Electrochemical Carbon Dioxide Reduction to Ethylene:From Mechanistic Understanding to Catalyst Surface Engineering

Electrochemical carbon dioxide reduction reaction(CO_(2)RR)provides a promising way to convert CO_(2)to chemicals.The multicarbon(C_(2+))products,especially ethylene,are of great interest due to their versatile industrial applications.However,selectively reducing CO_(2)to ethylene is still challenging as the additional energy required for the C–C coupling step results in large overpotential and many competing products.Nonetheless,mechanistic understanding of the key steps and preferred reaction pathways/conditions,as well as rational design of novel catalysts for ethylene production have been regarded as promising approaches to achieving the highly efficient and selective CO_(2)RR.In this review,we first illustrate the key steps for CO_(2)RR to ethylene(e.g.,CO_(2)adsorption/activation,formation of~*CO intermediate,C–C coupling step),offering mechanistic understanding of CO_(2)RR conversion to ethylene.Then the alternative reaction pathways and conditions for the formation of ethylene and competitive products(C_1 and other C_(2+)products)are investigated,guiding the further design and development of preferred conditions for ethylene generation.Engineering strategies of Cu-based catalysts for CO_(2)RR-ethylene are further summarized,and the correlations of reaction mechanism/pathways,engineering strategies and selectivity are elaborated.Finally,major challenges and perspectives in the research area of CO_(2)RR are proposed for future development and practical applications.

Enhanced MTO performance over acid treated hierarchical SAPO-34

Hierarchical SAPO‐34 crystals were synthesized by a facile acid etching post‐treatment. Butterfly‐shaped porous patterns on four side faces and hierarchical pores composed of micropores,mesopores and macropores were formed after a nitric acid or oxalic acid treatment. The catalyticperformance of the hierarchical SAPO‐34 for the methanol to olefins (MTO) process showed that thesynergistic effect of the hierarchical pores and acid sites resulted in a longer catalyst lifetime (from210 to 390 min for the acid treated SAPO‐34) and higher selectivity to light olefins of 92%–94%.The ethylene selectivity can be adjusted between 37.4% and 51.5% by the pore size. No hierarchical SAPO‐34 was obtained after a treatment with butanedioic acid, and with this sample, fast deactivation was detected after 100 min.

Polychlorinated biphenyls in the atmosphere of Taizhou,a major e-waste dismantling area in China

PM2.5, total suspended particles （TSP） and gas phase samples were collected at two sites of Talzhou, a major e-waste dismantling area in China. Concentrations, seasonal variations, congener profiles, gas-particle partitioning and size distribution of the atmospheric polychlorinated biphenyls （PCBs） were studied to assess the current state of atmospheric PCBs after the phase out of massive historical dismantling of PCBs containing e-wastes. The average ∑38PCBs concentration in the ambient air （TSP plus gas phase） near the e-waste dismantling area was （12,407 ± 9592） pg/m^3 in winter, which was substantially lower than that found one decade ago. However, the atmospheric PCBs level near the e-waste dismantling area was 54 times of the reference urban site, indicating that the impact of the historical dismantling of PCBs containing e-wastes was still significant. Tri-Penta-CBs were dominant homologues, consisting with their dominant global production. Size distribution of particle-bound PCBs showed that higher chlorinated CBs tended to partition more to the fine particles, facilitating its long range air transportation.

Diurnal variations of polycyclic aromatic hydrocarbons associated with PM_(2.5) in Shanghai, China

Forty-eight daily time interval PM2.5 samples were collected from December 2006 to January 2008 in an urban site in Shanghai, China. Concentrations and compositions of polycyclic aromatic hydrocarbons （PAHs） were analyzed with GC-MS to study the diurnal and seasonal variations and to identify the main emitting sources. The diurnal variation of the PAHs concentrations was greater in the late autumn and winter sampling days, and was greatly influenced by meteorological conditions such as wind speed and ambient temperature. The concentration of PAHs in the mornings （6：30–10：00） increased distinctly, and was high in the late autumn and winter sampling days, indicating the contribution from vehicle emissions during rush hours. The diurnal variation of the high molecular weight PAHs did not seem to be controlled by the shift of gas-particle partitioning due to temperature variation, instead, it could be indicative of the variation in the source. Statistical analyses showed that the concentrations of PAHs were negatively correlated with temperature and wind speed, and positively correlated with relative humidity. Diagnostic ratios of PAHs suggested mixed emission sources of petroleum and coal/biomass combustion for PAHs in the PM2.5 in Shanghai.

