Cu-doped Li₄Ti₅O₁₂–TiO₂ nanosheets were synthesized by a facile, cheap, and environmentally friendly solution-based method. These nanostructures were investigated as an anode material for lithium-ion batteries. Cu doping was found to enhance the electron conductivity of the materials, and the amount of Cu doped controlled the crystal structure and content of TiO₂. In addition, the samples, which benefit from multiphases and doping, exhibited much improved capacity, cycle performance, and high rate capability over Cu-free Li₄Ti₅O₁₂–TiO₂. The discharge capacity of the 0.05 Cu-doped sample was 190 mAh g⁻¹ at 1C, and even 144 mAh g⁻¹ was obtained at 30C after 100 cycles. Moreover, after 500 cycles at 30C, the discharge capacity remained at approximately 130 mAh g⁻¹. The excellent electrochemical performance of the cell demonstrated that Cu-doping was able to adjust and control the Li₄Ti₅O₁₂–TiO₂ system appropriately.

Size-controlled Ag_0.04@Co_0.48@Ni_0.48 core–shell nanoparticles (NPs) were synthesized by employing graphene (rGO) with different reduction degrees as supports. The number of CO and CO functional groups on the surface of rGO might play a major role in controlling the particle size. The strong steric-hindrance effect of CO resulted in the growth of large particles, whereas CO contributed to the formation of small particles. The particle size of Ag_0.04@Co_0.48@Ni_0.48 NPs supported on rGO with different reduction degrees decreased as the number of CO functional groups decreased. The decrease in the particle size probably led to the increase in the catalytic activity towards the hydrolysis of ammonia borane (AB). The enhanced catalytic activity largely stemmed from the increasing active sites on the surface of catalysts owing to the decreasing particle size.

Triple-layered Ag@Co@Ni core–shell nanoparticles (NPs) containing a silver core, a cobalt inner shell, and a nickel outer shell were formed by an in situ chemical reduction method. The thickness of the double shells varied with different cobalt and nickel contents. Ag_0.04@Co_0.48@Ni_0.48 showed the most distinct core–shell structure. Compared with its bimetallic core–shell counterparts, this catalyst showed higher catalytic activity for the hydrolysis of NH₃BH₃ (AB). The synergetic interaction between Co and Ni in Ag_0.04@Co_0.48@Ni_0.48 NPs may play a critical role in the enhanced catalytic activity. Furthermore, cobalt–nickel double shells surrounding the silver core in the special triple-layered core–shell structure provided increasing amounts of active sites on the surface to facilitate the catalytic reaction. These promising catalysts may lead to applications for AB in the field of fuel cells.

Bimetallic NiCo functional graphene (NiCo/rGO) was synthesized by a facile one-pot method. During the coreduction process, the as-synthesized ultrafine NiCo nanoparticles (NPs), with a typical size of 4–6 nm, were uniformly anchored onto the surface of reduced graphene oxide (rGO). The NiCo bimetal-supported graphene was found to be more efficient than their single metals. Synergetic catalysis of NiCo NPs and rGO was confirmed, which can significantly improve the hydrogen-storage properties of MgH₂. The apparent activation energy (E_a) of the MgH₂NiCo/rGO sample decreases to 105 kJ mol⁻¹, which is 40.7 % lower than that of pure MgH₂. More importantly, the as-prepared MgH₂NiCo/rGO sample can absorb 5.5 and 6.1 wt % hydrogen within 100 and 350 s, respectively, at 300 °C under 0.9 MPa H₂ pressure. Further cyclic kinetics investigation indicates that MgH₂NiCo/rGO nanocomposites have excellent cycle stability.