Versatile Synthesis of Pd−M (M=Cr, Mo, W) Alloy Nanosheets Flower‐like Superstructures for Efficient Oxygen Reduction Electrocatalysis

Abstract

Pd‐based nanoalloys are promising electrocatalysts for replacing Pt‐based ones toward oxygen reduction reaction. Despite that great progress has been achieved, universally synthesizing Pd‐based alloy nanosheets and further integrating them into porous or hierarchical superstructures remain a challenge, and their ORR performances are not systematically investigated. Herein, novel ultrathin and highly wrinkled Pd−M (M=Cr, Mo, W) alloy nanosheets flower‐like superstructures (NSFSs) are universally fabricated via a polyether and small molecules/ions ligand assisted solvothermal method. Such Pd−M NSFSs possess mesoporous structures and co‐exist single‐atom‐like and cluster‐like M species on their surfaces. Compared with pure Pd NSFSs, those Pd−M NSFSs show greatly enhanced ORR activity in alkaline media. Due to the unique microstructure feature, proper alloy constituent and stronger interatomic polarization or electronic coupling, the Pd−W NSFSs show the highest ORR activity with the half‐wave potential of 0.89 V (vs. RHE) and mass activity of 0.46 A mgPd−1 at 0.90 V (vs. RHE), outperforming commercial Pt/C, and most of reported Pd(or Pt)‐based catalysts. Moreover, the Pd−W NSFSs manifest outstanding durability and anti‐CO poisoning ability yet. This work may spur the development of 2D Pd‐based nanoalloy superstructures and promote their applications in fuel cells or other clean energy fields.

Fe-Modified Pd as an Effective Multifunctional Electrocatalyst for Catalytic Oxygen Reduction and Glycerol Oxidation Reactions in Alkaline Media

“…) at 900 mV RHE is significantly larger than the majority of the reports of j k = 0.05−3.7 mA cm noble-metal −2 (0.04−2.0 A mg noble-metal −1 ) for the anodic direction, 3,13,14,16,17 and j k = 0.2− 0.6 mA cm noble-metal −2 (0.08−2.0 A mg noble-metal −1 ) for the unspecified direction. 22−24 ).…”

“…For comparison, at 900 mV RHE , the achieved j k (A mg Pd –1 ) = 1.04 (PdFe/Vulcan) and 0.81 (PdFe/rGO) are 5.2–10.7 times higher than those of the reported nanoalloys of Pd 3 Fe/C ( j k = 0.097 A mg Pd –1 ) and PdFe/C ( j k = 0.157 A mg Pd –1 ) . In summary, the obtained j k = 2.2 mA cm Pd –2 (1.04 A mg Pd –1 ) at 900 mV RHE is significantly larger than the majority of the reports of j k = 0.05–3.7 mA cm noble‑metal –2 (0.04–2.0 A mg noble‑metal –1 ) for the anodic direction, ,,,, and j k = 0.2–0.6 mA cm noble‑metal –2 (0.08–2.0 A mg noble‑metal –1 ) for the unspecified direction. − These data do not include the unprecedented record of j k = 11.6 mA cm Pd –2 (16.4 A mg Pd –1 ) for PdMo-bimetallene/C and where the performance of Pd-metallene/C ( j k = 0.48 mA cm Pd –2 or 0.65 A mg Pd –1 ) was well below the monometallic Pd/Vulcan synthesized by the present method ( j k = 2.82 mA cm Pd –2 or 0.72 A mg Pd –1 ). The driving force underlying this excellent enhancement in the electrocatalytic efficiency of the engineered nanocatalysts is the same as those previously discussed in the study of glycerol oxidation and CO stripping.…”

“…Seminal studies have shown that the short list of metals that are likely to enable the aforementioned functional compromise is composed of Pt and Pd. , The addition of abundant d-block metals (Fe, Sn, Mn, Bi, Ni, and Ag) to noble metals of Pt, Pd, and Au is a strong means of significantly reducing the precious metal quantity and synergistically increasing the electrocatalytic indicators of performance during the oxidation of glycerol in alkaline media. − Recently, a number of reports have revealed that high electrocatalytic performance could be achieved in these types of nanocatalysts, that is, E onset = 0.2–0.6 V RHE at the onset and j p = 2–5 mA cm metal –2 (1–18 A mg metal –1 and 50–300 mA cm geo –2 ) at the peak. ,− Pd-based nanostructured materials that provide similar or even better ORR performance than those based on Pt in basic electrolytes are the best compromise for both processes of the ORR and glycerol oxidation. Quantitatively, rotating disk/ring electrode (RDE/RRDE, 1600 rpm) studies showed that the half-wave potential of the ORR is enhanced ( E 1/2 = 0.87–0.95 V RHE ) and the mass transport-free kinetic current density j k = 0.5–11.6 mA cm metal –2 = 0.5–16.4 A mg metal –1 in 0.1 M KOH. − However, there are currently no comprehensive studies about the multifunctional ability of these high-performance materials, that is, simultaneous use of the same material for the ORR and the electro-oxidation of organics in aqueous alkaline electrolytes.…”

Enhancing electrochemical nitrogen reduction with Ru nanowiresviathe atomic decoration of Pt

“…There is evidence that strain effect can be utilized to enhance the electrocatalytic activity and selectivity by modulating the binding energies of reactants and intermediates. 29,[32][33][34][35] Herein, we introduce tensile strain into Ru lattice by incorporating of a low concentration of Pt atoms to enhance ENRR performance. Pt-decorated Ru nanowires are synthesized with the atomic ratio of Ru:Pt=88:12.…”

Synthesis and Thermal Treatment of Pd-Cr@Carbon for Efficient Oxygen Reduction Reaction in Proton-Exchange Membrane Fuel Cells

“…To overcome these difficulties the Pd-based binary alloys could be used as alternative metal. There are many studies about using the Pdbased materials nanocatalysts for the ORR [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. To address this concern, the Pd nanoparticles with numerous morphologies such as icosahedron, sphere, spindle, cube, and rod are efficiently promoted for the Suzuki coupling reaction as well as the reduction of Cr(VI) [8].…”