Xili Tong

Cuprous oxide nanoparticles dispersed on reduced graphene oxide as an efficient electrocatalyst for oxygen reduction reaction

Cuprous oxide (Cu(2)O) nanoparticles dispersed on reduced graphene oxide (RGO) were prepared by reducing copper acetate supported on graphite oxide using diethylene glycol as both solvent and reducing agent. The Cu(2)O/RGO composite exhibits excellent catalytic activity and remarkable tolerance to methanol and CO in the oxygen reduction reaction.

Tubular TiC fibre nanostructures as supercapacitor electrode materials with stable cycling life and wide-temperature performance

Highly active electrode materials with judicious design of nanostructure are important for the construction of high-performance electrochemical energy storage devices. In this work, we have fabricated a tubular TiC fibre cloth as an interesting type of stable supercapacitive material. Hollow microfibres of TiC are synthesized by carbothermal treatment of commercial T-shirt cotton fibres. To demonstrate the rationale of nanostructuring in energy storage, the hollow fibres are further covered by interwoven TiC nanotube branches, forming 3D tubular all-TiC hierarchical fibres with high electrical conductivity, high surface area, and high porosity. For energy storage functions, organic symmetric supercapacitors based on the hollow fibre–nanotube (HFNT) TiC cloth electrodes are assembled and thoroughly characterized. The TiC-based electrodes show very stable capacitance in long charge–discharge cycles and at different temperatures. In particular, the integrated TiC HFNT cloth electrodes show a reasonably high capacitance (185 F g−1 at 2 A g−1), better cycling stability at high-rates (e.g., 97% retention at room temperature after 150 000 cycles, and 67% at −15 °C after 50 000 cycles) than other control electrodes (e.g., pure carbon fibre cloths). It is envisaged that this 3D tubular TiC fibre cloth is also useful for solar cells and electrocatalysis.

Enhanced Catalytic Activity for Methanol Electro‐oxidation of Uniformly Dispersed Nickel Oxide Nanoparticles—Carbon Nanotube Hybrid Materials

Highy crystalline NiO nanoparticles are uniformly grown on the walls of carbon nanotubes (CNTs) by atomic layer deposition (ALD) at moderate temperature.Their size and stoichiometry are controlled by the ALD process parameters. The obtained NiO/CNT hybrids exhibit excellent performance in the electro-oxidation of methanol.

Porous TiO2 Nanotubes with Spatially Separated Platinum and CoOx Cocatalysts Produced by Atomic Layer Deposition for Photocatalytic Hydrogen Production

Efficient separation of photogenerated electrons and holes, and associated surface reactions, is a crucial aspect of efficient semiconductor photocatalytic systems employed for photocatalytic hydrogen production. A new CoOx /TiO2 /Pt photocatalyst produced by template-assisted atomic layer deposition is reported for photocatalytic hydrogen production on Pt and CoOx dual cocatalysts. Pt nanoclusters acting as electron collectors and active sites for the reduction reaction are deposited on the inner surface of porous TiO2 nanotubes, while CoOx nanoclusters acting as hole collectors and active sites for oxidation reaction are deposited on the outer surface of porous TiO2 nanotubes. A CoOx /TiO2 /Pt photocatalyst, comprising ultra-low concentrations of noble Pt (0.046 wt %) and CoOx (0.019 wt %) deposited simultaneously with one atomic layer deposition cycle, achieves remarkably high photocatalytic efficiency (275.9 μmol h-1 ), which is nearly five times as high as that of pristine TiO2 nanotubes (56.5 μmol h-1 ). The highly dispersed Pt and CoOx nanoclusters, porous structure of TiO2 nanotubes with large specific surface area, and the synergetic effect of the spatially separated Pt and CoOx dual cocatalysts contribute to the excellent photocatalytic activity.

