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Main group Bi‐based materials have gained popularity as N2 reduction reaction (NRR) photo/electrocatalysts due to their ability to inhibit competitive H2 evolution reactions (HER) and the unique N2 adsorption activities. The introduction of defects in Bi‐based catalysts represents a highly effective strategy for enhancing light absorption, promoting efficient separation of photogenerated carriers, optimizing the activity of free radicals, regulating electronic structure, and improving catalytic performance. In this review, we outline the various applications of state of the defect engineering in Bi‐based catalysts and elucidate the impact of vacancies on NRR performance. In particular, the types of defects, methods of defects tailoring, advanced characterization techniques, as well as the Bi‐based catalysts with abundant defects and their corresponding catalytic behavior in NRR were elucidated in detail. Finally, the main challenges and opportunities for future development of defective Bi‐based NRR catalysts are discussed, which provides a comprehensive theoretical guidance for this field. [ABSTRACT FROM AUTHOR]

Development of highly active and selective electrocatalysts for the reduction of nitrate (NO3–) to ammonia is critical for the production of green ammonia. Herein, we designed and synthesized NiMoO4 nanocubes as an efficient electrocatalyst for nitrate reduction using deep eutectic solvents (DESs) as synthesis media. By constructing Mo and Ni dual-active sites, Mo facilitates NO3– adsorption/association, and Ni acts as an active hydrogen (*H) donating center. The amount and destination of *H can be regulated, which can effectively enhance the activity of the NO3– reduction to NH3 reaction (NO3–RR). The optimized sample possessed excellent NO3–RR activity. An NH3–N selectivity of up to 96.94% and a Faraday efficiency of up to 96.13% can be achieved at −0.4 V in a neutral solution. The catalytic NO3–RR mechanism was also investigated by density functional theory (DFT) calculations. This dual-active site electrocatalyst provides an alternative idea for the synthesis and application of high-performance NO3–RR catalysts. [ABSTRACT FROM AUTHOR]

Designing approaches to synthesizing nanostructure photocatalysts is crucial to boosting applications in photocatalytic H2 production. Herein, a Z-scheme p–n heterojunction for photocatalytic H2 production was designed and constructed by decorating p-type CoP3 quantum dots on n-type CdZnS nanorods. The flower-like CoP3/CdZnS nanorod assembly benefits from light absorption and full contact with the solution. An internal electric field forms at the interface of the p–n junction, which provides a Z-scheme charge transport path for efficient migration and separation of photogenerated charges. In result, the hydrogen production rate of the CoP3/CdZnS p–n junction is 33 times that of CdZnS. The study provided a novel approach to the synthesis of self-assembled nanostructures of quantum dots on nanorod assemblies that have important applications in photocatalysis for energy conversion. [ABSTRACT FROM AUTHOR]

Developing a highly efficient catalyst for the oxygen evolution reaction (OER) is of great significance for its application in electrocatalytic water splitting. Herein, a solid–solid transformation strategy has been developed to construct sulfur-doped Ni0.5Co0.5Fe2O4 spinel porous single-crystal nanosheet arrays on nickel foam (S-NCFO/NF). The single-crystalline nanosheet self-assembled nanostructures can provide fast charge transfer channels. With the effect of S-doping, a distorted/incomplete octahedral structure nanosheet can be formed. The unique porous S-NCFO nanosheets can provide a large number of active sites and sufficiently contact the electrolyte to adsorb OH– and desorb O2. By virtue of the porous single-crystal nanosheet, sulfur-doped spinel structure, and the unique self-assembled nanosheet configurations, the S-NCFO/NF electrode exhibits enhanced OER performance with low overpotentials at 100 mA cm–2 of 300 mV in 1 M KOH and 317 mV in 1 M KOH + 0.5 M NaCl. The synthesis strategy provides insight for the preparation and application of self-assembled nanostructures in electrocatalytic seawater splitting. [ABSTRACT FROM AUTHOR]

