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Herein, a layer of molybdenum oxide (MoOx), a transition metal oxide (TMO), which has outstanding catalytic properties in combination with a carbon‐based thin film, is modified to improve the hydrogen production performance and protect the MoOx in acidic media. A thin film of graphene is transferred onto the MoOx layer, after which the graphene structure is doped with N and S atoms at room temperature using a plasma doping method to modify the electronic structure and intrinsic properties of the material. The oxygen functional groups in graphene increase the interfacial interactions and electrical contacts between graphene and MoOx. The appearance of surface defects such as oxygen vacancies can result in vacancies in MoOx. This improves the electrical conductivity and electrochemically accessible surface area. Increasing the number of defects in graphene by adding dopants can significantly affect the chemical reaction at the interfaces and improve the electrochemical performance. These defects in graphene play a crucial role in the adsorption of H+ ions on the graphene surface and their transport to the MoOx layer underneath. This enables MoOx to participate in the reaction with the doped graphene. N‐ and S‐doped graphene (NSGr) on MoOx is active in acidic media and performs well in terms of hydrogen production. The initial overpotential value of 359 mV for the current density of −10 mA/cm2 is lowered to 228 mV after activation. [ABSTRACT FROM AUTHOR]

Improvement of the sluggish kinetics of the overall water splitting catalyst through N-doping and the formation of a carbon shell makes it possible to achieve carbon neutrality and to synthesize catalysts that can replace noble metals. Surprisingly, in Ni3FeN@NC catalysts, transition metals received an extra electron due to doping with the nitrogen element, and thus the electron distribution probability at the Fermi energy level increased. In addition, pyridinic-N in the N-doped carbon shell can contribute to the improvement of catalyst performance. Density functional theory (DFT) calculations demonstrated the electrical performance by specifying the model of Ni3FeN@NC and were able to elucidate the mechanism of the catalytic reaction (OER and HER). The OER and HER overpotentials of the synthesized Ni3FeN@NC were confirmed to be 246 mV and 181 mV at 10 mV cm−2 in 1.0 M KOH. It was proved that 98% of the performance was maintained even in overall water splitting performed for 24 h. [ABSTRACT FROM AUTHOR]

The introduction of inorganic nanoparticles into carbon nanotube (CNT) papers can provide a versatile route to the fabrication of CNT papers with diverse functionalities, but it may lead to a reduction in their mechanical properties. Here, we describe a simple and effective strategy for the fabrication of mechanically robust magnetic CNT papers for electromagnetic interference (EMI) shielding and magnetomechanical actuation applications. The magnetic CNT papers were produced by vacuum filtration of an aqueous suspension of CNTs, CoFe 2 O 4 nanoparticles, and poly(vinyl alcohol) (PVA). PVA plays a critical role in enhancing the mechanical strength of CNT papers. The magnetic CNT papers containing 73 wt % of CoFe 2 O 4 nanoparticles exhibited high mechanical properties with Young's modulus of 3.2 GPa and tensile strength of 30.0 MPa. This magnetic CNT paper was successfully demonstrated as EMI shielding paper with shielding effectiveness of ∼30 dB (99.9%) in 0.5-1.0 GHz, and also as a magnetomechanical actuator in an audible frequency range from 200 to 20 000 Hz.