Exploring the Roles of Single Atom in Hydrogen Peroxide Photosynthesis

This comprehensive review provides a deep exploration of the unique roles of single atom catalysts(SACs)in photocatalytic hydrogen peroxide(H_(2)O_(2))production.SACs offer multiple benefits over traditional catalysts such as improved efficiency,selectivity,and flexibility due to their distinct electronic structure and unique properties.The review discusses the critical elements in the design of SACs,including the choice of metal atom,host material,and coordination environment,and how these elements impact the catalytic activity.The role of single atoms in photocatalytic H_(2)O_(2)production is also analysed,focusing on enhancing light absorption and charge generation,improving the migration and separation of charge carriers,and lowering the energy barrier of adsorption and activation of reactants.Despite these advantages,several challenges,including H_(2)O_(2)decomposition,stability of SACs,unclear mechanism,and low selectivity,need to be overcome.Looking towards the future,the review suggests promising research directions such as direct utilization of H_(2)O_(2),high-throughput synthesis and screening,the creation of dual active sites,and employing density functional theory for investigating the mechanisms of SACs in H_(2)O_(2)photosynthesis.This review provides valuable insights into the potential of single atom catalysts for advancing the field of photocatalytic H_(2)O_(2)production.

Green and scalable electrochemical routes for cost‐effective mass production of MXenes for supercapacitor electrodes

One of the most unique properties of two-dimensional carbides and nitrides of transition metals(MXenes)is their excellent water dispersibility and yet possessing superior electrical conductivity but their industrial-scale application is limited by their costly chemical synthesis methods.In this work,the niche feature of MXenes was capitalized in the packed-bed electrochemical reactor to produce MXenes at an unprecedented reaction rate and yield with minimal chemical waste.A simple NH4F solution was employed as the green electrolyte,which could be used repeatedly without any loss in its efficacy.Surprisingly,both fluoride and ammonium were found to play critical roles in the electrochemical etching,functionalization,and expansion of the layered parent materials(MAXs)through which the liberation of ammonia gas was observed.The electrochemically produced MXenes with excellent conductivity,applied as supercapacitor electrodes,could deliver an ultrahigh volumetric capacity(1408 F cm^(−3))and a volumetric energy density(75.8 Wh L^(−1)).This revolutionary green,energy-efficient,and scalable electrochemical route will not only pave the way for industrial-scale production of MXenes but also open up a myriad of versatile electrochemical modifications for improved functional MXenes.

Cs-Induced Phase Transformation of Vanadium Oxide for High-Performance Zinc-Ion Batteries

Rechargeable aqueous zinc-ion batteries are promising candidate for gridscale energy storage.However,the development of zinc-ion batteries has been plagued by the lack of cathode materials with high specific capacity and superior lifespan.Herein,hexagonal Cs_(0.3)V_(2)O_(5)cathode is fabricated and investigated in zinc-ion batteries.Compared with the traditional vanadium oxides,the introduction of Cs changes the periodic atomic arrangements,which not only stabilizes the open framework structure but also facilitates the Zn^(2+)diffusion with a lower migration energy barrier.Consequently,high specific capacity of 543.8 mA h g^(-1)at 0.1 A g^(-1)is achieved,which surpasses most of reported cathode materials in zinc-ion batteries.The excellent cycle life is achieved over 1000 cycles with about 87.8%capacity retention at 2 A g^(-1).Furthermore,the morphological evolution and energy storage mechanisms are also revealed via a series of techniques.This work opens up a phase engineering strategy to fabricate the hexagonal vanadium oxide and elucidate the application of phase-dependent cathodes in zinc-ion batteries.

