Heterointerface-triggered electronic structure reformation: Pd/CuO nano-olives motivate nitrite electroreduction to ammonia

Liu, Songliang; Cui, Lin; Yin, Shuli; Ren, Hang; Wang, Ziqiang; Xu, You; Li, Xiaonian; Wang, Liang; Wang, Hongjing

doi:10.1016/j.apcatb.2022.121876

Cited by 52 publications

(29 citation statements)

References 56 publications

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“…Since CuO is identified as the major form of Cu present, it appears that surface sites on the CuO are the active sites for electroreduction of nitrate on the Cu@AC electrode surface prepared here. Since other studies have reported distinct electrochemical activity for various forms of copper (such as Cu(0), CuO, and Cu 2 O), − studies on optimizing the material synthesis strategy and comparing the performance of different forms of Cu should be performed in the future.…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Reduction of Nitrate with Simultaneous Ammonia Recovery Using a Flow Cathode Reactor

Sun

Garg

Xie

et al. 2022

Environ. Sci. Technol.

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The presence of excessive concentrations of nitrate in industrial wastewaters, agricultural runoff, and some groundwaters constitutes a serious issue for both environmental and human health. As a result, there is considerable interest in the possibility of converting nitrate to the valuable product ammonia by electrochemical means. In this work, we demonstrate the efficacy of a novel flow cathode system coupled with ammonia stripping for effective nitrate removal and ammonia generation and recovery. A copper-loaded activated carbon slurry (Cu@AC), made by a simple, low-cost wet impregnation method, is used as the flow cathode in this novel electrochemical reactor. Use of a 3 wt % Cu@AC suspension at an applied current density of 20 mA cm −2 resulted in almost complete nitrate removal, with 97% of the nitrate reduced to ammonia and 70% of the ammonia recovered in the acid-receiving chamber. A mathematical kinetic model was developed that satisfactorily describes the kinetics and mechanism of the overall nitrate electroreduction process. Minimal loss of Cu to solution and maintenance of nitrate removal performance over extended use of Cu@AC flow electrode augers well for long-term use of this technology. Overall, this study sheds light on an efficient, low-cost water treatment technology for simultaneous nitrate removal and ammonia generation and recovery.

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Section: Resultsmentioning

confidence: 99%

Electrochemical Reduction of Nitrate with Simultaneous Ammonia Recovery Using a Flow Cathode Reactor

Sun

Garg

Xie

et al. 2022

Environ. Sci. Technol.

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“…39,57,58 Therefore, direct electroreduction of NO 2 − , avoiding the NO 3 − -to-NO 2 − step on the CuPd catalyst in this work, is much easier, and the possible reaction mechanism is proposed as follows (Figure 5)�it includes three steps of both deoxidation reactions and hydrogenation reactions. 41,59 For the deoxidation reactions, first, NO − and the related intermediates on Cusites but also is conducive to the accumulation of H ads on Pdsites, further providing sufficient H ads to Cu-sites, and therefore accelerating the reaction toward NH 3 formation.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…According to previous studies of the reaction mechanism for electrocatalytic nitrate reduction on bimetallic PdCu catalysts, the whole reaction process includes multiple redox steps in which Cu served as a promoter metal to absorb the NO 3 – and other related intermediates, while Pd is more favorable to form H ads from H 2 O and continuously transfer to the Cu-sites for promoting ammonia formation. , Moreover, the first hydrogenation step of NO 3 – conversion to NO 2 – is usually the rate-determining step among the whole reaction process. ,, Therefore, direct electroreduction of NO 2 – , avoiding the NO 3 – -to-NO 2 – step on the CuPd catalyst in this work, is much easier, and the possible reaction mechanism is proposed as follows (Figure )it includes three steps of both deoxidation reactions and hydrogenation reactions. , For the deoxidation reactions, first, NO 2 – is absorbed on Cu-sites to form NO 2 – (ads) , while H ads is generated from Pd-sites in the meantime. Subsequently, H ads continuously transfers to NO 2 – (ads) on Cu-sites to form NO – (ads) and N – (ads) with concurrent release of H 2 O molecules.…”

Section: Resultsmentioning

confidence: 99%

Sustainable Nitrogen Fixation to Produce Ammonia by Electroreduction of Plasma-Generated Nitrite

Zhang

Liu

et al. 2023

ACS Sustainable Chem. Eng.

