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Electrochemical reduction of nitrite addresses the need for nitrite contaminant removal and provides an on-site, cost-effective, and sustainable route for rapidly generating ammonia/ammonium. Its practical implementation however requires advanced electrocatalysts with enhanced ammonium yield rates and faradaic efficiencies. Our study here introduces a Cu3P nanowire array supported on copper foam (Cu3P NA/CF) for the first time as an efficient electrocatalyst for nitrite-to-ammonium conversion in neutral media. In 0.1 M phosphate buffered saline containing 0.1 M NaNO2, the freestanding Cu3P NA/CF electrode displays a large ammonium yield rate of 1626.6 ± 36.1 μg h−1 cm−2 and a high FE of 91.2 ± 2.5% at −0.5 V vs. a reversible hydrogen electrode, with good stability. The catalytic mechanism is revealed by density functional theory calculations. [ABSTRACT FROM AUTHOR]

Electrochemical N2 reduction has emerged as a sustainable and eco-friendly route for the artificial synthesis of NH3 under ambient conditions, but active electrocatalysts are needed to drive the N2 reduction reaction (NRR). Here, Bi nanodendrites are reported as an efficient NRR electrocatalyst for N2 to NH3 conversion with excellent selectivity. In 0.1 M HCl, this catalyst achieves a large NH3 yield of 25.86 μg h−1 mg−1cat. and a high faradaic efficiency of 10.8% at −0.60 V and −0.55 V versus a reversible hydrogen electrode, respectively, with high electrochemical durability. [ABSTRACT FROM AUTHOR]

Electrochemical synthesis of ammonia through the nitrogen reduction reaction (NRR) has the possibility to revolutionize our production of ammonia and to save our planet from both emissions and large energy consumption. In this study, a perovskite structured lanthanum chromite catalyst (LaCrO3) is synthesized, characterized as well as electrochemically evaluated for NRR. The highest ammonia yield is obtained at −0.8 V vs. reversible hydrogen electrode with an ammonia formation rate of 24.8 μg h−1 mg−1cat, and a Faradaic efficiency of 15 %. Material calculation further confirms the possible mechanism of ammonia formation with the aid of LaCrO3 catalyst. The resulting conclusion offers a great alternative with the easily produced and low‐cost perovskite structured electrocatalysts for ammonia production. [ABSTRACT FROM AUTHOR]

For over a century, NH3 synthesis via the Haber–Bosch process has brought huge energy costs and high CO2 emission. The electrochemical N2 reduction reaction is an environmentally-benign alternative, which can be driven by renewable energy. In this work, CeO2 nanoparticle–reduced graphene oxide nanocomposites (CeO2–rGO) behave as an efficient non-noble-metal N2 reduction reaction electrocatalyst with excellent selectivity. In 0.1 M Na2SO4, CeO2–rGO achieves a high faradaic efficiency of 4.78% and a large NH3 yield of 16.98 μg h−1 mgcat.−1 at −0.7 V vs. reversible hydrogen electrode. The catalytic mechanism was explored using density functional theory calculations. [ABSTRACT FROM AUTHOR]

MOFs derived metals composites are good electrocatalyst for energy storage and conversion process. A synthesis of Ni composite with carbon (Ni/C) is formed by calcination of Ni-MOF at 600 °C and it's characterised with XRD, FE-SEM, FTIR and BET. After calcination, the derived Ni composite shows a lower crystalline size, high porosity and high surface area as compared to Ni-MOF. The derived material is used as an electrode for Hydrogen Evolution Reaction (HER) and it is carried out by Cyclic voltammetry (CV), Electrochemical impedance analysis (EIS) and Linear Sweep Voltammetry (LSV) in alkaline medium. The derived Ni/C shows a lowest Tafel slope of 61.56 mV/dec with an overpotential of 213.2 mV due to the surface area and accessible catalytic active sites which provides excellent mass transfer properties for derived Ni/C composite. • Ni-MOF was synthesized by hydrothermal method and Ni-MOF was calcined at 600 °C to produce Ni/C. • Ni-MOF and Ni/C based electrodes were used for Hydrogen Evolution Reaction (HER). • Ni/C exhibit higher activity in the HER with low overpotential of 213.2 mV and a Tafel slope of 61.56 mV/dec. • The rate determining step of hydrogen evolution process of Ni/C in basic medium follows Volmer-Heyrovsky mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • In this work, direct detection of Pb(II) in tap water is reported. • Detection was carried out using non-faradaic EIS sensors, which do not require the use of reference electrodes or redox probes. • The sensor performance is comparable to other conventional electrochemical sensors. This article describes a simple non-faradaic impedimetric sensor comprised of L-Cysteine self-assembled on top of an interdigitated gold electrode for the direct detection of lead ions (Pb(II)) in tap water. The sensor consists of only two electrodes and does not require redox probe during detection. During the detection of Pb(II) in tap water, changes in capacitance were observed with a sensitivity of 9.4 nF/log(nM) and a limit of detection of 45 pM at a biasing frequency as low as 10 Hz, which is well below the World Health Organization WHO recommendation for Pb(II). The sensor demonstrated satisfactory selectivity toward Pb(II) in comparison to Sn(II), Zn(II), Cu(II), Na(II), Mg(II) and Ca(II). In addition, the system allows a wide working frequency window up to ∼ 5 kHz, for which higher sensitivities can still be obtained. ATR-FTIR spectrum confirmed the functionalization of L-Cysteine onto interdigitated gold electrodes. Furthermore, XPS results confirmed complete thiolate-gold bonding, with no adsorbed sulfur or unbound thiol between L-Cysteine and the electrode surface. Also, the binding of Pb(II) to L-Cysteine was confirmed by XPS to take place mainly through the carboxyl group. The reported method is promising for constructing miniaturized sensors for the direct detection of Pb(II) in low-volume tap water samples. [ABSTRACT FROM AUTHOR]