High-throughput calculation-based rational design of Fe-doped MoS_(2) nanosheets for electrocatalytic p H-universal overall water splitting

Electrocatalytic water splitting is crucial for H2generation via hydrogen evolution reaction(HER)but subject to the sluggish dynamics of oxygen evolution reaction(OER).In this work,single Fe atomdoped MoS_(2)nanosheets(SFe-DMNs)were prepared based on the high-throughput density functional theory(DFT)calculation screening.Due to the synergistic effect between Fe atom and MoS_(2)and optimized intermediate binding energy,the SFe-DMNs could deliver outstanding activity for both HER and OER.When assembled into a two-electrode electrolytic cell,the SFe-DMNs could achieve the current density of 50 mA cm^(-2)at a low cell voltage of 1.55 V under neutral condition.These results not only confirmed the effectiveness of high-throughput screening,but also revealed the excellent activity and thus the potential applications in fuel cells of SFe-DMNs.

Graphitic‐shell encapsulated FeNi alloy/nitride nanocrystals on biomass‐derived N‐doped carbon as an efficient electrocatalyst for rechargeable Zn‐air battery

Oxygen reduction/evolution reactions(ORR/OERs)catalysts play a key role in the metal‐air battery and water‐splitting process.Herein,we developed a facile template‐free method to fabricate a new type of non–noble metal‐based hybrid catalyst which consists of binary FeNi alloy/nitride nanocrystals with graphitic‐shell and biomass‐derived N‐doped carbon(NC)(FexNiyN@C/NC).This novel nanostructure exhibits superior performance for ORR/OER,which can be attributed to the strong interactions between the graphitic‐shell encapsulated FeNi alloy/nitride nanocrystals and the N‐doped porous carbon substrate.The X‐ray absorption spectroscopy technique was employed to reveal the underlying mechanisms for the excellent performance.The assembled Zn‐air battery device exhibits outstanding charging/discharging performance and cycling stability,indicating the great potential of this type of novel catalysts.

3D Grid of Carbon Tubes with Mn3O4-NPs/CNTs Filled in their Inner Cavity as Ultrahigh-Rate and Stable Lithium Anode

Transition metal oxides are regarded as promising candidates of anode for next-generation lithium-ion batteries(LIBs)due to their ultrahigh theoretical capacity and low cost,but are restricted by their low conductivity and large volume expansion during Li^(+)intercalation.Herein,we designed and constructed a structurally integrated 3D carbon tube(3D-CT)grid film with Mn_(3)O_(4)nanoparticles(Mn_(3)O_(4)-NPs)and carbon nanotubes(CNTs)filled in the inner cavity of CTs(denoted as Mn_(3)O_(4)-NPs/CNTs@3D-CT)as high-performance free-standing anode for LIBs.The Mn_(3)O_(4)-NPs/CNTs@3D-CT grid with Mn_(3)O_(4)-NPs filled in the inner cavity of 3D-CT not only afford sufficient space to overcome the damage caused by the volume expansion of Mn_(3)O_(4)-NPs during charge and discharge processes,but also achieves highly efficient channels for the fast transport of both electrons and Li+during cycling,thus offering outstanding electrochemical performance(865 mAh g^(-1)at 1 A g^(-1)after 300 cycles)and excellent rate capability(418 mAh g^(-1)at 4 A g^(-1))based on the total mass of electrode.The unique 3D-CT framework structure would open up a new route to the highly stable,high-capacity,and excellent cycle and high-rate performance free-standing electrodes for highperformance Li-ion storage.

Material manufacturing from atomic layer

Atomic scale engineering of materials and interfaces has become increasingly important in material manufacturing.Atomic layer deposition(ALD)is a technology that can offer many unique properties to achieve atomic-scale material manufacturing controllability.Herein,we discuss this ALD technology for its applications,attributes,technology status and challenges.We envision that the ALD technology will continue making significant contributions to various industries and technologies in the coming years.