Boron Nanosheet-Supported Rh Catalysts for Hydrogen Evolution:A New Territory for the Strong Metal-Support Interaction Effect

High-efficiency electrochemical hydrogen evolution reaction(HER)offers a promising strategy to address energy and environmental crisis.Platinum is the most effective electrocatalyst for the HER.However,challenging scarcity,valuableness,and poor electrochemical stability still hinder its wide application.Here,we designed an outstanding HER electrocatalyst,highly dispersed rhodium(Rh)nanoparticles with an average diameter of only 3 nm supported on boron(B)nanosheets.The HER catalytic activity is even comparable to that of commercial platinum catalysts,with an overpotential of only 66 mV in 0.5 M H_(2)SO_(4) and 101 mV in 1 M KOH to reach the current density of 10 mA cm−2.Meanwhile,the catalyst exhibited impressive electrochemical durability during long-term electrochemical processes in acidic and alkaline media,even the simu-lated seawater environment.Theoretical calculations unraveled that the structure-activity relationship between B(104)crystal plane and Rh(111)crystal plane is beneficial to the release of hydrogen,and surface O plays a vital role in the catalysis process.Our work may gain insights into the development of supported metal catalysts with robust catalytic performance through precise engineering of the strong metal-supported interaction effect.

Size distribution of chemical elements and their source apportionment in ambient coarse, fine, and ultrafine particles in Shanghai urban summer atmosphere

Ambient coarse particles （diameter 1.8-10 μm）, fine particles （diameter 0.1-1.8 μm）, and ultrafine particles （diameter 〈 0.1 μm） in the atmosphere of the city of Shanghai were sampled during the summer of 2008 （from Aug 27 to Sep 08）. Microscopic characterization of the particles was investigated by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy （SEM/EDX）. Mass concentrations of Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, and Pb in the size-resolved particles were quantified by using synchrotron radiation X-ray fluorescence （SRXRF）. Source apportionment of the chemical elements was analyzed by means of an enrichment factor method. Our results showed that the average mass concentrations of coarse particles, fine particles and ultrafine particles in the summer air were 9.38 ± 2.18, 8.82 ± 3.52, and 2.02 ± 0.41 μg/m3, respectively. The mass percentage of the fine particles accounted for 51.47% in the total mass of PM10, indicating that fine particles are the major component in the Shanghai ambient particles. SEM/EDX results showed that the coarse particles were dominated by minerals, fine particles by soot aggregates and fly ashes, and ultrafine particles by soot particles and unidentified particles. SRXRF results demonstrated that crustal elements were mainly distributed in the coarse particles, while heavy metals were in higher proportions in the fine particles. Source apportionment revealed that Si, K, Ca, Fe, Mn, Rb, and Sr were from crustal sources, and S, Cl, Cu, Zn, As, Se, Br, and Pb from anthropogenic sources. Levels of P, V, Cr, and Ni in particles might be contributed from multi-sources, and need further investigation.

Atmospheric HULIS and its ability to mediate the reactive oxygen species (ROS)： A review

Atmospheric humic-like substances （HULIS） are not only an unresolved mixture of macro- organic compounds but also powerful chelating agents in atmospheric particulate matters （PMs）; impacting on both the properties of aerosol particles and health effects by generating reactive oxygen spedes （ROS）. Currently, the interests of HULIS are intensively shifting to the investigations of HULIS-metal synergic effects and kinetics modeling studies, as well as the development of HULIS quantification, findings of possible HULIS sources and generation of ROS from HULIS. In light of HULIS studies, we comprehensively review the current knowledge of isolation and physicochemical characterization of HULIS from atmospheric samples as well as HULIS properties （hygroscopic, surface activity, and colloidal） and possible sources of HULIS. This review mainly highlights the generation of reactive oxygen species （ROS） from PMs, HULIS and transition metals, especially iron. This review also summarized the mechanism of iron-organic complexation and recent findings of OH formation from HULIS-metal complexes. This review will be helpful to carry out the modeling studies that concern with HULIS-transition metals and for further studies in the generation of ROS from HULIS-metal complexes,

