Template-Free Synthesis of Highly Porous Boron Nitride: Insights into Pore Network Design and Impact on Gas Sorption

Abstract

Production of biocompatible and stable porous materials, e.g., boron nitride, exhibiting tunable and enhanced porosity is a prerequisite if they are to be employed to address challenges such as drug delivery, molecular separations, or catalysis. However, there is currently very limited understanding of the formation mechanisms of porous boron nitride and the parameters controlling its porosity, which ultimately prevents exploiting the material's full potential. Herein, we produce boron nitride with high and tunable surface area and micro/mesoporosity via a facile template-free method using multiple readily available N-containing precursors with different thermal decomposition patterns. The gases are gradually released, creating hierarchical pores, high surface areas (>1900 m/g), and micropore volumes. We use 3D tomography techniques to reconstruct the pore structure, allowing direct visualization of the mesopore network. Additional imaging and analytical tools are employed to characterize the materials from the micro- down to the nanoscale. The CO uptake of the materials rivals or surpasses those of commercial benchmarks or other boron nitride materials reported to date (up to 4 times higher), even after pelletizing. Overall, the approach provides a scalable route to porous boron nitride production as well as fundamental insights into the material's formation, which can be used to design a variety of boron nitride structures.

A Review on the Synergistic Features of Hexagonal Boron Nitride (White Graphene) as Adsorbent‐Photo Active Nanomaterial

“…In addition, the microporosity of the as‐synthesized samples gets enhanced with an increase in the amount of N precursors due to the generation of the additional porogens in the form of NH 3 , H 2 O, CO, N 2 , etc. The formation of porous BN structure as an outcome of the release of these porogens during the decomposition of the B and N based precursors was revealed ,. It was observed that porosity is a function of thermal decomposition characteristics of the N based precursors .…”

“…The formation of porous BN structure as an outcome of the release of these porogens during the decomposition of the B and N based precursors was revealed ,. It was observed that porosity is a function of thermal decomposition characteristics of the N based precursors . For instance, urea, biuret and melamine decompose at 150°C, 190°C, and 260°C respectively thereby providing a wide range of decomposition temperature for the formation of BN.…”

“…Moreover, some enhanced surface characteristic reflecting surface area, micropore and total pore volume were reported for melamine‐based BN samples, while biuret‐based samples showed contradictory. This inference clearly validates the role of porogens over an extended temperature profile where the porosity of the BN materials is enhanced by incorporating multiple precursors with varying thermal decay profiles . Other than that, the reaction temperature also plays a crucial role in determining the porosity and nature of h‐BN.…”

“…The formation of porous BN structure as an outcome of the release of these porogens during the decomposition of the B and N based precursors was revealed. [47,53] It was observed that porosity is a function of thermal decomposition characteristics of the N based precursors. [53] For instance, urea, biuret and melamine decompose at 1508C, 1908C, and 2608C respectively thereby providing a wide 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 [41] Ni foil.…”

“…This inference clearly validates the role of porogens over an extended temperature profile where the porosity of the BN materials is enhanced by incorporating multiple precursors with varying thermal decay profiles. [53] Other than that, the reaction temperature also plays a crucial role in determining the porosity and nature of h-BN. In case of high-temperature, h-BN with complete crystalline nature and greater porosity is achieved and this is not so with low.…”