The channel in the marine environment is a time-varying and space-varying channel. Pulse-truncated continuous wave (PCW) speed measurement is often used in sonar, but the instability effect of PCW signal in the channel limits the effectiveness of speed measurement. Hyperbolic frequency modulation (HFM) signal is insensitive to Doppler; therefore, HFM signals are widely used in ranging and velocity measurement of sonar and radar. However, due to the filtering effect of the marine environment, the HFM signal of a single frequency band may cause excessive transmission loss, and the echo energy may be too weak to detect the target. Based on the analysis of the influence of speed on the distance measurement of HFM signal, a pulse sequence method based on HFM for speed measurement (PHS) is proposed, which uses HFM signals of different frequency bands and pulse widths in the pulse sequence to perform speed measurement. Extensive simulation results show that PHS method not only guarantees the speed measurement but also makes full use of the energy of the HFM sequence to improve the accuracy of the distance measurement. And PHS method is valuable to the practical application of engineering. [ABSTRACT FROM AUTHOR]

Designing and developing low-cost, high-efficiency catalysts to reduce the overpotential and improve the efficiency of hydrogen energy conversion are current research hotspots. In this work, CoNi2S4 nanosheets on carbon cloth (CoNi2S4/CC) were prepared to use one-step pyrolysis of the deep eutectic solvent (DES) precursor. It is feasible to cover carbon cloth evenly with DES due to its intense adherence and liquid conditions at ambient temperature. The CoNi2S4 nanosheet's coupling a CC substrate increases the electron transport efficiency and prevents the catalyst from agglomeration and corrosion during catalytic processes. Self-supported CoNi2S4/CC exhibited excellent hydrogen evolution reaction (155 mV at 50 mA cm–2 and 30 mV at 10 mA cm–2) and oxygen evolution reaction (372 mV at 100 mA cm–2 and 153 mV at 10 mA cm–2) activities. Serving as a bifunctional catalyst, CoNi2S4/CC requires cell voltages of only 1.42 and 1.86 V to achieve 10 mA cm–2 and 100 mA cm–2 current density, respectively, in overall water splitting in 1.0 M KOH, exhibiting extraordinary durability. Moreover, CoNi2S4/CC exhibits excellent overall water-splitting activity in simulated seawater, which significantly advances the development of seawater electrolysis. [ABSTRACT FROM AUTHOR]

Atomically precise nanoclusters (NCs) provide opportunities for correlating the structure and electrocatalytic properties at atomic level. Herein, we report the single-atom doping effect and ligand effect on CO2 electroreduction (eCO2RR) by comparing monogold-doped Au1Cu24 and homocopper Cu25 NCs protected by triphenylphosphine or/and tris(4-fluorophenyl)phosphine. Catalytic results revealed that the electronic distribution of Cu25 NCs is enormously contracted by doping Au atoms, entitling it to exhibit the unique inhibition of hydrogen evolution reaction. And the inductive effect of ligand strongly favors the formation of formate in eCO2RR. Overall, this work will provide guidance for the rational design of the copper-based catalysts in the eCO2RR. Tuning the metal core and ligand environment of atomically precise nanoclusters enables the correlation of structural and electrocatalytic properties at an atomic level. Here, single-atom doping and ligand tuning of atomically precise copper clusters is shown to be an effective route to tuning CO2 electroreduction activity and selectivity. [ABSTRACT FROM AUTHOR]

In this brief, we consider the mean-field type H − index problem for stochastic Markovian jump systems. A sufficient condition is derived for stochastic Markovian jump systems with (x , u) -dependent noise based on generalized differential Riccati equations. Especially for stochastic Markovian jump systems with only x-dependent noise, a sufficient and necessary condition is developed to characterize H − index larger than some ξ > 0 . Finally, a numerical example is addressed to verify the effectiveness of our obtained results. [ABSTRACT FROM AUTHOR]