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Challenges remain to show good capacitive performance while achieving high loadings of active materials for supercapacitors. Trying to realize this version, a nickel-protecting carbon fiber paper@Co-doped NiSx(Ni-CP@Co–NiSx) electrode with high specific gravimetric, areal, and volumetric capacitance is reported in this work. This free-standing electrode is prepared by an electroplating-hydrothermal-electroplating (EHE) three-step method to achieve a high loading of almost 26.7 mg cm–2. The cobalt-doping and nickel-protection strategies effectively decrease the impedance and inhibit the active material dropping from the electrode resulting from the expansion stress, which endows the Ni-CP@Co–NiSxelectrode with a high rate and good cycling performance, especially with an ultrahigh specific areal/volumetric/gravimetric capacitance of 53.3 F cm–2/2807 F cm–3/1997 F g–1at 5 mA cm–2, respectively. Employing activated carbon functionalized with riboflavin (AC/VB2) as a negative electrode, the asymmetric supercapacitor device delivers a very high energy density of up to 60.4 W h kg–1. This work demonstrates that electrodes with a high loading density and excellent performance can be obtained by the combination of the EHE method to adjust the internal conductivity and external structural stability.

A H2/CO2fuel cell is a promising device that can convert CO2into hydrocarbon fuel with electricity generation. Herein, a facile electrospinning method has been used to synthesize the embedded Ru-CNF catalyst in which Ru nanoparticles are dispersed homogeneously within N-doped carbon nanofibers. This catalyst exhibits a high CH4production rate of 308.46 μmol gcat–1h–1at 170 °C, which is superior to that of the Ru/CNF (242.53 μmol gcat–1h–1) and Ru/CNT (194.24 μmol gcat–1h–1). The enhanced CO2RR performance of Ru-CNF is ascribed to the well-distributed Ru nanoparticles within the CNF matrix and synergistic effect of Ru sites with N species, which results in forming the increased CO2RR active sites, hence improving the catalytic activity. Simultaneously, it can achieve a peak power density of 1.8 W m–2on the strength of anodic (H2oxidation) and cathodic (CO2reduction and H2evolution) reactions with remarkable stability. Such findings give a theoretical basis of CO2RR in the H2/CO2fuel cell system, which could hold great value to further develop the high-efficiency catalysts for CO2reduction.