Anchoring Ni single atoms on sulfur-vacancy-enriched ZnIn_(2)S_(4) nanosheets for boosting photocatalytic hydrogen evolution

Structure manipulation of photocatalysts at an atomic scale is a promising way to improve its photocatalytic performance.Herein,we realize the anchoring of single Ni atoms on the ZnIn_(2)S_(4) nanosheets with rich sulfur vacancies.Experimental results demonstrate that single Ni atoms induce the formation of NiO-M(Zn/In) atomic interface,which can efficiently promote the carriers separation and prolong the carrier life time.In addition,in situ electron spin resonance spectroscopy(ESR) confirms that the single Ni atoms act as an electron trapping center for protons reduction.As a result,the single Ni atoms decorated ZnIn_(2)S_(4) nanosheets with rich sulfur vacancies(Ni/ZnIn_(2)S_(4)-RVs) shows a hydrogen evolution rate up to 89.4 μmol h^(-1), almost 5.7 and 2.3 times higher compared to that of ZnIn_(2)S_(4) nanosheets with poor sulfur vacancies and rich sulfur vacancies(denoted as ZnIn_(2)S_(4)-PVs and ZnIn_(2)S_(4)-RVs).This work opens up a new perspective manipulating the single-atom cocatalyst and sulfur vacancy on sulfide supports for improving photocatalytic hydrogen evolution.

Oxygen Penetration Through Full-Thickness Skin by Oxygen-Releasing Sutures for Skin Graft Transplantation

The transplantation of full-thickness skin grafts(FTSGs)is important for reconstructing skin barrier and promoting wound healing.Sufficient oxygen supply is closely related to the success of skin grafting.However,full-thickness oxygen delivery is limited by the poor oxygen permeability of skin.Oxygen-releasing sutures(O_(2)sutures)were developed to facilitate oxygen penetration through full-thickness skin.The O_(2)sutures delivered 100 times more oxygen than topical gaseous oxygen therapy at a 15 mm depth in the skin model.Under extreme hypoxia(<0.5%O_(2),v/v),O_(2)sutures could also promote endothelial cell proliferation.After the transplantation of FTSGs in mice,O_(2)sutures accelerated blood re-perfusion and increased the survival area of the skin graft.It is expected that O_(2)sutures will be adopted in clinical applications to increase the success rate of full-thickness skin transplantation.

Surpassing electrocatalytic limit of earth-abundant Fe^(4+)embedded in N-doped graphene for(photo)electrocatalytic water oxidation

Developing highly active,cost-effective,and environmental friendly oxygen evolution reaction(OER)electrocatalysts facilitates various(photo)electrochemical processes.In this work,Fe3N nanoparticles encapsulated into N-doped graphene nanoshells(Fe_(3)N@NG)as OER electrocatalysts in alkaline media were reported.Both the experimental and theoretical comparison between Fe_(3) N@NG and Fe_(3)N/NG,specifically including in situ Mossbauer analyses,demonstrated that the NG nanoshells improved interfacial electron transfer process from Fe_(3)N to NG to form high-valence Fe^(4+)ions(Fe^(4+)@NG),thus modifying electronic properties of the outer NG shells and subsequently electron transfer from oxygen intermediate to NG nanoshells for OER catalytic process.Meanwhile,the NG nanoshells also protected Fe-based cores from forming OER inactive and insulated Fe_(2)O_(3),leading to high OER stability.As a result,the as-formed Fe^(4+)@NG shows one of the highest electrocatalytic efficiency among reported Fe-based OER electrocatalysts,which can as well highly improve the photoelectrochemical water oxidation when used as the cocatalysts for the Fe_(2)O_(3) nanoarray photoanode.

Thiourea-assisted coating of dispersed copper electrocatalysts on Si photocathodes for solar hydrogen production

Photoelectrochemical water splitting can convert solar energy into clean hydrogen energy for storage.It is desirable to explore non-precious electrocatalysts for practical applications of a photoelectrode in a large scale.Here,we developed a facile spin-coating and in-situ photoelectrochemical reduction method to prepare a dispersed Cu electrocatalyst on a Si photocathode,which improves the performance remarkably.We find that thiourea in the precursor solution for spin-coating plays an important role in obtaining dispersed Cu particles on the surface of a Si photoelectrode.With thiourea in the precursor,the Cu/Si photocathode shows higher performance than the one without thiourea.Moreover,the Cu/Si photocathode also indicates good stability after 16 h illumination.

