Accelerated prediction of Cu-based single-atom alloy catalysts for CO_(2) reduction by machine learning

Various strategies,including controls of morphology,oxidation state,defect,and doping,have been developed to improve the performance of Cu-based catalysts for CO_(2) reduction reaction(CO_(2)RR),generating a large amount of data.However,a unified understanding of underlying mechanism for further optimization is still lacking.In this work,combining first-principles calculations and machine learning(ML)techniques,we elucidate critical factors influencing the catalytic properties,taking Cu-based single atom alloys(SAAs)as examples.Our method relies on high-throughput calculations of 2669 CO adsorption configurations on 43 types of Cu-based SAAs with various surfaces.Extensive ML analyses reveal that low generalized coordination numbers and valence electron number are key features to determine catalytic performance.Applying our ML model with cross-group learning scheme,we demonstrate the model generalizes well between Cu-based SAAs with different alloying elements.Further,electronic structure calculations suggest surface negative center could enhance CO adsorption by back donating electrons to antibonding orbitals of CO.Finally,several SAAs,including PCu,AgCu,GaCu,ZnCu,SnCu,GeCu,InCu,and SiCu,are identified as promising CO_(2)RR catalysts.Our work provides a paradigm for the rational design and fast screening of SAAs for various electrocatalytic reactions.

Co_(3)O_(4)/Mn_(3)O_(4) hybrid catalysts with heterointerfaces as bifunctional catalysts for Zn-air batteries

Zinc-air batteries(ZABs) with high energy density and safety are promising as next-generation energy storage systems, while their applications are severely hindered by the sluggish reaction kinetic of air cathodes. Developing a bifunctional catalyst with high activity and durability is an effective strategy to address the above challenges. Herein, a Co_(3)O_(4)/Mn_(3)O_(4) nanohybrid with heterointerfaces is designed as advanced cathode catalyst for ZABs. Density functional theory calculations show the heterogeneous interface between Co_(3)O_(4)/Mn_(3)O_(4) can improve the dynamics of carrier transport and thus enhancing the catalytic activity and durability. The Co_(3)O_(4)/Mn_(3)O_(4) catalyst anchored on reduced graphene oxide(rGO)exhibits high oxygen reduction reaction(ORR) activity with a half-wave potential of 0.86 V, and excellent oxygen evolution reaction(OER) activity with the potential of 1.59 V at 10 mA cm^(-2) , which are comparable to the commercial noble metal catalysts. The improved ORR/OER catalytic activity is ascribed to the synergistic effect of heterointerfaces between Co_(3)O_(4) and Mn_(3)O_(4)as well as the improved conductivity and contact area of oxygen/catalysts/electrolytes three-phase interface by r GO. Furthermore, a home-made ZAB based on Co_(3)O_(4)/Mn_(3)O_(4)/r GO shows a high open circuit voltage of 1.54 V, a large power density of 194.6 mW cm^(-2) and good long-term cycling stability of nearly 400 h at 5 mA cm^(-2) , which affords a promising bifunctional oxygen catalyst for rechargeable ZABs.

An in-situ polymerized interphase engineering for high-voltage allsolid- state lithium-metal batteries

All-solid-state lithium batteries(ASSLBs)have attracted great interest due to their promising energy density and strong safety.However,the interface issues,including large interfacial resistance between electrode and electrolyte and low electrochemical stability of solid-state electrolytes against high-voltage cathodes,have restricted the development of high-voltage ASSLBs.Herein,we report an ASSLB with stable cycling by adopting a conformal polymer interlayer in-situ formed at the Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)–cathode interfaces.The polymer can perfectlyfill the voids and create a stable interface contact between LLZTO and cathodes.In addition,the electric field across the polymer interlayer is reduced compared with pure solid polymer electrolyte(SPE),which facilitates the electrochemical stability with high-voltage cathode.The all-solid-state Li|LLZTO-SPE|LiFe_(0.4)Mn_(0.6)PO_(4)(LMFP)cells achieve a low interface impedance,high specific capacity,and excellent cycling performance.This work presents an effective and practical strategy to rationally design the electrode–electrolyte interface for the application of high-voltage ASSLBs.

Integrating molybdenum sulfide selenide-based cathode with C-O-Mo heterointerface design and atomic engineering for superior aqueous Zn-ion batteries

Transition metal dichalcogenides(TMDs)have been regarded as promising cathodes for aqueous zinc-ion batteries(AZIBs)but suffer from sluggish reaction kinetics due to their poor conductivity and the strong electrostatic interaction between Zn-ion and cathode materials.Herein,a well-defined structure with MoSSe nanosheets vertically anchored on graphene is used as the cathode for AZIBs.The dissolution of Se into MoS2 lattice together with heterointerface design via developing C-O-Mo bonds improves the inherent conductivity,enlarges interlayer spacing,and generates abundant anionic vacancies.As a result,the Zn2+intercalation/deintercalation process is greatly improved,which is confirmed by theoretical modeling and ex-situ experimental results.Remarkably,the assembled AZIBs exhibit high-rate capability(124.2 mAh·g^(−1)at 5 A·g^(−1))and long cycling life(83%capacity retention after 1,200 cycles at 2 A·g^(−1)).Moreover,the assembled quasi-solid-state Zn-ion batteries demonstrate a stable cycling performance over 100 cycles and high capacity retention over 94%after 2,500 bending cycles.This study provides a new strategy to unlock the electrochemical activity of TMDs via interface design and atomic engineering,which can also be applied to other TMDs for multivalent batteries.

Mass production of two-dimensional materials beyond graphene and their applications

Two-dimensional(2D)materials are promising candidates in wide applications including energy storage and conversion,sensors,flexible devices,etc.The low-cost production of 2D materials with large quantities and demanded quality is the precondition for their commercial uses.For graphene and its derivatives,relatively mature techniques have been established for their scalable preparation and industrial applications.Whereas the mass production of 2D materials beyond graphene is still in its early age and it lacks a summary on this topic.This review systematically describes the state-of-the-art approaches for high-yield preparation of 2D materials beyond graphene,including“top-down”exfoliation and“bottom-up”synthetic approaches.In particular,each method is discussed from the perspectives of its principle,optimization attempts,characteristics of the obtained 2D materials,and its scalability potential.The applications that require massively-produced 2D materials are highlighted,including electrocatalysis,batteries,supercapacitors,mechanical and chemical sensors,as well as electromagnetic interference shielding and microwave absorption devices.Finally,we propose the challenges and opportunities for scalable preparation and commercial applications of 2D materials.

Tunable valley band and exciton splitting by interlayer orbital hybridization

Magnetic proximity effect has been demonstrated to be an effective routine to introduce valley splitting in two-dimensional van der Waals heterostructures.However,the control of its strength and the induced valley splitting remains challenging.In this work,taking heterobilayers combining monolayer MSe_(2)(M=Mo or W)with room-temperature ferromagnetic VSe_(2)as examples,we demonstrate that the valley splitting for both band edges and excitons can be modulated by the tuning of the interlayer orbital hybridization,achieved by inclusion of different amounts of exact Hartree exchange potential via hybrid functionals.Besides,we show such tuning of orbital hybridization could be experimentally realized by external strain and electric field.The calculations suggest that large valley band splitting about 30 meV and valley exciton splitting over 150 meV can be induced in monolayer MSe_(2).Our work reveals a way to control proximity effects and provides some guidance for the design of optoelectronic and valleytronic devices.