Switching of K-Q intervalley trions fine structure and their dynamics in n-doped monolayer WS_(2)

Monolayer group VI transition metal dichalcogenides(TMDs)have recently emerged as promising candidates for photonic and opto-valleytronic applications.The optoelectronic properties of these atomically-thin semiconducting crystals are strongly governed by the tightly bound electron-hole pairs such as excitons and trions(charged excitons).The anomalous spin and valley configurations at the conduction band edges in monolayer WS_(2)give rise to even more fascinating valley many-body complexes.Here we find that the indirect Q valley in the first Brillouin zone of monolayer WS_(2)plays a critical role in the formation of a new excitonic state,which has not been well studied.By employing a high-quality h-BN encapsulated WS_(2)field-effect transistor,we are able to switch the electron concentration within K-Q valleys at conduction band edges.Consequently,a distinct emission feature could be excited at the high electron doping region.Such feature has a competing population with the K valley trion,and experiences nonlinear power-law response and lifetime dynamics under doping.Our findings open up a new avenue for the study of valley many-body physics and quantum optics in semiconducting 2D materials,as well as provide a promising way of valley manipulation for next-generation entangled photonic devices.

Durable hierarchical phosphorus‐doped biphase MoS_(2)electrocatalysts with enhanced H^(*)adsorption

Phase engineering is an efficient strategy for enhancing the kinetics of electrocatalytic reactions.Herein,phase engineering was employed to prepare high‐performance phosphorous‐doped biphase(1T/2H)MoS_(2)(P‐BMS)nanoflakes for hydrogen evolution reaction(HER).The doping of MoS_(2)with P atoms modifies its electronic structure and optimizes its electrocatalytic reaction kinetics,which significantly enhances its electrical conductivity and structural stability,which are verified by various characterization tools,including X‐ray photoelectron spectroscopy,high‐resolution transmission electron microscopy,X‐ray absorption near‐edge spectroscopy,and extended X‐ray absorption fine structure.Moreover,the hierarchically formed flakes of P‐BMS provide numerous catalytic surface‐active sites,which remarkably enhance its HER activity.The optimized P‐BMS electrocatalysts exhibit low overpotentials(60 and 72 mV at 10 mA cm^(−2))in H_(2)SO_(4)(0.5 M)and KOH(1.0 M),respectively.The mechanism of improving the HER activity of the material was systematically studied using density functional theory calculations and various electrochemical characterization techniques.This study has shown that phase engineering is a promising strategy for enhancing the H*adsorption of metal sulfides.

Chemical Scissors Tailored Nano‑Tellurium with High‑Entropy Morphology for Efficient Foam‑Hydrogel‑Based Solar Photothermal Evaporators

The development of tellurium(Te)-based semiconductor nanomaterials for efficient light-to-heat conversion may offer an effective means of harvesting sunlight to address global energy concerns.However,the nanosized Te(nano-Te)materials reported to date suffer from a series of drawbacks,including limited light absorption and a lack of surface structures.Herein,we report the preparation of nano-Te by electrochemical exfoliation using an electrolyzable room-temperature ionic liquid.Anions,cations,and their corresponding electrolytic products acting as chemical scissors can precisely intercalate and functionalize bulk Te.The resulting nano-Te has high morphological entropy,rich surface functional groups,and broad light absorption.We also constructed foam hydrogels based on poly(vinyl alcohol)/nano-Te,which achieved an evaporation rate and energy efficiency of 4.11 kg m^(−2)h^(−1)and 128%,respectively,under 1 sun irradiation.Furthermore,the evaporation rate was maintained in the range 2.5-3.0 kg m^(−2)h^(−1)outdoors under 0.5-1.0 sun,providing highly efficient evaporation under low light conditions.

Melamine-assisted pyrolytic synthesis of bifunctional cobalt-based core–shell electrocatalysts for rechargeable zinc–air batteries

Designing a highly active-and stable non-noble metal bifunctional oxygen catalyst for rechargeable Znair battery remains a great challenge. Herein, we develop a facile and melamine-assisted-pyrolysis(MAP)strategy for the synthesis of core–shell Co-based electrocatalysts@N-doped carbon nanotubes(Co@CNTs)derived from metal–organic frameworks. The Co@CNTs exhibited excellent bifunctional electrocatalytic performance for both oxygen evolution and reduction. DFT calculations demonstrated that the Gibbs free energy of the rate-determining step was small enough to improve ORR activities. As a result, a Zn-air battery assembled with Co@CNTs proves a lager power density, low voltage gap between charge–discharge and excellent stability. Thus, this work offers a facile strategy to realize the synthesis of non-noble metal electrocatalyst for Zn-air battery materials with high electrochemical performance.

