Controllably partial removal of thiolate ligands from unsupported Au_(25) nanoclusters by rapid thermal treatments for electrochemical CO_(2)reduction

Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported[Au_(25)(PET)_(18)]-nanoclusters with the preservation of the core structure.This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment,avoiding the reconfiguration or agglomeration of Au_(25)nanoclusters,where the degree of dethiolation can be regulated by the control of duration.This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction.Consequently,the activity and selectivity towards CO formation in electrochemical CO_(2)reduction reaction of Au_(25)nanoclusters can be promoted.This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.

Highly reversible lead-carbon battery anode with lead grafting on thecarbon surface

A novel C/Pb composite has been successfully prepared by electmless plating to reduce the hydrogenevolution and achieve the high reversibility of the anode of lead-carbon battery （LCB）. The depositedlead on the surface of C/Pb composite was found to be uniform and adherent to carbon surface. Becauselead has been stuck on the surface of C/Pb composite, the embedded structure suppresses the hydrogenevolution of lead-carbon anode and strengthens the connection between carbon additive and sponge lead.Compared with the blank anode, the lead-carbon anode with C/Pb composite displays excellent charge-discharge reversibility, which is attributed to the good connection between carbon additives and leadthat has been stuck on the surface of C/Pb composite during the preparation process. The addition of CIPb composite maintains a solid anode structure with high specific surface area and power volume, andthereby, it plays a significant role in the highly reversible lead-carbon anode.

A Comparative Investigation of Single Crystal and Polycrystalline Ni-Rich NCMs as Cathodes for Lithium-Ion Batteries

Nickel-rich LiNi_(1-x-y)Co_(x)Mn_(y)O_(2)(NCM,1-x-y≥0.6)is known as a promising cathode material for lithium-ion batteries since its superiority of high voltage and large capacity.However,polycrystalline Ni-rich NCMs suffer from poor cycle stability,limiting its further application.Herein,single crystal and polycrystalline LiNi_(0.84)Co_(0.07)Mn_(0.09)O_(2)cathode materials are compared to figure out the relation of the morphology and the electrochemical storage performance.According to the Li^(+)diffusion coefficient,the lower capacity of single crystal samples is mainly ascribed to the limited Li+diffusion in the large bulk.In situ XRD illustrates that the polycrystalline and single crystal NCMs show a virtually identical manner and magnitude in lattice contraction and expansion during cycling.Also,the electrochemically active surface area(ECSA)measurement is employed in lithium-ion battery study for the first time,and these two cathodes show huge discrepancy in the ECSA after the initial cycle.These results suggest that the single crystal sample exhibits reduced cracking,surface side reaction,and Ni/Li mixing but suffers the lower Li^(+)diffusion kinetics.This work offers a view of how the morphology of Ni-rich NCM effects the electrochemical performance,which is instructive for developing a promising strategy to achieve good rate performance and excellent cycling stability.

Bulk nanoporous platinum for electrochemical actuation

Bulk nanoporous platinum(np-Pt)samples with a remarkably fine ligament size down to 2 nm and good mechanical robustness were fabricated for the first time by electrochemically dealloying Pt15Cu85 master alloy in 1 mol L−1 H_(2)SO_(4)at 60℃.The as-prepared np-Pt shows an electrochemically active specific surface area as high as 25 m^(2)/g due to the ultrafine nanostructure.The active surface area remains almost invariable even after 15%macroscopic compressive strain.Furthermore,np-Pt shows considerably high thermal stability due to the low surface diffusivity of Pt.Np-Pt is a promising surface-or interface-controlled functional material,particularly when excellent electrochemical and mechanical performance are necessary due to its high surface-to-volume ratio and mechanical robustness.This work demonstrated the potential application of np-Pt as an electrochemical actuation material.In-situ dilatometry experiments revealed that the surface adsorp-tion-desorption of OH species on np-Pt causes significant strain variations.The proposed np-Pt electrochem-ical actuator shows an operating voltage down to 1.0 V,a large reversible strain amplitude of 0.37%,and a strain energy density of 1.64 MJ/m^(3).

Common Pitfalls of Reporting Electrocatalysts for Water Splitting

Rigorous assessment of heterogeneous electrocatalysts for electrochemical water splitting has been a critical issue mainly due to insufficient standard protocols to measure and report experimental data.In this perspective,we highlight some common pitfalls when measuring and reporting electrocatalytic data,which should be avoided to ensure the accuracy and reproducibility and to advance the water splitting field.We advocate to prevent the introduction of artefacts from the counter and reference electrodes,as well as the impurities in the electrolyte when conducting electrocatalyst activity measurements.In addition,we encourage the use of the electrochemically active surface area(ECSA)-normalized current densities to represent the intrinsic activity of the reported catalysts for a better comparison with previously known materials.Suitable ECSA measurement methods should be employed based on the nature of catalysts.Recommendations made in this perspective will hopefully assist in identifying advanced catalysts for water splitting research.