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Developing efficient and abundant electrocatalysts for hydrogen/oxygen evolution reactions (HER/OER) is a significant challenge in the electrochemical water splitting process. This study introduces a Cu3P nanoarray structure on a copper foam substrate, intricately coated with CoFe-LDH nanosheets (Cu3P–CoFe LDH/CF). This nanoscale design significantly enhances the electrochemically active surface area, promoting water molecule adsorption and facilitating a synergistic interaction at the nanoscale heterogeneous interface between CoFe LDH and Cu3P. This interaction boosts charge transfer and improves the conductive properties of CoFe LDH, notably enhancing HER kinetics (170 ± 6 mV at a current density of 10 mA cm–2) and optimizing OER kinetics (201 ± 3 mV at a current density of 10 mA cm–2) through a synergistic oxide/hydroxide mechanism during the reaction. Cu3P–CoFe LDH/CF also demonstrates a low cell voltage of 1.60 V in overall water splitting (10 mA cm–2) and exhibits strong stability for 20 h. These observations provide valuable evidence for the practical application potential of the catalyst and highlight its usefulness. [ABSTRACT FROM AUTHOR]

Constructing pH‐responsive smart material provides a new opportunity to address the problem that traditional electrocatalysts cannot achieve both alkaline oxygen evolution reaction (OER) and acidic hydrogen evolution reaction (HER) activities. In this study, amphoteric conjugated ligand (2‐aminoterephthalic acid, BDC‐NH2)‐modified 3d metal‐anchored graphitic carbon nitride (3d metal−C3N4) smart electrocatalysts are constructed, and self‐adaptation of the electronic structure is realized by self‐response to pH stimulation, which results in self‐adjustment of alkaline OER and acidic HER. Specifically, the amino and carboxyl functional groups in BDC‐NH2 undergo protonation and deprotonation respectively under different pH stimulation to adapt to environmental changes. Through DFT calculations, the increase or decrease of electron delocalization range brought by the self‐response characteristic is found to lead to redistribution of the Bader charge around the modified active sites. The OER and HER activities are greatly promoted roughly 4.8 and 8.5 times over Co−C3N4 after BDC−NH2‐induced self‐adaptive processes under different environments, arising from the reduced energy barrier of O* to OOH* and ΔGH*. Impressively, the proposed BDC‐NH2‐induced smart regulation strategy is applicable to a series of 3d metal anchors for C3N4, including Co, Ni and Fe, providing a general structural upgrading method for constructing smart electrocatalytic systems. [ABSTRACT FROM AUTHOR]

Summary: Recently, the development of durable electrocatalysts with bifunctional and high‐efficiency applications in overall water splitting has become a hot spot in the energy field. Herein, Mo2C@g‐C3N4@NiMn‐LDH, a bifunctional electrocatalyst, is obtained through self‐assembly strategies of heat treatment, g‐C3N4 coating, and hydrothermal growth of NiMn‐LDH nanosheets using homogeneous Mo2C precursor nanowire as template. Specifically, Mo2C and NiMn‐LDH are located on the inner wall and outer wall of g‐C3N4, respectively, realizing separate‐sided different functions of g‐C3N4 by electronic control of the interface. The Mo2C@g‐C3N4@NiMn‐LDH composite exhibits excellent bifunctional electrocatalytic performance, in which the inner Mo2C@g‐C3N4 are the dominant catalytic active center for hydrogen evolution reaction (HER) and the outer NiMn‐LDH acts as co‐catalyst, whereas the active center transfer to g‐C3N4@NiMn‐LDH for oxygen evolution reaction (OER) and the inner Mo2C turns into the co‐catalyst. The performance of Mo2C@g‐C3N4@NiMn‐LDH electrocatalyst is reflected by the overpotential of 116 mV (for HER) and 290 mV (for OER) at the current density of 10 mA cm−2 in alkaline medium, respectively. In addition, the voltage required for overall water splitting to reach 10 mA cm−2 is only 1.587 V, and the sample has excellent stability under constant applied voltage. This work provides a strategy for the development of high‐performance electrocatalysts with controllable active sites through interface engineering, so as to achieve competitive equilibrium of different reaction processes. [ABSTRACT FROM AUTHOR]

Slow reaction kinetics, significant overpotential, and high cost remained significant barriers to electrocatalytic water splitting. To address such issues, "cicada-wing-like" nitrogen-doped porous carbon-anchored Ni and CeO2 nanoparticles (CeO2/Ni/NC) were developed and manufactured as a bifunctional catalyst utilizing a modified electrospinning process for overall water splitting. It is worth mentioning that the resulting CeO2/Ni/NC catalyst had excellent oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) catalytic performance, as well as superior alkaline electrolyte durability. Compared with other nitrogen-doped carbon catalysts, in the OER, it revealed with a lower OER overpotential of 390 mV at 10 mA·cm–2 and a smaller value of the Tafel slope (123 mV·dec–1), while in the HER, it showed an overpotential of 320 mV at 10 mA·cm–2 and a Tafel slope of 150 mV·dec–1. The metallic Ni was the main center of excellent catalytic activity, and the abundant oxygen vacancies and outstanding oxidation/reduction capabilities in CeO2 promoted the overall water splitting. Moreover, the porous nanoarchitecture of matrix material well controlled the size of Ni and CeO2, providing a wealth of active sites, facilitating the electron/ion transfer. This work provided ideas for non-metal-doped carbon-supported catalyst particles, and the catalytic material obtained by the cheap and simple preparation method had an ultrathin microscopic appearance like cicada-wing-like and excellent bifunctional catalytic activity. [ABSTRACT FROM AUTHOR]

