Enhanced Water Electrolysis: Effect Of Temperature On The Oxygen Evolution Reaction At Cobalt Oxide Nanoparticles Modified Glassy Carbon Electrodes

Water splitting producing hydrogen and oxygen gases appears promising in view of the increasing need of renewable energy sources and storage strategies. Investigation of stable and highly efficient electrocatalysts for oxygen evolution reaction (OER) is targeted in this study at cobalt oxide nanoparticle modified glassy carbon (nano-CoOx/GC) electrodes. The effect of the preparation (Tp) and measuring temperature (Tm) on the electrocatalytic activity of nano-CoOx/GC towards the OER is investigated under various operating conditions. Linear sweep voltammetry (LSV), cyclic voltammetry (CV) as well as SEM and XRD techniques were used to probe the electrocatalytic and morphological characteristics of nano-CoOx prepared under various conditions. Increasing Tp and/or Tm results in improving the kinetics and electrocatalytic activity of the proposed anodes towards the OER as demonstrated in the value of the onset potential of the OER and the OER currents recorded at a fixed potential. The morphology as well as the surface characterization of the prepared catalyst are reported herein and evaluated

Efficient Catalytic Production Of Biodiesel Using Nano-sized Sugar Beet Agro-industrial Waste

This paper addresses the use of agro-industrial residue as a promising heterogeneous catalyst for the efficient production of biodiesel. That is, CaO-rich Sugarbeet agro-industrial waste (smashed down to nano-size) shows superb catalytic activity for biodiesel production via transesterification process employing sunflower oil and methanol. Physicochemical properties of the proposed catalyst are probed by TGA–DTG, XRF, XRD, FT-IR, SEM, BET, and CO2-TPD techniques. Biodiesel conversion (%) of Ca. 93% is achieved under the optimal conditions (catalyst loading of 1 wt%, methanol/oil molar ratio of 4.5:1, refluxed at 75 °C for 60 min). The relatively short reaction time indicates the enhanced kinetics of the process using the proposed agro-industrial residue which imparts its economic feasibility. Also, the proposed CaO-rich residue can be reused twice while retaining its catalytic activity. The thus-produced biodiesel fuel compiles the ASTM D6751 and EN-14214 specifications

Electrocatalytic Evolution of Oxygen Gas at Cobalt Oxide Nanoparticles Modified Electrodes

The electrocatalysis of oxygen evolution reaction (OER) at cobalt oxide nanoparticles (nano-CoOx) modified GC, Au and Pt electrodes has been examined using cyclic voltammetry. The OER is significantly enhanced upon modification of the electrodes with nano-CoOx, as demonstrated by a negative shift in the polarization curves at the nano-CoOx modified electrodes compared to that obtained at the unmodified ones. Scanning electron microscopy (SEM) revealed the electrodeposition of nanometer-size CoOx (average particle size of 200 nm) onto GC electrode. Optimization of the operating experimental conditions (i.e., solution pH and loading level of nano-CoOx) has been achieved to maximize the electrocatalytic activity of nano-CoOx modified electrodes. It has been found that the electrocatalytic activity of the nano-CoOx modified electrodes towards the OER is pH and loading level dependent, while it is substrate independent. The low cost as well as the marked stability of the thus-modified electrodes make them promising candidates in industrial water electrolysis proces

Electrodeposition of gold nanorods with a uni-directional crystal growth and lower Au(111) facets area

932-937Stable Au nanorods with a uni-directional pin-like morphology have been prepared on the surface of glassy carbon (GC) electrodes via a potential-step electrodeposition method from H2SO4 solution containing Na[AuCl4] in the presence of cysteine as an additive. The Au nanorods are characterized by a relatively low Au(111) facets area because of a continuous uni-directional growth of the crystal along the (111) orientation leading to a pin-like morphology of the crystals. In other words, there is a significant enrichment of Au(100) and Au(110) facets in contrast to the spherical Au anoparticles prepared in the absence of cysteine. The peak potential of the oxygen reduction react ion, measured in O2-saturated 0.5 M H2SO4, at the thus-prepared Au nanorods electrodeposited onto glassy carbon (nano Au/GC) electrodes shows a significant positive shift compared to that obtained at the nano Au/GC electrode prepared in the absence of cysteine, demonstrating a higher electrocatalytic activity of these Au nanorods