Table 2.
The representative examples of electrochemical CO2 reduction with different electrocatalysts, reaction conditions and selectivities
| Electrocatalyst | Electrolyte | Applied potential [V] | Major products [Faradaic efficiency, %] | Current density/mass activity | Ref. |
|---|---|---|---|---|---|
| 1. Selective production of HCOO−/HCOOH | |||||
| [Cu(cyclam)](ClO4)2 complex | DMF/H2O (97:3 v/v) | −2.0 (vs Fc/Fc+) | HCOOH (90%) | 1 mA cm−2 | 41 |
| Gas‐diffusion layer/CNT/Ir complex/polyethylene glycol | 0.5 m LiClO4/0.1 m NaHCO3/1% v/v MeCN | −1.40 (vs RHE) | HCOO− (83%) | 15.6 mA cm−2 | 54 |
| Pd‐polyaniline/CNTs | 0.1 m KHCO3 | −0.80 (vs SCE) | HCOO− (83%) | – | 57 |
| SnOx/Sn | 0.1 m KHCO3 | −1.36 (vs RHE) | HCOO− (71.6%) | 17.1 mA cm−2 | 71 |
| Nanostructured Sn | 0.1 m NaHCO3 | −1.80 (vs SCE) | HCOO− (93.6%) | 10.2 mA cm−2 | 72 |
| Sn | Ion liquids/H2O/MeCN | −2.30 (vs Ag/AgCl) | HCOOH (92.0%) | 32.1 mA cm−2 | 77 |
| Pb | HCOOH (91.6%) | 37.6 mA cm−2 | |||
| Pd NPs | 0.5 m NaHCO3 | −0.35 (vs RHE) | HCOO− (88%) | 3.45 mA cm−2 | 93 |
| Bi nanoflakes | 0.1 m KHCO3 | −0.40 (vs RHE) | HCOO− (79.5%) | – | 101 |
| Bi/BiOCl | 0.5 m KHCO3 | −1.50 (vs SCE) | HCOO− (≈92%) | 3.7 mA mg−1 | 161 |
| Cu pillars | 0.1 m KHCO3 | −0.50 (vs RHE) | HCOOH (28.7%) | ≈1.3 mA cm−2 | 107 |
| Cu nanofoam | 0.5 m KHCO3 | −1.50 (vs Ag/AgCl) | HCOOH (37%) | – | 162 |
| Ag–Sn alloy | 0.5 m NaHCO3 | −0.80 (vs RHE) | HCOOH (≈80%) | ≈16 mA cm−2 | 165 |
| PdxPt(100− x )/C | 0.1 m KH2PO4/0.1 m K2HPO4 | −0.40 (vs RHE) | HCOOH (88%) | ≈5 mA cm−2 | 120 |
| SnO2 porous nanowires | 0.1 m KHCO3 | −0.80 (vs RHE) | HCOO− (80%) | (−1.0 V) 10 mA cm−2 | 163 |
| Mesoporous SnO2 nanosheets/carbon paper | 0.5 m NaHCO3 | −1.60 (vs Ag/AgCl) | HCOO− (≈87%) | 50 mA cm−2 | 164 |
| Pb2O | 0.5 m KHCO3/NaHCO3 | −2.0 (vs Co3O4) | HCOOH (60%/50%) | – | 128 |
| Co3O4 atomic layers | 0.1 m KHCO3 | −0.88 (vs SCE) | HCOO− (64.3%) | 0.68 mA cm−2 | 130 |
| Partially oxidized Co atomic layers | 0.1 m Na2SO4 | −0.85 (vs RHE) | HCOO− (90.1%) | 10.59 mA cm−2 | 131 |
| PEI‐NCNTs/glassy carbon | 0.1 m KHCO3 | −1.80 (vs SCE) | HCOO− (85%) | 7.2 mA cm−2 | 146 |
| N‐doped graphene/carbon paper | 0.5 m KHCO3 | −0.84 (vs RHE) | HCOO− (73%) | 7.5 mA cm−2 | 148 |
| Boron‐doped graphene | 0.1 m KHCO3 | −1.40 (vs SCE) | HCOO− (66%) | 2 mA cm−2 | 151 |
| N‐doped nanodiamond/Si | 0.5 m NaHCO3 | −1.0 (vs RHE) |
HCOO− (13.6%) CH3COO− (77.6%) |
0.75 mA cm−2 | 155 |
| 2. Selective production of CO | |||||
| Fe TDHPP | DMF/2 m H2O | −1.16 (vs RHE) | CO (94%) | 0.31 mA cm−2 | 39 |
