Lattice strain controlled Ni@NiCu efficient anode catalysts for direct borohydride fuel cells

We successfully fabricated a novel tensile lattice strained Ni@NiCu catalyst with a popcorn-like morphology, which is composed of a crystalline Ni core and a NiCu alloy shell. It exhibits outstanding catalytic activity, selectivity, and stability towards borohydride electrooxidation. Moreover, a direct borohydride fuel cell (DBFC) with a Ni@NiCu anode can deliver a power density of 433 mW cm-2 and an open circuit voltage of 1.94 V, much better than the performances of DBFCs employing other anode catalysts reported in the literature. This could be attributed to the fact that the tensile lattice strain generated by the introduction of Cu leads to a rise in the d-band center of the Ni metal and promotes the final B-H decoupling, which is the rate-determining step in the borohydride oxidation reaction, thus improving remarkably the catalytic performances of Ni@NiCu.

Succulent-plant-like Ni-Co alloy efficient catalysts for direct borohydride fuel cells

A Ni-Co alloy catalyst with a unique succulent-plant-like morphology is prepared by a simple electrodeposition method, while the effects of deposition conditions on its performance are also investigated systematically. The research results show that the Ni_0.889-Co_0.111 catalyst exhibits excellent activity, selectivity, and stability to the borohydride oxidation reaction. Moreover, when Ni_0.889-Co_0.111 is assembled as the anode catalyst, the direct borohydride fuel cell delivers a peak power density of 490 mW cm^-2 and an open-circuit voltage of 1.87 V at 343 K and can run stably for dozens of hours. The significant improvement in Ni-Co catalyst performance can be attributed to its unique succulent-plant-like morphology and the introduction of an appropriate amount of Co.

Porous Ni-Cu Alloy Dendrite Anode Catalysts with High Activity and Selectivity for Direct Borohydride Fuel Cells

A porous Ni-Cu alloy dendrite catalyst covered by Ni nanoparticles (Ni-np@NC) has been fabricated by an ultrafast and controllable strategy. The research results show that the morphology of the Ni-Cu alloy depends strongly on the Cu²⁺concentration. Moreover, the Ni-np@NC catalyst demonstrates excellent selectivity and activity toward the borohydride oxidation reaction (BOR). Furthermore, on the Ni-np@NC catalyst electrode, the overpotential merely requires 169 mV at a current density of 10 mA cm^-2 for BOR, and the fuel efficiency may reach 70%. The direct borohydride fuel cell using the Ni-np@NC/C anode can export a maximum power density of 218 mW cm^-2, much higher than that using the noble-based anode reported in the literature. The remarkable enhancement of Ni-np@NC catalyst performances is on the back of the unique morphology of porous dendrite covered by nanoparticles and the introduction of Cu.

An efficient Ni-P amorphous alloy electrocatalyst with a hierarchical structure toward borohydride oxidation

Nickel has been widely researched in the electrooxidation of borohydride due to its low cost and abundant reserves, but its catalytic activity and stability need to be improved for practical application. In this work, a Ni and P deposited nickel foam (Ni-P@NF) catalyst electrode with a unique hierarchical structure is prepared by a simple one-step electrodeposition method. The structure, morphology, and catalytic performances of Ni-P@NF are investigated systematically. The results show that Ni-P@NF exhibits excellent catalytic activity, stability, and durability during borohydride electrooxidation. On the Ni-P@NF catalyst electrode, the current density for borohydride oxidation can reach 225 mA cm-2; the fuel utilization is up to 84% and 97% of the initial current is maintained even after 500 cycles of cyclic voltammetry (CV), while a traditional H-type direct sodium borohydride fuel cell (DBFC) assembled with a Ni-P@NF catalyst anode can deliver a maximum power density of 52.5 mW cm-2 and an open circuit potential of 1.87 V. These merits can be attributed to the unique hierarchical structure of the Ni-P catalyst and the introduction of phosphorus. The results also show that the Ni-P@NF catalyst has certain application potential in DBFCs.

Carbon supported Pd–Sn nanoparticle eletrocatalysts for efficient borohydride electrooxidation

Carbon supported Pd–Sn (Pd–Sn/C) nanoparticle electrocatalysts are prepared via a facile and environmentally friendly method and successfully applied in BH₄⁻ electrooxidation.