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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., 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 [...]

The making and breaking of atomic bonds are essential processes in chemical reactions. Although the ultrafast dynamics of bond breaking have been studied intensively using time-resolved techniques (1-3), it is very difficult to study the structural dynamics of bond making, mainly because of its bimolecular nature. It is especially difficult to initiate and follow diffusion-limited bond formation in solution with ultrahigh time resolution. Here we use femtosecond time-resolved X-ray solution scattering to visualize the formation of a gold trimer complex, [[Au[(CN).sub.2.sup.-]].sub.3] in real time without the limitation imposed by slow diffusion. This photoexcited gold trimer, which has weakly bound gold atoms in the ground state (4-6), undergoes a sequence of structural changes, and our experiments probe the dynamics of individual reaction steps, including covalent bond formation, the bent-to-linear transition, bond contraction and tetramer formation with a time resolution of ~500 femtoseconds. We also determined the three-dimensional structures of reaction intermediates with sub-angstrom spatial resolution. This work demonstrates that it is possible to track in detail and in real time the structural changes that occur during a chemical reaction in solution using X-ray free-electron lasers (7) and advanced analysis of time-resolved solution scattering data., The functional efficiencies of photoactive molecules are governed by long-lived electronic excited states that are directly involved in functional transitions of the molecules. In fact, early stages of their photoinduced [...]

Transient chemical changes during molecular dissociation could be detected by the use of ultrafast electron diffraction. These chemical and photobiochemical reactions are clocked by an initial femtosecond laser pulse and the second femtosecond pulse probed the dynamics. Photoelectron spectroscopy and mass spectroscopy are detection methods that have been used. The ability to clock changes is important in the study of the molecular structures dynamics.