Nanoporous (NP) PtRu alloys with three different bimetallic components were straightforwardly fabricated by dealloying PtRuAl ternary alloys in hydrochloric acid. Selective etching of aluminum from source alloys generates bicontinuous network nanostructures with uniform size and structure. The as-made NP-PtRu alloys exhibit superior catalytic activity toward the hydrolytic dehydrogenation of ammonia borane (AB) than pure NP-Pt and NP-Ru owing to alloying platinum with ruthenium. The NP-Pt₇₀Ru₃₀ alloy exhibits much higher specific activity toward hydrolytic dehydrogenation of AB than NP-Pt₃₀Ru₇₀ and NP-Pt₅₀Ru₅₀. The hydrolysis activation energy of NP-Pt₇₀Ru₃₀ was estimated to be about 38.9 kJ mol⁻¹, which was lower than most of the reported activation energy values in the literature. In addition, recycling tests show that the NP-Pt₇₀Ru₃₀ is still highly active in the hydrolysis of AB even after five runs, which indicates that NP-PtRu alloy accompanied by the network nanoarchitecture is beneficial to improve structural stability toward the dehydrogenation of AB.

Upon dealloying a carefully designed CoCuAl ternary alloy in NaOH solution at room temperature, a Co₃O₄/CuO nanocomposite with an interconnected porous microstructure assembled by a secondary structure of nanosheets was successfully fabricated. By using the dealloying strategy, the target metals directly grew to form uniform bimetallic oxide nanocomposites. Owing to the unique hierarchical structure and the synergistic effect of both active electrode materials, the Co₃O₄/CuO nanocomposite exhibits much enhanced electrochemical performance with higher capacities and better cycling stability compared to anodes of pure Co₃O₄. Moreover, it performs excellently in terms of cycle reversibility, Coulombic efficiency, and rate capability, at both low or high current rates. With the advantages of unique performance and ease of preparation, the as-made Co₃O₄/CuO nanocomposite demonstrates promising application potential as an advanced anode material for lithium-ion batteries.

A hierarchical nanoporous (HNP) PtCu alloy was successfully fabricated by two-step dealloying of a well-designed PtCuAl precursor alloy combined with an annealing operation. The as-made PtCu alloy has an interconnected hierarchical network architecture with controllable bimodal ligament/pore distributions obtained by adjusting the annealing temperature and the redealloying time. HNP-PtCu exhibits superior specific and mass activities for the oxygen-reduction reaction (ORR) compared with single-modal nanoporous PtCu and commercial Pt/C catalysts. More importantly, the HNP-PtCu alloy shows much higher structure stability with less loss of the electrochemical surface area of Pt and ORR activity upon long-term potential scans in acid solution. The excellent electrocatalytic performance for ORR makes the HNP-PtCu alloy attractive as efficient cathode electrocatalysts in fuel-cell-related technologies.

A nanoporous PdTi (NP-PdTi) alloy with uniform ligament size and controllable bimetallic ratio was easily fabricated by a one-step mild dealloying process of PdTiAl (precursor alloy). NP-PdTi consisted of an interconnected network of nanoscale ligaments with bicontinuous hollow channels extending in all three dimensions. Electrocatalytic measurements indicated that NP-PdTi had superior electrocatalytic activity in the oxygen reduction reaction (ORR) with enhanced specific and mass activities as well higher methanol tolerance relative to Pt/C. Interestingly, NP-PdTi showed higher catalytic durability than Pt/C with a lower decrease in the ORR activity and electrochemical surface area of the metal upon 5000 potential cycles in an acidic solution. DFT calculations demonstrated that alloying Pd with Ti could bring favorable electronic perturbation with the downshifted d-band center of Pd, leading to a weakened PdO bond and improved ORR performance. The excellent electrocatalytic performance in ORR renders NP-PdTi alloys attractive as efficient cathode electrocatalysts in fuel-cell-related technologies.

