Hierarchical Flowerlike Highly Synergistic Three-Dimensional Iron Tungsten Oxide Nanostructure-Anchored Nitrogen-Doped Graphene as an Efficient and Durable Electrocatalyst for Oxygen Reduction Reaction

Coating Porous TiO2 Films on Carbon Nanotubes to Enhance the Durability of Ultrafine PtCo/CNT Nanocatalysts for the Oxygen Reduction Reaction

The development of excellent activity and durability catalysts for the oxygen reduction reaction (ORR) is essential for the commercialization of proton exchange membrane fuel cells (PEMFCs). Reducing the size of catalyst particles can provide more reaction sites to mitigate the performance degradation caused by reduced platinum loading. However, at the same time, it makes the particles more prone to agglomeration and exfoliation, leading to a rapid reduction in catalyst activity. Here, we present the design of a composite support (TiO₂/CNT) with a porous TiO₂ film that immobilizes PtCo nanoparticles (NPs) loaded on the support while protecting the carbon nanotubes inside. The particle size of PtCo NPs was only 1.99 nm (determined by transmission electron microscopy), but the nanocatalyst (PtCo/TiO₂/CNT) maintained high catalytic performance and stability on account of the strong metal support interaction (SMSI). PtCo/TiO₂/CNT exhibited a high mass activity (MA, 0.476 A mg_Pt^-1) and was found to have MA retention rates of 91.7 and 88.8% in durability tests performed at 0.6-1.0 V and 1.0-1.5 V, respectively.

The Pt/g-C3N4-CNS catalyst via in situ synthesis process with excellent performance for methanol electrocatalytic oxidation reaction

g-C3N4-CNS prepared by the in situ synthetic method has a larger specific surface area and more anchoring sites for Pt, which promotes the dispersion of Pt and enhances the electrocatalytic performance.

Sponge Effect Boosting Oxygen Reduction Reaction at the Interfaces between Mullite SmMn2O5 and Nitrogen-Doped Reduced Graphene Oxide

Exploring the effect of interfacial structural properties on catalytic performance of hybrid materials is essential in rationally designing novel electrocatalysts with high stability and activity. Here, in situ growth of mullite SmMn₂O₅ on nitrogen-doped reduced graphene oxide (SMO@NrGO) is achieved for highly efficient oxygen reduction reaction (ORR). Combining X-ray photoelectron spectroscopy and density functional theory calculations, interfacial chemical interactions between Mn and substrates are verified. Interestingly, as revealed by charge density difference, the interfacial Mn-N(C) bonds display a sponge effect to store and compensate electrons to boost the ORR process. In addition, bidentate adsorption of oxygen intermediates instead of monodentate ones is observed in hybrid materials, which facilitates the interactions between intermediates and active sites. Experimentally, the hybrid catalyst SMO@NrGO exhibits a half-wave potential as high as 0.84 V, being comparable to benchmark Pt/C and higher than that of the pure SMO (0.68 V). The Zn-air battery assembled with SMO@NrGO shows a high discharge peak power density of 244 mW cm^-2 and superior cycling stability against noble metals.

Optimized Synthesis of Nitrogen and Phosphorus Dual-Doped Coal-Based Carbon Fiber Supported Pd Catalyst with Enhanced Activities for Formic Acid Electrooxidation

Development of a Pd-based catalyst with highly active and durable properties for formic acid oxidation reaction at the anode remains an important matter of interest in the research community. Herein, we have designed novel coal-based carbon fibers (Coal-CFs) with dicyandiamide (DCD) as nitrogen (N) source, triphenylphosphine (TPP) as phosphorus (P) source dual-doped to support Pd catalysts (Pd/NP-Coal-CFs(DCD/TPP)), which exhibit superior catalytic performance toward formic acid oxidation reaction. Mass activity of formic acid oxidation of Pd/NP-Coal-CFs(DCD/TPP) catalyst is 536.6 mA·mg^-1_Pd, which is 2.5 times higher than that of Pd/Coal-CFs catalyst. The higher specific surface areas, exclusive electron transport path, and the high synergistic interaction of N and P are the favorable phenomena for catalytic performance. The addition of coal not only increases the abundant defects sites but also makes the utilization of coal with high added value. This N and P dual-doped catalyst inspires an idea for promoting applications in practical fuel cells.