Design and Construction of Cu(OH)2/Ni3S2 Composite Electrode on Cu Foam by Two-Step Electrodeposition

Gold-Promoted Electrodeposition of Metal Sulfides on Silicon Nanowire Photocathodes To Enhance Solar-Driven Hydrogen Evolution

Constructing composite structures is the key to breaking the dilemma of slow reaction kinetics and easy oxidation on the surface of lightly doped p-type silicon nanowire (SiNW) array photocathodes. Electrodeposition is a convenient and fast technique to prepare composite photocathodes. However, the low conductivity of SiNWs limits the application of the electrodeposition technique in constructing composite structures. Herein, SiNWs were loaded with Au nanoparticles by chemical deposition to decrease the interfacial charge transfer resistance and increase active sites for the electrodeposition. Subsequently, co-catalysts CoS, MoS₂, and Ni₃S₂ with excellent hydrogen evolution activity were successfully composited by electrodeposition on the surface of SiNWs/Au. The obtained core-shell structures exhibited excellent photoelectrochemical hydrogen evolution activity, which was contributed by the plasma property of Au and the abundant hydrogen evolution active sites of the co-catalysts. This work provided a simple and efficient solution for the preparation of lightly doped SiNW-based composite structures by electrodeposition.

Emerging materials for electrochemical CO2 reduction: progress and optimization strategies of carbon-based single-atom catalysts

The electrochemical CO₂ reduction reaction can effectively convert CO₂ into promising fuels and chemicals, which is helpful in establishing a low-carbon emission economy. Compared with other types of electrocatalysts, single-atom catalysts (SACs) immobilized on carbon substrates are considered to be promising candidate catalysts. Atomically dispersed SACs exhibit excellent catalytic performance in CO₂RR due to their maximum atomic utilization, unique electronic structure, and coordination environment. In this paper, we first briefly introduce the synthetic strategies and characterization techniques of SACs. Then, we focus on the optimization strategies of the atomic structure of carbon-based SACs, including adjusting the coordination atoms and coordination numbers, constructing the axial chemical environment, and regulating the carbon substrate, focusing on exploring the structure-performance relationship of SACs in the CO₂RR process. In addition, this paper also briefly introduces the diatomic catalysts (DACs) as an extension of SACs. At the end of the paper, we summarize the article with an exciting outlook discussing the current challenges and prospects for research on the application of SACs in CO₂RR.

Hierarchical Design of Co(OH)2/Ni3S2 Heterostructure on Nickel Foam for Energy Storage

In this study, we rationally designed a facile stepwise route and successfully synthesized a Co(OH)2/Ni3S2 heterostructure supported on nickel foam (NF) as a binder-free electrode for energy storage. Galvanostatic deposition was first applied to produce uniform Co(OH)2 nanoflakes on NF. Then, Ni3S2 was applied to its surface by potentiostatic deposition to form a Co(OH)2/Ni3S2 heterostructure at room temperature. The added Co(OH)2 not only functions as a practical electrochemically active component but also provides support for the growth of Ni3S2, and the deposition amount of Ni3S2 is controlled by adjusting the electrodeposition duration of Ni3S2. Then, the electrochemical behaviors of the Co(OH)2/Ni3S2 composite can be optimized. A maximum areal specific capacitance (Cs) of 5.73 F cm−2 at 2 mA cm−2 was achieved, and the coulombic efficiency was as high as 94.14%. A capacitance retention of 84.38% was measured after 5000 charge–discharge cycles.

Facile Route to Achieve Self-Supported Cu(OH)2/Ni3S2 Composite Electrode on Copper Foam for Enhanced Capacitive Energy Storage Performance

Herein, a Cu(OH)2/Ni3S2 composite was successfully prepared through facile two-step electrodeposition. As the electrode substrate and the only copper source, the copper foam underwent surface oxidation by galvanostatic deposition technology to form Cu(OH)2, and the subsequent coverage of Ni3S2 was achieved by potentiostatic deposition. The Cu(OH)2 acts as a skeleton, providing support for Ni3S2 growth, thus providing more abundant electrochemical active sites. By virtue of the in situ growth strategy and the synergy of different components, the optimized Cu(OH)2/Ni3S2 electrode illustrates significantly enhanced pseudocapacitance performance, with an areal specific capacitance of 11.43 F cm−2 at 2 mA cm−2, good coulombic efficiency of 94.55%, and remarkable cyclic stability (83.33% capacitance retention after 5000 cycles).