Hexanuclear nickel-added silicotungstates as high-efficiency electrocatalysts for nitrate reduction to ammonia

Abstract

Ammonia (NH 3 ) is widely used in a wide range of fields because of its high energy density, and NH 3 is simple to liquefy and transport. Nitrate is also a source of pollution of the environment and drinking water sources. Therefore, there is a pressing demand for the design and production of high-efficiency catalysts for the nitrate reduction reaction (NO 3 RR). Herein, two nickel-added polyoxometalates (NiAPs), namely, [Ni(en(en = ethylenediamine, enMe = 1,2-diaminopropane), were effectively synthesized under hydrothermal conditions that contained several electrons and were used as electrocatalytic nitrate reduction reaction (e-NO 3 RR) catalysts. The structures of the compounds were characterized by using various instruments such as powder X-ray diffraction (PXRD) spectroscopy, infrared (IR) spectroscopy, thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) method, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). e-NO 3 RR tests were performed using electrochemical workstation. Results show that Ni 6 en and Ni 6 enMe have highefficient electrochemical catalytic nitrogen reduction to NH 3 . The highest NH 3 yield rate for Ni 6 en was 3.66 mg•h −1 •mg cat.−1 with Faradaic efficiency (FE) of 89.32%, whereas that for Ni 6 enMe was 3.46 mg•h −1 •mg cat.−1 with FE of 86.75% at a low voltage (−0.5 V vs. reversible hydrogen electrode (RHE)). This finding creates a novel path for manufacturing highly effective NO 3 RR electrocatalysts using metal-added polyoxometalate as the catalyst in ambient settings. Furthermore, the findings of this research provide practical advice for creating effective electrocatalytic catalysts.

Polyoxometalate-Intercalated Tremella-Like CoNi-LDH Nanocomposites for Electrocatalytic Nitrite–Ammonia Conversion

“…29−31 However, there are few reports focusing on the ammonia production efficiency in nitrite electroreduction. 32 In addition, POMs are a typical class of Lewis acids that would promote the adsorption of the weak Lewis base NO 2 − on their surfaces, thus further facilitating the whole NO 2 RR process. 33,34 Given the above discussion, it is anticipated that further exploration of the potential of POMs as available NO 2 RR electrocatalysts.…”

“…Inspired by the fact that POMs can modulate the electron transfer processes and further improve the activity and selectivity of these electrochemical reactions, we legitimately hypothesize that POMs could be ideal NO 2 RR molecular-based electrocatalysts. Indeed, the electrochemical sensing of nitrogen-containing oxyanions by virtue of the reversible redox properties of POMs is so ubiquitous that this reaction often serves as a standard reaction model for assessing the electrochemical response of new POM architectures. − However, there are few reports focusing on the ammonia production efficiency in nitrite electroreduction . In addition, POMs are a typical class of Lewis acids that would promote the adsorption of the weak Lewis base NO 2 – on their surfaces, thus further facilitating the whole NO 2 RR process. , Given the above discussion, it is anticipated that further exploration of the potential of POMs as available NO 2 RR electrocatalysts.…”

Design and synthesis of a deep-cavity aluminium-organic macrocycle to trap dyes and generate enhanced non-linear optical performance

“…3 Particular attention should be given to azo dyes 4,5 because they are the most commonly used chromophore and account for up to 70% of all produced textiles. Compared with chemical methods, 6–9 physical adsorption is generally considered a more efficient, low-cost, and environmentally friendly method for removing dyes from wastewater. 10–12 Ideally, adsorbents should be designed to utilize these trapped or adsorbed dyes to realize “Waste to Wealth”.…”