CO<sub>2</sub>电还原生成甲酸盐机理及催化剂研究

赵萍萍; 廉红蕾

doi:10.19906/j.cnki.JFCT.2023048

CO₂电还原生成甲酸盐机理及催化剂研究

doi: 10.19906/j.cnki.JFCT.2023048

赵萍萍^{1, 2,},
廉红蕾^{1, 2, ,}

1.
郑州大学化工学院先进功能材料制造教育部工程研究中心, 河南郑州 450000
2.
炼焦煤资源绿色开发全国重点实验室, 河南郑州 450000

详细信息

通讯作者:
Tel: 13663002080, E-mail: hongleilian@zzu.edu.cn

中图分类号: O643.3
计量
- 文章访问数: 357
- HTML全文浏览量: 155
- PDF下载量: 70
- 被引次数: 0
出版历程
- 收稿日期: 2023-04-25
- 修回日期: 2023-06-05
- 录用日期: 2023-06-06
- 网络出版日期: 2023-07-08
- 刊出日期: 2023-11-13

Research on mechanism and catalysts of CO₂ electroreduction to formate

ZHAO Ping-ping^{1, 2
,},
LIAN Hong-lei^{1, 2
, ,}

1.
Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education, School of Chemical Engineering, Zhengzhou University, Zhengzhou 450000, China
2.
National Key Laboratory of Coking Coal Green Process Research, Zhengzhou 450000, China

摘要

摘要: 本工作综述了近五年来CO₂电催化还原生成甲酸盐领域取得的最新进展。介绍了CO₂电还原生成甲酸盐的反应机理，以及该过程所使用的催化剂的类型，包括金属催化剂、原子分散催化剂、金属氧化物催化剂、炭材料及复合材料催化剂。从催化剂、电解液、反应气氛和电解池等多角度详细分析了影响产物选择性、催化活性和稳定性的主要因素。针对目前CO₂电还原生成甲酸盐研究现状，提出对纳米材料和复合材料进行创新，借助原位表征技术探究活性位点及反应路径，并用于指导高效催化剂的设计与合成，改进电化学反应器组件以提高催化效率等问题可以作为未来的研究重点和发展方向。
- CO₂电还原 /
- 反应机理 /
- 催化剂 /
- 甲酸盐
Abstract: This paper reviews the latest progress in the field of CO₂ electrocatalytic reduction to formate in the past five years. The reaction mechanism of CO₂ electroreduction to formate and the types of catalysts used in this process are introduced, including metal catalysts, atomic dispersion catalysts, metal oxide catalysts, carbon materials, and composite material catalysts. The main factors affecting product selectivity, catalytic activity and stability are analyzed in detail from the perspectives of catalyst, electrolyte, reaction atmosphere and electrolytic cell. In view of the current research status of carbon dioxide electroreduction to formate, it is proposed to innovate on nanomaterials and composites, explore the active site and reaction path with the help of in-situ characterization technology, and guide the design and synthesis of efficient catalysts, improve the electrochemical reactor module to improve the catalytic efficiency and other issues can be regarded as the future research focus and development direction.
- CO₂ electroreduction /
- reaction mechanism /
- catalyst /
- formate

HTML全文

FIG. 2763. FIG. 2763.

下载: 全尺寸图片幻灯片

图 1 CO₂-ECR生成甲酸盐、CO和其他产物的可能反应路径^[14]

Figure 1 Possible reaction pathways for CO₂-ECR to formate, CO and other products^[14] (with permission from Wiley publication)

下载: 全尺寸图片幻灯片

图 2 (a)Bi、Bi₂O₃和Bi₂O₃衍生物上CO₂电还原为甲酸自由能；(b)Bi和Bi₂O₃上CO₂还原过程示意图^[23]

Figure 2 (a) The free energy calculation of CO₂ conversion to formate over Bi, Bi₂O₃, and Bi₂O₃ derivative; (b) reduction process of CO₂ over Bi and Bi₂O₃^[23] (with permission from ACS publication)

下载: 全尺寸图片幻灯片

图 3 (a) PdCuAuAgBiIn HEAAs和(b) PdCuAuAgBiIn HEAPs的原位衰减全反射红外吸收光谱谱图^[27]

Figure 3 In-situ attenuated total reflectance infrared absorption spectroscopy of (a) PdCuAuAgBiIn HEAAs and (b) PdCuAuAgBiIn HEAPs^[27] (with permission from Wiley publication)

下载: 全尺寸图片幻灯片

图 4 (a)原位拉曼测试装置示意图；在0.5 mol/L KHCO₃电解液中，CO₂鼓泡条件下，BiCuSeO催化剂的原位拉曼光谱谱图：(b)不同还原电位，((c)−(d))不同反应时间^[28]

Figure 4 (a) Schematic illustration of the in situ Raman measurement device during the CO₂-ECR; (b) potential- dependent and ((c)−(d)) time-dependent in situ Raman spectra of BiCuSeO catalysts in 0.5 mol/L KHCO₃ solution under CO₂ bubbling^[28] (with permission from Nature publication)

下载: 全尺寸图片幻灯片

图 5 (a)基于Poisson-Nernst-Planck模拟得到的H⁺离子浓度C_{H +}与外亥姆霍兹面之间距离的关系；(b)不同K⁺浓度下的产物选择性；(c)在没有或存在K⁺的情况下，CO₂-ECR生成HCOOH的吉布斯自由能^[37]

Figure 5 (a) The ions concentration C_{H +} as function of distance from the outer Helmholtz plane (OHP) based Poisson-Nernst-Planck simulations; (b) product selectivity at different K⁺ concentrations; (c) Gibbs free energy diagram of CO₂-ECR to HCOOH in the absence or presence of K⁺ cations^[37] (with permission from ACS publication)

