A meso-macroporous borosilicate monolith prepared by a sol–gel method

A meso-macroporous borosilicate monolith was prepared for the first time using a sol–gel method. The proposed material was subsequently characterized by FTIR-ATR and solid-state NMR experiments to investigate the chemical environment of boron in the silica framework. The results showed that boron formed Si–O–B bonds and largely existed as three-coordinated symmetrical structure as well as some tetrahedral structure in the skeleton. According to the ICP-AES experiment, the highest [B]/[Si] molar ratio was 0.15 in the final product. And a bimodal porosity was investigated by SEM, mercury porosimeter and nitrogen adsorption–desorption experiments. This new borosilicate monolithic material could have potential application in both chemical and biological sciences for separation, enrichment or catalysis.

Graphical abstractSEM images (a, b, c) of bimodal porous borosilicate monolith with different batching ratio of TMOS and H3BO3 and one actual example of the proposed monolith (d).Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We report the first preparation of meso-macroporous borosilicate monoliths. ► The boron existed as three-coordinate and tetrahedral structure in the framework. ► The porosity could be adjusted by changing the batching ratio of TMOS and H3BO3.