High Fe‑Loading Single‑Atom Catalyst Boosts ROS Production by Density Effect for Efficient Antibacterial Therapy

The current single-atom catalysts(SACs)for medicine still suffer from the limited active site density.Here,we develop a synthetic method capable of increasing both the metal loading and mass-specific activity of SACs by exchanging zinc with iron.The constructed iron SACs(h^(3)-FNC)with a high metal loading of 6.27 wt%and an optimized adjacent Fe distance of~4 A exhibit excellent oxidase-like catalytic performance without significant activity decay after being stored for six months and promising antibacterial effects.Attractively,a“density effect”has been found at a high-enough metal doping amount,at which individual active sites become close enough to interact with each other and alter the electronic structure,resulting in significantly boosted intrinsic activity of single-atomic iron sites in h^(3)-FNCs by 2.3 times compared to low-and medium-loading SACs.Consequently,the overall catalytic activity of h^(3)-FNC is highly improved,with mass activity and metal mass-specific activity that are,respectively,66 and 315 times higher than those of commercial Pt/C.In addition,h^(3)-FNCs demonstrate efficiently enhanced capability in catalyzing oxygen reduction into superoxide anion(O_(2)·^(−))and glutathione(GSH)depletion.Both in vitro and in vivo assays demonstrate the superior antibacterial efficacy of h^(3)-FNCs in promoting wound healing.This work presents an intriguing activity-enhancement effect in catalysts and exhibits impressive therapeutic efficacy in combating bacterial infections.

楚雄地区黄龙尾(Agrimonia pilosa var.nepalensis)内生菌的分离及初步鉴定

从野生黄龙尾健康植株内分离得到的29株内生菌中,8株细菌全部为杆菌,有4株产芽孢;10株放线菌,都属于链霉菌属(Streptomyces sp.);11株真菌,其中7株为镰刀菌属(Fusarium sp.)、2株为炭疽菌属(Colletotrichum sp.)、1株为青霉属(Penicillium sp.)、1株为黑曲霉(Aspergillus niger)。生长特性实验结果表明,所有供试菌株的最适生长NaCl浓度范围在3%-5%之间,最适生长pH范围在6.0~8.0之间,最适生长温度在20℃~35℃之间,细菌的生长温度范围比放线菌的更为广泛。在生理生化特性实验中,供试菌株B-3-5-4对碳源、氮源的利用范围广,菌株B-3-1-6对碳源、氮源的利用范围窄。研究结果表明,黄龙尾不同组织内部分布着不同类群的内生菌群。本研究可为黄龙尾的进一步开发提供数据支持。

Human ACE2-Functionalized Gold“Virus-Trap”Nanostructures for Accurate Capture of SARS-CoV-2 and Single-Virus SERS Detection

The current COVID-19 pandemic urges the extremely sensitive and prompt detection of SARS-CoV-2 virus.Here,we present a Human Angiotensin-converting-enzyme 2(ACE2)-functionalized gold“virus traps”nanostructure as an extremely sensitive SERS biosensor,to selectively capture and rapidly detect S-protein expressed coronavirus,such as the current SARS-CoV-2 in the contaminated water,down to the single-virus level.Such a SERS sensor features extraordinary 106-fold virus enrichment originating from high-affinity of ACE2 with S protein as well as“virus-traps”composed of oblique gold nanoneedles,and 109-fold enhancement of Raman signals originating from multi-component SERS effects.Furthermore,the identification standard of virus signals is established by machine-learning and identification techniques,resulting in an especially low detection limit of 80 copies mL^(−1) for the simulated contaminated water by SARS-CoV-2 virus with complex circumstance as short as 5 min,which is of great significance for achieving real-time monitoring and early warning of coronavirus.Moreover,here-developed method can be used to establish the identification standard for future unknown coronavirus,and immediately enable extremely sensitive and rapid detection of novel virus.

