De Novo Design of a Pt Nanocatalyst on a Conjugated Microporous Polymer-Coated Honeycomb Carrier for Oxidation of Hydrogen Isotopes

Abstract

A booming demand for energy highlights the importance of an emergency cleanup system in the nuclear industry or hydrogen-energy sector to reduce the risk of hydrogen explosion and decrease tritium emission. The properties of the catalyst determine the efficiency of hydrogen isotope enrichment and removal in the emergency cleanup system. However, the aggregation behavior of Pt, deactivation effect of water vapor, and isotope effect induce a continuous decrease in the catalytic activity of the Pt catalyst. Herein, a de novo design of a Pt nanocatalyst is proposed for catalytic oxidation of the hydrogen isotope via modification of a conjugated microporous polymer onto honeycomb cordierite as a Pt support. The conjugated microporous polymer creates a microporous and hydrophobic environment to attenuate the deactivation effect of water vapor and shape Pt nanoparticles with a diameter of around 2.4 nm. Thus, the as-prepared catalysts exhibit excellent catalytic performance in the range of 25−65 °C and high space velocity (≤30 000 h −1 ) and a stable and high catalytic activity during 487 h of continuous and intermittent operation. Importantly, the charge of the Pt nanoparticles is redistributed by the conjugated skeletons, leading to a decreased energy barrier in the rate-limiting step of hydrogen isotope oxidation and a reduced isotope effect.

Surface Microstructure Modulation Strategy to Design an Amphiphobic Platinum Nanocatalyst for Efficient Catalytic Oxidation of Hydrogen Isotopes

“…The conversion of Pt@CDM-3 reached a plateau and remained at 95.4% after nine cycles of the start–pause operation. The service life of commercial Pt/Al 2 O 3 has been estimated under the same condition in our previous work . Pt/Al 2 O 3 showed a decline in H 2 conversion from 99.4 to 72.2% in the 24 h continuous working, and only 73.6% of H 2 conversion remained after the start–pause operation.…”

“…The service life of commercial Pt/Al 2 O 3 has been estimated under the same condition in our previous work. 39 Pt/Al 2 O 3 showed a decline in H 2 conversion from 99.4 to 72.2% in the 24 h continuous working, and only 73.6% of H 2 conversion remained after the start−pause operation. The higher catalytic performance of Pt@CDM-3 than that of commercial Pt/Al 2 O 3 revealed that the hydrophobic surface created by the surface microstructure modulation of the substrate can effectively reduce poisoning of water and enhance the restarting performance and service life of the catalyst.…”

Platinum Nanoparticles Anchored on Covalent Triazine Frameworks Modified Cordierite for Efficient Oxidation of Hydrogen Isotopes

“…In our previous works, a porous and hydrophobic Pt catalyst based on conjugated microporous polymers (HisoCat) was constructed. 26 Due to the microporous structure and good hydrophobicity of conjugated microporous polymers (CMPs), the catalyst had a decreasing platinum distribution and a reducing water deactivation, thus enhancing the catalytic activity. Nevertheless, the catalytic activity at high airspeeds and low temperatures as well as the isotope effect need to be further improved to realize high-efficiency oxidation of tritium with the lowest activity among hydrogen isotopes.…”

“…The successful grafting of organic frameworks on cordierite has been reported in our previous work. 26 Thus, it is expected that CTFs can be grafted onto cordierite and act as a desired support for Pt loading to produce a nano-dispersion of Pt, 27,28 along with providing a hydrophobic environment to reduce the deactivation from water vapor.…”

Ultrastable Porous Organic Polymers Containing Thianthrene and Pyrene Units as Organic Electrode Materials for Supercapacitors

“…When contrasted to metal–organic frameworks, they have several notable properties, such as large temperature durability, high Brunauer–Emmett–Teller (BET) surface areas, approachable permeability, large pore diameters, chemical inertness, nontoxicity, and improved electrical conductivity. − Covalent organic frameworks, , porous imine-linked networks, benzimidazole-linked polymers, covalent triazine frameworks, porous aromatic frameworks, carbazole-based microporous polymers, and hyper-cross-linked porous polymers, , conjugated microporous polymers (CMPs), − metal–organic frameworks, ,, and ferrocene-based CMPs are examples of COP materials . CMPs are a form of porous organic polymers (POPs) with a microporous structure that includes π-conjugation. − Because of the broad spectrum of essential components and reactions available, CMP materials could have a variety of structures and properties. CMPs, for example, have been produced utilizing both conventional coupling processes (such as Sonogashira–Hagihara, Suzuki–Miyaura, and Yamamoto coupling) and oxidative polymerization. − …”