下载: 全尺寸图片幻灯片

图 6 Sn-Bi界面结构催化剂的(a)扫描电镜照片；(b)透射电镜照片；不同样品（Sn-Bi界面，Sn-Bi合金，电沉积ED-Bi，水热法SnO_x，电沉积ED-Sn）的(c)FE_HCOOH和(d)PCD_HCOOH^[41]

Figure 6 (a) SEM image and (b) TEM image of Sn-Bi interfacial catalyst; (c) FE_HCOOH and (d) PCD_HCOOH over various samples (Sn-Bi interface, Sn-Bi alloy, electrodeposition ED-Bi, hydrothermal SnO_x and electrodeposition ED-Sn)^[41] (with permission from Nature publication)

下载: 全尺寸图片幻灯片

图 7 (a)Pd 3d精细XPS光谱谱图；(b)PdCuAuAgBiIn HEAAs的伏安曲线；(c)PdCuAuAgBiIn HEAAs和(d)Pd金属气凝胶（Pd MAs）在不同电位下各种产物的法拉第效率^[27]

Figure 7 (a) Pd 3d fine XPS spectra; (b) CO stripping curve of PdCuAuAgBiIn HEAAs; Reduction potential dependent FEs measured on (c) PdCuAuAgBiIn HEAAs and (d) Pd MAs^[27] (with permission from Wiley publication)

下载: 全尺寸图片幻灯片

图 8 (a)*OCHO和*COOH在In-N-C表面的稳定吸附的几何结构；(b)在In-N-C、In(101)、In(110)和In(112)表面CO₂-ECR自由能^[51]

Figure 8 (a) Stable adsorption geometry of *OCHO and *COOH on the surface of In-N-C; (b) free energy diagram on the surface of In-N-C, In(101), In(110) and In(112) under CO₂-ECR^[51] (with permission from ACS publication)

下载: 全尺寸图片幻灯片

图 9 NW-SnO₂的(a)低分辨率和((b)、(c))高分辨率透射电镜照片^[60]

Figure 9 (a) Low resolution TEM images and ((b), (c)) high resolution TEM images of NW-SnO₂^[60] (with permission from Elsevier publication)

下载: 全尺寸图片幻灯片

图 10 在含0.5 mol/L KHCO₃电解液的H型电解池中，Bi₂O₃@C/HB、Bi₂O₃@C/HL、C/HB、C/HL的(a)线性扫描伏安曲线，(b)甲酸盐法拉第效率，(c)甲酸盐部分电流密度；在含1 mol/L KOH电解液的流动池中，Bi₂O₃@C/HB和Bi₂O₃@C/HB的(d)线性扫描伏安曲线，(e)甲酸盐法拉第效率，(f)甲酸盐部分电流密度^[74]

Figure 10 (a) Linear sweep voltammetry curve, (b) FE_formate, (c) j_formate of Bi₂O₃@C/HB, Bi₂O₃@C/HL, C/HB, C/HL in a H-cell containing 0.5 mol/L KHCO₃ electrolyte, (d) Linear sweep voltammetry curve, (e) FE_formate, (f) j_formate of Bi₂O₃@C/HB, Bi₂O₃@C/HL in a flow cell containing 1 mol/L KOH electrolyte^[74] (with permission from ACS publication)

下载: 全尺寸图片幻灯片

图 11 SnCu-CNS的(a)扫描电镜照片；(b)透射电镜照片^[86]

Figure 11 (a) SEM and (b) TEM images of SnCu-CNS^[86] (with permission from Wiley publication)

下载: 全尺寸图片幻灯片

图 12 在−1.6 V vs. RHE电位下对(a)BiOCl_0.5Br_0.5，(b)BiOCl_0.5I_0.5，(c)BiOBr_0.5I_0.5进行恒电位电解^[89]

Figure 12 Controlled potential electrolysis on (a) BiOCl_0.5Br_0.5, (b) BiOCl_0.5I_0.5, (c) BiOBr_0.5I_0.5 at −1.6 V vs. RHE^[89] (with permission from Elsevier publication)

下载: 全尺寸图片幻灯片

图 13 Bi(012)和Bi(003)晶面上OCHO*形成的自由能^[91]

Figure 13 Free energy for OCHO* generation on (012) and (003) facet of Bi^[91] (with permission from Elsevier publication)

下载: 全尺寸图片幻灯片

图 14 (a)电解质类型和阳离子尺寸对电流密度和FE_HCOOH的影响 0.1 mol/L的MHCO₃(M= Li⁺、Na⁺、K⁺、Rb⁺、Cs⁺)电解液，−1.4 V vs. RHE电位，SnO₂/C电极；(b)0.1 mol/L的NaX和KX(X = ${\rm{HCO}}_3^- $、Cl⁻、Br⁻ and I⁻)电解液中，−1.4 V vs. RHE电位下，SnO₂/C电极上得到的电流密度和FE_HCOOH^[93]

Figure 14 (a) Current density and FE_HCOOH as functions of electrolyte type and the cation size, measured using an SnO₂/C electrode at −1.4 V in 0.1 mol/L MHCO₃ (M = Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺) electrolytes; (b) current density and FE_HCOOH at the SnO₂/C electrode at −1.4 V in 0.1 mol/L NaX and KX (X = ${\rm{HCO}}_3^- $, Cl⁻, Br⁻ and I⁻), respectively^[93] (with permission form Elsevier publication)

下载: 全尺寸图片幻灯片

图 15 在1 mol/L KHCO₃中100 mA/cm²的恒定电流密度下，在(a)Ag，(b)Sn和(c)Cu催化剂上的CO₂ + SO₂催化性能^[97]

Figure 15 Performance of CO₂ + SO₂ electrolysis over (a) Ag, (b) Sn and (c) Cu catalysts at constant current density of 100 mA/cm² in 1 mol/L KHCO₃^[97] (with permission from ACS publication)