In Situ Electrochemical Mn(Ⅲ)/Mn(Ⅳ) Generation of Mn(Ⅱ)O Electrocatalysts for High-Performance Oxygen Reduction

Among various earth-abundant and noble metal-free catalysts for oxygen reduction reaction(ORR),manganese-based oxides are promising candidates owing to the rich variety of manganese valence.Herein,an extremely facile method for the synthesis of cubic and orthorhombic phase coexisting Mn(Ⅱ)O electrocatalyst as an efficient ORR catalyst was explored.The obtained MnO electrocatalyst with oxygen vacancies shows a significantly elevated ORR catalytic activity with a half-wave potential(E1/2) of as high as 0.895 V,in comparison with that of commercial Pt/C(E1/2=0.877 V).More impressively,the MnO electrocatalyst exhibits a marked activity enhancement after test under a constant applied potential for 1000 s thanks to the in situ generation and stable presence of high-valence manganese species(Mn^3+ and Mn^4+) during the electrochemical process,initiating a synergetic catalytic effect with oxygen vacancies,which is proved to largely accelerate the adsorption and reduction of O_2 molecules favoring the ORR activity elevation.Such an excellent ORR catalytic performance of this MnO electrocatalyst is applied in Zn-air battery,which shows an extra-high peak power density of 63.2 mW cm^-2 in comparison with that(47.4 m W cm^-2) of commercial Pt/C under identical test conditions.

Adsorption Site Regulations of[W–O]‑Doped CoP Boosting the Hydrazine Oxidation‑Coupled Hydrogen Evolution at Elevated Current Density

Hydrazine oxidation reaction(HzOR)assisted hydrogen evolution reaction(HER)offers a feasible path for low power consumption to hydrogen production.Unfortunately however,the total electrooxidation of hydrazine in anode and the dissociation kinetics of water in cathode are critically depend on the interaction between the reaction intermediates and surface of catalysts,which are still challenging due to the totally different catalytic mechanisms.Herein,the[W–O]group with strong adsorption capacity is introduced into CoP nanoflakes to fabricate bifunctional catalyst,which possesses excellent catalytic performances towards both HER(185.60 mV at 1000 mA cm^(−2))and HzOR(78.99 mV at 10,00 mA cm^(−2))with the overall electrolyzer potential of 1.634 V lower than that of the water splitting system at 100 mA cm^(−2).The introduction of[W–O]groups,working as the adsorption sites for H2O dissociation and N2H4 dehydrogenation,leads to the formation of porous structure on CoP nanoflakes and regulates the electronic structure of Co through the linked O in[W–O]group as well,resultantly boosting the hydrogen production and HzOR.Moreover,a proof-of-concept direct hydrazine fuel cell-powered H_(2) production system has been assembled,realizing H_(2)evolution at a rate of 3.53 mmol cm^(−2)h^(−1)at room temperature without external electricity supply.

Bacterial Metabolism-Initiated Nanocatalytic Tumor Immunotherapy

The low immunogenicity of tumors remains one of the major limitations of cancer immunotherapy.Herein,we report a bacterial metabolisminitiated and photothermal-enhanced nanocatalytic therapy strategy to completely eradicate primary tumor by triggering highly effective antitumor immune responses.Briefly,a microbiotic nanomedicine,designated as Cu_(2)O@ΔSt,has been constructed by conjugating PEGylated Cu_(2)O nanoparticles on the surface of an engineered Salmonella typhimurium strain(ΔSt).Owing to the natural hypoxia tropism ofΔSt,Cu_(2)O@ΔSt could selectively colonize hypoxic solid tumors,thus minimizing the adverse effects of the bacteria on normal tis-sues.Upon bacterial metabolism within the tumor,Cu_(2)O@ΔSt generates H_(2)S gas and other acidic substances in the tumor microenvironment(TME),which will in situ trigger the sulfidation of Cu_(2)O to form CuS facilitating tumor-specific photothermal therapy(PTT)under local NIR laser irradiation on the one hand.Meanwhile,the dissolved Cu+ions from Cu_(2)O into the acidified TME enables the nanocatalytic tumor therapy by catalyzing the Fenton-like reaction of decom-posing endogenous H_(2)O_(2) into cytotoxic hydroxyl radicals(·OH)on the other hand.Such a bacterial metabolism-triggered PTT-enhanced nanocatalytic treatment could effectively destroy tumor cells and induce a massive release of tumor antigens and damage-associated molecular patterns,thereby sensitizing tumors to checkpoint blockade(ICB)therapy.The combined nanocatalytic and ICB therapy results in the much-inhibited growth of distant and metastatic tumors,and more importantly,induces a powerful immunological memory effect after the primary tumor ablation.

