Lightweight Hexagonal Boron Nitride Foam for CO2 Absorption
PS Owuor and OK Park and CF Woellner and AS Jalilov and S Susarla and J Joyner and S Ozden and L Duy and RV Salvatierra and R Vajtai and JM Tour and J Lou and DS Galvao and CS Tiwary and PM Ajayan, ACS NANO, 11, 8944-8952 (2017).
DOI: 10.1021/acsnano.7b03291
Weak van der Waals forces between inert hexagonal boron nitride (h-BN) nanosheets make it easy for them to slide over each other, resulting in an unstable structure in macroscopic dimensions. Creating interconnections between these inert nanosheets can remarkably enhance their mechanical properties. However, controlled design of such interconnections remains a fundamental problem for many applications of h-BN foams. In this work, a scalable in situ freeze-drying synthesis of low-density, lightweight 3D macroscopic structures made of h-BN nanosheets chemically connected by poly(vinyl alcohol) (PVA) molecules via chemical cross-link is demonstrated. Unlike pristine h-BN foam which disintegrates upon handling after freeze-drying, h-BN/PVA foams exhibit stable mechanical integrity in addition to high porosity and large surface area. Fully atomistic simulations are used to understand the interactions between h-BN nanosheets and PVA molecules. In addition, the h-BN/PVA foam is investigated as a possible CO, absorption and as laser irradiation protection material.
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