Strategies to achieve effective nitrogen activation

Ammonia serves as a crucial chemical raw material and hydrogen energy carrier.Aqueous electrocatalytic nitrogen reduction reaction(NRR),powered by renewable energy,has attracted tremendous interest during the past few years.Although some achievements have been revealed in aqueous NRR,significant challenges have also been identified.The activity and selectivity are fundamentally limited by nitrogen activation and competitive hydrogen evolution.This review focuses on the hurdles of nitrogen activation and delves into complementary strategies,including materials design and system optimization(reactor,electrolyte,and mediator).Then,it introduces advanced interdisciplinary technologies that have recently emerged for nitrogen activation using high-energy physics such as plasma and triboelectrification.With a better understanding of the corresponding reaction mechanisms in the coming years,these technologies have the potential to be extended in further applications.This review provides further insight into the reaction mechanisms of selectivity and stability of different reaction systems.We then recommend a rigorous and detailed protocol for investigating NRR performance and also highlight several potential research directions in this exciting field,coupling with advanced interdisciplinary applications,in situ/operando characterizations,and theoretical calculations.

Approaching the commercial threshold of solar water splitting toward hydrogen byⅢ-nitrides nanowires

In a recent article in Nature,Mi and coworkers from the University of Michigan reported a solar-to-hydrogen(STH)efficiency of>9%in converting water into hydrogen and oxygen[1],which represents an important breakthrough in this field due to the benchmarking leap in STH efficiency of photocatalytic overall water splitting under natural sunlight.

Physico-Chemical and Mineralogical Characterizations of Two Togolese Clays for Geopolymer Synthesis

Geopolymers are an alternative to Portland cement, well known for their contribution to greenhouse gas emissions. Finding materials that can validly replace Portland cement is a challenge. It is in this logic that this work was undertaken with the objective of characterizing two local clay resources of Togo as raw materials for geopolymers. The physico-chemical properties of these clays were determined by characterization using X-ray diffraction (XRD), Fourier transform infrared (FTIR), thermogravimetric (TGA) and elemental analysis (ICP-OES). The results show that these clays contain kaolinite and therefore can be used in the formulation of geopolymers. The characterized clays underwent heat treatments transforming the crystalline phases into more reactive amorphous phases and then were activated by an alkaline solution in order to formulate the geopolymer materials. These elaborated materials were analyzed by Fourier transform infrared to identify the types of bonds formed. The results of these analyses show that these two local clays are well suited to be used in synthesizing geopolymers. Our future work will focus on the constraints of consolidation as well as the mechanical properties of these geopolymer materials.

Multi-factor principle for electrolyte additive molecule design for facilitating the development of electrolyte chemistry

When I read the paper“Electrolytes enriched by potassium perfluorinated sulfonates for lithium metal batteries”from Prof.Jianmin Ma’s group,which was published in Science Bulletin(doi.org/10.1016/j.scib.2020.09.018),I felt excited as presented a multi-factor principle for applying potassium perfluorinated sulfonates to suppress the dendrite growth and protect the cathode from the viewpoint of electrolyte additives.The effects of these additives are revealed through experimental results,molecular dynamics simulations and first-principle calculations.Specifically,it involves the influence of additives on Li^(+)solvation structure,solid electrolyte interphase(SEI),Li growth and nucleation.Following the guidance of the multi-factor principle,every part of the additive molecule should be utilized to regulate electrolytes.This multifactor principle for electrolyte additive molecule design(EAMD)offers a unique insight on understanding the electrochemical behavior of iontype electrolyte additives on both the Li metal anode and high-voltage cathode.In these regards,I would be delighted to write a highlight for this innovative work and,hopefully,it may raise more interest in the areas of electrolyte additives.

Engineering Fe‑N_(4)Electronic Structure with Adjacent Co‑N_(2)C_(2)and Co Nanoclusters on Carbon Nanotubes for Efficient Oxygen Electrocatalysis

Regulating the local configuration of atomically dispersed transition-metal atom catalysts is the key to oxygen electrocatalysis performance enhancement.Unlike the previously reported singleatom or dual-atom configurations,we designed a new type of binary-atom catalyst,through engineering Fe-N_(4)electronic structure with adjacent Co-N_(2)C_(2)and nitrogen-coordinated Co nanoclusters,as oxygen electrocatalysts.The resultant optimized electronic structure of the Fe-N_(4)active center favors the binding capability of intermediates and enhances oxygen reduction reaction(ORR)activity in both alkaline and acid conditions.In addition,anchoring M-N-C atomic sites on highly graphitized carbon supports guarantees of efficient charge-and mass-transports,and escorts the high bifunctional catalytic activity of the entire catalyst.Further,through the combination of electrochemical studies and in-situ X-ray absorption spectroscopy analyses,the ORR degradation mechanisms under highly oxidative conditions during oxygen evolution reaction processes were revealed.This work developed a new binary-atom catalyst and systematically investigates the effect of highly oxidative environments on ORR electrochemical behavior.It demonstrates the strategy for facilitating oxygen electrocatalytic activity and stability of the atomically dispersed M-N-C catalysts.