下载: 全尺寸图片幻灯片

表 1 不同催化剂电还原CO₂生成甲酸盐的性能

Table 1 Performance of electroreduction CO₂ towards formate over various catalysts

Catalyst	Potential (V vs. RHE)	FE_HCOO⁻/%	J_HCOO⁻/(mA·cm⁻²)	Cell type	Electrolyte	Reference
PdCuAuAgBiIn HEAAs	−1.1	98.1	−	H-cell	0.1 mol/L KHCO₃	[27]
hp-In	−1.2	90	67.5	H-cell	0.1 mol/L KHCO₃	[33]
Bi NS	−1.23	92.2	237.1	flow cell	0.5 mol/L H₂SO₄(K⁺)	[37]
CuSn	−1.4	87.3	140.6	H-cell	0.5 mol/L KHCO₃	[40]
Sn-Bi	−0.84	96.4	−	H-cell	0.5 mol/L KHCO₃	[41]
Sn SA/ZnO	−1.2	80	−	flow cell	0.5 mol/L KHCO₃	[50]
In-N-C	−0.79	80	6.8	H-cell	0.5 mol/L KHCO₃	[51]
BiO_n	−	90	500	MEA	0.1 mol/L KOH	[58]
Bi₂O₃-A	−1.2	91	22	H-cell	0.5 mol/L KHCO₃	[59]
NW-SnO₂	−1.0	87.4	22	H-cell	0.5 mol/L KHCO₃	[60]
BDD	−	90	2	flow cell	0.5 mol/L KCl	[67]
Bi-HTC/OCNTs	−1.01	94	17.8	H-cell	0.5 mol/L KHCO₃	[72]
In₂S₃-rGO	−1.2	91	−	H-cell	0.1 mol/L KHCO₃	[73]
Bi₂O₃@C/HB	−0.7	93.8	−	H-cell	0.5 mol/L KHCO₃	[74]
	−1.5	−	285	flow cell	1 mol/L KOH
Bi₂O₃@C	−1.1	93	208	flow cell	1 mol/L KOH	[76]
In₂O₃@C	−1.1	94	−	flow cell	1 mol/L KOH	[77]
Bi₂S₃	−0.95	93	1900	flow cell	1 mol/L KOH	[84]
CuS/SnO₂-S	−0.8	84.9	18.8	H-cell	0.5 mol/L KHCO₃	[85]
SnCu-CNS	−0.9	95.1	−	H-cell	0.1 mol/L KHCO₃	[86]

下载: 导出CSV

参考文献(99)

