Electrocatalytic reduction of nitrate to dinitrogen by Cu2O/CF electrode
GUO Feng1,2, XIE Chen-xin2, HAN En-shan1, ZHANG Cheng-lei2, ZHAO Hui2, TENG Hou-kai2
1. School of Chemical Engineering, Hebei University of Technology, Tianjin 300401, China; 2. CNOOC Tianjin Chemical Industry Research and Design Institute, Tianjin 300131, China
Abstract：During the whole electrolysis process, the electrocatalytic activity of cathode materials is affected by the multi-electron kinetic reaction. Presently, copper-based materials have received much attention as one of the most significant electrochemical nitrate reduction reaction (NITRR) electrocatalysts. However, there are still no reports of effective solutions to the problems of activity limitation and selectivity. In this work, we compared the NITRR performance of s-Cu2O/CF and e-Cu2O/CF catalysts prepared on copper foam (CF) by in situ growth and electrodeposition, respectively. An extremely high NO3- removal rate of 92.1% and N2selectivity of 81.1% were attained by the s-Cu2O/CF catalyst in the electrolyte containing 0.05mol/L Cl- and 100mg/L NO3--N. Cyclic voltammetry and linear sweep voltammetry showed that the NITRR process was achieved by electron transfer between nitrate (NO3-) and Cu0derived from CF. In situ grown s-Cu2O/CF, as a bifunctional catalyst for electronic media or bridge, promotes not only NO3- reduction but also the production of reduced hydrogen (H*), which further enhances the conversion of NO2- to NH4+ or N2. After eight cycles of experiments, s-Cu2O/CF still maintained excellent electrocatalytic activity, which further demonstrates its great application potential in the NITRR. Furthermore, a two-step treatment strategy of Ir-Ru/Ti anodic pre-oxidation and s-Cu2O/CF cathodic post-reduction was adopted to remove 93.6% of chemical oxygen demand (COD) and 75.2% of total nitrogen (TN) from the actual wastewater.
Gruber N, Galloway J N. An Earth-system perspective of the global nitrogen cycle[J]. Nature, 2008,451(7176):293-296.
[2]
Pennino M J, Compton J E, Leibowitz S G. Trends in drinking water nitrate violations across the United States[J]. Environmental Science & Technology, 2017,51(22):13450-13460.
[3]
Martínez J B G, Ortiz A, Ortiz I. State-of-the-art and perspectives of the catalytic and electrocatalytic reduction of aqueous nitrates[J]. Applied Catalysis B-environmental, 2017,207(15):42-59.
[4]
Chen Y, Zhang Y, Liu H. Reduction of nitrate from groundwater: powder catalysts and catalytic membrane[J]. Journal of Environmental sciences, 2003,15(5):600-606.
[5]
Shih Y J, Wu Z L, Lin C Y, et al. Manipulating the crystalline morphology and facet orientation of copper and copper-palladium nanocatalysts supported on stainless steel mesh with the aid of cationic surfactant to improve the electrochemical reduction of nitrate and N2selectivity[J]. Applied Catalysis B: Environmental, 2020,273(15): 119053.
[6]
Yao F, Yang Q, Sun J, et al. Electrochemical reduction of bromate using noble metal-free nanoscale zero-valent iron immobilized activated carbon fiber electrode[J]. Chemical Engineering Journal, 2020,389(1):123588.
[7]
Garcia-Segura S, Lanzarini-Lopes M, Hristovski K D, et al. Electrocatalytic reduction of nitrate: Fundamentals to full-scale water treatment applications[J]. Applied Catalysis B: Environmental, 2018, 236(15):546-568.
[8]
Li Y, Ma J, Waite T D, et al. Development of a mechanically flexible 2D-MXene membrane cathode for selective electrochemical reduction of nitrate to N2: Mechanisms and implications[J]. Environmental Science & Technology, 2021,55(15):10695-703.