| Co protoporphyrin–pyrolytic graphite | Perchlorate solution (pH = 3) | −0.60 (vs RHE) | CO (60%) | 0.08 mA cm−2 | 40 |
| COF‐366‐Co | 0.5 m KHCO3 | −0.67 (vs RHE) | CO (90%) | 80 mA mg−1 (Co) | 201 |
| [Ru(‐6,6′‐dimesityl‐2,2′‐bipyridine)(CO)2Cl]0 | 0.1 m TBAPF6/MeCN | ≈−2.2 V (vs Fc/Fc+) | CO (95%) | – | 51 |
| Au‐1,3‐bis(2,4,6‐trimethylphenyl)imidazol‐2‐ylidene complex | 0.1 m KHCO3 | −0.57 (vs RHE) | CO (83%) | ≈2 mA cm−2 | 56 |
| Au NPs | 0.5 m KHCO3 | −0.67 (vs RHE) | CO (90%) | – | 79 |
| Au rhombic dodecahedrons | 0.5 m KHCO3 | −0.57 (vs RHE) | CO (93%) | – | 81 |
| Au/CNTs | 0.5 m NaHCO3 | −0.50 (vs RHE) | CO (≈94%) | ≈15 A g−1 (Au) | 82 |
| Au nanowires | 0.5 m KHCO3 | −0.35 (vs RHE) | CO (94%) | 1.84 A g−1 (Au) | 198 |
| Oxide‐derived Au | 0.5 m NaHCO3 | −0.35 (vs RHE) | CO (>96%) | 2–4 mA cm−2 | 199 |
| 6 µm thick highly porous Ag | 0.5 m KHCO3 | −0.50 (vs RHE) | CO (82%) | 10.5 mA cm−2 | 85 |
| Ag NPs | 0.5 m KHCO3 | −0.75 (vs RHE) | CO (79.2%) | 1 mA cm−2 | 86 |
| Nanoporous Ag | 0.5 m KHCO3 | −0.60 (vs RHE) | CO (≈92%) | ≈18 mA cm−2 | 87 |
| Ag nanocorals | 0.1 m KHCO3 | −0.60 (vs RHE) | CO (95%) | 6.62 mA cm−2 | 89 |
| Oxide‐derived Ag | 0.1 m KHCO3 | −0.80 (vs RHE) | CO (89%) | 1.15 mA cm−2 | 200 |
| Pd NPs | 0.1 m KHCO3 | −0.89 (vs RHE) | CO (91.2%) | 23.9 A g−1 (Pd) | 94 |
| Pd icosahedra/C | 0.1 m KHCO3 | −0.80 (vs RHE) | CO (91.1%) | – | 166 |
| Zn dendrites | 0.5 m NaHCO3 | −1.10 (vs RHE) | CO (79%) | – | 97 |
| Zn foil | 0.5 m NaCl | −1.60 (vs SCE) | CO (93%) | – | 98 |
| Hexagonal Zn | 0.5 m KHCO3 | −0.95 (vs RHE) | CO (85.4%) | 9.5 mA cm−2 | 99 |
| Surface activated Bi NPs | MeCN/[bmim][OTf] | −2.0 (vs Ag/AgCl) | CO (96.1%) | 15.6 mA mg−1 (Bi) | 100 |
| Cu fibers | 0.3 m KHCO3 | −0.40 (vs RHE) | CO (75%) | ≈9 mA cm−2 | 108 |
| Cu nanowires | 0.1 m KHCO3 | −0.40 (vs RHE) | CO (61.8%) | 1 mA cm−2 | 109 |
| Au3Cu alloy | 0.1 m KHCO3 | −0.73 (vs RHE) | CO (64.7%) | 3 mA cm−2 | 121 |
| Ordered AuCu NPs | 0.1 m KHCO3 | −0.77 (vs RHE) | CO (80%) | – | 167 |
| Cu–In alloy | 0.1 m KHCO3 | −0.60 (vs RHE) | CO (85%) | ≈0.75 mA cm−2 | 122 |
| Cu–Sn alloy | 0.1 m KHCO3 | −0.60 (vs RHE) | CO (>90%) | 1 mA cm−2 | 123 |
| Oxide‐derived Cu | CO (63%) | 2.1 mA cm−2 | |||
| TiO2 film | MeCN/0.1 m TEAP | −1.8 (vs Ag/AgCl) | CO (90%) | – | 133 |
| rGO–PEI–MoSx | 0.5 m NaHCO3 | −0.65 (vs RHE) | CO (85.1%) | 55 mA cm−2 | 136 |
| WSe2 nanoflakes | 50 vol%/50 vol% EMIMBF4/H2O | −0.164 (vs RHE) | CO (24%) | 18.95 mA cm−2 | 139 |
| MoSeS alloy monolayers | 4 mol%/96 mol% EMIMBF4/H2O | −1.15 (vs RHE) | CO (45.2%) | 43 mA cm−2 | 168 |
