Single‑Atom Catalysts:Advances and Challenges in Metal‑Support Interactions for Enhanced Electrocatalysis

Single-atom catalysts(SACs),which contain a single metal atom supported on a well-confined substrate,are among the most promising heterogeneous catalysts owing to their unique advantages,such as high intrinsic activity and selectivity,tunable bonds and coordination,abundant metal-containing active sites,and atomic economy.Since metal-support interactions(MSIs)in SACs exert a substantial influence on the catalytic properties,gaining a profound understanding and recognition of catalytic reactions depends greatly on investigating MSIs both experimentally and computationally.Hence,the engineer-ing and modulation of MSIs are regarded as one of the most efficient methods to rationally design SACs with disruptively enhanced catalytic properties.In this review,we track the recent advances in SACs from an MSI perspective.We then discuss the existing MSIs in SACs and elucidate the significant role of strong MSIs in catalytic properties and mechanisms.The chal-lenges hindering the rational design of supported SACs with strong MSIs,which are currently still far from being completely understood and overcome,are described.In addition,the correlation between strong MSIs and electrocatalytic activities in SACs,including an outlook to increase our understanding of MSIs,is discussed.Finally,the present review provides some perspectives and an in-depth understanding of strong MSIs to advance high-performing SACs.

A novel composite(FMC)to serve as a durable 3D-clam-shaped bifunctional cathode catalyst for both primary and rechargeable zinc-air batteries

Novel and highly durable air cathode electrocatalyst with three dimensional （3D）-clam-shaped structure, MnO2 nanotubes-supported Fe2O3 （Fe2O3/MnO2） composited by carbon nanotubes （CNTs） （（Fe2O3/ MnO2）3/4-（CNTs）1/4） is synthesized using a facile hydrothermal process and a following direct heat- treatment in the air. The morphology and composition of this catalyst are analyzed using scanning elec- tronic microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD） and energy dispersive X-ray spectroscopy （EDX）. The morphology characteristics reveal that flower-like Fe2O3 parti- cles are highly dispersed on both MnO2 nanotubes and CNT surfaces, coupling all three components firmly. Electrochemical measurements indicate that the synergy of catalyst exhibit superior bi- functional catalytic activity for both oxygen reduction reaction （ORR） and oxygen evolution reaction （OER） as well as stability than Pt/C and lrO2 catalysts. Using these catalysts for air-cathodes, both primary and rechargeable zinc-air batteries （ZABs） are assembled for performance validation. In a primary ZAB, this 3D-clamed catalyst shows a decent open circuit voltage （OCV, -1.48 V） and a high discharge peak power density （349 mW cm 2）, corresponding to a coulomhic efficiency of 92%. In a rechargeahle ZABs with this bifunctional catalyst, high OCV （〉1.3 V） and small charge-discharge voltage gap （〈1.1 V） are achieved along with high specific capacity （780 mAh g 1 at 30 mA cm-2） and robust cycle-life （1,390 cycles at cycle profile of 20 mA/10 min）.