[1]	LIU Z, DENG Z, DAVIS S J, GIRON C, CIAIS P. Monitoring global carbon emissions in 2021[J]. Nat Rev Earth Environ,2022,3:217−219. doi: 10.1038/s43017-022-00285-w
[2]	SHEN H, WANG Y Z, CHAKRABORTY T, ZHOU G Y, WANG C H, FU X B, WANG Y X, ZHANG J Y, LI C Y, XU F, CAO L, MUELLER T, WANG C. Asymmetrical C-C coupling for electroreduction of CO on bimetallic Cu-Pd catalysts[J]. ACS Catal,2022,12(9):5275−5283. doi: 10.1021/acscatal.2c00646
[3]	GUO C Y, GUO Y H, SHI Y M, LAN X E, WANG Y T, YU Y F, ZHANG B. Electrocatalytic reduction of CO₂ to ethanol at close to theoretical potential via engineering abundant electron-donating Cu^{δ +} species[J]. Angew Chem Int Ed,2022,61(32):202205909.
[4]	ZHAO Z, PENG X Y, LIU X J, SUN X M, SHI J, HAN L L, LI G L, LUO J. Efficient and stable electroreduction of CO₂ to CH₄ on CuS nanosheet arrays[J]. J Mater Chem A,2017,5:20239−20243. doi: 10.1039/C7TA05507B
[5]	HAN L L, SONG S J, LIU M J, YAO S Y, LIANG Z X, CHENG H, REN Z H, LIU W, LIN R Q, QI G C, LIU X J, WU Q, LUO J, XIN H L L. Stable and efficient single-atom Zn catalyst for CO₂ reduction to CH₄[J]. JACS,2020,142(29):12563−12567. doi: 10.1021/jacs.9b12111
[6]	CHEN C, KOTYK J F K, SHEEHAN S W. Progress toward commercial application of electrochemical carbon dioxide reduction[J]. Chem,2018,4(11):2571−2586. doi: 10.1016/j.chempr.2018.08.019
[7]	SONG C F, LIU Q L, QI Y, CHEN G Y, SONG Y J, KANSHA Y, KITAMURA Y. Absorption-microalgae hybrid CO₂ capture and biotransformation strategy-a review[J]. Int J Greenh Gas Con,2019,88:109−117. doi: 10.1016/j.ijggc.2019.06.002
[8]	LI C F, GUO R T, ZHANG Z R, WU T, PAN W G. Converting CO₂ into value-added products by Cu₂O-based catalysts: from photocatalysis, electrocatalysis to photoelectrocatalysis[J]. Small,2023,19(19):2207875. doi: 10.1002/smll.202207875
[9]	付豪, 廉红蕾. CO₂甲烷化反应路径的研究进展[J]. 燃料化学学报,2023,51(4):428−443. FU Hao, LIAN Hong-lei. Research progress on the reaction pathway of CO₂ methanation[J]. J Fuel Chem Technol,2023,51(4):428−443.
[10]	ZHOU Z Y, SUN S G. A breakthrough in electrocatalysis of CO₂ conversion[J]. NSR,2017,4(2):155−156.
[11]	DU C, WANG X, CHEN W, FENG S, WEN J, WU Y A. CO₂ transformation to multicarbon products by photocatalysis and electrocatalysis[J]. Mater Today Adv,2020,6:100071. doi: 10.1016/j.mtadv.2020.100071
[12]	GODIN J, LIU W Z, REN S, XU C C. Advances in recovery and utilization of carbon dioxide: A brief review[J]. J Environ Chem Eng,2021,9(4):105644. doi: 10.1016/j.jece.2021.105644
[13]	CHEN S Y, LI X Q, LI H M, CHEN K J, LUO T, FU J W, LIU K, WANG Q Y, ZHU M S, LIU M. Proton transfer dynamics mediated CO₂ electroreduction reaction[J]. ChemSusChem, 2023, 16(12): e202202251.
[14]	HAN N, DING P, HE L, LI Y Y, LI Y G. Promises of main group metal-based nanostructured materials for electrochemical CO₂ reduction to formate[J]. Adv Energy Mater,2020,10(11):1902338. doi: 10.1002/aenm.201902338
[15]	HSIEH Y C, SENANAYAKE S D, ZHANG Y, XU W Q, POLYANSKY D. Effect of chloride anions on the synthesis and enhanced catalytic activity of silver nanocoral electrodes for CO₂ electroreduction[J]. ACS Catal,2015,5(9):5349−5356. doi: 10.1021/acscatal.5b01235
[16]	LIU G B, LI Z H, SHI J J, SUN K, JI Y J, WANG Z G, QIU Y F, LIU Y Y, WANG Z J, HU P A. Black reduced porous SnO₂ nanosheets for CO₂ electroreduction with high formate selectivity and low overpotential[J]. Appl Catal B: Environ,2020,260:118134. doi: 10.1016/j.apcatb.2019.118134
[17]	KLINKOVA A, LUNA P D, DINH C T, VOZNYY O, LARIN E M, KUMACHEVA E, SARGENT E H. Rational design of efficient palladium catalysts for electroreduction of carbon dioxide to formate[J]. ACS Catal,2016,6(12):8115−8120. doi: 10.1021/acscatal.6b01719
[18]	WANG J G, NING S L, LUO M, XIANG D, CHEN W, KANG X W, JIANG Z, CHEN S W. In-Sn alloy core-shell nanoparticles In-doped SnO_x shell enables highstability and activity towards selective formate production from electrochemical reduction of CO₂[J]. Appl Catal B: Environ,2021,288:119979. doi: 10.1016/j.apcatb.2021.119979
[19]	CHEN S Y, LI X Q, LI H M, CHEN K J, LUO T, FU J W, LIU K, WANG Q Y, ZHU M S, LIU M. Proton transfer dynamics mediated CO₂ electroreduction reaction[J]. ChemSusChem,2023,16(12):e202202251.
[20]	LUO W, XIE W, MUTSCHLER R, OVEISI E, GREGORIO G L D, BUONSANTI R, ZÜTTEL A. Selective and stable electroreduction of CO₂ to CO at the copper/indium interface[J]. ACS Catal,2018,8:6571−6581. doi: 10.1021/acscatal.7b04457
[21]	YANG H, HU Y W, CHEN J J, BALOGUN M S, FANG P P, ZHANG S Q, CHEN J T, Y X. CO₂ electroreduction: intermediates adsorption engineering of CO₂ electroreduction reaction in highly selective heterostructure Cu-based electrocatalysts for CO production[J]. Adv Energy Mater,2019,9(27):1970107.
