Enhanced Nitrate Reduction Activity from Cu-Alloy Electrodes in an Alkaline Electrolyte

Abstract

The electrochemical nitrate reduction reaction (NO3 –RR) offers two-fold advantagesrestoring balance to the global nitrogen cycle and a less energy intensive pathway to the production of ammonia. We report the results of voltammetric and spectroscopic measurements examining NO3 –RR on Cu and Cu-alloyed electrodes (CuAg, CuSn, and CuPt) in an alkaline medium. Electrochemical results demonstrate that the overpotential for the NO3 –RR is ∼120 mV less on the CuAg catalyst as compared to the Cu-only catalyst. In situ surface enhanced Raman spectroscopy (SERS) obtained from these two Cu samples shows that the presence of dilute Ag maintains the Cu surface in a more reduced state (Cu(I)) during the course of NO3 –RR, while the neat Cu surface is heavily oxidized during NO3 –RR in an alkaline medium. Consistent with this behavior, the CuSn alloy also stabilizes Cu(I) on the electrode surface and results in increased NO3 –RR rates. Alternatively, the CuPt alloy does not yield a stabilized Cu(I) component and consequently results in NO3 –RR rates lower than those for neat Cu. These results indicate that alloying Cu with different metals can tune the nitrate reduction activity by making the Cu atoms more resistant to oxidation to Cu(II) and stabilizing the Cu atoms in lower oxidation states.

Electrochemical Co-Production of Ammonia and Biodegradable Polymer Monomer Glycolic Acid via the Co-Electrolysis of Nitrate Wastewater and Waste Plastic

“…With the continuous development of human society, waste and pollutants increasingly aggravate the destruction of the ecosystem and thus threaten human health and survival. Among all kinds of pollutants, nitrate (NO 3 – ), as a common environmental harmful pollutant, is accumulated in industrial wastewater and groundwater, leading to serious water eutrophication. − Therefore, the treatment of nitrate pollutants is urgent for purifying water resources and promoting the restoration of nitrogen cycle. Recently, a large number of waste plastics cause white pollution and endanger human health due to the excessive dependence on plastic products in human life. , As one of the largest annual output of polyester plastics, poly­(ethylene terephthalate) (PET) plastic waste is accumulated in a large number of landfills, causing groundwater and environmental pollution. , Based on this, the degradation and recycling of PET plastic waste has been widely studied.…”

Fluidic MXene Electrode Functionalized with Iron Single Atoms for Selective Electrocatalytic Nitrate Transformation to Ammonia

“…The overuse of nutrient-rich substances has led to the unavoidable accumulation of nitrogen-containing pollutants in the environment. − For example, surface leaching and runoff causes the concentration of nitrate (NO 3 – ) in natural bodies of water to grow to 10–50 mg-N L –1 , − which has prompted the adoption of stringent regulations globally to limit NO 3 – concentrations. Although a variety of technologically mature physical, chemical, and biological methods for NO 3 – removal are widely used , − the electrochemical NO 3 – reduction reaction (NO 3 RR) has gained significant attention. − Generally, the final products of the NO 3 RR are nitrogen (N 2 ) and/or ammonia (NH 3 ). However, the electrocatalytic conversion of NO 3 – to harmless N 2 is kinetically sluggish. , In contrast, NH 3 is a vital chemical feedstock and can be used as a medium for energy transport and storage. − Hence, the electroreduction of NO 3 – to NH 3 has recently been identified as a “two birds, one stone” strategy, offering a sustainable path for the removal of waste and the recovery of nutrients.…”

Enhanced Metal–Support Interfacial Interaction of Pd@FeNi-CoO Composites for Efficient Nitrate Reduction to Ammonia

“…However, the process of reacting inert nitrogen (N 2 ) and hydrogen (H 2 ) to produce NH 3 under high temperature and pressure is an energy-intensive synthesis method that generates significant energy consumption while also releasing large amounts of greenhouse gases. ,− Electrocatalytic nitrate (NO 3 – ) production of NH 3 can be an excellent method to solve the above problems, which is one of the candidates to replace the Haber–Bosch process in the future. Moreover, the excessive use of NO 3 – in agriculture, despite increasing crop yields, also contributes to water pollution. − Besides, industrial wastewater also contains large amounts of NO 3 – . Once NO 3 – enters the human body, it will convert into harmful nitrite (NO 2 – ) to induce diseases. − Accordingly, the electrocatalytic NO 3 – reduction reaction (NO 3 RR) can not only achieve efficient green NH 3 production but also promote waste NO 3 – conversion to reduce potential hazards.…”