The Lifetime of Hydroxyl Radical in Realistic Fuel Cell Catalyst Layer.

The lifetime of hydroxyl radicals (⋅OH) in the fuel cell catalyst layer remains uncertain, which hampers the comprehension of radical-induced degradation mechanisms and the development of longevity strategies for proton-exchange membrane fuel cells (PEMFCs). In this study, we have precisely determined that the lifetime of ⋅OH radicals can extend up to several seconds in realistic fuel cell catalyst layers. This finding reveals that ⋅OH radicals are capable of carrying out long-range attacks spanning at least a few centimeters during PEMFCs operation.

Revealing a Double-Volcano-Like Structure-Activity Relationship for Substitution-Functionalized Metal-Phthalocyanine Catalysts toward Electrochemical CO Reduction.

Electron-donating/-withdrawing groups (EDGs/EWGs) substitution is widely used to regulate the catalytic performance of transition-metal phthalocyanine (MPc) toward electrochemical CO reduction, but the corresponding structure-activity relationships and regulation mechanisms are still ambiguous. Herein, by investigating a series of substitution-functionalized MPc (MPc-X), this work reveals a double-volcano-like relationship between the electron-donating/-withdrawing abilities of the substituents and the catalytic activities of MPc-X. The weak-EDG/-EWG substitution enhances whereas the strong-EDG/-EWG substitution mostly lowers the CO selectivity of MPc.

Mechanism of Particle-Mediated Inhibition of Demetalation for Single-Atom Catalytic Sites in Acidic Electrochemical Environments.

Demetalation, caused by the electrochemical dissolution of metal atoms, poses a significant challenge to the practical application of single-atom catalytic sites (SACSs) in proton exchange membrane-based energy technologies. One promising approach to inhibit SACS demetalation is the use of metallic particles to interact with SACSs. However, the mechanism underlying this stabilization remains unclear.

Singlet Oxygen Induced Site-Specific Etching Boosts Nitrogen-Carbon Sites for High-Efficiency Oxygen Reduction.

Targeted construction of carbon defects near the N dopants is an intriguing but challenging way to boost the electrocatalytic activity of N-doped carbon toward oxygen reduction reaction (ORR). Here, we report a novel site-specific etching strategy that features targeted anchoring of singlet oxygen ( O ) on the N-adjacent atoms to directionally construct topological carbon defects neighboring the N dopants in N-doped carbon ( O -N/C). This O -N/C exhibits the highest ORR half-wave potential of 0.

Ampere-level current density ammonia electrochemical synthesis using CuCo nanosheets simulating nitrite reductase bifunctional nature.

The development of electrocatalysts capable of efficient reduction of nitrate (NO) to ammonia (NH) is drawing increasing interest for the sake of low carbon emission and environmental protection. Herein, we present a CuCo bimetallic catalyst able to imitate the bifunctional nature of copper-type nitrite reductase, which could easily remove NO via the collaboration of two active centers. Indeed, Co acts as an electron/proton donating center, while Cu facilitates NO adsorption/association.

Two-dimensional metal-organic frameworks and their derivatives for electrochemical energy storage and electrocatalysis.

Two-dimensional (2D) metal-organic frameworks (MOFs) and their derivatives with excellent dimension-related properties, high surface areas, abundantly accessible metal nodes, and tailorable structures, have attracted intensive attention as energy storage materials and electrocatalysts. A major challenge on the road toward the commercialization of 2D MOFs and their derivatives is to achieve the facile and controllable synthesis of 2D MOFs with high quality and at low cost. Significant developments have been made in the synthesis and applications of 2D MOFs and their derivatives in recent years.

Ultrasmall 2 D Co Zn (Benzimidazole) Metal-Organic Framework Nanosheets and their Derived Co Nanodots@Co,N-Codoped Graphene for Efficient Oxygen Reduction Reaction.

The development of nonprecious metal-nitrogen-carbon (M-N-C) materials with efficient metal utilization and abundant active sites for the oxygen reduction reaction (ORR) is of great significance for fuel cells and metal-air batteries. Ultrasmall 2 D Co Zn (benzimidazole) [Co Zn (bim) ] bimetallic metal-organic framework (MOF) nanosheets (≈2 nm thick) are synthesized by a novel bottom-up strategy and then thermally converted into a core-shell structure of sub-5 nm Co nanodots (NDs) wrapped with 2 to 5 layers of Co,N-codoped graphene (Co@FLG). The size of the Co NDs in Co@FLG could be precisely controlled by the Co/Zn ratio in the Co Zn (bim) nanosheet.

Morphology-dependent electrochemical performance of Ni-1,3,5-benzenetricarboxylate metal-organic frameworks as an anode material for Li-ion batteries.

The performance of energy storage materials is substantially dependent on their nanostructures. Herein, Ni-1,3,5-benzenetricarboxylate metal-organic frameworks (Ni-BTC MOFs) with different morphologies are controllably synthesized using a facile solvothermal method by simply adjusting the solvent and their electrochemical performance as an anode material for lithium-ion batteries is thoroughly investigated. Among the synthesized Ni-BTC MOFs with different morphologies, a hierarchical mesoporous flower-like Ni-BTC MOF (Ni-BTC) assembled from two-dimensional nanosheets shows the best electrochemical properties including a high capacity of 1085 mA h g at 100 mA g (358 mA h g at 5000 mA g), excellent cycling stability at 1000 mA g for 1000 cycles, and great rate performance, which is superior to most of the reported MOF-based anode materials for lithium-ion batteries.

Plasma-Induced Oxygen Vacancies in Urchin-Like Anatase Titania Coated by Carbon for Excellent Sodium-Ion Battery Anodes.

The incorporation of oxygen vacancies in anatase TiO has been studied as a promising way to accelerate the transport of electrons and Na ions, which is important for achieving excellent electrochemical properties for anatase TiO. However, wittingly introducing oxygen vacancies in anatase TiO for sodium-ion anodes by a facile and effective method is still a challenge. In this work, we report an innovative method to introduce oxygen vacancies into the urchin-like N-doped carbon coated anatase TiO (NC-DTO) by a facile plasma treatment.