Stabilizing sodium metal anode through facile construction of organicmetal interface

Implementation of sodium metal anode is highly desired for sodium batteries due to its high theoretical capacity and low redox potential.Unfortunately,formation of unstable solid electrolyte interphase(SEI)and uncontrollable growth of dendrites during charge/discharge cycles greatly hinder the practical application of sodium metal anode.In this study,an organic-metal artificial layer made of PVdF and Bi was constructed to protect Cu current collector via a facile coating method,leading to smooth and dense sodium plating/stripping,which in retern enables stable cycling and high coulombic efficiency(CE).At 1 mA cm^(−2),PB@Cu current collector presents extended lifetime of~2500 h with high sodium utilization of 50%,which is approximately six times higher than Cu current collector.PB@Cu electrode also displays high average CE of 99.92%and 99.95%over 2500 and 1300 cycles at 1 and 2 mA cm^(−2) respectively,which is in sharp contrast to the low and tremendously fluctuant CE gained from bare Cu electrode.Moreover,stable capacity of>90 mAh g^(−1) over 150 cycles is realized for PB@Cu-based full cell assembled with NVP cathode at a low negative-positive capacity ratio of~3.5,which is significantly higher than 37.2 mAh g^(−1) obtained from NVP/Cu at 150th cycle.The superior electrochemical performance of PB@Cu current collector is revealed to originate from the alloyed Na_(3)Bi phase with high sodium conductivity and robust mechanical strength as well as the formation of NaF-rich SEI with fast sodium ion migration,which enable dendrite-free morphology during plating/stripping cycles.

Boosting Sodium Storage of Fe1?xS/MoS2 Composite via Heterointerface Engineering

Improving the cycling stability of metal sulfide-based anode materials at high rate is of great significance for advanced sodium ion batteries.However,the sluggish reaction kinetics is a big obstacle for the development of high-performance sodium storage electrodes.Herein,we have rationally engineered the heterointerface by designing the Fe1?xS/MoS2 heterostructure with abundant“ion reservoir”to endow the electrode with excellent cycling stability and rate capability,which is proved by a series of in and ex situ electrochemical investigations.Density functional theory calculations further reveal that the heterointerface greatly decreases sodium ion diffusion barrier and facilitates charge-transfer kinetics.Our present findings not only provide a deep analysis on the correlation between the structure and performance,but also draw inspiration for rational heterointerface engineering toward the next-generation high-performance energy storage devices.

Atomic-level insights into surface engineering of semiconductors for photocatalytic CO_(2) reduction

Photocatalytic conversion of CO_(2)into solar fuels provides a bright route for the green and sustainable development of human society.However,the realization of efficient photocatalytic CO_(2)reduction reaction(CO_(2)RR)is still challenging owing to the sluggish kinetics or unfavorable thermodynamics for basic chemical processes of CO_(2)RR,such as adsorption,activation,conversion and product desorption.To overcome these shortcomings,recent works have demonstrated that surface engineering of semiconductors,such as introducing surface vacancy,surface doping,and cocatalyst loading,serves as effective or promising strategies for improved photocatalytic CO_(2)RR with high activity and selectivity.The essential reason lies in the activation and reaction pathways can be optimized and regulated through the reconstruction of surface atomic and electronic structures.Herein,in this review,we focus on recent research advances about rational design of semiconductor surface for photocatalytic CO_(2)RR.The surface engineering strategies for improved CO_(2)adsorption,activation,and product selectivity will be reviewed.In addition,theoretical calculations along with in situ characterization techniques will be in the spotlight to clarify the kinetics and thermodynamics of the reaction process.The aim of this review is to provide deep understanding and rational guidance on the design of semiconductors for photocatalytic CO_(2)RR.

