A method of producing graphene or other two-dimensional material such as graphene including heating the substrate held within a reaction chamber to a temperature that is within a decomposition range of a precursor, and that allows two-dimensional crystalline material formation from a species released from the decomposed precursor; establishing a steep temperature gradient (preferably >1000° C. per meter) that extends away from the substrate surface towards an inlet for the precursor; and introducing precursor through the relatively cool inlet and across the temperature gradient towards the substrate surface. The steep temperature gradient ensures that the precursor remains substantially cool until it is proximate the substrate surface thus minimizing decomposition or other reaction of the precursor before it is proximate the substrate surface. The separation between the precursor inlet and the substrate is less than 100 mm.

A method of producing graphene or other two-dimensional material such as graphene including heating the substrate held within a reaction chamber to a temperature that is within a decomposition range of a precursor, and that allows two-dimensional crystalline material formation from a species released from the decomposed precursor; establishing a steep temperature gradient (preferably >1000° C. per meter) that extends away from the substrate surface towards an inlet for the precursor; and introducing precursor through the relatively cool inlet and across the temperature gradient towards the substrate surface. The steep temperature gradient ensures that the precursor remains substantially cool until it is proximate the substrate surface thus minimizing decomposition or other reaction of the precursor before it is proximate the substrate surface. The separation between the precursor inlet and the substrate is less than 100 mm.

Methods for producing silver nanostructures with improved dimensional control, yield, purity, monodispersed, and scale of synthesis.

Methods for producing silver nanostructures with improved dimensional control, yield, purity, monodispersed, and scale of synthesis.

Core-shell nanostructures with platinum overlayers conformally coating palladium nano-substrate cores and facile solution-based methods for the preparation of such core-shell nanostructures are described herein. The obtained Pd@Pt core-shell nanocatalysts showed enhanced specific and mass activities towards oxygen reduction, compared to a commercial Pt/C catalyst.

Core-shell nanostructures with platinum overlayers conformally coating palladium nano-substrate cores and facile solution-based methods for the preparation of such core-shell nanostructures are described herein. The obtained Pd@Pt core-shell nanocatalysts showed enhanced specific and mass activities towards oxygen reduction, compared to a commercial Pt/C catalyst.

A post-synthetic method for stabilizing colloidal crystals programmed from nucleic acid is disclosed herein. In some embodiments, the method relies on Ag.sup.+ ions to stabilize the particle-connecting nucleic acid duplexes within the crystal lattice, essentially transforming them from loosely bound structures to ones with very strong interparticle links. In some embodiments, the nucleic acid is DNA. Such crystals do not dissociate as a function of temperature like normal DNA or DNA-interconnected colloidal crystals, and they can be moved from water to organic media or the solid state, and stay intact. The Ag.sup.+-stabilization of the nucleic acid (e.g., DNA) bonds is accompanied by a nondestructive contraction of the lattice, and both the stabilization and contraction are reversible with the chemical extraction of the Ag.sup.+ ions, e.g., by AgCl precipitation with NaCl.

A post-synthetic method for stabilizing colloidal crystals programmed from nucleic acid is disclosed herein. In some embodiments, the method relies on Ag.sup.+ ions to stabilize the particle-connecting nucleic acid duplexes within the crystal lattice, essentially transforming them from loosely bound structures to ones with very strong interparticle links. In some embodiments, the nucleic acid is DNA. Such crystals do not dissociate as a function of temperature like normal DNA or DNA-interconnected colloidal crystals, and they can be moved from water to organic media or the solid state, and stay intact. The Ag.sup.+-stabilization of the nucleic acid (e.g., DNA) bonds is accompanied by a nondestructive contraction of the lattice, and both the stabilization and contraction are reversible with the chemical extraction of the Ag.sup.+ ions, e.g., by AgCl precipitation with NaCl.

A method for preparing an electrolytic copper foil includes placing an anode and a cathode to be plated in a twin crystal growth agent containing electroplating solution in an electroplating tank, and, under conditions that the electroplating solution is provided with randomly alternating transitions of one or two of an ultrasonic wave at a frequency f11 and an ultrasonic wave at a frequency f12 and one or two of an ultrasonic wave at a frequency f21 and an ultrasonic wave at a frequency f22, performing direct current electroplating to obtain the electrolytic copper foil, wherein f11>40 kHz, 15 kHz<f12≤40 kHz, 0 kHz<f21≤15 kHz, and f22=0 kHz.

A method for preparing an electrolytic copper foil includes placing an anode and a cathode to be plated in a twin crystal growth agent containing electroplating solution in an electroplating tank, and, under conditions that the electroplating solution is provided with randomly alternating transitions of one or two of an ultrasonic wave at a frequency f11 and an ultrasonic wave at a frequency f12 and one or two of an ultrasonic wave at a frequency f21 and an ultrasonic wave at a frequency f22, performing direct current electroplating to obtain the electrolytic copper foil, wherein f11>40 kHz, 15 kHz<f12≤40 kHz, 0 kHz<f21≤15 kHz, and f22=0 kHz.