Rapid synthesis of highly active Pt/C catalysts with various metal loadings from single batch platinum colloid

A series of Pt/C catalysts for proton exchange membrane fuel cells(PEMFCs) with various metal loadings is synthesized by a microwave-assisted polyol process via mixing an extremely stable platinum colloid(> 3 months’ shelf life) from single batch preparation with activated carbon ethylene glycol suspension.21 wt%, 42 wt% and 61 wt% Pt loadings are employed to showcase the advantages of the improved polyol process. The ultraviolet(UV)–visible spectra and ζ-potential measurements are conducted to monitor the wet chemistry process during catalyst preparation. The powder X-ray diffraction(XRD), transmission electron microscopy(TEM) and thermogravimetric analysis(TGA) characterizations are carried out on catalysts. The catalyst activities are investigated using electrochemical and single cell tests. The stability of Pt nanoparticle colloid is explored by ORR, cyclic voltammetry(CV) and ζ-potential measurements. The TEM results show the Pt particle sizes of the colloid, and the sizes of the 21 wt%, 42 wt% and 61 wt%Pt/C samples are 2.1–3.9 nm. Because of the high Pt dispersion, the Pt/C catalysts exhibit superior electroactivity toward ORR. In addition, four 61 wt% Pt/C catalysts made from the Pt colloid with 0–3 months’ shelf life show almost the same performance, which exhibits superior stability of the Pt colloid system without surfactant protection.

Wettability control in electrocatalyst: A mini review

Electrocatalysis, as a typical heterogeneous catalysis, generally occurs in the di-or tri-phase interfaces.Wettability is an important property for describing the balance of a gas-liquid-solid system. Therefore,the wettability of reaction interface, especially hydrophilicity/hydrophobicity, plays an important role in the adsorption/desorption process of gas bubbles on the surface of the solid electrode. Herein, we present a comprehensive review of the wettability control of the electrode materials applied in electrocatalysis reactions, including hydrogen evolution reaction(HER), oxygen evolution reaction(OER), oxygen reduction reaction(ORR) and carbon dioxide reduction reaction(CO_(2) RR). Firstly, the basic theories of wettability as well as the impact on electrocatalysis were introduced in this review. Secondly, the overview of modifying methods of the wettability from electrocatalyst microstructure(structural modification, surface coating, introducing hydrophilic groups) and system design(electrode, device) were suggested. At last, the deficiencies and problems in the application of wettability control are discussed,and deeper and broader application prospects are proposed.

Voltage control magnetism and ferromagnetic resonance in an Fe_(19)Ni_(81)/PMN-PT heterostructure by strain

Voltage control magnetism has been widely studied due to its potential applications in the next generation of information technology.PMN-PT,as a single crystal ferroelectric substrate,has been widely used in the study of voltage control magnetism because of its excellent piezoelectric properties.However,most of the research based on PMN-PT only studies the influence of a single tensile(or compressive)stress on the magnetic properties due to the asymmetry of strain.In this work,we show the effect of different strains on the magnetic anisotropy of an Fe_(19)Ni_(81)/(011)PMN-PT heterojunction.More importantly,the(011)cut PMN-PT generates non-volatile strain,which provides an advantage when investigating the voltage manipulation of RF/microwave magnetic devices.As a result,a ferromagnetic resonance field tunability of 70 Oe is induced in our sample by the non-volatile strain.Our results provide new possibilities for novel voltage adjustable RF/microwave magnetic devices and spintronic devices.

Multiferroic properties in terbium orthoferrite

Multiferroic properties in a polycrystalline terbium orthoferrite are investigated. Different thermomagnetic behaviors are observed in different magnetic fields, which is attributed to the suppression of the low temperature magnetic phase by an external magnetic field. Further studies reveal that the ferroelectricity originates from the spin configuration below 3.5 K. In addition, the magnetic field control of electric polarization and dielectric constant is observed, which suggests a magnetoelectric effect in TbFeO3. The origin of ferroelectricity in this rare-earth orthoferrite is discussed.

Multiple sign reversals of the exchange bias field in polycrystalline SmCr_(0.9)Fe_(0.1)O_3

We synthesize the perovskite compound Sm Cr0.9Fe0.1O3 by the sol–gel method and investigate its exchange bias properties through thermomagnetic and isothermal magnetization measurements. The sign reversals of the exchange bias field are observed at the magnetization compensation temperatures 29.6 K and 96.2 K. It is demonstrated that the occurrence of the exchange bias originates from the antiferromagnetic coupling between the Cr-rich and Fe–Cr regions, of which the net magnetization is temperature-dependent. These results imply that there are potential applications in single systems with sign reversals of both magnetization and exchange bias.

