RESUMEN
The fixing of N2 to NH3 is challenging due to the inertness of the N≡N bond. Commercially, ammonia production depends on the energy-consuming Haber-Bosch (H-B) process, which emits CO2 while using fossil fuels as the sources of hydrogen and energy. An alternative method for NH3 production is the electrochemical nitrogen reduction reaction (NRR) process as it is powered by renewable energy sources. Here, we report a tiara-like nickel-thiolate cluster, [Ni6 (PET)12 ] (where, PET=2-phenylethanethiol)] as an efficient electro-catalyst for the electrochemical NRR at ambient conditions. Ammonia (NH3 : 16.2±0.8â µg h-1 cm-2 ) was the only nitrogenous product over the potential of -2.3â V vs. Fc + /Fc with a Faradaic efficiency of 25%±1.7. Based on theoretical calculations, NRR by [Ni6 (PET)12 ] proceeds through both the distal and alternating pathways with an onset potential of -1.84â V vs. RHE (i.e., -2.46â V vs. Fc + /Fc ) which corroborates with the experimental findings.
RESUMEN
In this work, multiwalled carbon nanotubes (MWCNTs) are functionalized using 4-nitrobenzenediazonium (NBD) salt, which is identified as an effective electrocatalyst for the detection of ß-nicotinamide adenine dinucleotide (NADH). The NBD functionalized MWCNT (NBD-MWCNT(w) (w-washed)) was characterized using various physicochemical characterization methods. Cyclic voltammetric measurements showed that NBD-MWCNT(w) modified glassy carbon electrode (NBD-MWCNT(w)/GCE) was able to produce the anodic wave for oxidizing NADH at the applied overpotential of 0.12 V, which is 0.67 V cathodic when compared to that of bare GCE. Besides, the sensitivity of the electrode also doubled. The sensitivity and limit of detection (LoD) were 8.5 × 10-4 A M-1 and 3.75 µM, respectively. The linear range of the sensor was 5 to 60 µM. The selectivity studies further proved that the matrix is specific towards detecting NADH in the presence of other possible interfering molecules. The diffusion co-efficient and apparent rate constant of NADH obtained were 3.8 × 10-6 cm2 s-1 and 1.12 × 107 mol-1 cm3 s-1 respectively. Additionally, the electrode is employed to detect the analyte in real samples.
RESUMEN
Inspired by copper-based oxygen reduction biocatalysts, we have studied the electrocatalytic behavior of a Cu-based MOF (Cu-BTT) for oxygen reduction reaction (ORR) in alkaline medium. This catalyst reduces the oxygen at the onset (Eonset ) and half-wave potential (E1/2 ) of 0. 940â V and 0.778â V, respectively. The high halfway potential supports the good activity of Cu-BTT MOF. The high ORR catalytic activity can be interpreted by the presence of nitrogen-rich ligand (tetrazole) and the generation of nascent copper(I) during the reaction. In addition to the excellent activity, Cu-BTT MOF showed exceptional stability too, which was confirmed through chronoamperometry study, where current was unchanged up to 12â h. Further, the 4-electrons transfer of ORR kinetics was confirmed by hydrodynamic voltammetry. The oxygen active center namely copper(I) generation during ORR has been understood by the reduction peak in cyclic voltammetry as well in the XPS analysis.