Experimentally validating sabatier plot by molecular level microenvironment customization for oxygen electroreduction.

Microenvironmental modifications on metal sites are crucial to tune oxygen reduction catalytic behavior and decrypt intrinsic mechanism, whereas the stochastic properties of traditional pyrolyzed single-atom catalysts induce vague recognition on structure-reactivity relations. Herein, we report a theoretical descriptor relying on binding energies of oxygen adsorbates and directly associating the derived Sabatier volcano plot with calculated overpotential to forecast catalytic efficiency of cobalt porphyrin. This Sabatier volcano plot instructs that electron-withdrawing substituents mitigate the over-strong *OH intermediate adsorption by virtue of the decreased proportion of electrons in bonding orbital.

Advanced Architectures of Air Electrodes in Zinc-Air Batteries and Hydrogen Fuel Cells.

The air electrode is an essential component of air-demanding energy storage/conversion devices, such as zinc-air batteries (ZABs) and hydrogen fuel cells (HFCs), which determines the output power and stability of the devices. Despite atom-level modulation in catalyst design being recently achieved, the air electrodes have received much less attention, causing a stagnation in the development of air-demanding equipment. Herein, the evolution of air electrodes for ZABs and HFCs from the early stages to current requirements is reviewed.

Electron-Donors-Acceptors Interaction Enhancing Electrocatalytic Activity of Metal-Organic Polymers for Oxygen Reduction.

Catalysts with metal-N sites have long been considered as effective electrocatalysts for oxygen reduction reaction (ORR), yet the accurate structure-property correlations of these active sites remain debatable. Report here is a proof-of-concept method to construct 1,4,8,11-tetraaza[14]annulene (TAA)-based polymer nanocomposites with well-managed electronic microenvironment via electron-donors/acceptors interaction of altering electron-withdrawing β-site substituents. DFT calculation proves the optimal -Cl substituted catalyst (CoTAA-Cl@GR) tailored the key OH* intermediate interaction with Co-N sites under the d-orbital regulation, hence reaching the top of ORR performance with excellent turnover frequency (0.

Polycation-Regulated Electrolyte and Interfacial Electric Fields for Stable Zinc Metal Batteries.

Zn metal as one of promising anode materials for aqueous batteries but suffers from disreputable dendrite growth, grievous hydrogen evolution and corrosion. Here, a polycation additive, polydiallyl dimethylammonium chloride (PDD), is introduced to achieve long-term and highly reversible Zn plating/stripping. Specifically, the PDD can simultaneously regulate the electric fields of electrolyte and Zn/electrolyte interface to improve Zn migration behaviors and guide dominant Zn (002) deposition, which is veritably detected by Zeta potential, Kelvin probe force microscopy and scanning electrochemical microscopy.

Longitudinally Grafting of Graphene with Iron Phthalocyanine-based Porous Organic Polymer to Boost Oxygen Electroreduction.

Iron phthalocyanine-based polymers (PFePc) are attractive noble-metal-free candidates for catalyzing oxygen reduction reaction (ORR). However, the low site-exposure degree and poor electrical conductivity of bulk PFePc restricted their practical applications. Herein, laminar PFePc nanosheets covalently and longitudinally linked to graphene (3D-G-PFePc) was prepared.

Solute-solvent dual engineering toward versatile electrolyte for high-voltage aqueous zinc-based energy storage devices.

Manufacturing cost-effective electrolytes featuring high (electro)chemical stability, high Zn anode reversibility, good ionic conductivity, and environmental benignity is highly desired for rechargeable aqueous zinc-based energy storage devices but remains a great challenge. Herein, a solute-solvent dual engineering strategy using lithium bis(trifluoromethane)sulfonimide (LiTFSI) and inexpensive poly(ethylene glycol) (PEG, = 200) as a coadditive with an optimized ratio accomplished an all-round performance enhancement of electrolytes. Due to the synergistic inhibition of water activity and Zn solvation structure reorganization by LiTFSI-PEG, as well as a stable F-rich interfacial layer and PEG adsorption on the Zn anode surface, dendrite-free Zn plating/stripping at nearly 100% Coulombic efficiency and stable cycling performance over 2000 h at 0.

