Mesoporous silica nanoparticles (MSNs) with controlled size, morphology, and tunable porosity have been receiving much attention due to their applications in the fields of drug delivery, catalysis, adsorption, separation, and fuel cells. [1][2][3] Various MSNs with different functional groups and structures have been prepared and utilized for drug and gene delivery, [4,5] while mesoporous nanoparticles composed of carbon and nitrogen are of particular interest for basic catalysis and the capture of carbon dioxide. Carbon nitride (CN) is a well known and fascinating material that has attracted worldwide attention because the incorporation of nitrogen atoms in the carbon nanostructure can enhance the mechanical, conducting, field-emission, and energy-storage properties. [6][7][8][9][10][11][12][13][14] Mesoporous CN (MCN) materials with large surface areas, small particle sizes, and tunable pore diameters promise access to an even wider range of applications due to their interesting electrical and conducting properties. Recently, Vinu et al. reported the preparation of mesoporous carbon nitride with tunable pore size using mesoporous silica SBA-15 as template. [15][16][17] Unfortunately, the materials had a low nitrogen content due to their low thermal stability and exhibited a large particle size.Ultrafine mesoporous nanoparticles are expected to provide excellent textural parameters and high chemical, thermal, and mechanical stability, which may help to achieve high nitrogen content in the walls of the CN framework. Controlling the nitrogen content in the mesoporous carbon matrix is extremely important, as the nitrogen atoms in the wall structure of MCN can offer basic sites in the form of amine or imine groups which dictate the basic character and basic catalytic performance of the materials. However, to the best of our knowledge, there has been no report on the preparation of MCNs with high nitrogen content and their application in base-catalyzed reactions. Herein we report for the first time on the preparation of well-ordered mesoporous CN nanoparticles with a size smaller than 150 nm (MCN-3) and a high nitrogen content (C 4 N 2 ) by using mesoporous ultrasmall silica nanoparticles as template. The nitrogen content of MCN-3 is twice that of MCN-1 and MCN-2, which were prepared from SBA-15 and SBA-16, respectively. [15][16][17] We also demonstrate for the first time the basic catalytic properties of MCN-3, which is the first highly ordered, mesoporous, metal-free basic catalyst, in the transesterification of b-keto esters; MCN-3 shows superior performance in the transesterification of b-keto esters with excellent conversion and 100 % product selectivity.The templates for the fabrication of MCN-3 are ultrasmall mesoporous silica nanoparticles, which were prepared by a process mediated by fluorocarbon polymer and Pluronic P123 surfactant, reported by Ying et al., and denoted IBN-4. [18] IBN-4 has two-dimensional hexagonally ordered mesoporous structure with a channel-type pore system and rod-shaped morphology. Th...

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A novel highly ordered three-dimensional mesoporous carbon-nitride-based hybrid material (MCN-2) with very high surface area, pore volume, and a possible cage type porous structure has been prepared using three-dimensional cage type mesoporous silica, SBA-16, as a template through a simple polymerization reaction between ethylenediamine and carbon tetrachloride. The material has been unambiguously characterized by various sophisticated techniques such as XRD, nitrogen adsorption, HRTEM, EELS, XPS, 13C DD-MAS, and FT-IR spectroscopy. The XD result reveals that MCN-2 possesses three-dimensional structure with a possible Im3m space group. The specific surface area and pore volume of MCN-2 are significantly higher as compared to those of the template and MCN-1. Because of the excellent textural characteristic and three-dimensional porous structure, we believe that the MCN-2 could offer great potential for the applications such as catalysis and adsorption.