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CoS2/CeO2, exhibiting the 3d–4f orbital coupling effect, is developed and shows exceptional OER activity, with an overpotential of 140 mV at 10 mA cm−2. DFT calculation and Raman spectra show the existence of a d–p–f electron transport ladder that can accelerate electron transfer through the Co–O(S)–Ce bond, optimize the adsorption free energy, and enhance the catalytic activity. [ABSTRACT FROM AUTHOR]

Herein, a N-doped carbon-supported Co and NiFe LDH (Co-NC@NiFe LDH) array was developed, which demonstrated superior catalytic activities for both the OER and UOR in an alkaline medium. The intrinsic electron transfer is effectively regulated by the construction of a built-in electric field, which reduces the reaction energy barrier and consequently leads to a significant enhancement in electrocatalytic activity. [ABSTRACT FROM AUTHOR]

Currently, single‐atom catalysts (SACs) research mainly focuses on transition metal atoms as active centers. Due to their delocalized s/p‐bands, the s‐block main group metal elements are typically regarded as catalytically inert. Herein, an s‐block potassium SAC (K−N−C) with K‐N4 configuration is reported for the first time, which exhibits excellent oxygen reduction reaction (ORR) activity and stability under alkaline conditions. Specifically, the half‐wave potential (E1/2) is up to 0.908 V, and negligible changes in E1/2 are observed after 10,000 cycles. In addition, the K−N−C offers an exceptional power density of 158.1 mW cm−2 and remarkable durability up to 420 h in a Zn‐air battery. Density functional theory (DFT) simulations show that K−N−C has bifunctional active K and C sites, can optimize the free energy of ORR reaction intermediates, and adjust the rate‐determining steps. The crystal orbital Hamilton population (COHP) results showed that the s orbitals of K played a major role in the adsorption of intermediates, which was different from the d orbitals in transition metals. This work significantly guides the rational design and catalytic mechanism research of s‐block SACs with high ORR activity. [ABSTRACT FROM AUTHOR]

The development of efficient non-noble metal catalysts that can operate at high current densities for sluggish oxygen evolution is crucial for the large-scale commercialization of water electrolysis. Herein, we have developed a heterostructure oxygen evolution anode material that satisfies the requirements of ampere-level current density using a straightforward calcination-electroplating approach. Due to the natural p–n junction interface, a built-in electric field is induced in the Ni3P/NiFe LDH electrode, resulting in high conductivity and low gas transmission resistance. As a result of its heterogeneous structure, abundant active sites, and rapid interfacial electron transfer, this Ni3P/NiFe LDH exhibits outstanding catalytic performance, achieving an oxygen evolution current density of 1.4 A cm−2 with an ultra-low overpotential of 304 mV. DFT calculations indicate that the formed p–n junction effectively drives electron transfer and directly influences the charge density surrounding the active center, thereby enhancing intrinsic activity. This study highlights the potential use of non-noble metal-based heterojunction materials as efficient catalysts for the oxygen evolution in alkaline water electrolysis. [ABSTRACT FROM AUTHOR]

A V-doped amorphous/crystalline heterostructure of NiFe (oxy)hydroxide with nanoflower morphology is developed, which exhibits excellent OER and UOR catalytic activities. V doping changes the local charge density, lowers the reaction barrier, and optimizes the electron arrangement of the NiFe LDH catalyst. [ABSTRACT FROM AUTHOR]

Fe, Mo-doped Ni3S2 nanosheets that are derived from NiFe-LDH by structural transformation have been successfully developed. The obtained Fe, Mo-Ni3S2 exhibits a low overpotential of 67 mV to enable a current density of 10 mA cm−2 for the HER and the overpotential for the OER is only 240 mV. Besides, the current density of 10 mA cm−2 can be achieved with a voltage of 1.53 V in a two-electrode hydrolysis device. [ABSTRACT FROM AUTHOR]

Defect and interface engineering are recognized as effective strategies to regulate electronic structure and improve activity of metal sulfide. However, the practical application of sulfide is restricted by their low conductivity and rapid decline in activity derived from large volume fluctuation during electrocatalysis process. More importantly, the determination of exact active site of sulfide is complicated due to the inevitable electrochemical reconstruction. Herein, ZnS nanoparticles with Zn defect are anchored onto the surface of NiCo2S4 nanosheet to construct NiCo2S4/ZnS hybrids, which exhibit outstanding oxygen evolution performance with an ultralow overpotential of 140 mV. The anchoring of defective ZnS nanoparticles inhibit the volume expansion of NiCo2S4 nanosheet during the cycling process. Density‐functional theory reveals that the build‐in interfacial potential and Zn defect can facilitate the thermodynamic formation of *O to *OOH, thus improve their intrinsic activity. [ABSTRACT FROM AUTHOR]

CoS 2 /CeO 2 , exhibiting the 3d-4f orbital coupling effect, is developed and shows exceptional OER activity, with an overpotential of 140 mV at 10 mA cm -2 . DFT calculation and Raman spectra show the existence of a d-p-f electron transport ladder that can accelerate electron transfer through the Co-O(S)-Ce bond, optimize the adsorption free energy, and enhance the catalytic activity.