Efficient benzaldehyde photosynthesis coupling photocatalytic hydrogen evolution

Photosynthesis of organic compounds in coupling with promoted hydrogen evolution under mild conditions of light irradiation is considered as one of the most efficient and promising approach to obtain high purity hydrogen and value-added chemicals concurrently by utilizing green solar energy.Here,we report the synthesis of Ni S nanoparticle-modified Cd S nanorod composites(Ni S/Cd S)as an efficient bifunctional catalyst for the highly selective photocatalytic synthesis of high-value-added product benzaldehyde(BAD)from aqueous solution of benzyl alcohol(BA)under oxygen-free conditions,in accompanying with the efficient hydrogen evolution.The synergetic catalytic effect between Ni S and Cd S is proposed to play an important role in elevating the photo-redox performance.The composition-optimized 30%Ni S/Cd S catalyst affords an extraordinarily high H;generation rate of 207.8μmol h^(-1)and a simultaneous BAD generation rate of 163.8μmol h^(-1)under visible light irradiation,which are respectively 139 and 950 times higher than those of Cd S without Ni S modification.To our knowledge,these are the highest photocatalytic production rates of both H_(2)and aldehyde ever reported on the concurrent photocatalytic of aldehyde synthesis and hydrogen evolution in green aqueous solution.This work provides a highly efficient photosynthesis strategy for the concurrent productions of high-value-added fine chemicals and hydrogen.

Corigendum to“Efficient benzaldehyde photosynthesis coupling photocatalytic hydrogen evolution”[J.Energy Chem.66(2022)52-60]

It is regretful that the wrong image of Fig.4 was used in the paperin the final proof stage by editor.The correct one should be as follow.

Microstructure and Mechanical Properties of Dy-α-sialon/Nano-size SiC Composites

The composite of Dy-α-sialon/10 wt pct nano-size SiC particles has been prepared from precursor powders of Si3N4, AIN, Al2O3, Dy2O3 and nano-size β-SiC. The hardness, toughness and bending strength of the composite at ambient temperature are a little higher than those of Dy-α-sialon.while the bending strength is maintained up to 1000℃ and about 2 times more than that of Dy-α-sialon at the same temperature. The fracture surfaces show that the grain size of the composite is smaller than that of Dy-α-sialon, and both Of them have predominately transgranular mode of fracture. It is believed that the decrease of the bending strength of Dy-α-sialon at elevated temperature is caused by the viscous flow of the grain boundary phase, while the addition of nanosize SiC particles effectively increases the viscosity of the grain boundary phase and therefore prevents the strength loss of Dy-α-sialon/nano-size SiC composites at elevated temperature

Two-dimensional ultrathin vanadium oxide nanosheets as catalytic bactericide

Infectious diseases caused by pathogenic bacteria are a serious threat to global public health.Nowadays,antibiotics and other clinical drugs suffer from some fundamental disadvantages such as narrow-spectrum antibacterial effect and the risk to induce drug resistance,while inorganic functional nanomaterials with biological catalytic activities have been developed as novel antibacterial agents.In this study,we prepared two-dimensional ultrathin vanadium oxide nanosheets(VO_(x)NSs)with mixed valence states from the oxidised layer of vanadium powder(bulk V)by ultrasonically assisted liquid exfoliation.By conveniently switching between V^(IV)and V^(V),VO_(x)NSs can efficiently catalyse H_(2)O_(2)enriched in bacterially infected areas to generate hydroxyl radicals(·OH),which induce bacterial oxidative stress and apoptosis.This process can occur in both weakly alkaline and acidic environments,thus being independent of the pH value in infection areas.In addition,contributed by the intrinsic characteristics of vanadium,two-dimensional morphology and reasonable valence state ratios,VO_(x)NSs exhibit the advantages of broad antibacterial spectrum,high catalytic activity and non-toxic by-products.This novel nanosheet offers a new strategy to heal infected wounds and extends the application of nanocatalytic medicine towards anti-infection.