[22]	LIU T Y, OHASHI K, NAGITA K, HARADA T, NAKANISHI S, KAMIYA K. A tin oxide-coated copper foam hybridized with a gas diffusion electrode for efficient CO₂ reduction to formate with a current density exceeding 1 A cm⁻²[J]. Small,2022,18(50):2205323. doi: 10.1002/smll.202205323
[23]	DENG P L, WANG H M, QI R J, ZHU J X, CHEN S H, YANG F, ZHOU L, QI K, LIU H F, XIA B Y. Bismuth oxides with enhanced bismuth-oxygen structure for efficient electrochemical reduction of carbon dioxide to formate[J]. ACS Catal,2020,10(1):743−750. doi: 10.1021/acscatal.9b04043
[24]	LIU S, FAN Y P, WANG Y, JIN S, HOU M C, ZENG W J, LI K, JIANG T L, QIN L, YAN Z H, TAO Z L, ZHENG X H, SHEN C Y, LIU Z C, AHMAD T, ZHANG K, CHEN W. Surface-oxygen-rich Bi@C nanoparticles for high-efficiency electroreduction of CO₂ to formate[J]. Nano Lett,2022,22(22):9107−9114. doi: 10.1021/acs.nanolett.2c03573
[25]	FIGUEIREDO M C, LEDEZMA-YANEZ I, KOPER M T M. In situ spectroscopic study of CO₂ electroreduction at copper electrodes in acetonitrile[J]. ACS Catal,2016,6(4):2382−2392. doi: 10.1021/acscatal.5b02543
[26]	MOTOBAYASHI K, MAENO Y, IKEDA K. In situ spectroscopic characterization of an intermediate of CO₂ electroreduction on a Au electrode in room-temperature ionic liquids[J]. J Phys Chem C,2022,126(29):11981−11986. doi: 10.1021/acs.jpcc.2c03012
[27]	LI H J, HUANG H G, CHEN Y, LAI F L, FU H, ZHANG L S, ZHANG N, BAI S X, LIU T X. High-entropy alloy aerogels: a new platform for carbon dioxide reduction[J]. Adv Mater,2023,35(2):2209242. doi: 10.1002/adma.202209242
[28]	DUAN J Y, LIU T Y, ZHAO Y H, YANG R O, ZHAO Y, WANG W B, LIU Y W, LI H Q, LI Y F, ZHAI T Y. Active and conductive layer stacked superlattices for highly selective CO₂ electroreduction[J]. Nat Commun,2022,13:2039. doi: 10.1038/s41467-022-29699-2
[29]	YOO J S, CHRISTENSEN, R, VEGGE T, NØRSKOV J K, STUDT F. Theoretical insight into the trends that guide the electrochemical reduction of carbon dioxide to formic acid[J]. ChemSusChem,2016,9(4):358−363. doi: 10.1002/cssc.201501197
[30]	CHEN Y H, KANAN M W. Tin oxide dependence of the CO₂ reduction efficiency on tin electrodes and enhanced activity for tin/tin oxide thin-film catalysts[J]. JACS,2012,134(4):1986−1989. doi: 10.1021/ja2108799
[31]	HAN N, WANG Y, YANG H, DENG J, WU J H, LI Y F, LI Y G. Ultrathin bismuth nanosheets from in situ topotactic transformation for selective electrocatalytic CO₂ reduction to formate[J]. Nat Commun,2018,9(1):1320−1328. doi: 10.1038/s41467-018-03712-z
[32]	VASILEFF A, XU C C, JIAO Y, ZHENG Y, QIAO S Z. Surface and interface engineering in copper-based bimetallic materials for selective CO₂ electroreduction[J]. Chem,2018,4(8):1809−1831. doi: 10.1016/j.chempr.2018.05.001
[33]	LUO W, XIE W, LI M, ZHANG J, ZÜTTEL A. 3D hierarchical porous indium catalyst for highly efficient electroreduction of CO₂[J]. J Mater Chem A,2019,7:4505−4515. doi: 10.1039/C8TA11645H
[34]	GREELEY J, JARAMILLO T F, BONDE J, CHORKENDORFF I, NØRSKOV J K. Computational high-throughput screening of electrocatalytic materials for hydrogen evolution[J]. Nat Mater,2006,5:909−913. doi: 10.1038/nmat1752
[35]	YANG J, WANG X L, QU Y T, WANG X, HUO H, FAN Q K, WANG J, YANG L M, WU Y E. Bi-based metal-organic framework derived leafy bismuth nanosheets for carbon dioxide electroreduction[J]. Adv Energy Mater,2019,45(9):11861−11867.
[36]	YI L C, CHEN J X, SHAO P, HUANG J H, PENG X X, LI J W, WANG G X, ZHANG C, WEN Z H. Molten-salt-assisted synthesis of bismuth nanosheets for long-term continuous electrocatalytic conversion of CO₂ to formate[J]. Angew Chem Int Ed,2020,59(45):20112−20119. doi: 10.1002/anie.202008316
[37]	QIAO Y, LAI W C, HUANG K, YU T T, WANG Q Y, GAO L, YANG Z L, MA Z S, SUN T L, LIU M, LIAN C, HUANG H W. Engineering the local microenvironment over Bi nanosheets for highly selective electrocatalytic conversion of CO₂ to HCOOH in strong acid[J]. ACS Catal,2022,12(4):2357−2364. doi: 10.1021/acscatal.1c05135
[38]	JOUNY M, LUC W, JIAO F. General techno-economic analysis of CO₂ electrolysis systems[J]. Ind Eng Chem Res,2018,57(6):2165−2177. doi: 10.1021/acs.iecr.7b03514
[39]	FENG G H, CHEN W, WANG B Y, SONG Y F, LI G H, FANG J H, WEI W, SUN Y H. Oxygenates from the electrochemical reduction of carbon dioxide[J]. Chem-Asian J,2018,13(16):1992−2008. doi: 10.1002/asia.201800637
[40]	LI Y, HUO C Z, WANG H J, YE Z X, LUO P P, CAO X X, LU T B. Coupling CO₂ reduction with CH₃OH oxidation for efficient electrosynthesis of formate on hierarchical bifunctional CuSn alloy[J]. Nano Energy,2022,98:107277. doi: 10.1016/j.nanoen.2022.107277