[9]
Zheng W, Zhu L, Yan Z, et al. Self-Activated Ni cathode for electrocatalytic nitrate reduction to ammonia: From fundamentals to scale-up for treatment of industrial wastewater[J]. Environmental Science & Technology, 2021,55(19):13231-13243.
[10]
Gao J, Shi N, Guo X, et al. Electrochemically selective ammonia extraction from nitrate by coupling electron- and phase-transfer reactions at a Three-phase interface[J]. Environmental Science & Technology, 2021,55(15):10684-10694.
[11]
Zeng Y, Priest C, Wang G, et al. Restoring the nitrogen cycle by electrochemical reduction of nitrate: Progress and prospects[J]. Small Methods, 2020,4(12):2000672.
[12]
Zhang C, He D, Ma J, et al. Active chlorine mediated ammonia oxidation revisited: Reaction mechanism, kinetic modelling and implications[J]. Water Research, 2018,145(15):220-230.
[13]
Bouzek K, Paidar M, Sadílková A, et al. Electrochemical reduction of nitrate in weakly alkaline solutions[J]. Journal of Applied Electrochemistry, 2001,31:1185-1193.
[14]
Mácová Z, Bouzek K, Serak J. Electrocatalytic activity of copper alloys for NO3- reduction in a weakly alkaline solution[J]. Journal of Applied Electrochemistry, 2007,37:557-566.
[15]
Reyter D, Bélanger D, Roué L. Nitrate removal by a paired electrolysis on copper and Ti/IrO2 coupled electrodes-influence of the anode/cathode surface area ratio[J]. Water research, 2010,44(6): 1918-1926.
[16]
Li M, Feng C, Zhang Z, et al. Efficient electrochemical reduction of nitrate to nitrogen using Ti/IrO2-Pt anode and different cathodes[J]. Electrochimica Acta, 2009,54:4600-4606.
[17]
Dash B P, Chaudhari S. Electrochemical denitrificaton of simulated ground water[J]. Water Res, 2005,39(17):4065-4072.
[18]
Dima G G, Vooys D A, Koper M M. Electrocatalytic reduction of nitrate at low concentration on coinage and transition-metal electrodes in acid solutions[J]. Journal of Electroanalytical Chemistry, 2003, 554-555(15):15-23.
[19]
Molodkina E B, Ehrenburg M R, Polukarov Y M, et al. Electroreduction of nitrate ions on Pt(111) electrodes modified by copper adatoms[J]. Electrochimica Acta, 2010,56(1):154-165.
[20]
Dima G G, Beltramo G G, Koper M M. Nitrate reduction on single-crystal platinum electrodes[J]. Electrochimica Acta, 2005, 50(21):4318-4326.
[21]
Wan L, Zhou Q, Wang X, et al. Cu2O nanocubes with mixed oxidation-state facets for (photo)catalytic hydrogenation of carbon dioxide[J]. Nature Catalysis, 2019,2:889-898.
[22]
Zhou J, Pan F, Yao Q, et al. Achieving efficient and stable electrochemical nitrate removal by in-situ reconstruction of Cu2O/Cu electroactive nanocatalysts on Cu foam[J]. Applied Catalysis B: Environmental, 2022,317(15):121811.
[23]
Zhao Q, Tang Z, Chen B, et al. Efficient electrocatalytic reduction of nitrate to nitrogen gas by a cubic Cu2O film with predominant (111) orientation[J]. Chemical Communications, 2022,58(22):3613-3616.
[24]
Xu H, Ma Y, Chen J, et al. Electrocatalytic reduction of nitrate-a step towards a sustainable nitrogen cycle[J]. Chem Soc Rev, 2022,51(7): 2710-2758.
[25]
Liu Y, Cao X, Cui L, et al. Zn-Ni-Co trimetallic carbonate hydroxide nanothorns branched on Cu(OH)2 nanorods array based on Cu foam for high-performance asymmetric supercapacitors[J]. Journal of Power Sources, 2019,437(15):226897.
