Highly efficient hydrogen storage with PdAg nanotubes
ABSTRACT Hydrogen storage is one of the vital and challenging issues for the commercialization of hydrogen-powered fuel cells. In this report, the synthesized PdAg nanotubes exhibit enhanced hydrogen-storage ability. The highest capacity for hydrogen absorption obtained on the PdAg nanotubes with 15% of Pd was over 200 times greater than the pure Pd nanoparticles.
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ABSTRACT: Through first-principles calculations, we found doping carbon atoms onto BN monolayers (BNC) could significantly strengthen the Li bond on this material. Unlike the weak bond strength between Li atoms and the pristine BN layer, it is observed that Li atoms are strongly hybridized and donate their electrons to the doped substrate, which is responsible for the enhanced binding energy. Li adsorbed on the BNC layer can serve as a high-capacity hydrogen storage medium, without forming clusters, which can be recycled at room temperature. Eight polarized H(2) molecules are attached to two Li atoms with an optimal binding energy of 0.16-0.28 eV/H(2), which results from the electrostatic interaction of the polarized charge of hydrogen molecules with the electric field induced by positive Li atoms. This practical carbon-tuned BN-Li complex can work as a very high-capacity hydrogen storage medium with a gravimetric density of hydrogen of 12.2 wt%, which is much higher than the gravimetric goal of 5.5 wt % hydrogen set by the U.S. Department of Energy for 2015.Nanoscale 11/2011; 3(11):4824-9. DOI:10.1039/c1nr10741k · 7.39 Impact Factor
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ABSTRACT: Bimetallic alloy PdAg nanowires were synthesized by a facile one-step wet chemical strategy. The unique nanostructure with large surface area and active surface (111) planes make them promising electrocatalysts for direct-liquid fuel cells. The electrochemical studies indicated that the PdAg alloy nanowires exhibit enhanced electrocatalytic activity toward formic acid oxidation with larger oxidation current density, higher tolerance to CO poisoning, and more negative onset potential in comparison with the commercial Pd/C catalysts. At the same potentials, the as-synthesized PdAg nanowires show higher long-term stability than Pd/C catalysts in the chronoamperometric analyses. The electron transfer kinetics of HCOOH oxidation on the PdAg nanowires was studied with electrochemical impedance spectroscopy (EIS). It was found that the charge transfer resistance (RCT) of formic acid oxidation on PdAg nanowires is much smaller than that obtained from a Pd/C catalyst, which suggests that the electron-transfer kinetics for formic acid oxidation at the synthesized PdAg nanowires is highly facilitated. The present work highlights the facile synthesis of the homogeneous PdAg alloy nanowires and their potential application as anode electrocatalyst of fuel cells.ACS Catalysis 12/2011; 2(1):84–90. DOI:10.1021/cs200538g · 9.31 Impact Factor
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ABSTRACT: Urea has been considered as a potential hydrogen source, while the conventional methods to extract hydrogen from urea are typically energy intensive processes. Here we report the first demonstration of solar driven hydrogen releasing from urea and human urine in a photoelectrochemical cell, with the assistance of Ni(OH)2 modified metal oxide photoelectrodes (e.g., TiO2 and α-Fe2O3). Ni(OH)2 serves as a urea oxidation catalyst. Under light illumination, photoexcited holes generated at the metal oxide electrode oxidize urea, while photoexcited electrons reduce water to produce hydrogen gas at the Pt counter electrode. Urea oxidation was achieved under a small external bias or even at zero bias. Significantly, we observed continuous and stable hydrogen evolution at the Pt electrode in both urea and human urine electrolyte solutions under AM 1.5G (100 mW cm−2) light illumination. This work presents a safe, low energy cost, environmentally friendly and sustainable method to produce hydrogen, and simultaneously treat urine.Energy & Environmental Science 07/2012; 5(8):8215-8219. DOI:10.1039/C2EE22087C · 20.52 Impact Factor