NiO/SiC Nanocomposite Prepared by Atomic Layer Deposition Used as a Novel Electrocatalyst for Nonenzymatic Glucose Sensing

NiO nanoparticles are deposited onto SiC particles by atomic layer deposition (ALD). The structure of the NiO/SiC hybrid material is investigated by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The size of the NiO nanoparticles is flexible and can be adjusted by altering the cycle number of the NiO ALD. Electrochemical measurements illustrate that NiO/SiC prepared with 600 cycles for NiO ALD exhibits the highest glucose sensing ability in alkaline electrolytes with a low detection limit of 0.32 μM (S/N = 3), high sensitivity of 2.037 mA mM(-1) cm(-2), a linear detection range from approximately 4 μM to 7.5 mM, and good stability. Its sensitivity is about 6 times of that for commercial NiO nanoparticles and NiO/SiC nanocomposites prepared by a traditional incipient wetness impregnation method. It is revealed that the superior electrochemical ability of ALD NiO/SiC is ascribed to the strong interaction between NiO and the SiC substrate and the high dispersity of NiO nanoparticles on the SiC surface. These results suggest that ALD is an effective way to deposit NiO on SiC for nonenzymatic glucose sensing.

Mesoporous NiCo2O4 Nanoplates on Three-Dimensional Graphene Foam as an Efficient Electrocatalyst for the Oxygen Reduction Reaction

Catalysts for the oxygen reduction reaction (ORR) are highly important in fuel cells and metal-air batteries. Cheap ORR catalysts with ultrahigh electrochemical activity, selectivity, and stability are extremely desirable but still remain challenging. Herein, mesoporous NiCo2O4 nanoplate (NP) arrays on three-dimensional (3D) graphene foam are shown to be a highly economical ORR catalyst. This mesoporous mixed-valence oxide can provide more electrocatalytic active sites with increased accessible surface area. In addition, graphene-foam-supported NiCo2O4 NP arrays have a 3D hierarchical porous structure, which is of great benefit to ion diffusion and electron transfer. As a result, the mesoporous NiCo2O4 NP arrays/graphene foam catalyst exhibits outstanding ORR performance with the four-electron reduction of O2 to H2O in alkaline media. Furthermore, the mesoporous catalyst shows enhanced electrocatalytic activity with a half-wave potential of 0.86 V vs RHE and better stability compared with a commercial Pt/C catalyst.

High photoelectrocatalytic performance of a MoS2–SiC hybrid structure for hydrogen evolution reaction

A flower-like MoS2–SiC hybrid structure assembled from folded MoS2–SiC nanosheets can activate hydrogen evolution at a very low overpotential (0.04 V) and produce a large cathodic current, which compares favorably with that produced by a commercial 20 wt% Pt/C catalyst.

Black silicon with controllable macropore array for enhanced photoelectrochemical performance

Macroporous silicon with multiscale texture for reflection suppression and light trapping was achieved through a controllable electrochemical etching process. It was coated with TiO2 by atomic laye ...

Efficient oxygen reduction reaction using mesoporous Ni-doped Co3O4 nanowire array electrocatalysts

Herein, mesoporous Ni-doped Co3O4 nanowire (NW) arrays are reported as a highly efficient and low-cost catalyst for oxygen reduction reaction (ORR) in alkaline electrolyte. The Ni doping affords more electroactive sites and enhanced conductivity, and the mesoporous structure provides increased surface exposure, which may improve ion/electron transport and reduce charge transfer resistance. The NW arrays exhibit a high ORR activity with a four-electron transfer reaction in alkaline media, a half-wave potential of 0.86 V vs. RHE and a superior stability when compared to the commercial Pt (20 wt%)/C catalyst. Our results suggest that the mesoporous Ni-doped Co3O4 NW arrays could be a promising ORR catalyst for fuel cells and metal–air batteries.

CNT–Ni/SiC hierarchical nanostructures: preparation and their application in electrocatalytic oxidation of methanol

CNT–Ni/SiC composites with three-dimensional hierarchical nanostructures were fabricated via in situ pyrolysis of methane to grow CNTs on a novel flake-like NiO/SiC material. The NiO/SiC was prepared by hydrothermally growing Ni(OH)2 on SiC. After calcination, Ni(OH)2 was converted to porous NiO flakes. During the methane pyrolysis, NiO was in situ converted to Ni nanoparticles, which acted as the catalyst for growing CNTs. Due to the combination of Ni nanoparticles, in situ grown CNTs and the SiC support, the CNT–Ni/SiC composites exhibit excellent catalytic activity and stability in electro-oxidation of methanol. The catalytic activity shows a dependence on the pyrolysis temperature of methane, and a pyrolysis temperature of 700 °C can lead to a mass activity of 10 A mg−1 Ni, which is about 15 times higher than that of the catalyst obtained from methane pyrolysis at 500 °C and about 4000 times higher than that of the original NiO/SiC catalyst.