[26]
Shih Y J, Wu Z L, Huang Y H, et al. Electrochemical nitrate reduction as affected by the crystal morphology and facet of copper nanoparticles supported on nickel foam electrodes (Cu/Ni)[J]. Chemical Engineering Journal, 2020,383(1):123157.
[27]
Sugimoto W, Iwata H, Yokoshima K, et al. Proton and electron conductivity in hydrous ruthenium oxides evaluated by electrochemical impedance spectroscopy: The origin of large capacitance[J]. The Journal of Physical Chemistry B, 2005,109(15): 7330-7338.
[28]
Gao J, Jiang B, Ni C, et al. Non-precious Co3O4-TiO2/Ti cathode based electrocatalytic nitrate reduction: Preparation, performance and mechanism[J]. Applied Catalysis B: Environmental, 2019,254(5): 391-402.
[29]
Zhang D, Wang B, Gong X, et al. Selective reduction of nitrate to nitrogen gas by novel Cu2O-Cu0@Fe0composite combined with Hcooh under UV radiation[J]. Chemical Engineering Journal, 2019, 359(1):1195-1204.
[30]
Yao F, Jia M, Yang Q, et al. Electrochemical Cr(VI) removal from aqueous media using titanium as anode: Simultaneous indirect electrochemical reduction of Cr(VI) and in-situ precipitation of Cr(III)[J]. Chemosphere, 2020,260:127537.
[31]
Anglada A, Ibañez R, Urtiaga A, et al. Electrochemical oxidation of saline industrial wastewaters using boron-doped diamond anodes[J]. Catalysis Today, 2010,151(1):178-184.
[32]
Duan W, Li G, Lei Z, et al. Highly active and durable carbon electrocatalyst for nitrate reduction reaction[J]. Water Research, 2019,161:126-135.
[33]
Wang D M, Lin H Y, Shah S I, et al. Indirect electrochemical reduction of perchlorate and nitrate in dilute aqueous solutions at the Ti-water interface[J]. Separation and Purification Technology, 2009,67(2):127-134.
[34]
Yao F, Yang Q, Zhong Y, et al. Indirect electrochemical reduction of nitrate in water using zero-valent titanium anode: Factors, kinetics, and mechanism[J]. Water Research, 2019,157(15):191-200.
[35]
Gao J, Jiang B, Ni C, et al. Enhanced reduction of nitrate by noble metal-free electrocatalysis on P doped three-dimensional Co3O4 cathode: Mechanism exploration from both experimental and DFT studies[J]. Chemical Engineering Journal, 2020,382(15):123034.
[36]
Hamid S, Kumar M A, LEE W. Highly reactive and selective Sn-Pd bimetallic catalyst supported by nanocrystalline ZSM-5for aqueous nitrate reduction[J]. Applied Catalysis B: Environmental, 2016,187(15):37-46.
[37]
Wang Y, Zhou W, Jia R, et al. Unveiling the Activity Origin of a Copper-based Electrocatalyst for Selective Nitrate Reduction to Ammonia[J]. Angewandte Chemie International Edition, 2020,59(13): 5350-5354.
[38]
Anglada Á, Urtiaga A, Ortiz I, et al. Boron-doped diamond anodic treatment of landfill leachate: Evaluation of operating variables and formation of oxidation by-products[J]. Water Research, 2011, 45(2):828-838.
[39]
Anglada A, Ortiz D, Urtiaga A M, et al. Electrochemical oxidation of landfill leachates at pilot scale: evaluation of energy needs[J]. Water Science and Technology, 2010,61(9):2211-2217.
[40]
Yao Q, Zhou X, Xiao S, et al. Amorphous nickel phosphide as a noble metal-free cathode for electrochemical dechlorination[J]. Water Research, 2019,165(15):114930.
