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Development of efficient and easy‐to‐prepare low‐cost oxygen reaction electrocatalysts is essential for widespread application of rechargeable Zn‐air batteries (ZABs). Herein, we mixed NaCl and ZIF‐8 by simple physical milling and pyrolysis to obtain a metal‐free porous electrocatalyst doped with Cl (mf‐pClNC). The mf‐pClNC electrocatalyst exhibits a good oxygen reduction reaction (ORR) activity (E1/2=0.91 V vs. RHE) and high stability in alkaline electrolyte, exceeding most of the reported transition metal carbon‐based electrocatalysts and being comparable to commercial Pt/C electrocatalysts. Likewise, the mf‐pClNC electrocatalyst also shows state‐of‐the‐art ORR activity and stability in acidic electrolyte. From experimental and theoretical calculations, the better ORR activity is most likely originated from the fact that the introduced Cl promotes the increase of sp3‐hybridized carbon, while the sp3‐hybridized carbon and Cl together modify the electronic structure of the N‐adjacent carbons, as the active sites, while NaCl molten‐salt etching provides abundant paths for the transport of electrons/protons. Furthermore, the liquid rechargeable ZAB using the mf‐pClNC electrocatalyst as the cathode shows a fulfilling performance with a peak power density of 276.88 mW cm−2. Flexible quasi‐solid‐state rechargeable ZAB constructed with the mf‐pClNC electrocatalyst as the cathode exhibits an exciting performance both at low, high and room temperatures. [ABSTRACT FROM AUTHOR]

Developing a high‐efficiency, stable, and CO‐toxicant‐resistant low‐cost hydrogen oxidation reaction (HOR) electrocatalyst is challenging but is vital for practical proton/anion exchange membrane fuel cells. Herein, an efficient pH‐universal HOR catalyst Pt1@Co1CN is fabricated, in which the electronic structure of single Pt sites is modulated by isolated Co atoms pre‐anchored on nitrogen‐doped carbon. Pt1@Co1CN exhibits superior HOR activity and durability under pH‐universal media than Pt1@CN (anchored single Pt atoms on nitrogen‐doped carbon) and commercial PtRu/C and Pt/C. More importantly, Pt1@Co1CN possesses much better CO anti‐poisoning ability than Pt1@CN and commercial PtRu/C and Pt/C. It is speculated that the superior pH‐universal HOR performance can be attributed to the inter‐regulation of adjacent Co and Pt sites, leading to the downshift of anti‐bonding state and consequently strengthening the *H adsorption, which promotes the kinetics of HOR. [ABSTRACT FROM AUTHOR]

Flexible Zn–air batteries (ZABs) draw much attention due to the merits of high energy density, stability, and safety, and show potential applications for wearable devices. However, the development of flexible ZABs with great energy density, high round‐trip efficiency, and long cycle life for practical applications is highly restricted by the lack of highly active oxygen catalysts, high ion‐conducting solid‐state electrolytes, appropriate Zn anodes, and advanced battery configuration. Promising oxygen catalysts should possess both, superior oxygen reduction reaction and oxygen evolution reaction performance and can be directly used as self‐supporting cathodes without loading catalysts on support materials such as carbon cloth. In addition, electrolytes play an important role in ZABs; a good electrolyte should be in all‐solid state with high ion conductivity. Moreover, for an excellent Zn anode, it is required to stably contact the electrolyte interface during the bending process. Therefore, in this review, recent advances in ZABs are summarized, including: i) the powder and 3D self‐supporting oxygen catalysts, ii) the species of solid‐state electrolytes, and iii) the rational design of Zn anodes. Finally, the challenges and opportunities of this promising field are presented. [ABSTRACT FROM AUTHOR]

