Electron and configuration engineering of atomic Cu and multioxidated Cu_(2+1)O centers via gasifiable reductant strategy for efficient oxygen reduction toward Zn-air battery

Efforts in a large number of transition metal-carbon systems are devoted to the development of efficient catalysts for oxygen reduction reaction(ORR).However,unsatisfied O_(2)adsorption and slow reduction of OH*at the active centers hinder the further development of these catalysts.We here report a gasifiable reductant strategy,of which a new Cu-based metal organic framework(MOF:termed NTU-83)nanosheet was co-pyrolyzed with melamine to produce the N-coordinated atomic Cu and multi-oxidated Cu_(2+1)O active centers on the carbon foam with ultrathin skeleton.The engineered electrons and configuration of the active centers boost the catalyst(Cu/NC-1000)to show superior ORR activity(E_(1/2)=0.85 V),excellent stability,and methanol resistance.Further modeling calculation and controlled experiments reveal that the Cu_(2+1)O species play a crucial role in kinetically accelerated adsorption and activation of O_(2),while the N_(4)coordinated atomic Cu facilitates fast reduction of OH*.Such characteristics endow the Zn-air battery that containing Cu/NC-1000 as air cathode to show a high peak power density(138 mW·cm^(−2)),a high specific capacity of 763 mAh·gZn^(−1),and outstanding long-term cycle stability.The plausible mechanism and excellent performance show that gasifiable reductant strategy opens up a new route for regulation of the electronic of active sites but also provides a candidate for the practical application in energy conversion/storage devices.

A chemically stable nanoporous coordination polymer with fixed and free Cu^(2+)ions for boosted C_(2)H_(2)/CO_(2)separation

Safely and highly selective acetylene(C_(2)H_(2))capture is a great challenge,because of its highly explosive nature,as well as its nearly similar molecule size and boiling point toward the main impurity of carbon dioxide(CO_(2)).Adsorption separation has shown a promising future.Herein,a new nanoporous coordination polymer(PCP)adsorbent with fixed and free Cu ions(termed NTU-66-Cu)was prepared through post-synthetic approach via cation exchanging from the pristine NTU-66,an anionic framework with new 3,4,6-c topology and two kinds of cages.The NTU-66-Cu shows significantly improved C_(2)H_(2)/CO_(2)selectivity from 6 to 32(v/v:1/1)or 4 to 4_(2)(v/v:1/4)at low pressure under 298 K,along with enhanced C_(2)H_(2)capacity(from 89.22to 111.53 cm^(3)·g^(-1)).More importantly,this observation was further validated by density functional theory(DFT)calculations and breakthrough experiments under continuous and dynamic conditions.Further,the excellent chemical stability enables this adsorbent to achieve recycle C_(2)H_(2)/CO_(2)separation without loss of C_(2)H_(2)capacity.

Efficient CO_2/N_2 separation by mixed matrix membrane with amide functionalized porous coordination polymer filler

Mixed matrix membrane used to selective removal of CO2 was considered as an efficient solution to energy and environmental sustainability. In this study, a MMM that consists of amide functionalized porous coordination polymer filler（MIL-53-NH2） was successfully prepared, which sharply promotes the CO2/N2 selectivity from 44（neat polymeric membrane） to 75. Remarkably, the positive effect of amide group and nanochannel of MIL-53-NH2 filler was illustrated by decreased selectivity of the MMM with formic acid modified MIL-53-NH2 filler（MIL-53-NHCOH）.