Synthesis and Electrochemical Study of Pd-Based Trimetallic Nanoparticles for Enhanced Hydrogen Storage

Abstract

The success of acceptable hydrogen storage capacities on high surface area carbon materials at ambient temperature requires the combination of both physisorption and chemisorption. Despite the sole reliance on physisorption for hydrogen uptake in carbon, the dispersal of transition metal catalysts on carbon materials significantly enhances hydrogen uptake at ambient temperatures, via the process of hydrogen spillover. In the present study, hydrogen electrosorption onto activated carbon materials modified with different tri-metallic dissociation catalysts (Pd-Ag-Cd) was investigated in an acidic medium using cyclic voltammetry and chronoamperometry. A significant synergistic effect on hydrogen storage was observed, which could be attributed to the electrochemical reduction of hydrogen ions initially at the Pd-based nanoparticles and the hydrogen surface diffusion subsequently to the activated carbon. Utilizing electrochemical methods, the optimized composition of the Pd-Ag-Cd alloys was determined to be Pd 80 Ag 10 Cd 10 with the highest hydrogen sorption capacity at a hydrogen desorption charge of 18.49 C/cm 2 ·mg.With increased kinetics and a decrease in the phase transition, the significant enhancement of hydrogen sorption, in comparison to the Pd-Ag and Pd-Cd bi-metallic alloys, was further demonstrated, making Pd-Ag-Cd catalysts attractive for use as hydrogen dissociation catalysts for applications in both hydrogen purification and storage.

Pd‐Ni/Cd loaded PPy/Ti composite electrode: Synthesis, characterization, and application for hydrogen storage

“…The peak becomes broader and a positive directional shift in the peak potential appears on the Pd‐Ni/Cd/PPy/Ti electrodes with lower Cd compositions. Similar results have been obtained in previous studies concerning Pd‐Ag‐Cd/PAC200 nanoparticles . The Q H per unit weight of the Pd catalyst on the PPy/Ti‐supported electrodes follows the sequence Pd 22 ‐Ni 6 /Cd 74 (S3) < Pd 31 ‐Ni 5 /Cd 64 (S6) < Pd 36 ‐Ni 7 /Cd 57 (S7).…”

“…Hydrogen spillover is depicted as a dissociative adsorption of H 2 on a transition metal catalyst, followed by H atoms migrating to the support, and subsequently, diffusing on the support or reacting at remote surface sites . Hydrogen spillover can enhance the amount of hydrogen absorbed on materials . Of such metal catalysts, palladium (Pd), with its satisfactory performance with respect to its adhesion coefficient, hydrogen selectivity, diffusivity, and low activation barrier to hydrogen absorption, is thought to be a strong contender for hydrogen storage .…”

“…It can absorb approximately 1000 times its own volume of hydrogen at ambient pressure and temperature and is itself extremely stable. It is possible to alloy or immobilize Pd with other metals, which can reduce the cost and synergistic effect of metals used to improve the selectivity, stability, and activity of the catalyst and further result in higher permeability and solubility for hydrogen as compared with pure Pd . The hydrogen spillover phenomenon can also be further enhanced.…”

Probing the catalytic activity of bimetallic versus trimetallic nanoshells

“…The addition of a third metal to produce trimetallic compositions represents an emerging approach to optimize catalytic activities on noble metal nanostructures [11,[20][21][22]. Trimetallic nanoparticles have shown improved catalytic performances relative to their mono-and bimetallic counterparts for a variety of reactions that include cyclohexene and glucose oxidation, the electrooxidation of formic acid, and C-C coupling [23][24][25][26].…”

“…Trimetallic nanoparticles have shown improved catalytic performances relative to their mono-and bimetallic counterparts for a variety of reactions that include cyclohexene and glucose oxidation, the electrooxidation of formic acid, and C-C coupling [23][24][25][26]. It has been proposed that trimetallic systems may present distinct properties relative to their mono-and bimetallic counterparts, which enables, at least in principle, the design of nanomaterials with optimized performances [11,21,22,27,28]. Despite these very attractive features, studies on the synthesis of trimetallic noble metal nanomaterials are still limited, and the role of the third metal over the performances, relative to their bimetallic systems, remains unclear.…”