A Spatially Confined gC3N4-Pt Electrocatalyst with Robust Stability

Strong Metal Support Effect of Pt/g-C3N4 Photocatalysts for Boosting Photothermal Synergistic Degradation of Benzene

Catalysis is the most efficient and economical method for treating volatile organic pollutants (VOCs). Among the many materials that are used in engineering, platinized carbon nitride (Pt/g-C₃N₄) is an efficient and multifunctional catalyst which has strong light absorption and mass transfer capabilities, which enable it to be used in photocatalysis, thermal catalysis and photothermal synergistic catalysis for the degradation of benzene. In this work, Pt/g-C₃N₄ was prepared by four precursors for the photothermal synergistic catalytic degradation of benzene, which show different activities, and many tests were carried out to explore the possible reasons for the discrepancy. Among them, the Pt/g-C₃N₄ prepared from dicyanamide showed the highest activity and could convert benzene (300 ppm, 20 mL·min^-1) completely at 162 °C under solar light and 173 °C under visible light. The reaction temperature was reduced by nearly half compared to the traditional thermal catalytic degradation of benzene at about 300 °C.

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.

MXene (Ti3C2Tx) and Carbon Nanotube Hybrid-Supported Platinum Catalysts for the High-Performance Oxygen Reduction Reaction in PEMFC

The metal-support interaction offers electronic, compositional, and geometric effects that could enhance catalytic activity and stability. Herein, a high corrosion resistance and an excellent electrical conductivity MXene (Ti₃C₂T_x) hybrid with a carbon nanotube (CNT) composite material is developed as a support for Pt. Such a composite catalyst enhances durability and improved oxygen reduction reaction activity compared to the commercial Pt/C catalyst. The mass activity of Pt/CNT-MXene demonstrates a 3.4-fold improvement over that of Pt/C. The electrochemical surface area of Pt/CNT-Ti₃C₂T_x (1:1) catalysts shows only 6% drop with respect to that in Pt/C of 27% after 2000 cycle potential sweeping. Furthermore, the Pt/CNT-Ti₃C₂T_x (1:1) is used as a cathode catalyst for single cell and stack, and the maximum power density of the stack reaches 138 W. The structure distortion of the Pt cluster induced by MXene is disadvantageous to the desorption of O atoms. This issue can be solved by adding CNT on MXene to stabilize the Pt cluster. These remarkable catalytic performances could be attributed to the synergistic effect between Pt and CNT-Ti₃C₂T_x.

Encapsulating Pt Nanoparticles inside a Derived Two-Dimensional Metal-Organic Frameworks for the Enhancement of Catalytic Activity

The development of highly active and stable electrocatalysts toward oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) is a key for commercial application of fuel cells and water splitting. Here, we report a highly active and stable Pt nanoparticles (NPs) encapsulated in ultrathin two-dimensional (2D) carbon layers derived from the ultrathin 2D metal-organic framework precursor (ZIF-67). Electrochemical tests reveal that our approach not only stabilized Pt NPs successfully but also boosted Pt activities toward ORR and HER. We found that our Pt catalysts encapsulated in ultrathin 2D carbon layers exhibited an ORR activity of 5.9 and 12 times greater than those of the commercial Pt/C and Pt/RGO without 2D carbon layer protection. Our encapsulated Pt catalysts also show more than nine times higher stability than those of Pt/C catalysts. In addition to ORR, our novel encapsulated Pt catalysts display an extraordinary stability and activity toward HER, with a lower overpotential (14.3 mV in acidic media and 37.2 mV in alkaline media) at a current density of 10 mA cm^-2 than Pt/C catalysts (23.1 mV in acidic media and 92.1 mV in alkaline media). The enhanced electrochemical activities and stability of our encapsulated Pt catalysts are attributed to the synergistic effect of Pt-based NPs and ultrathin 2D carbon layers derived from ZIF-67 with enriched active sites Co-N_x. First-principles simulations reveal that the synergistic catalysis of Pt-based NPs and Co-N_x derived from ZIF-67 improves the activity for ORR and HER.

Structurally ordered PtSn intermetallic nanoparticles supported on ATO for efficient methanol oxidation reaction

The development of cost-effective methanol oxidation reaction (MOR) catalysts with a high activity and stability is highly desirable for direct methanol fuel cells. In this study, the structurally ordered PtSn intermetallic nanoparticles supported on Sb-doped SnO₂ (ATO) have been successfully synthesized in ethylene glycol (EG) solution at 200 °C. Pt NPs were firstly formed on ATO, followed by the transformation from Pt into hexagonal PtSn on the surface of ATO. The obtained structurally ordered PtSn intermetallic NPs supported on ATO demonstrate significantly enhanced MOR activity and durability in comparison with commercial Pt/C. Our PtSn intermetallic NPs supported on ATO show a MOR activity 4.1 times higher than that of commercial Pt/C catalysts. Accelerated durability tests indicate that the commercial Pt/C catalysts lose about 50% of their initial current density after 500 cycles while the Pt/ATO-200-3 h catalyst loses only about 15% of its initial current density. Our PtSn intermetallic NPs supported on ATO are also found to have higher CO tolerance than commercial Pt/C. This work demonstrates an important strategy to rationally design high-performance structurally ordered Pt-based intermetallic NP catalysts for fuel cells and other applications.