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Zeolites are a family of microporous crystalline aluminosilicate materials, which fall into more than 200 structural types (16). Each structural type is distinguished by its unique pore structure--for example, in [...], Three-dimensional graphene architectures with periodic nanopores--reminiscent of zeolite frameworks--are of topical interest because of the possibility of combining the characteristics of graphene with a three-dimensional porous structure (1-6). Lately, the synthesis of such carbons has been approached by using zeolites as templates and small hydrocarbon molecules that can enter the narrow pore apertures (7-15). However, pyrolytic carbonization of the hydrocarbons (a necessary step in generating pure carbon) requires high temperatures and results in non-selective carbon deposition outside the pores. Here, we demonstrate that lanthanum ions embedded in zeolite pores can lower the temperature required for the carbonization of ethylene or acetylene. In this way, a graphene-like carbon structure can be selectively formed inside the zeolite template, without carbon being deposited at the external surfaces. X-ray diffraction data from zeolite single crystals after carbonization indicate that electron densities corresponding to carbon atoms are generated along the walls of the zeolite pores. After the zeolite template is removed, the carbon framework exhibits an electrical conductivity that is two orders of magnitude higher than that of amorphous mesoporous carbon. Lanthanum catalysis allows a carbon framework to form in zeolite pores with diameters of less than 1 nanometre; as such, microporous carbon nanostructures can be reproduced with various topologies corresponding to different zeolite pore sizes and shapes. We demonstrate carbon synthesis for large-pore zeolites (FAU, EMT and beta), a one-dimensional medium-pore zeolite (LTL), and even small-pore zeolites (MFI and LTA). The catalytic effect is a common feature of lanthanum, yttrium and calcium, which are all carbide-forming metal elements. We also show that the synthesis can be readily scaled up, which will be important for practical applications such as the production of lithium-ion batteries and zeolite-like catalyst supports.

Nanoscale CH3NH3PbI3 perovskite sensitizers are grown by delivering each precursor successively onto the surface of mesoporous (meso) TiO2 electrodes. Using Pb(NO3)2 ions as a lead(II) source and CH3NH3I (MAI) for methylammonium and iodide sources, repetitive cycles of the two dipping steps are successful in growing few nanometer‐sized MAPbI3 gradually on the TiO2 surface inside the meso‐TiO2 film. However, some aggregates are observed on the top surface of the meso‐TiO2 film due to slight dissolution of PbI2 and its accumulation/reaction with MAI at the top surface of the meso‐TiO2 film. To solve this inhomogeneity of the deposition, a nondestructive multiple deposition route for nanoscale MAPbI3 is suggested as a successive precursor layer adsorption and reaction (SPLAR) process where, from the second cycle of deposition, PbI2 is delivered with the help of an ionic liquid compound dissolved in dichloromethane. With this new Pb precursor in less‐polar solvents, nanoscale MAPbI3 sensitizers are grown without dissolution of preformed perovskites or formation of some aggregates at the top surface. After the third cycle of SPLAR deposition, about 7.0 nm–sized MAPbI3 sensitizers are prepared and display enhanced photovoltaic performance (7.18 ± 0.31%) compared with devices obtained from only one cycle (5.74 ± 0.30%). [ABSTRACT FROM AUTHOR]