无模板插层-剥离勃姆石合成具有优异稳定性的多孔硅掺杂氧化铝二维纳米片

Template-free synthesis of highly porous silica-doped alumina with exceptional stability via intercalation-exfoliation of boehmite into two-dimensional nanosheets

高比表面积和大孔容的多孔氧化铝已被广泛应用在各种领域,但不使用有机模板合成多孔氧化铝仍面临巨大挑战.在此,我们报道了基于插层-剥离策略的多孔氧化铝合成方法,利用硅物种削弱勃姆石(氧化铝前体)的层间作用力,从而在不使用有机模板的情况下将勃姆石剥离成二维纳米片.该合成过程可放大到3 L,并获得厚度为2 nm的二维纳米片.此外,这些二维纳米片可组装成比表面为542 m^(2)g^(-1)和孔容为2.43 cm^(3)g^(-1)的勃姆石.在不同温度下对二维纳米片进行热/水热处理得到的多孔氧化铝其孔结构优于多数有机模板法合成的氧化铝,并表现出优异的吸附性能.本研究为合成二维勃姆石纳米片和多孔氧化铝材料提供了一种新策略.

Porous alumina with high specific surface area(SSA)and large pore volume(PV)is highly desired in various applications;however,its synthesis without an organic tem-plate faces a great challenge.Herein,we propose a novel template-free strategy based on intercalation-exfoliation with silica to weaken boehmite(alumina precursor)interlayer forces and achieve the exfoliation of boehmite into two-dimensional(2D)nanosheets,which can easily be scaled up.The as-prepared 2D nanosheets with 2-nm thickness could be assembled to form boehmite with 542 m^(2)g^(-1) SSA and 2.43 cm^(3)g^(-1) PV.The porous alumina obtained from the thermal/hydrothermal treatment of the 2D nanosheets at different temperatures possesses a hierarchical porous struc-ture superior to most of the reported alumina synthesized with organic templates,exhibiting excellent performance in the adsorption of large organic molecules.This research provides a new strategy for synthesizing 2D boehmite nanosheets and porous alumina materials,demonstrating great potential in catalysis and adsorption.