Preparation Of Copper Based Nanomaterials And Its Electrocatalytic Performance

Catalytically active non-noble metal nanomaterials are widely used as catalysts to photocatalysis,electrocatalysis,electroanalysis and biosensors.In this paper,low-cost copper-based materials are used to build efficient activity interface of an electrode by adjusting surface/interface of the electrode.The catalytic abilities in electrochemical processes of prepared materials are studied.The main results are as follows:1.By adjusting the stoichiometric ratio of copper acetate and urea in a facile hydrothermal process,four types of CuO microspheres are fabricated in situ on Ni foam electrode without any binders.The CuO microspheres are constructed by nano-structured CuO with different morphologies,i.e.,1D nanorod or 2D nanosheets in different thickness,which increase the electrode/electrolyte contact area and provide good pathways for charge transfer,and thus improved the sensitivity of glucose detection effectively.Especially,the CNF-2 electrode consisting of ultrathin CuO nanoslice of?6 nm thickness with through-holes presentes outstanding electrochemical performances.It shows excellent electro-catalytic activity to glucose oxidation and gives an ultrahigh sensitivity of 1.864×10⁴?A mM^-1 cm^-2 for glucose concentration from 1?M to 100?M in 0.1 M NaOH,which is higher than that of similar electrochemical non-enzymatic glucose sensors reported in the literature.2.Hierarchical CuO-CoO 3D structure over the copper foam electrode via chemical bath deposition?CBD?process and subsequent calcination in inert atmosphere are obtained.The delicate CuO-CoO hetero-nanostructures composed of porous CuO as the core together with decorated CoO shell.The nano-CuO core forms a good interface with the Cu foam electrode,which is conducive to electron transfer.Meanwhile,theoretical calculation shows that when the thin layer CoO is deposited on the CuO surface,the adsorption energy of H₂O₂ on the CoO?2 0 0?surface is significantly reduced.Owing to the synergistic effect of nano CuO and CoO,the optimized leaf-like CuO-CoO-2.5h structure exhibits an ultrahigh sensitivity(6349?A mM^-1 cm^-2),excellent selectivity,as well as wide detection range for H₂O₂.3.Polyoxometalate-based metal organic frameworks?POMOFs?material is introduced into electrochemical detection of dopamine.A Cu-based MOF is selected to provide planar structure with?bond and cationic centers.The MOF framework,polymetallic oxylate?POM?clusters,and reduced graphene oxide?rGO?are then effectively combined through electrostatic,H-bond,and?-?interactions to obtain highly active non-noble metal based dopamine?DA?sensing interface.Well-dispersed POMOF crystals were attached to rGO sheets via strong interactions in the composite material that provides abundant and accessible metal centers,high electrical conductivity,and large specific surface area upon deposited onto GCE?glassy carbon electrode?.Meanwhile,the aromatic interaction between POMOF/rGO complex and DA?dopamine?molecule improves the adsorpion and diffusion of DA on the electrode surface.The obtained POMOF/rGO/GCE electrode exhibites satisfactory stability and reproducibility with a wide linear detection range from 1×10^-6 to 2×10^-4 M and low detection limit of 80.4×10^-9 M,and also has excellent selectivity and anti-interference.4.Copper-based chalcogenides compounds has been used in electrocatalytic hydrogen evolution?HER?for the first time in this paper.The cylindrical hollow Cu_2-xSe hierarchical structures are prepared on the surface of copper foam electrode by solution oxidation and in situ anion exchange.The wall of the hierarchical structure is composed of ultrathin Cu_2-xSe nanosheets with a thickness of about 3.3-3.5 nm.Such a structure has a large specific surface area,which can effectively promote electrolyte diffusion and accelerate electron transfer at the interface.The Cu_2-xSe/Cu foam electrode achieves a large geometric current density of-100 mA cm^-2 for HER at a small overpotential of 313 mV,and also exhibits outstanding long-term operational stability.In general,several copper based nanomaterials are prepared and the highly active interfaces for electrochemical processes are obtained.The results not only have guiding significance for designing high-performance electrochemical devices,but also provide a new perspective for understanding the synergistic effect in composite catalytic materials.