite the remarkably similar physicochemical properties of Rh, Pd, and Pt. To bolster the environmental sustainability of our method, we harness sunlight as the energy source to activate the photocatalysts, facilitating the complete dissolution of precious metals under natural light irradiation. This ecofriendly recovery approach demonstrated on commercial air purifiers, exhibits promise for broader application to a diverse range of deactivated air purification catalysts, potentially enabling implementation on a large scale.

Ordered mesoporous Fe/TiO_2 with light enhanced photo-Fenton activity

Ordered mesoporous Fe/TiO2 was prepared by an evaporation-induced self-assembly method. The iron ions were in situ embedded in the pore wall of the TiO2 framework. The catalyst has excellent light-assisted Fenton catalytic performance under UV and visible light irradiation. X-ray diffraction and transmission electron microscopy results showed that the TiO2 samples have an ordered two-dimensional hexagonal pore structure and an anatase phase structure with high crystallinity. The ordered pore structure of the TiO2 photocatalyst with a large specific surface area is beneficial to mass transfer and light harvesting. Furthermore, iron ions can be controlled by embedding them into the TiO2 framework to prevent iron ion loss and inactivation. After five cycles, the reaction rate of the ordered mesoporous Fe/TiO2 remained unchanged, indicating that the material has stable performance and broad application prospects for the purification of environmental pollutants.

Magnetic Fe_3O_4-Reduced Graphene Oxide Nanocomposites-Based Electrochemical Biosensing

An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the magnetism, conductivity and biocompatibility of the Fe3O4-RGO nanosheets, the nanocomposites could be facilely adhered to the electrode surface by magnetically controllable assembling and beneficial to achieve the direct redox reactions and electrocatalytic behaviors of GOx immobilized into the nanocomposites. The biosensor exhibited good electrocatalytic activity, high sensitivity and stability. The current response is linear over glucose concentration ranging from 0.05 to 1.5 m M with a low detection limit of0.15 μM. Meanwhile, validation of the applicability of the biosensor was carried out by determining glucose in serum samples. The proposed protocol is simple, inexpensive and convenient, which shows great potential in biosensing application.

Pyroelectricity effect on photoactivating palladium nanoparticles in PbTiO3 for Suzuki coupling reaction

Combining microwave radiation with photocatalytic systems is a promising method to inhibit photogenerated electron-hole recombination and enhance the photocatalytic reaction performance. In this study, we have designed Pd/Pb TiO3 catalysts that can use both microwave fields and photocatalysis. Benefiting from the synergistic effect of microwave field and UV light, the Pb TiO3 crystals convert thermal energy into electrical energy via the pyroelectricity effect, generating positive and negative charges(q+ and q-), while Pd nanoparticles significantly improve the quantum efficiency of the photocatalytic process. The composite catalyst significantly enhances the reaction rate and selectivity of the model Suzuki coupling reaction performed with bromobenzene. Microwave fields can directly act on chemical systems, promoting or changing various chemical reactions in unique ways.

Nanotube array-like WO_3/W photoanode fabricated by electrochemical anodization for photoelectrocatalytic overall water splitting

Photoactive WO3is attractive as a photocatalyst for green energy evolution through water splitting.In the present work,an electrochemical anodic oxidation method was used to fabricate a photo‐responsive nanotube array‐like WO3/W(NA‐WO3/W)photoanode from W foil as a precursor.Compared with a reference commercial WO3/W electrode,the NA‐WO3/W photoanode exhibited enhanced and stable photoelectrocatalytic(PEC)activity for visible‐light‐driven water splitting with a typical H2/O2stoichiometric ratio of2:1and quantum efficiency of approximately5.23%under visible‐light irradiation from a light‐emitting diode(λ=420nm,15mW/cm2).The greatly enhanced PEC performance of the NA‐WO3/Wphotoanode was attributed to its fast electron–hole separation rate,which resulted from the one‐dimensional nanotube array‐like structure,high crystallinity of monoclinic WO3,and strong interaction between WO3and W foil.This work paves the way to a facile route to prepare highly active photoelectrodes for solar light transfer to chemical energy.

Engineering Pt heterogeneous catalysts for accelerated liquid–solid redox conversion in Li-S batteries

The shuttle effect caused by soluble lithium polysulfides (LiPSs) deteriorates multiphase transformation reaction kinetics of sulfur species,and gives rise to an unserviceable lithium-sulfur (Li-S) battery.Catalysis,as a process optimization approach,offers an option to eliminate the intrinsic issues.However,exploring and understanding the role of catalysts on electrode reaction remains critical bottlenecks,particularly as they are prone to continuous evolution under complex dynamic environment.Herein,platinum nanoparticles loaded on MXene nanosheets,as sulfur host,and the action of catalysts on the reaction process are investigated via ex-situ monitors upon solid–liquid–solid chemical transformation of sulfur species.These traces confirm that the high performance originates from electron transfer between catalysts and LiPSs,which lowers the nucleation barrier from liquid LiPSs to solid Li_(2)S/Li_(2)S_(2).Further,the accelerated liquid–solid conversion can alleviate the accumulation of LiPSs,and boost the reaction kinetics in Li-S batteries.The findings corroborate the electronic modulation between catalysts and LiPSs,which is a generalizable strategy to optimize energy conversion efficiency of Li-S batteries.