Leaf-inspired design of mesoporous Sb_(2)S_(3)/N-doped Ti_(3)C_(2)T_(x) composite towards fast sodium storage

Owing to excellent conductivity and abundant surface terminals,MXene-based heterostructures have been intensively investigated as energy storage materials.However,elaborate design of the structure and composition of MXene-based hybrids towards superior electrochemical performance is still challenging.Herein,we present an ingenious leaf-inspired design for preparing a unique Sb_(2)S_(3)/nitrogen-doped Ti_(3)C_(2)T_(x)MXene(L-Sb_(2)S_(3)/Ti_(3)C_(2))hybrid.In-situ TEM observations reveal that the leaflike Sb_(2)S_(3)nanoparticles with numerous mesopores can well relieve the large volume changes via an inward pore filling mechanism with only 20%outward expansion,whereas highly conductive N-doped Ti_(3)C_(2)T_(x)nanosheets can serve as the robust mechanical support to reinforce the structural integrity of the hybrid.Benefiting from the structural and constituent merits,the L-Sb_(2)S_(3)/Ti_(3)C_(2)anode fabricated exhibits a fast sodium storage behavior in terms of outstanding rate capability(339.5 mA h g^(-1)at 2,000 mA g^(-1))and high reversible capacity at high current density(358.2 mA h g^(-1)at 1,000 mA g^(-1)after 100 cycles).Electrochemical kinetic tests and theoretical simulation further manifest that the boosted electrochemical performance mainly arises from such a unique leaf-like Sb_(2)S_(3)mesoporous nanostructure with abundant active sites,and enhanced Na^(+)adsorption energy on the heterojunction formed between Sb_(2)S_(3)nanoparticles and Ti_(3)C_2)matrix.

Boosting sodium storage of mesoporous TiO2 nanostructure regulated by carbon quantum dots

It has been demonstrated that the conductivity and electrochemical properties of TiO2 nanomate rials can be significantly improved by an incorporation of carbon additives.In the study,we develop a novel Ndoped TiO2 mesoporous nanostructure via the addition of carbon quantum dots(CQDs)solution following a scalable hydrothermal process.The as-made TiO2 product shows well-defined morphology,high conductivity,large surface area,and abundant mesopores.When evaluated as anodes for sodiumion batteries,the CQDs@TiO2 product annealed at 500℃exhibits a superior sodium storage capability.It delivers a high reversible capacity of 168.8 mAh/g at 100 mA/g over 500 cycles and long cycling stability.The remarkable performance of CQDs@TiO2 mainly arises from the large surface area and mesoporous architecture constructed by ultrathin TiO2 nanosheets,as well as the full coope ration between CQDs and TiO2.

Altering sub-cellular location for bioimaging by engineering the carbon based fluorescent nanoprobe

In recent years,numerous classes of carbon-based nanomaterials,such as carbon nanotubes(CNTs),carbon dots(CDs),graphene and its derivatives,graphene quantum dots(GQDs)and fullerene,have been deeply explored for potential applications in the biological fields,e.g.,bioimaging[1-5],biosensing[6,7],drug nanocarrier[8-12],etc.,owing to their unique and alluring physical and chemical properties.Among them,GQDs are a subject of interesting and promising research with many advantages such as strong signal strength,resistance to photobleaching,tunable fluorescence emissions,high sensitivity and biocompatibility[13-35].Compared with those semiconductor QDs,GQDs have remarkable superior让y in low toxicity,excellent biocompatibility,low cost,and abundance of original materials in nature[36].High quality GQDs have a wide range of applications,such as light emitting diodes(LEDs)[37,38],solar cells[39,40]and photocatalysis[41,42],aside from biological fields.Up to now,various GQDs with different photoluminescent(PL)colors have been synthesized by two dominating approaches including top-down and bottomup methods.The top-down method refers to cutting bulk carbon materials into nanoscale-carbon materials by necessary physical and chemical processes[43].

