Development of Bimetallic PdNi Electrocatalysts toward Mitigation of Catalyst Poisoning in Direct Borohydride Fuel Cells

Abstract

Cost-effective and highly active borohydride oxidation reaction (BOR) electrocatalysts are crucial for the advancement of direct borohydride fuel cells (DBFCs). Noble-metal electrocatalysts, such as Pd, are used as benchmark electrocatalysts because of their superior BOR activity. However, Pd suffers from catalyst poisoning because of strong binding with BH x intermediates at a high BOR overpotential, making it unsuitable for high DBFC performance, whereas Ni exhibits a low degree of catalyst poisoning because of a relatively weak binding of BH x intermediates. Density functional theory (DFT) calculations indicate a lowering of H-and OH-binding energies on bimetallic PdNi surfaces in comparison to their individual counterparts, thereby freeing more sites for BH 4 adsorption that is crucial for a high BOR rate. The as-synthesized bimetallic PdNi/C electrocatalyst exhibits higher current densities at a BH 4 concentration range of 50−500 mM than Pd/C and Ni/C. A DBFC unit with a pH-gradientenabled microscale bipolar interface employing PdNi/C, Pt/C, and H 2 O 2 as the anode, cathode, and oxidant, respectively, exhibits a power density of 466 ± 1.5 mW/cm 2 at 1.5 V, a peak power density of 630 ± 2 mW/cm 2 at 1.1 V, with an open-circuit voltage of 1.95 ± 0.01 V. Our bimetallic alloy electrocatalyst shows high DBFC performance, providing a pathway for the development of suitable BOR electrocatalysts.

Microfabrication of the Ammonia Plasma-Activated Nickel Nitride–Nickel Thin Film for Overall Water Splitting in the Microfluidic Membraneless Electrolyzer

“…A low resistance ionic route through the membrane is achieved using a high acidic media in the cation exchange membrane and a strong alkaline media in the anion exchange membrane. , The extreme electrolyte pH accelerates membrane degradation in the electrolyzer, initiating the cross-over of counterions and gas products. Electrolyzers operating in acidic pH require noble metal-based catalysts for stable operation at high current density. , Transition metal-based catalysts that are abundant can be used in an alkaline electrolyzer but suffer from the low performance of the electrolyzer due to the poor conductivity of the anion exchange membrane. − Electrolyzers include additional components such as a liquid transport layer and flow plates (Figure ), whose primary functions are reactants/products transport to and from the reaction sites and electron and heat conduction, with minimum ohmic, activation, fluidic, thermal, and interfacial losses. − …”

Precisely Tuning the Surface Nanostructure of Ni@Pd Nanocatalysts for Enhanced Formic Acid Oxidation

“…Compared with the peak of standard fcc‐structured Pd (JCPDS no. 46‐1043), each reflection peak of Pd shifts to a higher degree, which is mainly caused by the incorporation of Ni atoms into Pd lattice [33] . The lattice parameter of those Ni@Pd alloys is about 2.226 Å.…”

Bimetallic Nanocrystals: Structure, Controllable Synthesis and Applications in Catalysis, Energy and Sensing

“…Bimetallic nanocrystals have been widely used in many important fields from science to technology [16,17,[136][137][138]. In comparison to single metal nanocrystals, bimetallic nanocrystals possess many unique properties due to the adjustable composition, controllable morphology and variable electronic structure, so they also have many practical and potential applications including catalysis, sensing, biodetection, biomedicine, and so on.…”