Influence of charge transport layer on the crystallinity and charge extraction of pure tin-based halide perovskite film

As one of the most compelling photovoltaic devices, halide perovskite (PVK) solar cells have achieved a new surprising record power conversion efficiency (PCE) of 25.8%in 2021 [1]. This demonstrates the great potential of halide PVK solar cells as a highly competitive substitute to replace silicon-based solar cells in the photovoltaic market [2–6].

Nonvolatile control of transport and magnetic properties in magnetoelectric heterostructures by electric field

Nonvolatile manipulation of transport and magnetic properties by external electric field is significant for information storage. In this study, we investigate the electric field control of resistance and magnetization in a magnetoelectric heterostructure comprising an electronic phase-separated La0.325Pr0.3Ca0.375MnO3（LPCMO） thin film and a ferroelectric（011）-oriented 0.7Pb（Mg1/3Nb2/3）O3-0.3PbTiO3（PMN-PT） substrate. In a room-temperature poled sample, the metal-toinsulator transition temperature of an LPCMO film increases and the resistance decreases with variation in the effect of the remnant strain. Meanwhile, the increase in the magnetization of the sample is observed as well. This effect would be beneficial for the development of novel storage devices with low power consumption.

High efficiency and selectivity catalyst for photocatalytic oxidative coupling of methane

Methane(CH_(4))holds great promise in replacing oil as a building block for chemical commodities[1].However,due to the low-polar nature and high C-H bond energy(439 kJ/mol)of CH_(4),the conversion of CH_(4)by traditional thermocatalysis requires harsh reaction conditions(e.g.high temperature and high pressure)and thus,is energy-consuming[2].To be worse,the production of undesired products like CO_(2)is unavoidable as a result of hydrocarbon combustion reactions[2].

热催化活性差的过渡金属用于光驱动裂解氨

As a zero-or near zero-emission energy carrier,hydrogen,especially"green hydrogen"from renewable energy and water,is the key piece for decarbonizing existing energy systems and transiting into a carbon-neutral world[1,2].Unfortunately,challenges associated with storage and transportation greatly restrict the large-scale application of hydrogen energy,which requires the development of efficient hydrogen storage materials[3-5].Among the various proposed candidates,ammonia(NH_(3))is regarded as a promising hydrogen carrier owing to its low carbon footprint,high gravimetric/volumetric hydrogen storage capacity,easy liquidation,safe storage and transportation,and well-developed synthesis approach at the industrial scale[6-8].

Facile grafting strategy synthesis of single-atom electrocatalyst with enhanced ORR performance

Single-atom catalysts(SACs)have become one of the most considered research directions today,owing to their maximum atom utilization and simple structures,to investigate structure-activity relationships.In the field of non-precious-metal electrocatalysts,atomically dispersed Fe-N4 active sites have been proven to possess the best oxygen reduction activity.Yet the majority of preparation methods remains complex and costly with unsatisfying controllability.Herein,we have designed a surface-grafting strategy to directly synthesize an atomically dispersed Fe-NVC electrocatalyst applied to the oxygen reduction reaction(ORR).Through an esterification process in organic solution,metal-containing precursors were anchored on the surface of carbon substrates.The covalent bonding effect could suppress the formation of aggregated particles during heat treatment.Melamine was further introduced as both a cost-effective nitrogen resource and blocking agent retarding the migration of metal atoms.The optimized catalyst has proven to have abundant atomically dispersed Fe-N4 active sites with enhanced ORR catalytic performance in acid condition.This method has provided new feasible ideas for the synthesis of SACs.

Reactive Inorganic Vapor Deposition of Perovskite Oxynitride Films for Solar Energy Conversion

The synthesis of perovskite oxynitrides,which are promising photoanode candidates for solar energy conversion,is normally accomplished by high-temperature ammonolysis of oxides and carbonate precursors,thus making the deposition of their planar films onto conductive substrates challenging.Here,we proposed a facile strategy to prepare a series of perovskite oxynitride films.Taking SrTaO_(2)N as a prototype,we prepared SrTaO_(2)N films on Ta foils under NH_(3) flow by utilizing the vaporized SrCl_(2)/SrCO_(3) eutectic salt.The SrTaO_(2)N films exhibit solar water-splitting photocurrents of 3.0 mA cm^(-2) at 1.23 V vs.RHE(reversible hydrogen electrode),which increases by 270%compared to the highest photocurrent(1.1 mA cm^(-2) at 1.23 V vs.RHE)of SrTaO_(2)N reported in the literature.This strategy may also be applied to directly prepare a series of perovskite oxynitride films on conductive substrates such as ATaO_(2)N(A=Ca,Ba)and ANbO_(2)N(A=Sr,Ba).