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One-step electrocatalytic N 2 fixation is of emerging interest but is retarded due to the tough dissociation of the N 2 triple bond and low NH 3 selectivity. Here, a plasma-electrocatalytic integrated strategy is reported to be effective to circumvent this dilemma and realize high-performance N 2 fixation via decoupling the reaction to two steps with NO x − serving as an intermediary: (i) non-thermal plasma (NTP) drives air activation into highly active NO x − intermediates, and (ii) subsequent electroreduction of the resultant NO x − into NH 3 . A gliding arc−microwave conjunction plasma mode was found to be preferred to achieve an optimal NO 2 − -N concentration of 2844.31 μg mL −1 , adopting 0.5 M KOH as the absorption solution in the first step. For the next ENO 2 − RR step, plasma-treated 0.5 M KOH was directly used as electrolyte, with well-designed Cu 2 Pd nanodots anchored on carbonized bacterial cellulose (Cu 2 Pd/CBC) as electrocatalyst. An exceptional ENO 2 − RR performance, including a superior R NHd 3 of 1956.65 μg h −1 mg −1 , highest FE of 93.79%, and long time stability of 30 h, was attained for Cu 2 Pd/CBC, outperforming the counterparts Cu/CBC and Pd/CBC. The synergism of CuPd bifunctional catalytic sites is the key to the greatly enhanced electrocatalytic activity via improving the adsorption of NO 2 − and the related intermediates while simultaneously supplying sufficient protons. This work provides an alternative strategy toward sustainable and distributed on-site ammonia synthesis.

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“…With the increase of nitrous oxides caused by fossil fuel combustion and agriculture sewage emission, the concentration of nitrate in surface and groundwater is about to surpass the Safe Drinking Water Act regulations . However, current NO 3 RR electrocatalysts are still unsatisfactory owing to the weak mass transfer, complex reaction processes, as well as highly toxic NO 2 – production. − Therefore, it is becoming progressively essential to develop NO 3 RR electrocatalysts with high selectivity and efficiency as well as nontoxic byproducts. In a typical reaction in which nitrate is reduced to ammonia, it involves NO 3 – dissociation and subsequent reactions between adsorbed hydrogen and adsorbed NO 3 RR intermediates with eight-electron and nine-proton transfer processes (NO 3 – + 9H + + 8e – → NH 3 + 3H 2 O): acidic media, NO 3 – → *NO 3 → *NO 2 → *NO → *NH 3 → NH 3 ; neutral and alkaline media, NO 3 – → *NO 3 → *NO 2 → *NO → *N → *NH 3 → NH 3 . , Lu and colleagues synthesized a NO 3 RR electrocatalyst (CuCl_BEF) by stacking CuCl (111) and rutile TiO 2 (110) layers with different work functions together.…”

Section: Bief In Electrocatalysismentioning

confidence: 99%

Designing a Built-In Electric Field for Efficient Energy Electrocatalysis

et al. 2022

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To utilize intermittent renewable energy as well as achieve the goals of peak carbon dioxide emissions and carbon neutrality, various electrocatalytic devices have been developed. However, the electrocatalytic reactions, e.g., hydrogen evolution reaction/ oxygen evolution reaction in overall water splitting, polysulfide conversion in lithium− sulfur batteries, formation/decomposition of lithium peroxide in lithium−oxygen batteries, and nitrate reduction reaction to degrade sewage, suffer from sluggish kinetics caused by multielectron transfer processes. Owing to the merits of accelerated charge transport, optimized adsorption/desorption of intermediates, raised conductivity, regulation of the reaction microenvironment, as well as ease to combine with geometric characteristics, the built-in electric field (BIEF) is expected to overcome the above problems. Here, we give a Review about the very recent progress of BIEF for efficient energy electrocatalysis. First, the construction strategies and the characterization methods (qualitative and quantitative analysis) of BIEF are summarized. Then, the up-to-date overviews of BIEF engineering in electrocatalysis, with attention on the electron structure optimization and reaction microenvironment modulation, are analyzed and discussed in detail. In the end, the challenges and perspectives of BIEF engineering are proposed. This Review gives a deep understanding on the design of electrocatalysts with BIEF for nextgeneration energy storage and electrocatalytic devices.

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Heterointerface-triggered electronic structure reformation: Pd/CuO nano-olives motivate nitrite electroreduction to ammonia

Cited by 52 publications

References 56 publications

Electrochemical Reduction of Nitrate with Simultaneous Ammonia Recovery Using a Flow Cathode Reactor

Electrochemical Reduction of Nitrate with Simultaneous Ammonia Recovery Using a Flow Cathode Reactor

Sustainable Nitrogen Fixation to Produce Ammonia by Electroreduction of Plasma-Generated Nitrite

Designing a Built-In Electric Field for Efficient Energy Electrocatalysis

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