A nanoporous (NP) PdCo alloy with uniform structure size and controllable bimetallic ratio was fabricated simply by one-step mild dealloying of a PdCoAl precursor alloy. The as-made alloy consists of a nanoscaled bicontinuous network skeleton with interconnected hollow channels that extend in all three dimensions. With a narrow ligament size distribution around 5 nm, the NP PdCo alloy exhibits much higher electrocatalytic activity towards the oxygen-reduction reaction (ORR) with enhanced specific and mass activities relative to NP Pd and commercial Pt/C catalysts. A long-term stability test demonstrated that NP PdCo has comparable catalytic durability with less loss of ORR activity and electrochemical surface area than Pt/C. The NP PdCo alloy also shows dramatically enhanced catalytic activity towards formic acid electrooxidation relative to NP Pd and Pd/C catalysts. The as-made NP PdCo holds great application potential as a promising cathode as well as an anode electrocatalyst in fuel cells with the advantages of superior catalytic performance and easy preparation.

A novel nonenzymatic immunosensor for sensitive detection of Microcystin-LR (MC-LR) is constructed using a graphene platform combined with mesoporous PtRu alloy as a label for signal amplification. Primary antibody-Microcystin-LR (Ab₁) is immobilized onto the surface of a graphene sheet (GS) through an amidation reaction between the carboxylic acid groups attached to the GS and the available amine groups of Ab₁. Mesoporous PtRu alloy, prepared by corrosion PtRuAl alloys, is employed as a label to immobilize secondary antibody (Ab₂). The resulting nanoparticles, PtRu-Ab₂, are used as labels for the immunosensor to detect MC-LR. Under optimal conditions, the immunosensor exhibits a wide linear response to MC-LR that ranges from 0.01 to 28 ng·mL⁻¹, with a low detection limit of 9.63 pg·mL⁻¹ MC-LR. The proposed immunsensor shows good reproducibility, selectivity, and stability. The assayed results of polluted water with the sandwich-type sensor are acceptable. Importantly, this methodology may provide a promising ultrasensitive assay strategy for other environmental pollutants.

Co₃O₄ nanosheets are straightforwardly fabricated through an in situ dealloying and oxidation process of etching CoAl alloy in alkaline solutions. X-ray diffraction and electron spectroscopy characterizations demonstrate the formation of a Co₃O₄ nanostructure with an intricate hierarchical nanosheet morphology comprising interconnected nanoslices with the diameter as small as 6 nm. Upon calcination in O₂ atmosphere, these novel Co₃O₄ nanosheets exhibit excellent catalytic activity toward CO oxidation in normal feed gas at ambient temperature. Catalytic tests reveal the strong influence of calcination temperature on the resultant catalytic activities, whereby 300 °C is found to be preferable possibly due to an optimum balance between the surface area and the amount of active species as compared with 200 and 450 °C. Moreover, Co₃O₄ nanosheets showed good time-on-stream catalytic stability; CO conversion at T₅₀ (the temperature for 50 % CO conversion) reduced to 37 % after 20 h, and at T₁₀₀ (the temperature for full CO conversion) the conversion only decreased to about 90 % after 15 h.

Nanoporous silver (NPS) is fabricated by selectively dissolving Al from AgAl alloys in corrosive electrolytes at room temperature. Electron spectroscopy characterizations demonstrate that the NaOH electrolyte is beneficial to the formation of a three-dimensional bicontinuous porous nanostructure with uniform and tunable pore and ligament dimensions of a few tens of nanometers, while processing in HCl electrolyte easily lead to coarsened porous nanostructures. The high-surface-area Ag nanostructures are demonstrated as novel effective template materials to the construction of nanotubular mesoporous Pt/Ag and Pd/Ag alloy structures, which are realized via room temperature galvanic replacement reactions with H₂PtCl₆ and K₂PdCl₄ solutions by adding a high concentration of Cl⁻ ions as a coordinating agent. Electrochemical measurements indicate that the resulting hollow and porous bimetallic nanostructures show enhanced electrocatalytic activities and CO-tolerance with better durability toward methanol and formic acid oxidation due to alloying with Ag.