Surface modification of phosphate ion to promote photocatalytic recovery of precious metals

Photocatalytic recovery,a novel precious metal recycling technology,dedicates to solving the environmental and energy consumption problems caused by traditional technologies.The activation of molecular oxygen (O_(2)) is one of the most critical steps in the whole process.Herein,we regulated the different adsorption intensity of oxygen on the surface by designing phosphate (PO_(4)^(3-)) modified titanium oxide(TiO_(2)).The results show that the adsorption of oxygen on the photocatalyst surface is gradually enhanced,which effectively improves the dissolution rate of precious metals.PO_(4)^(3-)modification increased the photocatalytic dissolution rate of gold (Au) by 2.8 times.The photocatalytic activity of other precious metals dissolution (such as palladium (Pd),platinum (Pt),rhodium (Rh),ruthenium (Ru) and iridium (Ir)) was also significantly improved.It is applied to the recovery of precious metals from spent catalysts and electronic devices to significantly promote the recovery efficiency.This indicates the direction for designing more efficient photocatalysts for precious metal recovery.

Immobilization and Bioelectrochemistry of Hemoglobin Based on Carrageenan and Room Temperature Ionic Liquid Composite Film

A novel biopolymer/room-temperature ionic liquid composite film based on carrageenan, room temperature ionic liquid （IL） [1-butyl-3-methylimidazolium tetrafluoroborate （[BMIM]BF4）] was explored for immobilization of hemoglobin （Hb） and construction of biosensor. Direct electrochemistry and electrocatalytic behaviors of Hb entrapped in the IL-carrageenan composite film on the surface of glassy carbon electrode （GCE） were investigated. UV-vis spectroscopy demonstrated that Hb in the IL-carrageenan composite film could retain its native secondary structure. A pair of well-defined redox peaks of Hb was obtained at the Hb-IL-carrageenan composite film modified electrode through direct electron transfer between the protein and the underlying electrode. The heterogeneous electron transfer rate constant （ks） was 2.02 s 1, indicating great facilitation of the electron transfer between Hb and IL-carrageenan composite film modified electrode. The modified electrode showed excellent electrocatalytic activity toward reduction of hydrogen peroxide with a linear range of 5.0 × 10-6 to 1.5 ×10-4 mol/L and the detection limit was 2.12 ×10 7 mol/L （S/N= 3）. The apparent Michaelis-Menten constant KM^app for hydrogen peroxide was estimated to be 0.02 mmol/L, indicating that the biosensor possessed high affinity to hydrogen peroxide. In addition, the proposed biosensor showed good reproducibility and stability.

Pressure-dependent band-bending in ZnO:A near-ambient-pressure X-ray photoelectron spectroscopy study

ZnO-based catalysts have been intensively studied because of their extraordinary performance in lower olefin synthesis,methanol synthesis and water-gas shift reactions.However,how ZnO catalyzes these reactions are still not well understood.Herein,we investigate the activations of CO_(2),O_(2)and CO on single crystalline ZnO polar surfaces at room temperature,through in-situ near-ambient-pressure X-ray photoelectron spectroscopy(NAP-XPS).It is revealed that O_(2)and CO_(2)can undergo chemisorption on ZnO polar surfaces at elevated pressures.On the ZnO(0001)surface,molecular CO_(2)(O_(2))can chemically interact with the top layer Zn atoms,leading to the formation of CO_(2)^(δ-)(O_(2)^(δ-))or partially dissociative atomic oxygen(O-)and hence the electron depletion layer in ZnO.Therefore,an apparent upward band-bending in ZnO(0001)is observed under the CO_(2)and O_(2)exposure.On the ZnO(0001)surface,the molecular chemisorbed CO_(2)(O_(2))mainly bond to the surface oxygen vacancies,which also results in an upward bandbending in ZnO(0001).In contrast,no band-bending is observed for both ZnO polar surfaces upon CO exposure.The electron-acceptor nature of the surface bounded molecules/atoms is responsible for the reversible binding energy shift of Zn 2 p_(3/2)and O 1 s in ZnO.Our findings can shed light on the fundamental understandings of CO_(2)and O_(2)activation on ZnO surfaces,especially the role of ZnO in heterogeneous catalytic reactions.