Development of efficient and easy-to-prepare low-cost oxygen reaction electrocatalysts is essential for widespread application of rechargeable Zn-air batteries (ZABs). Herein, we mixed NaCl and ZIF-8 by simple physical milling and pyrolysis to obtain a metal-free porous electrocatalyst doped with Cl (mf-pClNC). The mf-pClNC electrocatalyst exhibits a good oxygen reduction reaction (ORR) activity (E 1/2 =0.91 V vs. RHE) and high stability in alkaline electrolyte, exceeding most of the reported transition metal carbon-based electrocatalysts and being comparable to commercial Pt/C electrocatalysts. Likewise, the mf-pClNC electrocatalyst also shows state-of-the-art ORR activity and stability in acidic electrolyte. From experimental and theoretical calculations, the better ORR activity is most likely originated from the fact that the introduced Cl promotes the increase of sp 3 -hybridized carbon, while the sp 3 -hybridized carbon and Cl together modify the electronic structure of the N-adjacent carbons, as the active sites, while NaCl molten-salt etching provides abundant paths for the transport of electrons/protons. Furthermore, the liquid rechargeable ZAB using the mf-pClNC electrocatalyst as the cathode shows a fulfilling performance with a peak power density of 276.88 mW cm -2 . Flexible quasi-solid-state rechargeable ZAB constructed with the mf-pClNC electrocatalyst as the cathode exhibits an exciting performance both at low, high and room temperatures., (© 2023 Wiley-VCH GmbH.)

The present energy crisis and environmental challenges may be efficiently resolved by converting carbon dioxide (CO 2 ) into various useful carbon products. The development of more effective catalysts has been the main focus of current research on photocatalytic CO 2 reduction. Due to their high atomic efficiency and superior catalytic activity, single-atom catalysts (SACs) have attracted considerable interest in catalytic CO 2 conversion. This review discusses the current research developments, obstacles, and potential of SACs for photocatalytic CO 2 reduction. And further, discusses the principle of photocatalytic carbon dioxide reduction. This work has compared and analyzed the effects of support materials and active site types in SACs on photocatalytic CO 2 reduction performance. This work believes that by sharing these developments, some inspiration for the rational design and development of stable and effective photocatalytic CO 2 reduction catalysts based on SACs can be provided., (© 2023 Wiley-VCH GmbH.)

Electrocatalysis of the four-electron oxygen reduction reaction (ORR) provides a promising approach for energy conversion, storage, and oxygen monitoring. However, it is always accompanied by the reduction of hydrogen peroxide (H 2 O 2 ) on most employed catalysts, which brings down the electrocatalytic selectivity. Here, we report a single-atom Co-N 4 electrocatalyst for the four-electron ORR at an onset potential of 0.68 V (vs RHE) in neutral media while with high H 2 O 2 tolerance, outperforming commercial Pt electrocatalysts. Electrochemical kinetic analysis confirms that the Co-N 4 catalytic sites dominantly promote the direct four-electron pathway of the ORR rather than the two sequential two-electron reduction pathways with H 2 O 2 as the intermediate. Density functional theory calculations reveal that H 2 O 2 reduction is hampered by the weak adsorption of H 2 O 2 on the porphyrin-like Co centers. This endows the electrocatalyst with improved resistance to current interference from H 2 O 2 , enabling highly selective O 2 sensing as validated by the reliable sensing performance in vivo. Our study demonstrates the intriguing advantage of single-atom catalysts with high capacity for tailoring metal-adsorbate interactions, broadening their applications in environmental and life monitoring.

In cooperative catalysis, the combination of chemo- and biocatalysts to perform one-pot reactions is a powerful tool for the improvement of chemical synthesis. Herein, UiO-66-NH 2 was employed to stepwise immobilize Pd nanoparticles (NPs) and Candida antarctica lipase B (CalB) for the fabrication of biohybrid catalysts for cascade reactions. Distinct from traditional materials, UiO-66-NH 2 has a robust but tunable structure that can be utilized with a ligand exchange approach to adjust its hydrophobicity, resulting in excellent catalyst dispersity in diverse reaction media. These attractive properties contribute to the formation of MOF-based biohybrid catalysts with high activity and selectivity in the synthesis of benzyl hexanoate from benzaldehyde and ethyl hexanoate. With this proof-of-concept, we reasonably expect that future tailor-made MOFs can combine other catalysts, ranging from chemical to biological catalysts for applications in industry., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)