Size Regulation and Stability Enhancement of Pt Nanoparticle Catalyst via Polypyrrole Functionalization of Carbon-Nanotube-Supported Pt Tetranuclear Complex

Copper nanoparticles embedded in polyaniline derived nitrogen-doped carbon as electrocatalyst for bio-energy generation in microbial fuel cells

Microbial fuel cells (SC-MFCs) have emerged as green energy devices to resolve the growing energy and environmental crisis. However, the technology's application depends on the sluggish oxygen reduction reaction (ORR) kinetics. Among the electrocatalysts explored, transition metal-nitrogen-carbon composites exhibit satisfactory ORR activity. Herein, we investigate the performance of copper-nitrogen-carbon (Cu/NC) electrocatalysts for ORR, highlighting the effect of temperature, role of nitrogen functionalities, and Cu-Nx sites in catalyst performance. Cu/NC-700 demonstrated satisfactory ORR activity with an onset potential of 0.7 V (vs. RHE) and a limiting current density of 3.4 mA cm-2. Cu/NC-700 modified MFC exhibited a maximum power density of 489.2 mW m-2, higher than NC-700 (107.3 mW m-2). These observations could result from synergistic interaction between copper and nitrogen atoms, high density of Cu-Nx sites, and high pyridinic-N content. Moreover, the catalyst exhibited superior stability, implying its use in long-term operations. The electrocatalytic performance of the catalyst suggests that copper-doped carbon catalysts could be potential metal-nitrogen-carbon material for scaled-up MFC applications.

Morphology and Structure Controls of Single-Atom Fe–N–C Catalysts Synthesized Using FePc Powders as the Precursor

Understanding the origin of the high electrocatalytic activity of Fe–N–C electrocatalysts for oxygen reduction reaction is critical but still challenging for developing efficient sustainable nonprecious metal catalysts used in fuel cells. Although there are plenty of papers concerning the morphology on the surface Fe–N–C catalysts, there is very little work discussing how temperature and pressure control the growth of nanoparticles. In our lab, a unique organic vapor deposition technology was developed to investigate the effect of the temperature and pressure on catalysts. The results indicated that synthesized catalysts exhibited three kinds of morphology—nanorods, nanofibers, and nanogranules—corresponding to different synthesis processes. The growth of the crystal is the root cause of the difference in the surface morphology of the catalyst, which can reasonably explain the effect of the temperature and pressure. The oxygen reduction reaction current densities of the different catalysts at potential 0.88 V increased in the following order: FePc (1.04 mA/cm2) < Pt/C catalyst (1.54 mA/cm2) ≈ Fe–N–C-f catalyst (1.64 mA/cm2) < Fe–N–C-g catalyst (2.12 mA/cm2) < Fe–N–C-r catalyst (2.35 mA/cm2). By changing the morphology of the catalyst surface, this study proved that the higher performance of the catalysts can be obtained.

Enhanced oxygen reduction reaction performance of size-controlled Pt nanoparticles on polypyrrole-functionalized carbon nanotubes

Enhanced oxygen reduction reaction performances were achieved on size-controlled Pt nanoparticle catalysts prepared by the copolymerization of a Pt₄-pyrrole complex and pyrrole monomer in the presence of multi-wall carbon nanotubes.

Novel Flexible Self-Standing Pt/Al2O3 Nanofibrous Membranes: Synthesis and Multifunctionality for Environmental Remediation

In spite of intensive research investigating the prevalent Pt/Al₂O₃ catalysts, achieving macroscopic morphology beyond the powder form limitations remains highly challenging. Meanwhile, current impregnation-based preparation approaches show the drawbacks of tedious procedures and inefficient use of noble metals. Therefore, it is important to search for new methods for the fabrication of Pt/Al₂O₃ catalysts with a novel morphology. In this study, a novel Pt/Al₂O₃ nanofibrous membrane catalyst is fabricated via a facile one-pot electrospinning process. The embedding of Pt nanoparticles is performed simultaneously with the formation of Al₂O₃ nanofibers. The Pt/Al₂O₃ membranes show remarkable mechanical properties with tensile stresses as high as 44.14 MPa. Notably, the Pt/Al₂O₃ membranes exhibit multifunctionality with excellent performance characteristics. The catalytic experiments indicate that 100% of bisphenol A is removed within 60 min, and 100% of CO is completely converted to CO₂ at 242 °C when Pt/Al₂O₃ membranes are used as catalysts. The membranes also exhibit excellent filtration performance, clearly decreasing the turbidity of water, and meet the high efficiency of particulate air filter standards. The excellent flexibility, satisfying mechanical property, and multifunctionality extend the range of potential application of the Pt/Al₂O₃ membranes. Moreover, the facile synthesis suggests new possibilities for the fabrication of many membrane-form Al₂O₃-supported catalysts.