Advancements on metal oxide semiconductor photocatalysts in photo-electrochemical conversion of carbon dioxide into fuels and other useful products

Due to its fascinating and tunable optoelectronic properties,semiconductor nanomaterials are the best choices for multidisciplinary applications.Particularly,the use of semiconductor photocatalysts is one of the promising ways to harness solar energy for useful applications in the field of energy and environment.In recent years,metal oxide-based tailored semiconductor photocatalysts have extensively been used for photocatalytic conversion of carbon dioxide(CO_(2))into fuels and other useful products utilizing solar energy.This is very significant not only from renewable energy consumption but also from reducing global warming point of view.Such current research activities are promising for a better future of society.The present mini-review is focused on recent developments(2–3 years)in metal oxide semiconductor hybrid photocatalysts-based photo-electrochemical conversion of CO_(2)into fuels and other useful products.First,general mechanism of photo-electrochemical conversion of CO_(2)into fuels or other useful products has been discussed.Then,various metal oxide-based emerging hybrid photocatalysts including tailoring of their morphological,compositional,and optoelectronic properties have been discussed with emphasis on their role in enhancing photoelectrochemical efficienty.Afterwards,mechanism of their photo-electrochemical reactions and applications in CO_(2)conversion into fuels/other useful products have been discussed.Finally,challenges and future prospects have been discussed followed by a summary.

Ga(X)N/Si nanoarchitecture:An emerging semiconductor platform for sunlight-powered water splitting toward hydrogen

Sunlight-powered water splitting presents a promising strategy for converting intermittent and virtually unlimited solar energy into energy-dense and storable green hydrogen.Since the pioneering discovery by Honda and Fujishima,considerable efforts have been made in this research area.Among various materials developed,Ga(X)N/Si(X=In,Ge,Mg,etc.)nanoarchitecture has emerged as a disruptive semiconductor platform to split water toward hydrogen by sunlight.This paper introduces the characteristics,properties,and growth/synthesis/fabrication methods of Ga(X)N/Si nanoarchitecture,primarily focusing on explaining the suitability as an ideal platform for sunlight-powered water splitting toward green hydrogen fuel.In addition,it exclusively summarizes the recent progress and development of Ga(X)N/Si nanoarchitecture for photocatalytic and photoelectrochemical water splitting.Moreover,it describes the challenges and prospects of artificial photosynthesis integrated device and system using Ga(X)N/Si nanoarchitectures for solar water splitting toward hydrogen.

Interface Engineering of NixSy@MnOxHy Nanorods to Efficiently Enhance Overall-Water-Splitting Activity and Stability

Exploring highly active and stable transition metal-based bifunctional electrocatalysts has recently attracted extensive research interests for achieving high inherent activity, abundant exposed active sites, rapid mass transfer, and strong structure stability for overall water splitting. Herein, an interface engineering coupled with shell-protection strategy was applied to construct three-dimensional(3D) core-shell NixSy@MnOxHy heterostructure nanorods grown on nickel foam(NixSy@MnOxHy/NF) as a bifunctional electrocatalyst. NixSy@MnOxHy/NF was synthesized via a facile hydrothermal reaction followed by an electrodeposition process. The X-ray absorption fine structure spectra reveal that abundant Mn-S bonds connect the heterostructure interfaces of N ixSy@MnOxHy, leading to a strong electronic interaction, which improves the intrinsic activities of hydrogen evolution reaction and oxygen evolution reaction(OER). Besides, as an efficient protective shell, the MnOxHy dramatically inhibits the electrochemical corrosion of the electrocatalyst at high current densities, which remarkably enhances the stability at high potentials. Furthermore, the 3D nanorod structure not only exposes enriched active sites, but also accelerates the electrolyte diffusion and bubble desorption. Therefore, NixSy@MnOxHy/NF exhibits exceptional bifunctional activity and stability for overall water splitting, with low overpotentials of 326 and 356 mV for OER at 100 and 500 mA cm^(–2), respectively, along with high stability of 150 h at 100 mA cm^(–2). Furthermore, for overall water splitting, it presents a low cell voltage of 1.529 V at 10 mA cm^(–2), accompanied by excellent stability at 100 mA cm^(–2) for 100 h. This work sheds a light on exploring highly active and stable bifunctional electrocatalysts by the interface engineering coupled with shell-protection strategy.