Dissolution and reconstruction of organic ligands in electrocatalysts for efficient OER

Electrocatalytic water splitting is a highly promising method for green hydrogen production,which is highly important for sustainable and low-carbon societal development.Despite tremendous scientific and technological efforts dedicated to thisfield,its practical application faces challenges owing to heavy energy consumption,mostly from the elevated potentials needed for the oxygen evolution reaction(OER)at the anode[1].Strategies such as developing efficient OER electrocatalysts and using sacrificial agents or electrosynthesis-assisted water splitting have emerged,collectively known as‘‘electrocatalytic hydrogen production trilogy”[2,3].While the latter two strategies show potential,especially the last one,they are still in the early development stages.Currently,there is a pressing need for efficient OER electrocatalysts to promote the commercialization of electrocatalytic water splitting.

无机纳米与多孔材料合成中的凝聚态化学

所谓凝聚态,一般意义上是指液态和固态,而凝聚态化学,即是在固相和液相中的各种化学过程。在无机材料,特别是无机纳米与多孔材料的合成制备中,凝聚态化学过程贯穿其中,几乎无处不在。在固相材料合成过程中,通过液相中的各种化学反应以获得目标固体材料的所需组分和物相,也许就是无机材料合成中一个最基本的凝聚态化学问题;而多孔如微孔或介孔材料合成中,更涉及伴随组分和物相形成过程中的孔结构形成与调控;进一步,在制备面向实际应用如催化剂和药物载体时,则在以上的各项要求之外,还必须考虑材料的表面活性位、缺陷等关键因素,以及颗粒尺寸、分散性和形貌等几何和物理特性。本文以无机氧化物为对象,讨论了无机材料在凝聚态化学合成过程中的几个侧面,包括纳米颗粒和粉体的化学合成方法,多孔材料的合成和多孔复相结构的合成调控,以及多级孔结构沸石的合成制备与催化性能,以期能加深对材料合成中凝聚态化学过程的认识,并期待以凝聚态化学为指导,进一步推动无机材料特别是纳米多孔材料合成的发展。

Two-dimensional titanium carbide MXenes as efficient non-noble metal electrocatalysts for oxygen reduction reaction

MXenes, a new family of multifunctional two dimensional(2D) solid crystals integrating high electroconductivity and rich surface chemistries, are promising candidates for electrolysis, which, however, have rarely been reported. Herein, free-standing ultrathin 2D MXene nanosheets were successfully fabricated from bulky and rigid MAX phase ceramics by liquid exfoliation with HF etching(delamination) and TPAOH intercalation(disintegration).The high oxygen reduction reaction(ORR) performance has been obtained, due to the extremely small thickness of the asfabricated Ti3C2 around 0.5–2.0 nm, equivalent to the dimensions of single-layer or double-layer Ti3C2 nanosheets in thickness. The ORR performance of the obtained Ti3C2 MXene-based catalyst exhibits desirable activity and stability in alkaline media. This study demonstrates the potential of earth-abundant 2D MXenes for constructing high-performance and cost-effective electrocatalysts.

Size effects of platinum particles@CNT on HER and ORR performance

Platinum(Pt)is an efficient catalyst for hydrogen evolution reaction(HER)and oxygen reduction reaction(ORR),but the debate of the relevance between the Pt particle size and its electrocatalytic activity still exist.The strong metal–support interaction(SMSI)between the metal and carrier causes the charge transfer and mass transport from the support to the metal.Herein,Pt species(0.5 wt.%)with various particle sizes supported on carbon nanotubes(CNTs)have been synthesized by a photo-reduction method.The^1.5 nm-sized Pt catalyst shows much higher HER performance than the counterparts in all pH solutions,and the mass activity of it is even 23–36 times that of Pt/C.While for ORR,the^3 nm-sized Pt catalyst exhibits the optimal performance,and the mass activity is 3 times and even 16 times that of Pt/C in acidic and alkaline media,respectively.The high HER and ORR performances of the^1.5 nm-and^3 nm-sized Pt catalysts benefit from the SMSI between Pt and the CNTs matrix and the higher ratio of face sites to edge sites,which is meaningful for the design of efficient electrocatalysts for renewable energy application.