The mixed‐phase BiVO4 nanosheet with different ratios of solvents was prepared by a one‐step hydrothermal method. The viscosity of ethylene glycol helps form a homogeneous thin nanosheet, which can be compared with the microstructure of BiVO4 with different ratios of solvents (deionised water and ethylene glycol). Also, both XRD and Raman diagrams indicate that the synthesis of BiVO4 nanosheet constitutes with a mixture of two crystal types. The mixed‐phase BiVO4 possesses higher photocurrent density, smaller electron transport resistance and longer lifetime. Enhanced photoelectrochemical performance can be attributed to the mixed‐phase BiVO4 has a large specific surface area, as well as o‐BiVO4 (orthorhombic BiVO4) and s‐BiVO4 (monocline BiVO4), form heterogeneous junction to promote photogenerated carries separation and reduce the recombination of photogenerated electron–hole. [ABSTRACT FROM AUTHOR]

In this work, a nitrogen-rich BiVO4 nanosheet sample prepared by one-step hydrothermal method and characterized by XRD, TEM, Raman, XPS. With the introduction of N, partial oxygen atoms of BiVO4 were replaced by N to form Bi–N and V–N bonds, lead to the deviation of binding energy and the right shift of Raman peak. PEC measurements show that photocurrent density of nitrogen-rich BiVO4 photocatalyst is nearly two times higher than the pristine BiVO4, have longer electronic life and higher carrier concentration. These are mainly attributed to the Bi–N and V–N bonds are serve as the main OER catalytic active sites, and facilitate the transmission of electrons from the semiconductor surface to the FTO. The possible catalytic mechanism of nitrogen-rich BiVO4 system has also been proposed. [ABSTRACT FROM AUTHOR]

Constructing pH-responsive smart material provides a new opportunity to address the problem that traditional electrocatalysts cannot achieve both alkaline oxygen evolution reaction (OER) and acidic hydrogen evolution reaction (HER) activities. In this study, amphoteric conjugated ligand (2-aminoterephthalic acid, BDC-NH 2 )-modified 3d metal-anchored graphitic carbon nitride (3d metal-C 3 N 4 ) smart electrocatalysts are constructed, and self-adaptation of the electronic structure is realized by self-response to pH stimulation, which results in self-adjustment of alkaline OER and acidic HER. Specifically, the amino and carboxyl functional groups in BDC-NH 2 undergo protonation and deprotonation respectively under different pH stimulation to adapt to environmental changes. Through DFT calculations, the increase or decrease of electron delocalization range brought by the self-response characteristic is found to lead to redistribution of the Bader charge around the modified active sites. The OER and HER activities are greatly promoted roughly 4.8 and 8.5 times over Co-C 3 N 4 after BDC-NH 2 -induced self-adaptive processes under different environments, arising from the reduced energy barrier of O* to OOH* and ΔG H* . Impressively, the proposed BDC-NH 2 -induced smart regulation strategy is applicable to a series of 3d metal anchors for C 3 N 4 , including Co, Ni and Fe, providing a general structural upgrading method for constructing smart electrocatalytic systems., (© 2023 Wiley-VCH GmbH.)

Designing an excellent acidic and alkaline general-purpose hydrogen evolution electrocatalyst plays an important role in promoting the development of the energy field. Here, a feasible strategy is reported to use the strongly coupled MoS 2 @sulfur and molybdenum co-doped g-C 3 N 4 (MoS 2 @Mo-S-C 3 N 4 ) heterostructure with transferable active centers for catalytic reactions in acidic and alkaline media. Research studies have shown that the unsaturated S site at the edge of MoS 2 and the active N atom on the Mo-S-C 3 N 4 substrate are, respectively, the active centers of acidic and alkaline hydrogen evolution reaction. Specifically, Mo-S-C 3 N 4 is regarded as a synergistic catalyst for the active species MoS 2 in acidic hydrogen evolution, while MoS 2 acts as a co-catalyst when the alkaline active species are transferred to Mo-S-C 3 N 4 . The coordination of the electrons between the interfaces achieves a synergistic balance, which provides the optimal sites for the adsorption of the reactants. Such an electrocatalyst exhibits overpotentials of 193 and 290 mV at 10 mA cm -2 in 0.5 M H 2 SO 4 and 1 M KOH, respectively, which was better than numerous previous reports. This research provides an outstanding avenue to realize multifunctional electrocatalysts.