Ultrafine Pd nanocrystals were grown on the cobalt phosphide (Co₂P) decorated Vulcan XC-72 carbon (C/Co₂P), which is realized by first implementing the corresponding metal precursor and then the further chemical reduction process. The as-synthesized C/Co₂P/Pd composite was further constructed to form a gas permeable electrode. This electrode can be applied for formaldehyde (HCHO) detection. The results demonstrate that the Co₂P nanocrystal can significantly improve the sensing performance of the C/Co₂P/Pd electrode for catalytic oxidation of HCHO, which is considered to be attributed to the effective electron transfer from Co₂P to Pd in the C/Co₂P/Pd composites. Furthermore, the assembled C/Co₂P/Pd sensor exhibits high sensitivity of 617 nA/ppm and good selectivity toward various interfering gases such as NO₂, NO, SO₂, CO₂, and CO. It also shows the excellent linear response that the correlation coefficient is 0.994 in the concentration range of 1–10 ppm. Therefore, the proposed cost-effective C/Co₂P/Pd nanocomposite, which owns advantages such as high activity and good stability, has the potential to be applied as an effective electrocatalyst for amperometric HCHO detection.

The ZnO/Ni₂S₃ composite has been designed and in situ synthesized on Ni foam substrate by two steps of electrodeposition. ZnO was achieved on Ni foam by a traditional potentiostatic deposition, followed by cyclic voltammetric (CV) electrodeposition, to generate Ni₂S₃, where the introduction of ZnO provides abundant active sites for the subsequent Ni₂S₃ electrodeposition. The amount of deposit during CV electrodeposition can be adjusted by setting the number of sweep segment and scan rate, and the electrochemical characteristics of the products can be readily optimized. The synergistic effect between the ZnO as backbones and the deposited Ni₂S₃ as the shell enhances the electrochemical properties of the sample significantly, including a highly specific capacitance of 2.19 F cm⁻² at 2 mA cm⁻², good coulombic efficiency of 98%, and long-term cyclic stability at 82.35% (4000 cycles).

The Ag/Ni(OH)2 composite electrode has been designed and in situ constructed on a copper substrate by combining electroless deposition technology with electrodeposition. The products can be directly used as a high performance binder free electrode. The synergistic effect between the Ag nanocubes (AgNCs) as backbones and the deposited Ni(OH)2 as the shell can significantly improve the electrochemical properties of the composite electrode. Moreover, this in situ growth strategy forms a strong bonding force of active materials to the substrate, which can improve the cycling performance and lower the equivalent series resistance. The Ag/Ni(OH)2 composite electrode exhibits enhanced electrochemical properties with a high specific capacitance of 3.704 F cm−2, coulombic efficiency of 88.3% and long-term cyclic stability.

Hierarchical Ag@Ni(OH)₂ nanospheres were achieved directly on copper foam substrate through a convenient two-step process. Ag nanoflowers were formed on copper substrate by galvanic replacement technology between AgNO₃ and copper foam followed by electrodeposition of a layer of Ni(OH)₂. Ag nanostructures as cores not only dominated the final morphology of the composites, but also improved the electrical conductivity, increased the specific surface area of the active electrode material, and even directly participated in the electrochemical reactions. The resulted Ag@Ni(OH)₂ nanospheres could be directly used as high-performance binder-free electrodes and exhibited enhanced electrochemical performance with a high specific capacitance of 1.864 F cm⁻² and long cycling lifespans of 90.43% capacity retaining after 3000 cycles.

We prepared transparent conducting composite electrodes composed of silver nanowires (Ag NWs) and reduced graphene oxide (r-GO). We present a simple approach to welding the cross-positions of the Ag NWs by applying pressure at a relatively low temperature (100°C). We examined the Ag NWs/r-GO composite films in terms of their transmission, conductivity, and stability. The plasmonic features of the Ag NWs were used to assist the ultraviolet (UV) light-induced reduction of the GO coating. The r-GO coatings used to form Ag NWs/r-GO composite structures increased the conductivity of the film by providing more efficient electron conductive pathways. The G/D intensity ratios of the GO and r-GO produced by the UV light-induced method without and with Ag NWs were 0.95, 1.01, and 1.04, respectively. The lowest sheet resistance of the composite films was 7 ohm/sq with approximately 82% transparency in the visible spectrum region. No degradation of the films was observed after 2 months. This excellent environmental stability might facilitate applications of Ag NWs/r-GO composite films in optoelectronic devices.