Modified Cu active sites by alloying for efficient electrocatalytic reduction CO_(2) to CO

Transition metals like Au,Ag,and Cu have been reported to be quite active for CO_(2) reduction.In this study,we use density functional theory(DFT)calculation to investigate the electronic structure and catalytic performance of Au,Ag,Cu and their alloys for CO_(2) reduction reaction(CO_(2)RR).Theoretical calculations identified the combination of Ag,Cu,and Au in a face-centered cubic(fcc)alloy as an outstanding electrocatalyst for CO_(2) reduction to CO,with Cu as the active site.The d-orbital projected density of state(PDOS)profile suggests that alloying alters the electronic structure of the Cu site,thereby affecting the Gibbs free energy change for the formation of*COOH intermediate(ΔG_(*COOH)).To demonstrate the theoretical prediction experimentally,we employ a top-down dealloying approach to synthesize a nanoporous structured AgCuAu alloy(NP-Ag_(5)Cu_(5)Au_(5)).Electrochemical experiments validate that the ternary alloy catalyst is clearly better than unary and binary catalysts,showing a Faradaic efficiency(FE)for CO over 90%across a broad potential range of 0.6 V,with a peak of approximately 96%at-0.573 V vs.RHE.This study underscores the potential of multi-component alloys in CO_(2)RR and establishes a theoretical basis for designing efficient catalysts for CO_(2) utilization.

Potassium pre-inserted K1.04Mn8O16 as cathode materials for aqueous Li-ion and Na-ion hybrid capacitors

For the applications of aqueous Li-ion hybrid capacitors and Na-ion hybrid capacitors,potassium ions are pre-inserted into MnO2 tunnel structure,the as-prepared K1.04Mn8 O16 materials consist of nanoparticles and nanorods were prepared by facile high-temperature solid-state reaction.The as-prepared materials were well studied and they show outstanding electrochemical behavior.We assembled hybrid supercapacitors with commercial activated carbon(YEC-8 A)as anode and K1.04Mn8 O16 as cathode.It shows high energy and power densities.Li-ion capacitors reach a high energy density of 127.61 Wh kg-1 at the power density of 99.86 W kg-1 and Na-ion capacitor obtains 170.96 Wh kg-1 at 133.79 W kg-1.In addition,the hybrid supercapacitors demonstrate excellent cycling performance which maintain 97%capacitance retention for Li-ion capacitor and 85%for Na-ion capacitor after 10,000 cycles.

Tuning interfacial charge transfer for efficient visible-light-driven photodegradation and simultaneous H_(2)evolution

The edge-graphitized carbon nitride(C_(3)N_(4)-C g)was prepared by secondary pyrolysis to construct ZnO/C_(3)N_(4)-C g(ZCN)type-Ⅱheterojunction photocatalyst via a facile sonication dispersion method,which achieved∼7.04-fold and∼18.3-fold enhanced visible-light-driven photocatalytic performance for refrac-tory micropollutant removal and simultaneous hydrogen(H_(2))evolution respectively compared to con-ventional ZnO/g-C_(3)N_(4)Step-scheme heterojunction.The apparent quantum efficiency of the ZCN_(0.4)het-erojunction reaches 0.92%(λ=420 nm).Such excellent performance stems from that the edge-graphene moieties stitched onto the interface of heterojunction extend light absorption to the full visible spec-trum,meanwhile,the built-in electric field generated during Fermi level alignment accompanying fa-vorable band-bending structure provides an effective pathway for the rapid migration of photoinduced electrons via the edge graphene channel to improve interfacial charge separation efficiency.Interestingly,the midgap states introduced in ZCN heterojunction could temporarily retain photoexcited electrons to effectively inhibit the in situ carrier recombination for improved photocatalytic H_(2)evolution.Moreover,ZCN/peroxymonosulfate system exhibited excellent anti-interference performance against complex water bodies under visible illumination due to the synergistic effect between the co-existing anions and organic matter.Meanwhile,the eco-friendly nature of the ZCN/peroxymonosulfate system showed no biotoxicity of reaction filtrate on cell proliferation after treatment,which avoided secondary contamination.Consid-ering the outstanding performance in photocatalysis,the ZCN system exhibits broad potential for practical applications in water pollution control and green energy production.

Surface cobaltization for boosted kinetics and excellent stability of nickel-rich layered cathodes

The feasibility of LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2) as a primary cathode material has decreased due to the fragile cobalt(Co)supply chain and its undesirable effects on structural degradation.LiNi_(0.6)Mn_(0.4)O_(2) deserves greater attention because of its high thermal and cyclic stability,coupled with low raw material and production costs.However,this material suffers from low reversible capacity and poor rate performance.Herein,we rationally design a high-performance cathode structure composed of a robust conductive protective layer,gradient Li^(+)ions conductive layer and stable bulk phase of LiNi_(0.6)Mn_(0.4)O_(2) through surface cobaltization,which not only boosts the reaction kinetics of the electrode but also suppresses particle cracking and mitigates surface structural degradation.As a result,a dramatically improved rate capacity(118.7 vs 53.5 mAh g^(-1) at 5 C)and impressive capacity retention after 300 cycles(90.4% in a full cell)at a high cutoff voltage(4.4 V)are obtained.Co-modified Li-Ni_(0.6)Mn_(0.4)O_(2) is promising to challenge commercial position of LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2) attributed to the accessible capacity,superior rate capacity,excellent cycle performance,good thermal stability and low cost.Our results open a door for optimizing the use of Co and the structural design of high-nickel cathodes.