[41]	REN B H, WEN G B, GAO R, LUO D, ZHANG Z, QIU W B, MA Q Y, WANG X, CUI Y, RICARDEZ-SANDOVAL L, YU A P, CHEN Z W. Nano-crumples induced Sn-Bi bimetallic interface pattern with moderate electron bank for highly efficient CO₂ electroreduction[J]. Nat Commun,2022,13:2486. doi: 10.1038/s41467-022-29861-w
[42]	GEORGE E P, RAABE D, RITCHIE R O. High-entropy alloys[J]. Nat Rev Mater,2019,4:515−534. doi: 10.1038/s41578-019-0121-4
[43]	WANG X, GUO W, FU Y Z. High-entropy alloys: Emerging materials for advanced functional applications[J]. J Mater Chem A,2021,9:663−701. doi: 10.1039/D0TA09601F
[44]	LU X L, RONG X, ZHANG C, LU T B. Carbon-based single-atom catalysts for CO₂ electroreduction progress and optimization strategies[J]. J Mater Chem A,2020,8:10695−10708. doi: 10.1039/D0TA01955K
[45]	LI X, PEREIRA-HERNÁNDEZ X I, CHEN Y Z, XU J, ZHAO J K, PAO C W, FANG C Y, ZENG J, WANG Y, GATES B C, LIU J Y. Functional CeO_x nanoglues for robust atomically dispersed catalysts[J]. Nature,2022,611:284−288. doi: 10.1038/s41586-022-05251-6
[46]	HERZING A A, KIELY C J, CARLEY A F, LANDON P, HUTCHINGS G J. Identification of active gold nanoclusters on Iron oxide supports for CO oxidation[J]. Science,2008,321(5894):1331−1335. doi: 10.1126/science.1159639
[47]	CREISSEN C E, FONTECAVE M. Keeping sight of copper in single-atom catalysts for electrochemical carbon dioxide reduction[J]. Nat Commun,2022,13:2280. doi: 10.1038/s41467-022-30027-x
[48]	CHEN Y, LIN J, JIA B H, WANG X D, JIANG S Y, MA T Y. Isolating single and few atoms for enhanced catalysis[J]. Adv Mater,2022,34(39):2201796. doi: 10.1002/adma.202201796
[49]	YANG X F, WANG A Q, QIAO B T, LI J, LIU J Y, ZHANG T. Single-atom catalysts: A new frontier in heterogeneous catalysis[J]. Accounts Chem Res,2013,46(8):1740−1748. doi: 10.1021/ar300361m
[50]	ZHANG Y Z, JANG H, GE X, ZHANG W, LI Z J, HOU L Q, ZHAI L, WEI X Q, WANG Z, KIM M G, LIU S G, QIN Q, LIU X E, CHO J. Single-atom Sn on tensile-strained ZnO nanosheets for highly efficient conversion of CO₂ into formate[J]. Adv Energy Mater,2022,12(45):2202695. doi: 10.1002/aenm.202202695
[51]	LU P L, TAN X, ZHAO H T, XIANG Q, LIU K L, ZHAO X X, YIN X M, LI X Z, HAI X, XI S B, WEE A T S, PENNYCOOK S J, YU X F, YUAN M L, WU J B, ZHANG G J, SMITH S C, YIN Z Y. Atomically dispersed indium sites for selective CO₂ electroreduction to formic acid[J]. ACS Nano,2021,15(3):5671−5678. doi: 10.1021/acsnano.1c00858
[52]	LIANG X M, WANG H J, ZHANG C, ZHONG D C, LU T B. Controlled synthesis of a Ni₂ dual-atom catalyst for synergistic CO₂ electroreduction[J]. Appl Catal B: Environ,2023,322:122073. doi: 10.1016/j.apcatb.2022.122073
[53]	LI Y F, CHEN C, CAO R, PAN Z W, HE H, ZHOU K B. Dual-stom Ag₂/graphene catalyst for efficient electroreduction of CO₂ to CO[J]. Appl Catal B: Environ,2020,268:118747. doi: 10.1016/j.apcatb.2020.118747
[54]	YAO D Z, TANG C, ZHI X, JOHANNESSEN B, SLATTERY A, CHERN S, QIAO S Z. Inter-metal interaction with a threshold effect in NiCu dual-atom catalysts for CO₂ electroreduction[J]. Adv Mater,2022,35(11):2209386.
[55]	GONG Y N, CAO C Y, SHI W J, ZHANG J H, DENG J H, LU T B, ZHONG D C. Modulating the electronic structures of dual-atom catalysts via coordination environment engineering for boosting CO₂ electroreduction[J]. Angew Chem Int Ed,2022,61(51):202215187.
[56]	LIU L J, WANG Z Y, WANG Z Y, WANG R, ZANG S Q, MAK T C W. Mediating CO₂ electroreduction activity and selectivity over atomically precise copper clusters[J]. Angew Chem Int Ed,2022,61(35):202205626.
[57]	WANG Y X, CUI X Z, ZHANG J Q, QIAO J L, HUANG H T, SHI J L, WANG G X. Advances of atomically dispersed catalysts from single-atom to clusters in energy storage and conversion applications[J]. Prog Mater,2022,128:100964. doi: 10.1016/j.pmatsci.2022.100964
[58]	JIANG X L, LIN L, RONG Y W, LI R T, JIANG Q K, YANG Y Y, GAO D F. Boosting CO₂ electroreduction to formate via bismuth oxide clusters[J]. Nano Res, 2023, 16: 12050–12057.
[59]	MIAO C C, YUAN G Q. Morphology-controlled Bi₂O₃ nanoparticles as catalysts for selective electrochemical reduction of CO₂ to formate[J]. ChemElectroChem,2018,5(23):3741−3747. doi: 10.1002/celc.201801036
[60]	CHEN Z, FAN T T, ZHANG Y Q, XIAO J, GAO M R, DUAN N Q, ZHANG J W, LI J H, LIU Q X, YI X D, LUO J L. Wavy SnO₂ catalyzed simultaneous reinforcement of carbon dioxide adsorption and activation towards electrochemical conversion of CO₂ to HCOOH[J]. Appl Catal B: Environ,2020,261:118243. doi: 10.1016/j.apcatb.2019.118243
