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Sotgiu G, De Santis S, Orsini M, Bavasso I, Sarasini F, Petrucci E. Copper-Decorated Titanium Electrodes: Impact of Surface Modifications of Substrate on the Morphology and Electrochemical Performance. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 38691769 DOI: 10.1021/acsami.4c00203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
This study investigates the effect of surface modifications of the titanium substrate on the growth of electrochemically deposited copper. These materials are intended to serve as cathodes in the electroreduction of nitrates in aqueous solutions. Surface modifications included the use of hydrogen fluoride for titanium etching and anodization to promote the growth of a structured titania nanotube array. The effect of an intermediate calcination step for the nanotubes before deposition was assessed along with a comparison to an untreated substrate electrode. The materials were comprehensively characterized by SEM, XRD, contact angle, potentiodynamic tests, EIS, and cyclic voltammetry. Their electrocatalytic ability was tested in the reduction of aqueous solutions containing nitrates. The results reveal that surface finishing impacted the shape and size of the Cu microparticles, as well as the nucleation mechanism enabling a crystal-facet-controllable synthesis. All the materials exhibited microsized copper particles with a spherical shape with some clusters. On the etched titanium surface, a high number of heterogeneous submicroscopic particles were also present. The thermally treated anodized substrate promoted the development of a combination of sparse microparticles corresponding to defect sites in amorphous titanium and the presence of a diffuse coating of octahedral nanosized particles whose growth was promoted by the tetragonal structure of anatase crystals. Electrochemical tests display reduced charge transfer resistance upon copper deposition on the modified substrates, which is indicative of the enhanced conductivity of the coated materials. Additionally, cyclic voltammetry and electrolysis experiments reveal the electrodes' potential for nitrate reduction, showing a better response for the etched titanium substrate (30% nitrate removal, after 2 h at 25 mA cm-2).
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Affiliation(s)
- Giovanni Sotgiu
- Department of Industrial, Electronic and Mechanical Engineering, Roma Tre University, Via Vito Volterra 62, 00146 Roma, Italy
| | - Serena De Santis
- Department of Industrial, Electronic and Mechanical Engineering, Roma Tre University, Via Vito Volterra 62, 00146 Roma, Italy
| | - Monica Orsini
- Department of Industrial, Electronic and Mechanical Engineering, Roma Tre University, Via Vito Volterra 62, 00146 Roma, Italy
| | - Irene Bavasso
- Department of Chemical Engineering Materials Environment, Sapienza University of Rome, Via Eudossiana 18, 00184 Roma, Italy
| | - Fabrizio Sarasini
- Department of Chemical Engineering Materials Environment, Sapienza University of Rome, Via Eudossiana 18, 00184 Roma, Italy
| | - Elisabetta Petrucci
- Department of Chemical Engineering Materials Environment, Sapienza University of Rome, Via Eudossiana 18, 00184 Roma, Italy
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Gao Y, Shen J, Yinzhang H, Yang L. Performance and microbial response to nitrate nitrogen removal from simulated groundwater by electrode biofilm reactor with Ti/CNT/Cu5-Pd5 catalytic cathode. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2024; 96:e10974. [PMID: 38214427 DOI: 10.1002/wer.10974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/08/2023] [Accepted: 12/13/2023] [Indexed: 01/13/2024]
Abstract
To enhance the removal of nitrate nitrogen (NO3 - -N) in groundwater with a low C/N ratio, electrocatalytic reduction of NO3 - -N has received extensive attention since its electrons can be directly produced in situ while simultaneously providing a clean electronic donor of hydrogen for denitrifying bacteria. In this study, Ti/CNT/CuPd bimetallic catalytic electrodes with different copper-palladium (CuPd) ratios were prepared by electrodeposition onto carbon nanotube (CNT) using titanium (Ti) plates. The results showed that the NO3 - -N conversion rate by Ti/CNT/Cu5-Pd5 electrode was the highest (53.60%) compared with other CuPd electrode ratios because of the combined role of the copper's high NO3 - -N catalytic activity and the palladium's high N2 selectivity. A new type of electrode biofilm reactor (EBR) with Ti/CNT/Cu5-Pd5 cathode, biochar substrate was constructed to explore the removal ability of NO3 - -N in simulated low C/N groundwater. When the influent NO3 - -N concentration was 30 mg/L, under the condition of a 30 mA electronic current and hydraulic retention time (HRT) of 12 h, the removal rate of NO3 - -N could reach as high as 78.1 ± 1.2%, and the N2 conversion rate was 99.7%. The horizontal distribution of microbial communities in EBR showed that the denitrification capacity was significantly improved through the electrochemical catalytic reduction of the Ti/CNT/Cu5-Pd5 cathode and the supply of the hydrogen electron donor to autotrophic denitrogenerating microbes such as Anaerobacillus, Thauera, and Hydrophaga. This study provides a new bimetallic catalytic cathode to enhance the removal of NO3 - -N in groundwater with a low C/N ratio. PRACTITIONER POINTS: The Cu5Pd5/CNTs/Ti electrode is beneficial to the adsorption and reduction of NO3 - -N to N2 . The production of hydrogen electron donors by cathode promoted nitrogen degradation. Activated electrodes together with denitrifying microorganisms contributed to the improved N removal rate.