Construction of point-line-plane （0-1-2 dimensional） Fe2O3-SnO2/graphene hybrids as the anodes with excellent lithium storage capability

The assembly of hybrid nanomaterials has opened up a new direction for the construction of high-performance anodes for lithium-ion batteries （LIBs）. In this work, we present a straightforward, eco-friendly, one-step hydrothermal protocol for the synthesis of a new type of Fe2OB-SnO2/graphene hybrid, in which zero-dimensional （0D） SnO2 nanoparticles with an average diameter of 8 nm and one-dimensional （1D） Fe203 nanorods with a length of -150 nm are homogeneously attached onto two-dimensional （2D） reduced graphene oxide nanosheets, generating a unique point-line-plane （0D-1D-2D） architecture. The achieved Fe203-SnO2/graphene exhibits a well-defined morphology, a uniform size, and good monodispersity. As anode materials for LIBs, the hybrids exhibit a remarkable reversible capacity of 1,530 mA·g^-1 at a current density of 100 ma·g^-1 after 200 cycles, as well as a high rate capability of 615 mAh·g^-1 at 2,000 mA·g^-1 Detailed characterizations reveal that the superior lithium-storage capacity and good cycle stability of the hybrids arise from their peculiar hybrid nanostructure and conductive graphene matrix, as well as the synergistic interaction among the components.

Direct Imaging of Titania Nanotubes Located in Mouse Neural Stem Cell Nuclei

Titania nanotubes(TiO2-NTs)are a potential drug vehicle for use in nanomedicine.To this end,a preliminary study of the interaction of a model cell with TiO2-NTs has been carried out.TiO2-NTs were first conjugated with a fl uorescent label,fl uorescein isothiocyanate(FITC).FITC-conjugated titania nanotubes(FITC-TiO2-NTs)internalized in mouse neural stem cells(NSCs,line C17.2)can be directly imaged by confocal microscopy.The confocal imaging showed that FITC-TiO2-NTs readily entered into the cells.After co-incubation with cells for 24 h,FITC-TiO2-NTs localized around the cell nucleus without crossing the karyotheca.More interestingly,the nanotubes passed through the karyotheca entering the cell nucleus after co-incubation for 48 h.Atomic force microscopy(AFM)and transmission electron microscopy(TEM)were also employed in tracking the nanotubes in the cell.These results will be of benefit in future studies of TiO2-NTs for use as a drug vehicle,particularly for DNA-targeting drugs.

Advances in direct production of value-added chemicals via syngas conversion

Syngas conversion to fuels and chemicals is one of the most challenging subjects in the field of C1 chemistry. It is considered as an attractive alternative non-petroleum-based production route. The direct synthesis of olefins and alcohols as high value-added chemicals from syngas has drawn particular attention due to its process simplicity, low energy consumption and clean utilization of carbon resource, which conforms to the principles of green carbon science. This review describes the recent advances for the direct production of lower olefins and higher alcohols via syngas conversion. Recent progress in the development of new catalyst systems for enhanced catalytic performance is highlighted. We also give recommendations regarding major challenges for further research in syngas conversion to various chemicals.

B-incorporated,N-doped hierarchically porous carbon nanosheets as anodes for boosted potassium storage capability

Carbonaceous nanomaterials with porous structure have become the highly promising anode materials for potassium-ion batteries(PIBs)due to their abundant resources,low-cost,and excellent conductivity.Nevertheless,the sluggish reaction kinetics and inferior cycling life caused by the large radius of K ions severely restrict their commercial development.Herein,B,N co-doped hierarchically porous carbon nanosheets(BNPC)are achieved via a facile template-assisted route,followed by a simple one-step carbonization process.The resultant BNPC possesses a unique porous structure,large surface area,and high-level B,N co-doping.The structural features endows it with remarkable potassium storage performances,which delivers a high reversible capacity(242.2 mA h/g at100 m A/g after 100 cycles),and long cycling stability(123.1 m Ah/g at 2000 m A/g and 62.9 m Ah/g at5000 mA/g after 2000 cycles,respectively).Theoretical simulations further validate that the rich B doping into N-modified carbon configuration can greatly boost the potassium storage capability of the BNPC anode.