An Extrinsic Faradaic Layer on CuSn for High-Performance Electrocatalytic CO_(2) Reduction

An intrinsic Faradaic layer on the surface of a metal electrocatalyst is usually considered an active site for CO_(2) reduction.Different strategies have been used to improve the performance of CO_(2) reduction by adjusting the intrinsic Faradaic layer.However,it is still challenging to achieve CO_(2) reduction with high activity,selectivity,and stability.In this study,for the first time,we improve the three parameters simultaneously by introducing a Zn(OH)_(x) over layer onto a CuSn electrocatalyst.We find that the intrinsic Faradaic layer of Sn(OH)_(x) on the surface of CuSn provides active sites for CO_(2) reduction,while Zn(OH)_(x) plays multiple roles as an adsorption/activation layer,a cover layer,and a protective layer.Further studies suggest that the enhanced activity comes from a Faradaic reaction of Zn(OH)_(x) during CO_(2) reduction,which can be considered as an extrinsic Faradaic layer.This new strategy of introducing an extrinsic Faradaic layer can deepen understanding of electrocatalytic process and offers guidance to design other high-performance electrocatalysts.

Near 100% selectivity for visible-light-driven CO2 reduction to CH4 on a dual-metal site photocatalyst

solar energy to chemicals,which has aroused extensive attention during the past decades.However,the process of CO2 reduction is a multiple proton coupled electron transfer reaction,which leads to a wide variety of final products,such as CO,CH4.Moreover,H^+ reduction is a competitive reaction and further lowers the selectivity of CO2 reduction[1-3].Different methods,including loading suitable co-catalysts and controlling exposed crystal surfaces of a photocatalyst,have been used to improve the selectivity in previous studies[4].

Photosynthetic microorganisms coupled photodynamic therapy for enhanced antitumor immune effect

The ideal photodynamic therapy(PDT)should effectively remove the primary tumor,and produce a stronger immune memory effect to inhibit the tumor recurrence and tumor metastasis.However,limited by the hypoxic and immunosuppressive microenvironment,the PDT efficiency is apparently low.Here,Chlorella(Chl.)is exploited to enhance local effect by producing oxygen to reverse hypoxia,and release adjuvants to reverse immunosuppressive microenvironment to enhance abscopal effect afterwards.Results from different animal models indicated that Chl.could enhance local effect and PDT related immune response.Ultimately,Chl.coupled PDT elicited anti-tumor effects toward established primary tumors(inhibition rate:90%)and abscopal tumors(75%),controlled the challenged tumors(100%)and alleviated metastatic tumors(90%).This Chl.coupled PDT strategy can also produce a stronger anti-tumor immune memory effect.Overall,this Chl.coupled PDT strategy generates enhanced local tumor killing,boosts PDT-induced immune responses and promotes anti-tumor immune memory effect,which may be a great progress for realizing systemic effect of PDT.

Recent advances in bacterial therapeutics based on sense and response

Intelligent drug delivery is a promising strategy for cancer therapies.In recent years,with the rapid development of synthetic biology,some properties of bacteria,such as gene operability,excellent tumor colonization ability,and host-independent structure,make them ideal intelligent drug carriers and have attracted extensive attention.By implanting condition-responsive elements or gene circuits into bacteria,they can synthesize or release drugs by sensing stimuli.Therefore,compared with traditional drug delivery,the usage of bacteria for drug loading has better targeting ability and controllability,and can cope with the complex delivery environment of the body to achieve the intelligent delivery of drugs.This review mainly introduces the development of bacterial-based drug delivery carriers,including mechanisms of bacterial targeting to tumor colonization,gene deletions or mutations,environment-responsive elements,and gene circuits.Meanwhile,we summarize the challenges and prospects faced by bacteria in clinical research,and hope to provide ideas for clinical translation.

Super stable CsPbBr3@SiO2 tumor imaging reagent by stress-response encapsulation

Great photoelectric properties can herald the high potentials of CsPbBr3 nanocrystals(NCs)to function as the fluorescent probes for early tumor diagnosis.However,the intrinsic water vulnerability of CsPbBr3 NCs highly restricts their biomedical applications.To conquer this challenge,we herein introduce a nature inspired"stress-response"method to tightly encapsulate CsPbBr3 into SiO2 nano-shells that can dramatically improve the water stability of CsPbBr3@SiO2 nanoparticles for over 48 h.We further highlighted the advantageous features of CsPbBr3@SiO2 by using them as the fluorescent probes for CT26 tumor cell imaging with their high water stability,biocompatibility,and low cytotoxicity.Our work for the first time exhibited the potential of lead halide perovskite NCs for tumor diagnosis,and can highly anticipate the further in vivo biomedical applications that light up live cells.