Hydrogen Evolution and Oxygen Reduction Reactions in Acidic Media Catalyzed by Pd₄S Decorated N/S Doped Carbon Derived from Pd Coordination Polymer

Abstract

The template‐free synthesis and the characterization of an active electrocatalyst are performed for both the hydrogen evolution and oxygen reduction reactions in acidic media. In this work, the unique chelation mode of benzene‐1,4‐dithiocarboxamide (BDCA) is first used to synthesize a novel palladium‐BDCA coordination polymer (PdBDCA) as a precursor of palladium sulfide nanoparticles‐decorated nitrogen and sulfur doped carbon (Pd4S‐SNC). The newly synthesized PdBDCA and Pd4S‐SNC nanoparticles are characterized using chemical, electrochemical, and surface analysis methods. Notably, the nanoparticles obtained at 700 °C exhibit the remarkable catalytic property for the hydrogen evolution reaction in 0.5 m H2SO4, showing the overpotential of 32 mV (vs reversible hydrogen electrode (RHE)) and Tafel slope of 52 mV dec−1, which are comparable to that of Pt/C. The catalyst also shows a high oxygen reduction activity, offering the half‐wave and onset potentials of 0.92 and 0.77 V (vs RHE) in 0.5 m H2SO4, with improved methanol tolerance and long‐term stability compared with Pt/C. The present study gives a way for the design of excellent electrocatalyst for the energy conversion devices in the corrosive acidic environment.

Identifying the Role of Hydroxyl Binding Energy in a Non‐Monotonous Behavior of Pd‐Pd4S for Hydrogen Oxidation Reaction

“…As displayed in Figure 1a, the coexistence of cubic Pd phase (PDF#88-2335) and tetragonal Pd 4 S phase (PDF#89-2744) can be observed from the X-ray diffraction (XRD) pattern, indicating successful formation of Pd-Pd 4 S/C. [12] In addition, its counterpart Pd 4 S/C and Pd/C were also prepared through the similar synthesis approach (see Experimental Section for details). Their XRD patterns are also shown in Figure 1a.…”

Si regulation of hydrogen adsorption on nanoporous PdSi hybrids towards enhancing electrochemical hydrogen evolution activity

“…3,54 Meanwhile, the reduction peaks are formed at 41.4 and 51.3 mV for Pd 15 Si and Pd 3 Si, which indicate that OPD-H ads transfers to the underpotential deposition of H abs (UPD-H abs ). 22,37,42,52,53 This phenomenon of UPD of H is more likely to occur on electrocatalysts with high HER activity similar to Pt. At the same time, it is proved from the H ad that transferring H 2 gas on the surface Pd 15 Si and Pd 3 Si is easier than that of Pd.…”

“…Light atom (defined here as being within the third-row elements) doping can improve the HER activity of Pd-based catalysts. These light atoms include H, 3,10,47,48 N, 42,49,50 S, 22,50–52 B 53,54 and P, 55 among others. These light atoms doped into the lattice of Pd can induce a lattice strain of Pd, thus promoting the hydrogen adsorption and desorption strength at the reactive sites of Pd.…”

Ethanol‐Induced Hydrogen Insertion in Ultrafine IrPdH Boosts pH‐Universal Hydrogen Evolution

“…[17] However, Pd is exceptionally inapplicable for HER compared to Pt (more than 30 times lower than Pt) owing to the strong Pd-H bonding and difficult H desorption, thus leading to an inferior HER performance. [18] Alloy with light elements to form the interstitial Pd-H, [19,20] Pd-C, [21] Pd-O, [22,23] Pd-B, [24,25] Pd-P, [26,27] Pd-S [28] and Pd-N [29] compounds have been proved to be a powerful strategy to optimize the electrocatalytic performance. [30,31] The doping light elements can reform the performance of conventional Pd-based catalysts in the following ways [32] : i) The light elements (e.g., H, C, and B) can evenly infiltrate into the metal lattice in consequence of their smaller atomic size resulting in the lattice expansion of Pd; ii) There would occur a significant electron transfer between doping light atoms and adjacent Pd atoms on the basis of the different electronegativities; iii) The orbital hybrid mode in Pd-nonmetal alloys is s, p-d orbital hybridization between light elements and Pd atoms, distinct from the d-d orbital hybridization in conventional Pd-based catalysts, which can change the charge distribution of Pd atoms and ameliorate the adsorption free energy of catalytic sites.…”