CRISPR-Cas12a-Empowered Electrochemical Biosensor for Rapid and Ultrasensitive Detection of SARS-CoV-2 Delta Variant

Coronavirus disease 2019(COVID-19)is a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).The gold standard method for the diagnosis of SARS-CoV-2 depends on quantitative reverse transcription-polymerase chain reaction till now,which is time-consuming and requires expensive instrumentation,and the confirmation of variants relies on further sequencing techniques.Herein,we first proposed a robust technique-methodology of electrochemical CRISPR sensing with the advantages of rapid,highly sensitivity and specificity for the detection of SARS-CoV-2 variant.To enhance the sensing capability,gold electrodes are uniformly decorated with electro-deposited gold nanoparticles.Using DNA template identical to SARS-CoV-2 Delta spike gene sequence as model,our biosensor exhibits excellent analytical detection limit(50 fM)and high linearity(R2=0.987)over six orders of magnitude dynamic range from 100 fM to 10 nM without any nucleic-acid-amplification assays.The detection can be completed within 1 h with high stability and specificity which benefits from the CRISPR-Cas system.Furthermore,based on the wireless micro-electrochemical platform,the proposed biosensor reveals promising application ability in point-of-care testing.

Coupling of Cu Catalyst and Phosphonated Ru Complex Light Absorber with TiO2 as Bridge to Achieve Superior Visible Light CO2 Photoreduction

Visible light photocatalytic CO2 conversion is a promising solution to global warming and energy shortage.Herein,we build a well-designed bridge-like nanostructure,that is,the phosphonated Ru complex(RuP)light absorber–TiO2 bridge–Cu catalyst.In this nanostructure,brookite TiO2 serving as a bridge is spatially connected to the RuP and Cu on each of its sides and could thus physically separate the photoexcited holes and electrons over the RuP and Cu,respectively.Given its eff ective charge separation,this RuP–TiO2–Cu assembly exhibits superior CO2 photoreduction activity relative to RuP–SiO2–Cu under visible light irradiation(λ>420 nm).The catalytic activity is further optimized by adopting brookite TiO2 with various electronic band structures.Results reveal the rapid movement of electrons from the RuP through the conduction band of TiO2 and fi nally to the Cu surface.This property is crucial in CO2 photoreduction activity.

In-depth understanding of ionic liquid assisted perovskite film formation mechanism for two-step perovskite photovoltaics

Ionic liquids(ILs)have been widely applied in the one-step fabrication of perovskite with noticeable enhancement in the device performance.However,in-depth mechanism of ionic-liquid-assisted perovskite film formation is not well understood for also important two-step perovskite fabrication method,with better control of crystallization behavior.In this work,we introduced ionic liquid methylammonium formate(MAFa)into organic salt to produce perovskite film via a two-step method.Systematic investigations on the influence of MAFa on the perovskite thin film formation mechanism were performed.Ionic liquid is shown to assist lowering the perovskite formation enthalpy upon the density functional theory(DFT)calculation,leading to an accelerated crystallization process evidenced by in-situ UV-Vis absorption measurement.A gradient up-down distribution of ionic liquid has been confirmed by timeof-flight SIMS.Importantly,besides the surface passivation,we found the HCOO-can diffuse into the perovskite crystals to fill up the halide vacancies,resulting in significant reduction of trap states.Uniform perovskite films with significantly larger grains and less defect density were prepared with the help of MAFa IL,and the corresponding device efficiency over 23%was obtained by two-step process with remarkably improved stability.This research work provides an efficient strategy to tune the morphology and opto-electronic properties of perovskite materials via ionic-liquid-assisted two-step fabrication method,which is beneficial for upscaling and application of perovskite photovoltaics.

