Pt–Ru bimetallic nanoparticles anchored on carbon nanotubes/polyaniline composites with coral-like structure for enhanced methanol oxidation

Lattice Strain and Composition Effects on the Methanol Oxidation Performance of Platinum–Ruthenium–Nickel Ternary Nanocatalysts

“…The corresponding equivalent circuit included solution resistance (R s ), high-frequency constant phase element (Q 1 ), charge-transfer resistance (R ct ), and constant phase element related to adsorbed reaction intermediates (Q 2 and R 0 ). 2 EIS Nyquist plots demonstrated S4. The aforementioned outcomes suggested that the introduction of suitable Ni content can promote the kinetic rate of the C−H cleavage due to a balance between synergistic and electronic effects, thereby improving the overall MOR efficiency, while the too-large Ni content suppressed the reaction kinetically and decreased the overall MOR activity.…”

“…At the suitable Ni content, Pt-based alloys possessed sufficient Pt sites for enhancing the kinetic of the methanol dehydrogenation step, thereby boosting the MOR activity. , What is more, the ratios between forward and backward current peaks (i.e., I f / I b ratio) of the Pt 70 Ru 30 /C, Pt 70 Ru 20 Ni 10 /C, Pt 60 Ru 20 Ni 20 /C, and Pt 50 Ru 20 Ni 30 /C catalysts were 1.39, 1.43, 1.57, and 1.49 (Table S2), reflecting the efficacious MOR and less poisoning intermediates produced in the backward potential scan by adding the Ni atom, leading to the enhanced anti-CO-tolerance of Pt-based ternary catalysts. ,, To consider the reaction kinetics of all studied MOR catalysts, electrochemical impedance spectroscopy (EIS) was carried out in the frequency range from 0.1 to 10 5 Hz at the 0.4 V RHE potential, as shown in Figure d. The corresponding equivalent circuit included solution resistance ( R s ), high-frequency constant phase element ( Q 1 ), charge-transfer resistance ( R ct ), and constant phase element related to adsorbed reaction intermediates ( Q 2 and R 0 ) . EIS Nyquist plots demonstrated that the Pt 60 Ru 20 Ni 20 /C catalyst exhibited the smallest diameter of the impedance arc among the investigated catalysts, meaning the Pt 60 Ru 20 Ni 20 /C had the lowest charge transfer resistance, resulting in the rapid charge transfer rate between the Pt 60 Ru 20 Ni 20 /C surface and methanol molecules during the MOR process.…”

“…Alloying Pt with Ru is one of the most well-known and advanced nanomaterials to address detriments (i.e., CO poisoning, sluggish reaction kinetics, etc.) of the commercially available C-supported Pt catalyst for the anodic methanol oxidation reaction (MOR) process in direct methanol fuel cells, which are a potential substitute power source for energy-related applications. − In the PtRu catalyst system, Ru sites are more active than Pt in the water-discharge process at a negative potential to form hydroxyl groups, serving as activators to boost the CO ads oxidation step on Pt active sites, thereby releasing more Pt surface and enhancing the MOR rate. − In addition, Abruña et al reported that the interatomic distance between Pt and neighboring Ru atoms played an important role in an efficient interaction between Pt-CO ads and Ru–OH ads species to generate a transition state (Pt-CO ads ···OH ads -Ru) for the oxidation of the CO ads during the MOR . Although the PtRu catalyst can reduce the Pt content and enhance the overall MOR efficiency, their electrochemical durability is restricted by the component leaching in strongly acidic media. , Also, Ru metal belongs to the Pt-group metal, which is a major challenge for the widespread commercialization of the PtRu catalyst.…”

Enhanced Methanol Oxidation in Alkaline Media on Electrodeposited Ni Electrodes by Morphological and Crystallographic Evolution

“…The most important factors for methanol oxidation are onset potential the lower the better and current density, the higher the better. 72,73 Hence, we estimated that the best electrochemical activity belongs to Ni electrodeposited using PRC method. These results are reasonable and could be well interpreted with the morphology and crystallographic texture of Ni electrodeposited using DC, PC, or PRC methods as reported before in Fig.…”

Descriptor for C2N-Supported Single-Cluster Catalysts in Bifunctional Oxygen Evolution and Reduction Reactions

“…Similar to SACs, SCCs provide an alternative way to efficiently utilize transition metal (TM) atoms in various catalytic processes. − Some of the remarkable advantages of cluster catalysts are their special structural and electronic properties. − The exposed atoms of clusters with a suitable ensemble size can serve as a mutisite active center during catalysis, which has become very attractive in a wide range of applications in the field of heterogeneous catalysis. − However, previous reports often represent case studies, such as computational investigation of specific clusters, like Fe 3 and W 4 . Other theoretical studies focus on computational screening of precious trimetallic clusters supported on N-doped graphene for the OER and ORR .…”