Exploring the Predominant Factors Influencing the Oxygen Reduction Performance of PtCo/C Catalysts

PtCo nanoalloys(NAs)deposited on carbon black are emerging as robust electrocatalysts for addressing the sluggish kinetic issue of oxygen reduction reaction(ORR).However,developing a simple and low-cost method to synthesize PtCo/C with excellent performance is still a great challenge.In this work,a one-pot method was used to successfully obtain the PtCo NAs on commercial carbon supports of acetylene black and Ketjenblack ECP600JD,respectively.Compared with those grown on Ketjenblack ECP600JD,the PtCo NAs grown on acetylene black exhibited higher electrochemical surface area(ECSA)and mass activity(MA),which may be attributed to the different particle sizes of PtCo NAs,distinct hydrophilicity,electroconductivity and charge distribution between the carbon supports and PtCo NAs.Our study provides valuable insights into the optimal design of carbon-supported ORR electrocatalysts with exceptional activity and durability.

Supercapacitors as redox mediators for decoupled water splitting

With the help of the redox mediator, decoupled water-splitting allows O_(2)and H_(2)to be produced at different times, at different rates, and even in different cells, which promotes both the operation safety and the utilization of renewable power sources. However, the current densities and stabilities of these redox mediators are commonly low, which require further improvements for practical applications. Here, we propose to use supercapacitors as solid state redox mediators for decoupled water splitting. For demonstration, Na_(0.5)MnO_(2)(pseudocapacitor) and active carbon(double layer capacitor), are both used as the redox mediator. These supercapacitors show superior current density(1 A/cm^(2)) and ultralong cycle-life(8000 cycles) compared with commonly investigated battery-based mediators(NiOOH/Ni(OH)_(2)). Our research proves supercapacitors can be used as redox relay with high current density and stability, which may bring new insights in the design of decoupled water splitting systems.

Solid-state room-temperature phosphorescence activated by the end-capping strategy of cyano groups

Avoiding the tedious process of crystal cultivation and directly obtaining organic crystals with desirable phosphorescent performance is of great significance for studying their structure and properties.Herein,a set of benzophenone-cored phos-phors with bright green afterglow are obtained on a large scale through in-situ generation via an end-capping strategy to suppress non-radiative triplet excitons and reinforce the intermolecular interactions.The ordered arrangement of phosphors with alkyl-cyano groups as regulators is crucial for the enhancement of room-temperature phosphorescence(RTP)emission,which has been further verified by the attenuated lifetimes in isolated states through the formation of inclusion complexes upon binding with pillar[5]arenes.Moreover,the hierarchical interactions of phos-phors,including hydrogen bonding,π-πstacking interactions,and van der Waals forces,are quantified by crystal structures and theoretical calculation to deeply inter-pret the origins of RTP emission.With this study,we provide a potential strategy for the direct acquisition of crystalline organic phosphors and modulation of RTP.

The cathode catalysts of hydrogen fuel cell:From laboratory toward practical application

Proton exchange membrane fuel cells(PEMFCs)have received a sustained world-wide attention owing to their promising applications based on clean energy.However,their widespread applications are still restricted by the sluggish oxygen reduction reaction(ORR)process.Over the past decades,significant efforts have been devoted to developing efficient ORR catalysts,which have been summarized in numerous previous reviews.Unfortunately,most of them mainly focused on ORR activity on the rotating disk electrode(RDE)level,which cannot truly represent the performance in real applications.Developing and showcasing efficient catalysts evaluated at the membrane electrode assembly(MEA)level is of vital importance.In this review,we first briefly showcased the recent development of ORR catalysts and then put more emphasis on the discussion of designing efficient catalysts at MEA and full-cell level,aiming to help stimulate more attention on their practical applications.