Structured Pt/NiCo2O4/C/NF Superhydrophobic Catalyst for Water-hydrogen Exchange Reactions

Abstract

Hydrophobic catalysts are essential for water-hydrogen exchange reactions to facilitate the separation of hydrogen isotopes. However, existing hydrophobic catalysts are primarily small-sized pelleted forms, which are not suitable for large-scale systems. In contrast, structured catalysts, which offer a low pressure drop and enhanced mass and heat transfer properties, present promising applications. In this work, cake-like nickel foam (NF) was selected as the structural support. Activated carbon was initially loaded onto the NF using silica sol, followed by hydrothermal deposition of NiCo₂O₄ with a rough morphology, resulting in a carrier with high roughness and a large specific surface area. The carrier attained a superhydrophobic state after modification with heptadecafluorodecyltrimethoxysilane (FD-TMS), achieving a contact angle of 163.8°. The Pt/NiCo₂O₄/C/NF superhydrophobic catalyst was subsequently prepared by loading Pt particles via an impregnation-gas phase reduction method. This method exposes the active metal on the surface, enhancing the Pt utilization rate. Furthermore, the extensive surface area of the carrier provided numerous attachment sites for Pt, leading to smaller particle sizes and greater exposure of Pt precursors for reduction to zero-valent Pt. The results indicated that the Pt particle size in the catalyst was 2.31 nm, with 73% of the Pt in the zero-valent form. In water-hydrogen exchange reactions, the total volume mass transfer coefficient Kya for the Pt/NiCo₂O₄/C/NF superhydrophobic catalyst reached 17.35 × 10^–2 s^–1, indicating strong catalytic performance.