Dual synergetic catalytic effects boost hydrogen electric oxidation performance of Pd/W_(18)O_(49)

Developing anode catalysts of substantially enhanced activity for hydrogen oxidation reaction(HOR)and anti-CO poisoning performance is of great importance for the application of proton exchange membrane fuel cells(PEMFCs).Herein,we report Pd cluster in situ decorated urchin-like W_(18)O_(49)(WO_(2.72))electrocatalysts by a photo-reduction method for high performance HOR.The synthesized Pd-WO_(2.72)-L composite of low loading amount of 0.44 wt.%Pd by Xenon light reduction exhibits markedly high HOR catalytic activity and stability in 0.5 M H_(2)SO_(4),and the specific HOR current density and mass activity of Pd-WO_(2.72)-L are~1.5 and~80 times those of 20 wt.%Pt/C catalyst,respectively.Moreover,excellent anti-CO poisoning ability has also been obtained.The excellent HOR activity and anti-CO poisoning performance of Pd-WO_(2.72)-L have been discussed mainly in terms of the dual synergetic catalytic effects between Pd and WO_(2.72):Pd activation to Pd^(δ+)by the electron transfer from Pd to W promotes the hydrogen adsorption and activation to H*species,which results in largely elevated HOR activity;Pd degradation due to the CO poisoning is effectively prevented by WO_(2.72),which is responsible for the excellent CO-tolerance performance.

A facile strategy for ultrasmall Pt NPs being partiallyembedded in N-doped carbon nanosheet structure for efficient electrocatalysis

A facile strategy is established for constructing composite nanostructure with ultrasmall Pt nanoparticles(NPs) of ~2 nm in diameter being homogeneously embedded in N-doped carbon nanosheets. The strong coordination between Pt atoms in cisplatin and N atoms in pyrrole contributes to the robust embedding of Pt NP into the N-doped carbon nanosheets after annealing. Such a unique partially-embedding structure facilitates the active site exposure while stabilizing the ultrasmall Pt NPs, leading to the comparable electrochemical activities for hydrogen evolution and oxygen reduction reactions, and substantially improves durability performance compared to that of the state-of-the-art Pt/C(20 wt%).

3D interconnected nanoporous TaN films for photoelectrochemical water splitting: thickness-controlled synthesis and insights into stability

Solar-driven photoelectrochemical(PEC) water splitting is a promising technology for sustainable hydrogen production, which relies on the development of efficient and stable photoanodes for water oxidation reaction. The thickness and microstructure of semiconductor films are generally crucial to their PEC properties. Herein, three-dimensional(3D) interconnected nanoporous Ta3N5 film photoanodes with controlled thickness were successfully fabricated via galvanostatic anodization and NH3 nitridation. The porous Ta3N5 nanoarchitectures(NAs) of 900 nm in thickness showed the highest PEC performance due to the optimal lightharvesting and charge separation. Compared with the holeinduced photocorrosion, the electrochemical oxidation at high anodic potentials resulted in severer performance degradation of Ta3N5. Although the surface oxide layer on deteriorated Ta3N5 photoanodes could be removed by NH3 re-treatment,the PEC performance was only partially recovered. As an alternative, anchoring a dual-layer Co(OH)x/Co OOH co-catalyst shell on the porous Ta3N5 NAs demonstrated substantially enhanced PEC performance and stability. Overall, this work provides reference to controllably fabricate 3D nanoporous Ta3N5-based photoanodes for efficient and stable PEC water splitting via optimizing the light absorption, hole extraction,charge separation and utilization.