Engineering the Local Coordination Environment of Single-Atom Catalysts and Their Applications in Photocatalytic Water Splitting:A Review

Single-atom catalysts(SACs),with atomically dispersed metal atoms anchored on a typical support,representing the utmost utilization effi ciency of the atoms,have recently emerged as promising catalysts for a variety of catalytic applications.The electronic properties of the active center of SACs are highly dependent on the local environment constituted by the single metal atom and its surrounding coordination elements.Therefore,engineering the coordination environment near single metal sites,from the fi rst coordination shell to the second shell or higher,would be a rational way to design effi cient SACs with optimized electronic structure for catalytic applications.The wide range of coordination confi gurations,guaranteed by the multiple choices of the type and heterogeneity of the coordination element(N,O,P,S,etc.),further off er a large opportunity to rationally design SACs for satisfactory activities and investigate the structure-performance relationship.In this review,the coordination engineering of SACs by varying the type of coordination element was elaborated and the photocatalytic water splitting of SACs was highlighted.Finally,challenging issues related to the coordination engineering of SACs and their photocatalytic applications were discussed to call for more eff orts devoted to the further development of single-atom catalysis.

From protonation & Li-rich contamination to grain-boundary segregation: Evaluations of solvent-free vs. wet routes on preparing Li_(7)La_(3)Zr_(2)O_(12) solid electrolyte

Garnet-type Li_(7)La_(3)Zr_(2)O_(12)(LLZO) has been recognized as a candidate solid electrolyte for high-safety Lianode based solid-state batteries because of its electro-chemical stability against Li-metal and high ionic conductivity. Solvent(e.g., isopropanol(IPA)) has been commonly applied for preparing LLZO powders and ceramics. However, the deterioration of the proton-exchange between LLZO and IPA/absorbed moisture during the mixing and tailoring route has aroused less attention. In this study, a solvent-free dry milling route was developed for preparing the LLZO powders and ceramics. For orthogonal four categories of samples prepared using solvent-free and IPA-assisted routes in the mixing and tailoring processes, the critical evaluation was conducted on the crystallinity, surficial morphology, and contamination of ascalcinated and as-tailored particles, the cross-sectional microstructure of green and sintered pellets,the morphology and electro-chemical properties of grain boundaries in ceramics, as well as the interfacial resistance and performance of Li anode based symmetric batteries. The wet route introduced Li-rich contaminations(e.g., Li OH·H)_(2)O and Li)_(2)CO)_(3)) onto the surfaces of LLZO particles and Li-Ta-O segregations at the adjacent and triangular grain boundaries. The LLZO solid electrolytes prepared through dry mixing in combination with the dry tailoring route without the use of any solvent were found to the optimal performance. The fundamental material properties in the whole LLZO preparation process were found, which are of guiding significance to the development of LLZO powder and ceramic production craft.

Spectral polarization-encoding of broadband laser pulses by optical rotatory dispersion and its applications in spectral manipulation

We propose a kind of spectral polarization-encoding(SPE)for broadband light pulses,which is realized by inducing optical rotatory dispersion(ORD),and decoded by compensating ORD.Combining with polarization-sensitive devices,SPE can not only work to control polarization-dependent transmission for central wavelength or bandwidth-tunable filtering,but also can be used for broadband regenerative or multi-pass amplification with a polarization-dependent gain medium to improve output bandwidth.SPE is entirely passive thus very simple to be designed and aligned.By using an ORD crystal with a good transmission beyond 3-μm mid-infrared region,e.g.,Ag Ga S_(2),SPE promises to be applied for the wavelength tuning lasers in mid-infrared region,where the tunning devices are rather under developed compared with those in visible and near-infrared region.

Selective excitation of multipolar surface plasmon in a graphene-coated dielectric particle by Laguerre Gaussian beam

Localized surface plasmonic resonance has attracted extensive attention since it allows for great enhancement of local field intensity on the nanoparticle surface.In this paper,we make a systematic study on the excitation of localized surface plasmons of a graphene coated dielectric particle.Theoretical results show that both the intensity and frequency of the plasmonic resonant peak can be tuned effectively through modifying the graphene layer.Furthermore,high order localized surface plasmons could be excited and tuned selectively by the Laguerre Gaussian beam,which is induced by the optical angular orbital momentum transfer through the mutual interaction between the particle and the helical wavefront.Moreover,the profiles of the multipolar localized surface plasmons are illustrated in detail.The study provides rich potential applications in the plasmonic devices and the wavefront engineering nano-optics.