Carbon Nanocage with Maximum Utilization of Atomically Dispersed Iron as Efficient Oxygen Electroreduction Nanoreactor.

As key parameters of electrocatalysts, the density and utilization of active sites determine the electrocatalytic performance toward oxygen reduction reaction. Unfortunately, prevalent oxygen electrocatalysts fail to maximize the utilization of active sites due to inappropriate nanostructural design. Herein, a nano-emulsion induced polymerization self-assembly strategy is employed to prepare hierarchical meso-/microporous N/S co-doped carbon nanocage with atomically dispersed FeN (denoted as Meso/Micro-FeNSC).

Simultaneously Integrate Iron Single Atom and Nanocluster Triggered Tandem Effect for Boosting Oxygen Electroreduction.

Atomically nitrogen-coordinated iron atoms on carbon (FeNC) catalysts are emerging as attractive materials to substitute precious-metal-based catalysts for the oxygen reduction reaction (ORR). However, FeNC usually suffers from unsatisfactory performance due to the symmetrical charge distribution around the iron site. Elaborately regulating the microenvironment of the central Fe atom can substantially improve the catalytic activity of FeNC, which remains challenging.

High Energy and Power Zinc Ion Capacitors: A Dual-Ion Adsorption and Reversible Chemical Adsorption Coupling Mechanism.

Zinc ion capacitors (ZICs) hold great promise in large-scale energy storage by inheriting the superiorities of zinc ion batteries and supercapacitors. However, the mismatch of kinetics and capacity between a Zn anode and a capacitive-type cathode is still the Achilles' heel of this technology. Herein, porous carbons are fabricated by using tetra-alkali metal pyromellitic acid salts as precursors through a carbonization/self-activation procedure for enhancing zinc ion storage.

Deciphering the Precursor-Performance Relationship of Single-Atom Iron Oxygen Electroreduction Catalysts via Isomer Engineering.

Single atom Fe-nitrogen-carbon (Fe-N-C) catalysts have high catalytic activity and selectivity for the oxygen reduction reaction (ORR), and are possible alternatives for Pt-based materials. However, the reasonable design and selection of precursors to establish their relationship with Fe-N-C catalyst performance is still a formidable task. Herein, precursors with controllable structures are easily achieved through isomer engineering, with the purpose of regulating the active site density and microscopic morphology of the final electrocatalyst.

Optimizing Microenvironment of Asymmetric N,S-Coordinated Single-Atom Fe via Axial Fifth Coordination toward Efficient Oxygen Electroreduction.

Single-atom catalysts (SACs) are attractive candidates for oxygen reduction reaction (ORR). The catalytic performances of SACs are mainly determined by the surrounding microenvironment of single metal sites. Microenvironment engineering of SACs and understanding of the structure-activity relationship is critical, which remains challenging.

Simultaneously Integrating Single Atomic Cobalt Sites and Co S Nanoparticles into Hollow Carbon Nanotubes as Trifunctional Electrocatalysts for Zn-Air Batteries to Drive Water Splitting.

The development of rechargeable metal-air batteries and water electrolyzers are highly constrained by electrocatalysts for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). However, the construction of efficient trifunctional electrocatalysts for ORR/OER/HER are highly desirable yet challenging. Herein, hollow carbon nanotubes integrated single cobalt atoms with Co S nanoparticles (CoSA + Co S /HCNT) are fabricated by a straightforward in situ self-sacrificing strategy.

FeO-Encapsulating N-doped porous carbon materials as efficient oxygen reduction reaction electrocatalysts for Zn-air batteries.

FeO nanoparticle-encapsulating N-doped porous carbon was synthesized. Owing to the large specific surface area, hierarchical porous structure, and sufficient number of active sites from the graphitic carbon wrapped FeO NPs as well as the joint effect with Fe-N moieties, the as-prepared 2D-FeO@FeNC-700 electrocatalyst exhibits exceptional performance in Zn-air batteries.