Construction of layered h-BN/TiO2 hetero-structure and probing of the synergetic photocatalytic effect

A novel layered hexagonal boron nitride/titanium dioxide(h-BN/TiO2) composite photocatalyst has been constructed by anchoring TiO2 nanoflakes on the surface of hBN flakes via a solvothermal method. The morphology and dispersion of TiO2 can be tuned by controlling the amount of flake h-BN. Benefiting from the unique hetero-structure, the photocatalytic performance of the obtained composite toward rhodamine B(Rh B) degradation is greatly enhanced, among which 12 wt% h-BN/TiO2 composites show 3.5 and 6.9 times higher degradation rate than the synthesized TiO2 and commercial TiO2(P25), respectively, and an excellent cycling stability has also been obtained. Moreover, the first-principles calculation reveals the synergetic catalytic effect between TiO2 and h-BN flake, which is found to be responsible for the significantly enhanced photocatalytic performance of h-BN/TiO2 composites.

A Ni/Ni_(2)P heterostructure in modified porous carbon separator for boosting polysulfide catalytic conversion

The intrinsic sluggish conversion kinetics and severe shuttle effect in lithium-sulfur(Li-S)batteries are responsible for their poor reversible capacity and cycling longevity,which have greatly hindered their practical applications.To address these drawbacks,herein,we design and construct a heterostructured Ni/Ni_(2)P embedded in a mesoporous carbon nanosphere composite(Ni/Ni_(2)P-MCN)for boosting polysulfide catalytic conversion in Li-S batteries.The Ni/Ni_(2)PMCN-modified separator could not only prevent the shuttle effect significantly through abundant chemical adsorptive sites,but also demonstrate superior catalytic reactivities for the conversion of polysulfides.More importantly,the conductive carbon matrix with an exposed mesoporous structure can serve as an effective physical barrier to accommodate deposited insoluble Li_(2)S.Consequently,the cells with the Ni/Ni_(2)P-MCN-modified separator exhibit greatly boosted rate capability(431 mA h g^(-1) at 5 C)and cycling stability(a capacity decay of 0.031% per cycle after 1500 cycles).Even at an enhanced sulfur loading of 4.2 mg cm^(-2),a stable and superior areal capacity(about 3.5 mA h cm^(-2))has been demonstrated.We envision that the unique Ni/Ni_(2)P heterostructure in the porous carbon matrix could offer great potential for highperformance and sustained energy storage devices.

Starvation-Sensitized and Oxygenation-Promoted Tumor Sonodynamic Therapy by a Cascade Enzymatic Approach

The therapeutic outcomes of noninvasive sonodynamic therapy(SDT)are always compromised by tumor hypoxia,as well as inherent protective mechanisms of tumor.Herein,we report a simple cascade enzymatic approach of the concurrent glucose depletion and intratumoral oxygenation for starvation-sensitized and oxygenation-amplified sonodynamic therapy using a dual enzyme and sonosensitizer-loaded nanomedicine designated as GOD/CAT@ZPF-Lips.In particular,glucose oxidase-(GOD-)catalyzed glycolysis would cut off glucose supply within the tumor,resulting in the production of tumor hydrogen peroxide(H_(2)O_(2))while causing tumor cells starvation.The generated H_(2)O_(2)could subsequently be decomposed by catalase(CAT)to generate oxygen,which acts as reactants for the abundant singlet oxygen(^(1 O_(2))production by loaded sonosensitizer hematoporphyrin monomethyl ether(HMME)upon the US irradiation,performing largely elevated therapeutic outcomes of SDT.In the meantime,the severe energy deprivation enabled by GOD-catalyzed glucose depletion would prevent tumor cells from executing protective mechanisms to defend themselves and make the tumor cells sensitized and succumbed to the cytotoxicity of^(1 O_(2)).Eventually,GOD/CAT@ZPF-Lips demonstrate the excellent tumoral therapeutic effect of SDT in vivo without significant side effect through the cascade enzymatic starvation and oxygenation,and encouragingly,the tumor xenografts have been found completely eradicated in around 4 days by the intravenous injection of the nanomedicine without reoccurrence for as long as 20 days.