Atomically Dispersed Transition Metal-Nitrogen-Carbon Bifunctional Oxygen Electrocatalysts for Zinc-Air Batteries:Recent Advances and Future Perspectives

Rechargeable zinc-air batteries(ZABs)are currently receiving extensive attention because of their extremely high theoretical specific energy density,low manufacturing costs,and environmental friendliness.Exploring bifunctional catalysts with high activity and stability to overcome sluggish kinetics of oxygen reduction reaction and oxygen evolution reaction is critical for the development of rechargeable ZABs.Atomically dispersed metal-nitrogen-carbon(M-N-C)catalysts possessing prominent advantages of high metal atom utilization and electrocatalytic activity are promising candidates to promote oxygen electrocatalysis.In this work,general principles for designing atomically dispersed M-N-C are reviewed.Then,strategies aiming at enhancing the bifunctional catalytic activity and stability are presented.Finally,the challenges and perspectives of M-N-C bifunctional oxygen catalysts for ZABs are outlined.It is expected that this review will provide insights into the targeted optimization of atomically dispersed M-N-C catalysts in rechargeable ZABs.

Single‐pixel terahertz imaging:a review

This paper is devoted to reviewing the results achieved so far in the application of the single-pixel imaging technique to terahertz(THz)systems.The use of THz radiation for imaging purposes has been largely explored in the last twenty years,due to the unique capabilities of this kind of radiation in interrogating material properties.However,THz imaging systems are still limited by the long acquisition time required to reconstruct the object image and significant efforts have been recently directed to overcome this drawback.One of the most promising approaches in this sense is the so-called“single-pixel”imaging,which in general enables image reconstruction by patterning the beam probing the object and measuring the total transmission(or reflection)with a single-pixel detector(i.e.,with no spatial resolution).The main advantages of such technique are that i)no bulky moving parts are required to raster-scan the object and ii)compressed sensing(CS)algorithms,which allow an appropriate reconstruction of the image with an incomplete set of measurements,can be successfully implemented.Overall,this can result in a reduction of the acquisition time.In this review,we cover the experimental solutions proposed to implement such imaging technique at THz frequencies,as well as some practical uses for typical THz applications.

Proton Exchange Membrane(PEM)Fuel Cells with Platinum Group Metal(PGM)-Free Cathode

Proton exchange membrane(PEM)fuel cells have gained increasing interest from academia and industry,due to its remarkable advantages including high efficiency,high energy density,high power density,and fast refueling,also because of the urgent demand for clean and renewable energy.One of the biggest challenges for PEM fuel cell technology is the high cost,attributed to the use of precious platinum group metals(PGM),e.g.,Pt,particularly at cathodes where sluggish oxygen reduction reaction takes place.Two primary ways have been paved to address this cost challenge:one named low-loading PGM-based catalysts and another one is non-precious metal-based or PGM-free catalysts.Particularly for the PGM-free catalysts,tremendous efforts have been made to improve the performance and durability-milestones have been achieved in the corresponding PEM fuel cells.Even though the current status is still far from meeting the expectations.More efforts are thus required to further research and develop the desired PGM-free catalysts for cathodes in PEM fuel cells.Herein,this paper discusses the most recent progress of PGM-free catalysts and their applications in the practical membrane electrolyte assembly and PEM fuel cells.The most promising directions for future research and development are pointed out in terms of enhancing the intrinsic activity,reducing the degradation,as well as the study at the level of fuel cell stacks.

Physicochemical and Mineralogical Characterizations of Wastes Coming from Phosphate Ore Processing of Hahotoéand KpogaméMines

In the framework of various phosphates discharges valorization, we have realized physicochemical and mineralogical characterizations of these discharges. We have undertaken the physicochemical and mineralogical characterizations of this waste by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), thermal analysis and Atomic Emission Spectrometry Coupled to an Inductive Plasma Source. The results of these analyze show that phosphate sludge and screen rejects could be used in ceramics, in the manufacture of aggregates, in agriculture and other fields. On the other hand, rich magnetic waste could be used in heterogeneous photocatalysis in waste liquids treatment.

