Facile Synthesis of Graphene-Like Copper Oxide Nanofilms with Enhanced Electrochemical and Photocatalytic Properties in Energy and Environmental Applications

Abstract

Novel graphene-like CuO nanofilms are grown on a copper foam substrate by in situ anodization for multifunctional applications as supercapacitor electrodes and photocatalysts for the degradation of dye pollutants. The as-prepared CuO consists of interconnected, highly crystalline, conductive CuO nanosheets with hierarchical open mesopores and a large surface area. The CuO nanofilms supported on a copper foam are employed as freestanding, binder-free electrodes for supercapacitors, which exhibit wonderful electrochemical performance with a large specific capacitance (919 F g(-1) at 1 A g(-1)), an excellent cycling stability (7% capacitance loss after 5000 cycles), and a good rate capability (748 F g(-1) at 30 A g(-1)). The porous CuO nanofilms also demonstrate excellent photocatalytic activities for degradation of methylene blue, with a degradation rate 99% much higher than 54% of the commercial CuO powders after 60 min. This excellent energy storage and photocatalytic performance of the graphene-like CuO nanofilms can open a new avenue for large-scale applications in energy and environmental fields.

Safe-by-Design CuO NanoparticlesviaFe-Doping, Cu–O Bond Length Variation, and Biological Assessment in Cells and Zebrafish Embryos

“…Although Fe doping was considered to be a key strategy to reduce ZnO toxicity in the environment, 46, 87 there are major differences in the toxicity reduction mechanism between Fe doped CuO and/or ZnO. In the case of Fe doped CuO NPs, the Fe incorporation has two effects: (1) stabilizes the CuO crystal lattice through distortion (4.1% when 10% Fe is doped in CuO) Considering d 9 configuration for CuO, Cu 2+ finds itself in the center of the six octahedral oxygen ligands (2 in the apical positon and 4 in the planar position) [see Figure 3(A)]. When Fe is doped in CuO, one of the d sub-orbitals of Cu is vacant making the electronic states of e g orbital degenerate, resulting in a Jahn-Teller distortion.…”

Sodium‐Salt‐Promoted Growth of Self‐Supported Copper Oxides with Comparative Supercapacitive Properties

“…Copper oxides have been extensively studied in energy storage devices including supercapacitors and lithium‐ion batteries, because of their ease of preparation, low environmental impact and high electrochemical activity . In order to improve the electrode's performance, self‐supported materials have been created by directly growing the active material on the surface of the current collector ,.…”

“…This creates both a larger reactive surface area and a continuous electron transfer pathway, from the electrolyte to the active film and then to the conductive current collector, thus offering highly efficient electron transport kinetics ,,. Inspired by this idea, self‐supported copper oxides with different morphologies including 1D nanotubes/nanorods,,,, 2D nanosheets,, and nanofilms,, have been fabricated using various synthesis systems. Despite the versatility demonstrated by the reported preparation methods, most of these systems required the input of a certain copper salt precursor, such as copper nitrate,,, copper acetate .…”

Hierarchical nanoparticle-induced superhydrophilic and under-water superoleophobic Cu foam with ultrahigh water permeability for effective oil/water separation

“…For instances, Dong et al 19 reported a three-dimensional Cu foam coated by Cu 2 O nanothorn arrays for efficient nonenzymatic detection of glucose in 2015; Li and his coworkers 20 had a similar research, in which the Cu foam was decorated by CuO nanowires and exhibited high sensitivity for glucose mainly due to its high electrical conductivity and specific surface area. Owing to the porosity and stability, Cu foam had been regarded as a template for the design of novel materials, such as graphene-like copper oxide nanofilms, 21 metal-organic framework-5, 14 3D-graphene network, 22 electrodes, 12,23 and so on. Besides, Cu foam also shows enormous potential in the field of heat transfer 24 and removal of heavy metal ions.…”