One-dimensional cobalt oxide nanotubes with rich defect for oxygen evolution reaction

For the electrochemcial hydrogen production, the oxygen evolution reaction (OER) is a pivotal half-reaction in water splitting. However, OER suffers sluggish kinetics and high overpotential, leading to the increase of overall energy consumption and decrease of the energy efficiency. In this work, high-quality cobalt oxide porous nanotubes (Co3O4-PNTs) are easily obtained by simple self-template approach. One-dimensional (1D) porous structure provides the large specific surface area, enough abundant active atoms and effective mass transfer. In addition, Co3O4-PNTs also own self-stability of 1D architecture, benefitting the their durability for electrocatalytic reaction. Thus, Co3O4-PNTs with optimal annealing temperature and time reveal the attractive alkaline OER performance (Tafel slope of 56 mV dec-1 and 323 mV overpotential at 10 mA cm-2), which outperform the Co3O4 nanoparticles and benchmark commercial RuO2 nanoparticles. Furthermore, Co3O4-PNTs also exhibit excellent OER durability for least 10 h at the 10 mA cm-2. Overall, Co3O4-PNTs with low cost can be serve as a highly reactive and economical catalyst for OER.

An Analytical Method Based on Electrochemical Sensor for the Assessment of Insect Infestation in Flour

Uric acid is an important indicator of the insect infestation assessment in flour. In this work, we propose a method for uric acid detection based on voltammetry. This technique is particularly considered for the physicochemical properties of flour and contains a simple pretreatment process to rapidly achieve extraction and adsorption of uric acid in flour. To achieve specific recognition of uric acid, graphene and poly(3,4-ethylenedioxythiophene) (PEDOT) were used for the adsorption and concentration of uric acid in flour. The adsorbed mixture was immobilized on the surface of a screen-printed electrode for highly sensitive detection of the uric acid. The results showed that electrocatalytic oxidation of uric acid could be achieved after adsorption by graphene and PEDOT. This electrocatalytic reaction allows its oxidation peak to be distinguished from those of other substances that commonly possess electrochemical activity. This voltammetry-based detection method is a portable and disposable analytical method. Because it is simple to operate, requires no professional training, and is inexpensive, it is a field analysis method that can be promoted.

Facile Route Fabrication of Steam Exploded Poplar Loaded with Non-metal Doped Ni-Fe Nanoparticles: Catalytic Activities in 4-nitrophenol Reduction and Electrocatalytic Reaction

A simple and effective method for the preparation of non-metallic ion-doped nickel-supported catalyst is reported. Using economical and recyclable fiber raw materials as carriers, nickel-supported catalysts are prepared by adsorption and reduction at room temperature. The nanoparticles dispersedly anchored on a rational support can efficiently inhibit the aggregation and thus enhance the catalytic activity. For the model catalytic hydrogenation of 4-NP by NaBH4, the N-B-Ni2P/SEP and N-B-NiFeP/SEP catalysts exhibited much better catalytic performances than other catalysts recently reported in terms of the catalytic activity (reaction completed within 5 min), reaction rate constant (1.617 and 0.765 min− 1) and the activity factor K (539 and 255 min− 1·g− 1), respectively. The catalyst showed activities for electrocatalytic HER and OER under ambient conditions. In general, the reported preparation method of nickel-supported catalyst is convenient, economical and environmentally friendly, which is in line with many green chemistry and sustainable development principles and widely available starting materials.