Designing heterostructured FeP–CoP for oxygen evolution reaction:Interface engineering to enhance electrocatalytic performance

It is significant to develop highly efficient electrocatalysts for energy conversion systems.Interface engineering is one of the most feasible approaches to effectively enhance the electrocatalytic activity.Herein,the density functional theory(DFT)calculations predict that the potential barriers of Fe sites at the interface of FeP–CoP heterostructures are lower than that of Fe sites in FeP nanoparticles(NPs),Co sites in CoP NPs,or Co sites in heterostructures.Motivated by the DFT calculation results,FeP–CoP heterostructures have been designed and synthesized by a metal–organic frameworks(MOFs)confined-phosphorization method.The FeP–CoP exhibits the lowest overpotential of 230 mV at the current density of 10 mA·cm^(−2)for oxygen evolution reaction(OER),compared with FeP(470 mV)and CoP(340 mV),which outperforms most of transition metal-based catalysts.The Tafel analysis of FeP–CoP heterostructures shows an improved reaction kinetic pathway with the smallest slope of 90.3 mV·dec^(−1),as compared to the Tafel slopes of FeP NPs(137 mV·dec^(−1))and CoP NPs(114 mV·dec^(−1)).And the FeP–CoP shows extraordinary long-term stability over 24 h.The excellent activity and long-term stability of FeP–CoP derive from the synergistic effect between FeP and CoP.

Real-time identification of multiple nanoclusters with a protein nanopore in single-cluster level

It is important and challenging to analyze nanocluster structure with atomic precision.Herein,α-hemolysin nanopore was used to identify nanoclusters at the single molecule level by providing two-dimensional(2D)dwell time–current blockage spectra and translocation event frequency which sensitively depended on their structures.Nanoclusters such as Anderson,Keggin,Dawson,and a few lacunary Dawson polyoxometalates with very similar structures,even with only a two-atom difference,could be discriminated.This nanopore device could simultaneously measure multiple nanoclusters in a mixture qualitatively and quantitatively.Furthermore,molecular dynamics(MD)simulations provided microscopic understandings of the nanocluster translocation dynamics and yielded 2D dwell time–current blockage spectra in close agreement with experiments.The nanopore platform provides a novel powerful tool for nanocluster characterization.

Constructing of highly porous thermoelectric structures with improved thermoelectric performance

As more than 60%of worldwide consumed energy is unused and becomes waste heat every year,high-efficiency waste heat to power technologies are highly demanded for the conversion of wasted heat to electricity.Thermoelectrics which can convert the wasted heat directly into electricity represent a promising approach for energy recovery.Thermoelectric technology has existed for several decades,but its usage has been limited due to low efficiencies.Recent advances in nanotechnology have enabled the improving of thermoelectric properties which open up the thermoelectrics’feasibility in industry.In this paper,we present an overview of recent progress in increasing the porosity of thermoelectric materials from atomic scale to microscale,leading to the enhancement of figure of merit.

FeNi nanoparticles on Mo_(2)TiC_(2)T_(x)MXene@nickel foam as robust electrocatalysts for overall water splitting

The development of cost-effective electrocatalysts for overall water splitting is highly desirable,remaining a critical challenge at current stage.Herein,a class of composite FeNi@MXene(Mo_(2)TiC_(2)T_(x))@nickel foam(NF)has been synthesized through introducing Fe2+ions and in-situ combining with surface nickel atoms on nickel foam.The obtained FeNi@Mo_(2)TiC_(2)T_(x)@NF exhibited high activity with overpotentials of 165 and 190 mV for the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)at a current density of 10 mA·cm^(-2),respectively.The synergetic effects of Mo_(2)TiC_(2)T_(x)and FeNi nanoalloys lead to increasing catalytic activities,where MXene provides high active surface area and rich active sites for HER,and FeNi nanoalloys promote the OER.Theoretical simulation of electron exchange capacity between FeNi and MXene in FeNi@Mo_(2)TiC_(2)T_(x)catalyst shows that electrons transferred from surface Mo atoms to the interface between FeNi and MXene,indicating that the electrons are accumulated near the FeNi nanoparticles.This kind of electronic distribution facilitates the formation of intermediate of NiOOH.Correspondingly,(H++e-)is more inclined onto Mo-Ni interfaces for HER.The Gibbs free energy changes for H*to HER and potential-limiting step for-OOH intermediate in OER over FeNi@Mo_(2)TiC_(2)T_(x)are much less than those on bare MXene.The catalyst can be further used for overall water splitting in alkaline solution,realizing a current density of 50 mA·cm^(-2)at 1.74 V.This work provides a facile strategy to achieve efficient and cheap catalysts for new energy production.