Currently, single-atom catalysts (SACs) research mainly focuses on transition metal atoms as active centers. Due to their delocalized s/p-bands, the s-block main group metal elements are typically regarded as catalytically inert. Herein, an s-block potassium SAC (K-N-C) with K-N 4 configuration is reported for the first time, which exhibits excellent oxygen reduction reaction (ORR) activity and stability under alkaline conditions. Specifically, the half-wave potential (E 1/2 ) is up to 0.908 V, and negligible changes in E 1/2 are observed after 10,000 cycles. In addition, the K-N-C offers an exceptional power density of 158.1 mW cm -2 and remarkable durability up to 420 h in a Zn-air battery. Density functional theory (DFT) simulations show that K-N-C has bifunctional active K and C sites, can optimize the free energy of ORR reaction intermediates, and adjust the rate-determining steps. The crystal orbital Hamilton population (COHP) results showed that the s orbitals of K played a major role in the adsorption of intermediates, which was different from the d orbitals in transition metals. This work significantly guides the rational design and catalytic mechanism research of s-block SACs with high ORR activity., (© 2023 Wiley-VCH GmbH.)

The slow kinetics of the bifunctional (OER/ORR) oxygen electrocatalyst is the bottleneck problem restricting the performance of zinc-air batteries (ZABs). The design and synthesis of an efficient and stable electrocatalyst at the air cathode to improve the performance of ZABs is of great significance for the development of sustainable energy conversion devices. Herein, we have developed a sulfur vacancy-rich Mott-Schottky catalyst (Co@Co 9 S 8 -NCNT), which shows superior ORR/OER bifunctional electrochemical activity and stability. Specifically, the OER overpotential is only 210 mV at 10 mA cm -2 , and the half-wave potential ( E 1/2 ) of ORR is up to 0.88 V. Furthermore, a ZAB has been assembled using the Co@Co 9 S 8 -NCNT, which delivers a high power density (196.7 mW cm -2 ) and an open-circuit voltage (1.501 V), showing excellent battery performance. Density functional theory calculations demonstrate that the Co@Co 9 S 8 Mott-Schottky heterojunction and S vacancy defects are beneficial to elevate the d-band central energy level to the Fermi level, significantly enhancing the adsorption/desorption capacity of oxygen-containing intermediates, thereby effectively improving the OER activity. Moreover, the N-doped carbon nanotubes can promote the continuous electron transfer between the metal and semiconductor interface. This work proposes a valid method for the construction and structural regulation of Mott-Schottky catalysts and offers new insights into the development of catalytic materials for energy conversion equipment.

Fe, Mo-doped Ni 3 S 2 nanosheets that are derived from NiFe-LDH by structural transformation have been successfully developed. The obtained Fe, Mo-Ni 3 S 2 exhibits a low overpotential of 67 mV to enable a current density of 10 mA cm -2 for the HER and the overpotential for the OER is only 240 mV. Besides, the current density of 10 mA cm -2 can be achieved with a voltage of 1.53 V in a two-electrode hydrolysis device.

Metal ion substitution and anion exchange are two effective strategies for regulating the electronic and geometric structure of spinel. However, the optimal location of foreign metallic cations and the exact role of these metals and anions remain elusive. Herein, CoFe 2 O 4 -based hollow nanospheres with outstanding oxygen evolution reaction activity are prepared by Cr 3+ substitution and S 2- exchange. X-ray absorption spectra and theoretical calculations reveal that Cr 3+ can be precisely doped into octahedral (Oh) Fe sites and simultaneously induce Co vacancy, which can activate adjacent tetrahedral (Td) Fe 3+ . Furthermore, S 2- exchange results in structure distortion of Td-Fe due to compressive strain effect. The change in the local geometry of Td-Fe causes the *OOH intermediate to deviate from the y -axis plane, thus enhancing the adsorption of the *OOH. The Co vacancy and S 2- exchange can adjust the geometric and electronic structure of Td-Fe, thus activating the inert Td-Fe and improving the electrochemical performance.