Weakening CO poisoning over size-and support-dependent Pt_(n)/X-graphene catalyst(X=C,B,N,n=1-6,13)

CO poisoning is one of the obstacles for platinum catalysts toward the electro-catalysis process for proton exchange membrane fuel cell(PEMFC)or direct methanol fuel cell(DMFC).Herein,we aim to weaken the CO poisoning on Pt by varying the cluster sizes and supports via doping graphene with B and N based on DFT+D3 calculations.

Oxidization-induced structural optimization of Ni_(3)Fe-N-C derived from 3D covalent organic framework for high-efficiency and durable oxygen evolution reaction

NiFe composites have been regarded as promising candidates to replace commercial noble-based electrocatalysts for the oxygen evolution reaction(OER).However,their practical applications still suffer from poor conductivity,limited activity,durability.To address these issues,herein,by utilizing three-dimensional covalent organic framework(3D-COF)with porous confined structures and abundant coordinate N sites as the precursor,the partially oxidized Ni_(3)Fe nanoalloys wrapped by Ndoped carbon(N-C)layers are constructed via simple pyrolysis and subsequent oxidization.Benefiting from the 3D curved hierarchical structure,high-conductivity of Ni_(3)Fe and N-C layers,well-distributed active sites,the as-synthesized O-Ni_(3)Fe-NC catalyst demonstrates excellent activity and durability for catalyzing OER.Experimental and theoretical analyses disclose that both high-temperature oxidization and the OER process greatly promote the formation and exposure of the Ni(Fe)OOH active species as well as lower charge transfer resistance,inducing its optimized OER activity.The robust graphitized N-C layers with superior conductivity and their couplings with oxidized Ni_(3)Fe nanoalloys are beneficial for stabilizing catalytic centers,thereby imparting O-Ni_(3)Fe-N-C with such outstanding stability.This work not only provides a rational guidance for enriching and stabilizing high-activity catalytic sites towards OER but also offers more insights into the structural evolution of NiFe-based OER catalysts.

Toward carbon neutrality by artificial photosynthesis

CO_(2)is not only the primary cause of climate change but also an abundant and recyclable carbon resource.The breakthrough in emerging disruptive technologies such as carbon capture and storage(CCS),power-to-X,and direct air capture(DAC)is fundamental to achieving carbon neutrality.Among these technologies,artificial photosynthesis offers an attractive method for recycling carbon dioxide and water into fuels and chemicals using solar energy(CO_(2)+H_(2)O+sunlight→fuels+chemicals).It holds great promise for addressing the critical challenges associated with elevated CO_(2)concentrations and securing a sustainable supply of fuels and chemicals for economic sectors.

NiS_(2) nanosheet arrays on stainless steel foil as binder-free anode for high-power sodium-ion batteries

Owing to the wide range and low cost of sodium resources,sodium-ion batteries(SIBs)have received extensive attention and research.Metal sulfides with high theoretical capacity are used as promising anode materials for SIBs.This paper presents the electrochemical performance of the binder-free NiS_(2)nanosheet arrays grown on stainless steel(SS)substrate(NiS_(2)/SS)using an in situ growth and sulfidation strategy as anode for sodium ion batteries.Owing to the close connection between the NiS_(2)nanosheet arrays and the SS current collector,the NiS_(2)/SS anode demonstrates high rate capability with a reversible capacity of 492.5 mAh·g^(-1)at 5.0C rate.Such rate capability is superior to that of NiS_(2)nanoparticles(NiS_(2)/CMC:41.7 mAh·g^(-1)at 5.0C,NiS_(2)/PVDF:7.3 mAh·g^(-1)at 5.0C)and other Ni sulfides(100–450 mAh·g^(-1)at 5.0C)reported.Furthermore,the initial reversible specific capacity and Coulombic efficiency of NiS_(2)/SS are 786.5 mAh·g^(-1)and 81%,respec-tively,demonstrating a better sodium storage ability than those of most NiS_(2)anodes reported for SIBs.In addition,the amorphization and conversion mechanism during the sodiation/desodiation process of NiS_(2)are proposed after investigation by in situ X-ray diffraction(XRD)measurements of intermediate products at successive charge/discharge stages.