The adsorption of O on Pt(111) was studied with Density Functional Theory calculations. Various adsorbed states of O were evaluated on clean and OH/HO-covered Pt(111) surfaces at the solid/gas and solid/liquid interfaces. The results reveal that the adsorption of O on OH/HO-covered Pt(111) surface starts with the physical adsorption of O. Two other adsorption states are reachable from the physisorbed state, the end-on, and bridging chemisorbed O. Analysis of the energetics of these adsorption states shows that O physically adsorbed at the OH/HO-covered Pt( 111) surface is a high energy state that requires activation to transition to the end-on chemisorbed O state. On the other hand, the end-on chemisorbed state can transition to the bridging chemisorbed state with only a small activation energy when a nearby Pt adsorption site is available. Frequency analysis of the physisorbed, end-on, and bridging adsorption states shows that adsorbed O stretching frequencies are close to 1400, 1300, and 900 cm, respectively.

Direct ethanol fuel cells (DEFC) still lack active and efficient electrocatalysts for the alkaline ethanol oxidation reaction (EOR). In this work, a new instant reduction synthesis method was developed to prepare carbon supported ternary PdNiBi nanocatalysts with improved EOR activity. Synthesized catalysts were characterized with a variety of structural and compositional analysis techniques in order to correlate their morphology and surface chemistry with electrochemical performance. The modified instant reduction synthesis results in well-dispersed, spherical PdNiBi nanoparticles on Vulcan XC72R support (PdNiBi/C), with sizes ranging from 3.7 ± 0.8 to 4.7 ± 0.7 nm. On the other hand, the common instant reduction synthesis method leads to significantly agglomerated nanoparticles (PdNiBi/C). EOR activity and stability of these three different carbon supported PdNiBi anode catalysts with a nominal atomic ratio of 85:10:5 were probed via cyclic voltammetry and chronoamperometry using the rotating disk electrode method. PdNiBi/C showed the highest electrocatalytic activity (150 mA⋅cm; 2678 mA⋅mg) with low onset potential (0.207 V) for EOR in alkaline medium, as compared to a commercial Pd/C and to the other synthesized ternary nanocatalysts PdNiBi/C and PdNiBi/C. This new synthesis approach provides a new avenue to developing efficient, carbon supported ternary nanocatalysts for future energy conversion devices. Graphical AbstractThe modified instant reduction method for synthesis of ternary PdNiBi/C nanocatalyst using Vulcan XC72R as carbon support initiates an agglomeration reduction, provides low average particle size, and enables enhanced activity for the alkaline ethanol oxidation reaction (EOR) compared to the common instant reduction method and to a commercial Pd/C catalyst.

In this study, the surface of the glassy carbon electrode was modified with glutardialdehyde. The modified glassy carbon electrode showed electrocatalytic activity against ivermectin. The glassy carbon electrode modified with glutardialdehyde showed high sensitivity, selectivity, and stability in the determination of ivermectin. The peak current of glutardialdehyde oxidation obtained by differential pulse voltammetry decreased inversely with the ivermectin concentration. Ivermectin inhibited the oxidation reaction of glutardialdehyde and caused a decrease in current. This change made the analysis of ivermectin electrochemically possible. In order to demonstrate the applicability of the developed method in real samples, recovery studies were carried out in tap water and urine. The highest sensitivity (0.45 µA/((µmol·L)(cm))) was achieved with urine sample and the lowest detection limit as 2.66 × 10 mol·L was obtained with BRT solution sample.

This work investigates how bovine serum albumin (BSA), a commonly used protein in the fabrication of electrochemical immunosensors, can impact on the sensitivity of detection when integrated with antibody (Ab) pre-encapsulated with (i) insulating polyacrylonitrile (PAN) fibre (i.e., GCE-PAN-Ab-BSA immunosensor) or (ii) conducting PAN-grafted iron (II) phthalocyanine (FePc) (i.e., GCE-PAN@FePc-Ab-BSA immunosensor), using toxin as a case study bioanalyte. Both immunosensors show different charge-transfer kinetics that strongly impact on their immunosensitive detection. From the electrochemical data, GCE-PAN-Ab-BSA is more insulating with the presence of BSA, while the GCE-PAN@FePc-Ab-BSA is more conducting with BSA. The CV of the GCE-PAN-Ab-BSA is dominated by radial diffusion process, while that of the GCE-PAN@FePc-Ab-BSA is planar diffusion process. The behaviour of GCE-PAN@FePc-Ab-BSA has been associated with the facile coordination of BSA and FePc that permits co-operative charge-transport of the redox probe, while that of the GCE-PAN-Ab-BSA is related to the interaction-induced PAN-BSA insulating state that suppresses charge-transport. As a consequence of these different interaction processes, GCE-PAN-Ab-BSA immunosensor provides higher electroanalytical performance for the detection of toxin (with sensitivity of 16.12 Ω/log [VCT, g/mL] and limit of detection (LoD) of 3.20 × 10 g/mL compared to those of the GCE-PAN@FePc-Ab-BSA (4.16 Ω/log (VCT, g mL) and 2.00 × 10 g/mL). The study confirms the need for a thorough understanding of the physico-chemistries of the electrode platforms for the construction of immunosensors. Although this work is on immunosensors for cholera infection, it may well apply to other immunosensors.

The electrocoagulation method using stainless steel anodes was applied to a corrugated cardboard box manufacturing plant's wastewater with high COD content. The effects of current density, processing time and stirring speed on response functions were studied using the Response Surface Methodology (RSM). The removal efficiency of chemical oxygen demand (COD) and energy consumption were selected as response functions. The Central Composite Design (CCD) was chosen to explain the single and combined effects of independent variables on response functions. The COD concentration of the real industrial wastewater used in the experiments was 9130 mg L. The maximum COD removal efficiency of 91.6% is obtained with 19.78 Wh g energy consumption. Current density and treatment time were effective parameters for both COD removal and energy consumption. Optimization for maximum COD removal with minimum energy consumption showed 80.9% of COD removal with 6.7 Wh g of energy consumption at 15 mA cm, 700 rpm, and 28 min treatment time. The variables are optimized with a few experiments using the response surface method.