[61]	SHU Z Y, YE G Y, WANG J, LIU S Q, HE Z, ZHU W W, LIU B, LIU M. Nitrogen-doped carbon with high graphitic-N exposure for electroreduction of CO₂ to CO[J]. Ionics,2021,27:3089−3098. doi: 10.1007/s11581-021-04077-y
[62]	SONG Y F, CHEN W, ZHAO C C, LI S G, WEI W, SUN Y H. Metal-free nitrogen-doped Mesoporous carbon for electroreduction of CO₂ to ethanol[J]. Angew Chem Int Ed,2017,56(36):10840−10844. doi: 10.1002/anie.201706777
[63]	JIA C, DASTAFKAN K, REN W H, YANG W F, ZHAO C. Carbon-based catalysts for electrochemical CO₂ reduction[J]. Sustainable Energy Fuels,2019,3(11):2890−2906. doi: 10.1039/C9SE00527G
[64]	DUAN X C, XU J T, WEI Z X, MA J M, GUO S J, WANG S Y, LIU H K, DOU S X. Metal-free carbon materials for CO₂ electrochemical reduction[J]. Adv Mater,2017,29(41):1701784. doi: 10.1002/adma.201701784
[65]	LIN J, YAN S L, ZHANG C X, HU Q, CHENG Z M. Electroreduction of CO₂ toward high current density[J]. Processes,2022,10(5):826. doi: 10.3390/pr10050826
[66]	ZANG D J, GAO X J J, LI L Y, WEI Y G, WANG H Q. Confined interface engineering of self-supported Cu@N-doped graphene for electrocatalytic CO₂ reduction with enhanced selectivity towards ethanol[J]. Nano Res,2022,15:8872−8879. doi: 10.1007/s12274-022-4698-3
[67]	NATSUI K, IWAKAWA H, IKEMIYA N, NAKATA K, EINAGA Y. Stable and highly efficient electrochemical production of formic acid from carbon dioxide using diamond electrodes[J]. Angew Chem Int Ed,2018,57(10):2693−2643.
[68]	CAO W T, HUANG Y F, LI D, CHEN W H, QIE Z P, PI X X, DU Q J, LAI X Y, LI Y H. N/S co-doped microporous zeolite-templated carbon for efficient CO₂ adsorption and separation[J]. J Energy Inst,2023,106:101159. doi: 10.1016/j.joei.2022.101159
[69]	LIANG X D, TIAN N, ZHOU Z Y, SUN S G. N, P dual-doped porous carbon nanosheets for high-efficiency CO₂ electroreduction[J]. ACS Sustainable Chem Eng,2022,10(5):1880−1887. doi: 10.1021/acssuschemeng.1c07601
[70]	MA X Y, DU J J, SUN H, YE F H, WANG X, XU P F, HU C G, ZHANG L P, LIU D. Boron, nitrogen co-doped carbon with abundant mesopores for efficient CO₂ electroreduction[J]. Appl Catal B: Environ,2021,298:120543. doi: 10.1016/j.apcatb.2021.120543
[71]	LI W B, YU C, TAN X Y, CUI S, ZHANG Y F, QIU J S. Recent advances in the electroreduction of carbon dioxide to formic acid over carbon-based materials[J]. New Carbon Mater,2022,37(2):277−287. doi: 10.1016/S1872-5805(22)60592-4
[72]	YANG F F, ZHANG W F, MA X Y, ZHANG D J. Ultrafine Bi nanoparticles confined in hydrothermal carbon-modified carbon nanotubes for highly efficient CO₂ electroreduction to formate[J]. J Electrochem Soc,2022,169:44524. doi: 10.1149/1945-7111/ac6703
[73]	NING H, FEI X, TAN Z H, WANG W H, YANG Z X, WU M B. In situ-fabricated In₂S₃-reduced graphene oxide nanosheet composites for enhanced CO₂ electroreduction to formate[J]. ACS Appl Nano Mater,2022,5(2):2335−2342. doi: 10.1021/acsanm.1c04016
[74]	LIU S Q, SHAHINI E, GAO M R, GONG L, SUI P F, TANG T, ZENG H B, LUO J L. Bi₂O₃ nanosheets grown on carbon nanofiber with inherent hydrophobicity for high-performance CO₂ electroreduction in a wide potential window[J]. ACS Nano,2021,15(11):17757−17768. doi: 10.1021/acsnano.1c05737
[75]	ABDELKADER-FERNÁNDEZ V K, FERNANDES D M, FREIRE C. Carbon-based electrocatalysts for CO₂ electroreduction produced via MOF, biomass, and other precursors carbonization: A review[J]. J CO₂ Util,2020,42:101350. doi: 10.1016/j.jcou.2020.101350
[76]	DENG P L, YANG F, WANG Z T, CHEN S H, ZHOU Y Z, ZAMAN S, XIA B Y. Metal-organic frameworks-derived carbon nanorods encapsulated bismuth oxides for rapid and selective CO₂ electroreduction to formate[J]. Angew Chem Int Ed,2020,59(27):10807−10813. doi: 10.1002/anie.202000657
[77]	WANG Z T, ZHOU Y S, LIU D Y, QI R J, XIA C F, LI M T, YOU B, XIA B Y. Carbon-confined indium oxides for efficient carbon dioxide reduction in a solid-state electrolyte flow cell[J]. Angew Chem Int Ed,2022,61(21):202200552.
[78]	OHYA S, KANECO S, KATSUMATA H, SUZUKI T, OHTA K. Electrochemical reduction of CO₂ in methanol with aid of CuO and Cu₂O[J]. Catal Today,2009,148(3):329−334.
[79]	LIU S Y, PANG F J, ZHANG Q W, GUO R J, WANG Z F, WANG Y C, ZHANG W Q, OU J Z. Stable nanoporous Sn/SnO₂ composites for efficient electroreduction of CO₂ to formate over wide potential range[J]. Appl Mater Today,2018,13:135−143. doi: 10.1016/j.apmt.2018.08.014
[80]	DAIYAN R, CHEN R, KUMAR P, BEDFORD N M, QU J T, CAIRNEY J M, LU X Y, AMAL R. Tunable syngas production through CO₂ electroreduction on cobalt-carbon composite electrocatalyst[J]. ACS Appl Mater Inter,2020,12(8):9370−9315.