Band offsets and electronic properties of the Ga_(2)O_(3)/FTO heterojunction via transfer of free-standing Ga_(2)O_(3) onto FTO/glass

The determination of band offsets is crucial in the optimization of Ga_(2)O_(3)-based devices,since the band alignment types could determine the operations of devices due to the restriction of carrier transport across the heterogeneous interfaces.In this work,the band offsets of the Ga_(2)O_(3)/FTO heterojunction are studied using x-ray photoelectron spectroscopy(XPS)based on Kraut’s method,which suggests a staggered type-II alignment with a conduction band offset(DEC)of 1.66 eV and a valence band offset(DEV)of2.41 eV.Furthermore,the electronic properties of the Ga_(2)O_(3)/FTO heterostructure are also measured,both in the dark and under ultraviolet(UV)illuminated conditions(254 nm UV light).Overall,this work can provide meaningful guidance for the design and construction of oxide hetero-structured devices based on wide-bandgap semiconducting Ga_(2)O_(3).

Li-richening strategy in Li_(2)ZrCl_(6) lattice towards enhanced ionic conductivity

All-solid-state Li batteries(ASSLBs) with solid-state electrolytes(SSEs) are exciting candidates for nextgeneration energy storage and receive considerable attention owing to their reliability. Halide SSEs are promising candidates due to their excellent stability against 4 V-class layered cathodes. Compared with Li3InCl6or Li_(3)ScCl_(6), the low ionic conductivity of Li_(2)ZrCl_(6)(LZC) is a challenge despite its low raw-material cost. Herein, we report a family of Li-Richened chloride, Li_(2+2x)Zr_(1–x)MxCl_(6), which can be used in highperformance ASSLBs owing to its high ionic conductivity(up to 0.62 mS cm^(-1)). The theoretical(ab initio molecular dynamics simulations) and experimental results prove that the strategy of aliovalent substitution with divalent metals to obtain Li-Richened LZC is effective in improving Li^(+)conductivity in SSEs. By combining Li_(2.1)Zr_(0.95)Mg_(0.05)Cl_(6)(Mg5-LZC) with a Li–In anode and a LiCoO_(2)cathode, a room-temperature ASSLBs with excellent long-term cycling stability(88% capacity retention at 0.3C for 100 cycles) and highrate capability(121 m A h g^(-1)at 1C) is reported. This exploratory work sheds light on improving the Li^(+)conductivity of low-cost LZC-family SSEs for constructing high performance ASSLBs.

Achieving Tunable Cold/Warm White‑Light Emission in a Single Perovskite Material with Near‑Unity Photoluminescence Quantum Yield

Single materials that exhibit efficient and stable white-light emission are highly desirable for lighting applications.This paper reports a novel zero-dimensional perovskite,Rb_(4)CdCl_(6):Sn^(2+),Mn^(2+),which demonstrates exceptional white-light properties including adjustable correlated color temperature,high color rendering index of up to 85,and near-unity photoluminescence quantum yield of 99%.Using a co-doping strategy involving Sn^(2+)and Mn^(2+),cyan-orange dual-band emission with complementary spectral ranges is activated by the self-trapped excitons and d-d transitions of the Sn^(2+)and Mn^(2+)centers in the Rb_(4)CdCl_(6)host,respectively.Intriguingly,although Mn^(2+)ions doped in Rb_(4)CdCl_(6)are difficult to excite,efficient Mn^(2+)emission can be realized through an ultra-high-efficient energy transfer between Sn^(2+)and Mn^(2+)via the formation of adjacent exchange-coupled Sn–Mn pairs.Benefiting from this efficient Dexter energy transfer process,the dual emission shares the same optimal excitation wavelengths of the Sn^(2+)centers and suppresses the non-radiative vibration relaxation significantly.Moreover,the relative intensities of the dual-emission components can be modulated flexibly by adjusting the fraction of the Sn^(2+)ions to the Sn–Mn pairs.This co-doping approach involving short-range energy transfer represents a promising avenue for achieving high-quality white light within a single material.