MOF/PCP‑based Electrocatalysts for the Oxygen Reduction Reaction

The oxygen reduction reaction(ORR)is the fundamental reaction at the cathode of a fuel cell.Although the commercial precious metal catalyst Pt/C has unique catalytic activity,its high cost,low storage capacity and poor stability limit the commercial application of fuel cells.Therefore,it is essential to explore catalysts with abundant functional materials and develop fuel cells with high activity and high stability.Metal–organic frameworks(MOFs)or porous coordination polymers(PCPs)are highly designable structures composed of organic ligands and metal ions.Because of their large specific surface area,high porosity and tunable chemical structure,MOFs/PCPs are considered the most promising catalytic material for the ORR.This review discusses the research progress and latest development of MOF/PCP applications as ORR catalysts,including the basic principles and the design rules of MOFs/PCPs as ORR catalysts.In addition,this work also elaborates on the active sites of ORR catalysts,which originate from the MOFs/PCPs.Ultimately,we present a research review of the last 5 years and the prospects in the field of using MOFs/PCPs for the fabrication of ORR catalysts.

The cytotoxicity of oxidized multi-walled carbon nanotubes on macrophages

Carbon nanotubes(CNTs) have been developed for medical and biotechnological applications in the past decades. Their widespread applications make it important to understand their potential hazards to human and the environment. In this study, the possible toxicological effects of the oxidized multi-walled carbon nanotubes(O-MWCNTs) were assessed on RAW 264.7 macrophages in vitro. Several toxicological endpoints, such as cell viability, the release of LDH and IL-8, GSH/GSSG ratio, intracellular calcium concentration and ultrastructural changes in cell morphology, were carried out. The results showed that O-MWCNTs had very limited effects on oxidative stress, cellular toxicity and apoptosis. Transmission electron microscope clearly demonstrates RAW 264.7 macrophages engulfed plenty of O-MWCNTs, and some of them resided in the cytoplasm, while the morphology was not altered by O-MWCNTs. As the control, the pristine MWCNTs(p-MWCNTs) show higher cytotoxicity than O-MWCNTs, damaging cell viability and inducing cell apoptosis. All these toxicological data are of benefit to more wide applications of O-MWCNTs in the future.

Double interface regulation: Toward highly stable lithium metal anode with high utilization

The undesirable Li dendrite growth and other knock-on issues have signifi-cantly plagued the application of Li metal anodes(LMAs).Herein,we report that the synergistic regulation of double interfaces adjacent to the metallic Li anode can effectively prevent the dendritic Li growth,significantly improving the cycling performance of LMAs under harsh conditions including high cur-rent density and high depth of discharge.Thorough comparison of electrolytes demonstrated that 1 M lithium bis(fluorosulfonyl)imide(LiFSI)in 1,2-dimethoxyethane(DME)can yield a robust and lithiophobic LiF-rich upper interface(solid electrolyte interphase).Besides,the Sb-based buffer layer forms a lithiophilic lower interface on current collector.The synergy of the upper and lower interfacial engineering plays an important role for outstanding cyclability of LMAs.Consequently,the plating/stripping of Li can be stably repeated for 835 and 329 cycles with an average Coulombic efficiency(CE)above 99%at 1 and 3 mA h cm?2,respectively.Surprisingly,the Li||Li symmetric cell can even withstand the baptism of current density up to 20 mA cm?2.The excellent performance validates that the facile synergistic regulating of interfaces adjacent to the metallic Li anode provides an effective pathway to stabilize LMAs.

Correction to:MOF/PCP-based Electrocatalysts for the Oxygen Reduction Reaction

Correction to:Electrochemical Energy Reviews(2022)5:32-81 https://doi.org/10.1007/s41918-021-00113-7 The original version of this article unfortunately contained a mistake.The name of co-author Minghong Wu was wrong.The original article has been corrected.