[81]	ZHANG Y Y, LI K, CHEN M M, WANG J, LIU J D, ZHANG Y T. Cu/Cu₂O nanoparticles supported on vertically ZIF-L-coated nitrogen-doped graphene nanosheets for electroreduction of CO₂ to ethanol[J]. ACS Appl Nano Mater,2019,3(1):257−263.
[82]	JIANG X X, LI X, KONG Y, DENG C, LI X J, HU Q, YANG H P, HE C X. A hierarchically structured tin-cobalt composite with an enhanced electronic effect for high-performance CO₂ electroreduction in a wide potential range[J]. J Energy Chem,2023,76:462−469. doi: 10.1016/j.jechem.2022.10.008
[83]	CHAIKA M Y, VOLKOV V V, KRAVCHENKO T A, KONEV D V, GORSHKOV V S, KRYSANOV V A, BOSYACHENKO A A. Oxygen electroreduction on the anthraquinone-modified thin-film carbon-polymer composite in alkaline solution[J]. Russ J Electrochem,2019,55:1284−1291. doi: 10.1134/S102319351911003X
[84]	LIN L, HE X Y, ZHANG X G, MA W C, ZHANG B, WEI D Y, XIE S J, ZHANG Q H, YI X D, WANG Y. A nanocomposite of Bi clusters and Bi₂O₂CO₃ sheets for highly efficient electrocatalytic reduction of CO₂ to formate[J]. Angew Chem Int Ed,2023,62(3):202214959.
[85]	DOU T, HE J Q, DIAO S T, WANG Y P, ZHAO X H, ZHANG F Z, LEI X D. Dynamic reconstructuring of CuS/SnO₂-S for promoting CO₂ electroreduction to formate[J]. J Energy Chem,2023,82:497−506. doi: 10.1016/j.jechem.2023.03.016
[86]	JIANG X X, LI X, KONG Y, DENG C, LI X J, HU Q, YANG H P, HE C X. Oxidation state modulation of bimetallic tin-copper oxide nanotubes for selective CO₂ electroreduction to formate[J]. Small,2022,18(47):2204148. doi: 10.1002/smll.202204148
[87]	MENG F L, ZHANG Q, LIU K H, ZHANG X B. Integrated bismuth oxide ultrathin nanosheets/carbon foam electrode for highly selective and energy-efficient electrocatalytic conversion of CO₂ to HCOOH[J]. Chem Eur J,2020,26(18):4013−4018. doi: 10.1002/chem.201903158
[88]	WANG M, LIU S, CHEN B, HUANG M J, PENG C. Co-regulation of intermediate binding and water activation in sulfur-doped bismuth nanosheets for electrocatalytic CO₂ reduction to formate[J]. Chem Eng J,2023,451:139056. doi: 10.1016/j.cej.2022.139056
[89]	QIU Y, DU J, DONG W, DAI C N, TAO C Y. Selective conversion of CO₂ to formate on a size tunable nano-Bi electrocatalyst[J]. J CO₂ Util,2017,20:328−335. doi: 10.1016/j.jcou.2017.05.024
[90]	YANG H, HAN N, DENG J, WU J H, WANG Y, HU Y P, DING P, LI Y F, LI Y G, LU J. Selective CO₂ reduction on 2D mesoporous Bi nanosheets[J]. Adv Energy Mater,2018,8(35):1801536. doi: 10.1002/aenm.201801536
[91]	WEI X Y, ZHANG W N, LIU D P, LIU D D, YAN Y D, ZHANG J, YANG Y D, YAN S C, ZOU Z G. Bi particles with exposed (012) facet on 3D substrate as highly active and durable electrode for CO₂ reduction to formate[J]. J CO₂ Util,2022,55:101797. doi: 10.1016/j.jcou.2021.101797
[92]	ZHANG B, CHANG Y, WU Y Z, FAN Z Z, ZHAI P L, WANG C, GAO J F, SUN L C, HOU J G. Regulating OCHO Intermediate as rate-determining step of defective oxynitride nanosheets enabling robust CO₂ electroreduction[J]. Adv Energy Mater,2022,12(27):2200321. doi: 10.1002/aenm.202200321
[93]	ZHANG Q, SHAO X L, YI J, LIU Y Y, ZHANG J J. An experimental study of electroreduction of CO₂ to HCOOH on SnO₂/C in presence of alkali metal cations (Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺) and anions (HCO₃⁻, Cl⁻, Br⁻ and I⁻)[J]. Chin J Chem Eng,2020,28(10):2549−2554. doi: 10.1016/j.cjche.2020.04.015
[94]	CHEN S Y, LI X Q, KAO C W, LUO T, CHEN K J, FU J W, MA C, LI H M, LI M, CHAN T S, LIU M. Unveiling the proton-feeding effect in sulfur-doped Fe−N−C single-atom catalyst for enhanced CO₂ electroreduction[J]. Angew Chem Int Ed,2022,61(32):202206233.
[95]	CHEN X, CHEN J X, CHEN H Y, ZHANG Q Q, LI J X, CUI J W, SUN Y H, WANG D F, YE J H, LIU L Q. Promoting water dissociation for efficient solar driven CO₂ electroreduction via improving hydroxyl adsorption[J]. Nat Commun,2023,14:751. doi: 10.1038/s41467-023-36263-z
[96]	HORI Y, KONISHI H, FUTAMURA T, MURATA A, KOGA O, SAKURAI H, OGUMA K. “Deactivation of copper electrode” in electrochemical reduction of CO₂[J]. Electrochimica Acta,2005,50(27):5354−5369. doi: 10.1016/j.electacta.2005.03.015
[97]	LUC W, KO B H, KATTEL S, LI S, SU D, CHEN J G, JIAO F. SO₂-induced selectivity change in CO₂ electroreduction[J]. JACS,2019,141(25):9902−9909. doi: 10.1021/jacs.9b03215
[98]	QIAN Y, LIU Y F, TANG H H, LIN B L. Highly efficient electroreduction of CO₂ to formate by nanorod@2D nanosheets SnO[J]. J CO₂ Util,2020,42:101287. doi: 10.1016/j.jcou.2020.101287
[99]	XIA C, ZHU P, JIANG Q, PAN Y, LIANG W T, STAVITSKI E, ALSHAREEF H N, WANG H T. Continuous production of pure liquid fuel solutions via electrocatalytic CO₂ reduction using solid-electrolyte devices[J]. Nat Energy,2019,4:776−785. doi: 10.1038/s41560-019-0451-x