Few-Layered Graphene-like Boron Nitride: A Highly Efficient Adsorbent for Indoor Formaldehyde Removal

Abstract

Highly porous boron nitride (BN) composed of a flexible network of hexagonal BN nanosheets was synthesized via thermal treatment of a boric acid/urea mixture. The as-prepared sponge-like BN displayed fast adsorption rates and ultrahigh adsorption capacities for gaseous formaldehyde (HCHO), e.g., 19 mg/g in equilibrium with approximately 20 ppm of HCHO in air, which is an order of magnitude higher than those of other tested materials, including commercial hexagonal BN and various metal oxides. The superb HCHO adsorption performance of the porous BN is mainly due to its large specific surface area (627 m 2 /g), as well as the abundant surface hydroxyl and amine groups. Moreover, chemisorption can occur on the BN layers and contribute to the high HCHO uptake capacity via Cannizzaro-type disproportionation reactions, during which HCHO is transformed into less toxic formic acid and methanol. This porous BN is a promising adsorbent for indoor HCHO removal and may serve as the support for highly efficient HCHO decomposition catalysts.

Structural evaluation and mechanical property of boron nitride fibers during melt‐drawn fabrication process

“…For the 450°C samples, the diffuse (002) and (100) diffraction bread peaks were observed, which reveal the amorphous BN material were obtained in this condition. However, when the heat‐treated temperature increased to 1750°C, the XRD pattern exhibits 2 broadened peaks corresponding to the (002) and (100) planes of hexagonal BN, which is characteristic of partially disordered BN phases with low crystallinity . The gradual changes of XRD patterns of the products indicate that the structural parameters of BN materials are varied with the heat‐treated temperature.…”

“…When the heat‐treated temperature was between 450 and 850°C, both the XRD curves and the crystalline structure of BN materials show no obvious change. The position of the peaks was different from those in h ‐BN crystal material, and the diffraction peaks remain diffuse and broad . Even though it is hard to calculate the grain size of the BN fiber material treated below 850°C because of the diffuse peaks, the apparent average grain size remains unchanged.…”

“…However, when the heat-treated temperature increased to 1750°C, the XRD pattern exhibits 2 broadened peaks corresponding to the (002) and (100) planes of hexagonal BN, which is characteristic of partially disordered BN phases with low crystallinity. 28 The gradual changes of XRD patterns of the products indicate that the structural parameters of BN materials are varied with the heat-treated temperature. The interlayer spacing (d 002 ) and the average stacking thickness of the microcrystalline layer along the c axis (L c(002) ) changing with the heat-treated temperature are shown in Table 1.…”

“…The position of the peaks was different from those in h-BN crystal material, and the diffraction peaks remain diffuse and broad. 28 Even though it is hard to calculate the grain size of the BN fiber material treated below 850°C because of the diffuse peaks, the apparent average grain size remains unchanged. In addition, the interlayer d-spacing values with minor changes show large amount of disordered structure of BN materials treated below 850°C.…”

Progress of Catalytic Oxidation of Formaldehyde over Manganese Oxides

“…Various approaches were used to remove HCHO, such as adsorption, plasma technique, photocatalysis and thermal catalytic oxidation . The adsorption method is limited by the maximum adsorption capacity; plasma technique has problems of secondary pollution, high energy consumption, and high cost; photocatalysis is limited by the excitation light source .…”