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Affiliation(s)
- Yan Gao
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing, Jiangsu, P. R. China
| | - Jianing Shen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, P. R. China
| | - Hongyu Yinzhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, P. R. China
| | - Liuyan Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, P. R. China
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Zheng X, Yan Y, Li X, Liu Y, Yao Y. Theoretical insights into dissociative-associative mechanism for enhanced electrochemical nitrate reduction to ammonia. JOURNAL OF HAZARDOUS MATERIALS 2023; 446:130679. [PMID: 36580786 DOI: 10.1016/j.jhazmat.2022.130679] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 12/20/2022] [Accepted: 12/25/2022] [Indexed: 06/17/2023]
Abstract
The development of electrochemical nitrate reduction reaction (NO3RR) is a "two birds-one stone" method, which can not only remove NO3- pollutant, but also produce valuable ammonia (NH3). However, a mechanistic understanding of the nitrate reduction process remains very limited. Herein, we highlighted a dissociative-associative mechanism for the NO3RR, in which the N-O bond of nitrate is initially broken to form *O and *NO2 intermediate adsorbed on two active sites (dissociation process) and then subsequently hydrogenated and reduced to ammonia (association process). By taking a series of diatomic site catalysts (CuTM/g-CN and CuTM/N6C, TM= Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) as models, we systematically investigate the dissociative-associative mechanism for the NO3RR and compared with the Cu-based single-atom catalysts which follows the traditional directly associative mechanism. Density functional theory (DFT) calculations show that dissociative-associative mechanism is energetically favorable on seven catalysts (CuTi/g-CN, CuV/g-CN, CuMn/g-CN, CuCo/g-CN, CuV/N6C, CuCr/N6C and CuFe/N6C) with the significantly reduced limiting potential of - 0.14 V to - 0.47 V. Specifically, an efficiently screening strategy was proposed to determine the dissociative-associative or directly associative mechanism for NO3RR. This work can provide useful guideline for the rational design and development of NO3RR electrocatalysts.
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Affiliation(s)
- Xiaonan Zheng
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150080, PR China; College of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang 453003, PR China
| | - Yu Yan
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150080, PR China
| | - Xiaoxiao Li
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150080, PR China
| | - Yang Liu
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150080, PR China.
| | - Yuan Yao
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150080, PR China.
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Xu H, Ma Y, Chen J, Zhang WX, Yang J. Electrocatalytic reduction of nitrate - a step towards a sustainable nitrogen cycle. Chem Soc Rev 2022; 51:2710-2758. [PMID: 35274646 DOI: 10.1039/d1cs00857a] [Citation(s) in RCA: 129] [Impact Index Per Article: 64.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Nitrate enrichment, which is mainly caused by the over-utilization of fertilisers and industrial sewage discharge, is a major global engineering challenge because of its negative influence on the environment and human health. To solve this serious problem, many technologies, such as the activated sludge method, reverse osmosis, ion exchange, adsorption, and electrodialysis, have been developed to reduce the nitrate levels in water bodies. However, the applications of these traditional techniques are limited by several drawbacks, such as a long sludge retention time, slow kinetics, and undesirable by-products. From an environmental perspective, the most promising nitrate reduction technology is enabled to convert nitrate into benign N2, and features low cost, high efficiency, and environmental friendliness. Recently, electrocatalytic nitrate reduction has been proven by satisfactory research achievements to be one of the most promising methods among these technologies. This review provides a comprehensive account of nitrate reduction using electrocatalysis methods. The fundamentals of electrocatalytic nitrate reduction, including the reaction mechanisms, reactor design principles, product detection methods, and performance evaluation methods, have been systematically summarised. A detailed introduction to electrocatalytic nitrate reduction on transition metals, especially noble metals and alloys, Cu-based electrocatalysts, and Fe-based electrocatalysts is provided, as they are essential for the accurate reporting of experimental results. The current challenges and potential opportunities in this field, including the innovation of material design systems, value-added product yields, and challenges for products beyond N2 and large-scale sewage treatment, are highlighted.
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Affiliation(s)
- Hui Xu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
| | - Yuanyuan Ma
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
| | - Jun Chen
- ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, Australian Institute of Innovative Materials, Innovation Campus, University of Wollongong, Wollongong, NSW 2522, Australia.
| | - Wei-Xian Zhang
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China
| | - Jianping Yang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
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Rajmohan KS, Gopinath M, Chetty R. Bioremediation of Nitrate-Contaminated Wastewater and Soil. ENERGY, ENVIRONMENT, AND SUSTAINABILITY 2018. [DOI: 10.1007/978-981-10-7485-1_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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