| NCNTs | 0.1 m KHCO3 | −1.05 (vs RHE) | CO (80%) | – | 144 |
| N‐doped graphene foam | 0.1 m KHCO3 | −0.58 (vs RHE) | CO (≈85%) | ≈1.8 mA cm−2 | 150 |
| 3. Selective production of HCHO | |||||
| Boron‐doped diamond | MeOH electrolyte | −1.70 (vs Ag/AgCl) | HCHO (74%) | 97.5 µA cm−2 | 157 |
| Cu NPs/boron‐doped diamond | (10 × 10−6 m) H2O/bmim‐PF6 | −1.3 (vs RHE) | HCOOH and HCHO (>80%) | 5.1 mA cm−2 | 158 |
| 4. Selective production of methane and ethylene | |||||
| Cu–porphyrin complex | 0.5 m KHCO3 | −0.976 (vs RHE) | CH4 and C2H4 (44%) | 13.2 mA cm−2 (CH4) | 176 |
| 8.4 mA cm−2 (C2H4) | |||||
| Cu NPs supported on glassy carbon | 0.1 m NaHCO3 | −1.25 (vs RHE) | CH4 (80%) | ≈9 mA cm−2 | 110 |
| Cu nanowires | 0.1 m KClO4 | −1.10 (vs RHE) | C2H6 (20.3%) | 4–5 mA cm−2 | 113 |
| 0.1 m KHCO3 | C2H6 (17.4%) | ||||
| 0.1 m K2HPO4 | C2H6 (10%) | ||||
| Plasma‐treated Cu foil | 0.1 m KHCO3 | −0.90 (vs RHE) | C2H4 (60%) | – | 114 |
| Cu foam | 0.5 m NaHCO3 | −0.80 (vs RHE) | C2H4, C2H6 (55%) | – | 115 |
| Glycine/Cu nanowires | 0.1 m KHCO3 | −1.90 (vs Ag/AgCl) | C2H4, C2H6, C3H6 (34.1%) | ≈11 mA cm−2 | 116 |
| Cu nanocubes [44 nm] | 0.1 m KHCO3 | −1.1 (vs RHE) | C2H4 (41%) | ≈5.5 mA cm−2 | 119 |
| Cu NPs | 0.1 m KHCO3 | −1.1 (vs RHE) | CH4 (57%) | 23 mA cm−2 | 174 |
| C2H4 (<20%) | |||||
| CO (<5%) | |||||
| HCOOH (<5%) | |||||
| Pd–Au alloy | 0.1 m KH2PO4/0.1 m K2HPO4 | −0.60 (vs RHE) | CO (30.9%) | – | 203 |
| −1.40 (vs RHE) | CH4 (2%) | ||||
| −1.40 (vs RHE) | C2 hydrocarbons (0.7%) | ||||
| −1.40 (vs RHE) | C3 hydrocarbons (0.3%) | ||||
| −1.30 (vs RHE) | 1‐Butene (0.16%) | ||||
| Cu2Pd alloy | 0.1 m TBAPF6/CH3CN/1 m H2O | −1.8 (vs Ag/AgNO3) | CH4 (51%) | ≈6 mA cm−2 | 177 |
| NixGay alloy | 0.1 m NaHCO3 | −0.48 (vs RHE) | CH4 (>2%) | (−1.18 V) 140 µA cm−2 | 124 |
| C2H4 (1.3%) | (−1.18 V) 100 µA cm−2 | ||||
| Cu2O/Cu | 0.1 m KHCO3 | −0.98 (vs RHE) | C2H4 (42.6%) | 13.3 mA cm−2 | 179 |
| C2H5OH (11.8%) | 3.7 mA cm−2 | ||||
| C3H7OH (5.4%) | 1.7 mA cm−2 | ||||
| Mo2C | 0.1 m KHCO3 | –1.10 (vs RHE) | CH4 (29%) | >30 mA cm−2 | 141 |
| H2 (≈39%) | |||||
| N‐doped carbon | [bmim]BF4/H2O | −1.4 (vs RHE) | CH4 (93.5%) | 1.42 mA cm−2 | 149 |
| Pyridinic‐N rich graphene/Cu | 0.5 m KHCO3 | −0.90 (vs RHE) | C2H4 (19%) | 7.7 A g−1 | 202 |
| 5. Selective production of alcohols | |||||
| Enzymes | Phosphate buffer solution | −1.20 (vs Ag/AgCl) | CH3OH (≈10%) | – | 180 |
| [4‐(3‐Phenoxy‐2,2‐bis(phenoxymethyl)propoxy)pyridine]@Cu–Pd | 0.5 m KCl | −0.04 (vs RHE) | CH3OH (26%) | 21 mA cm−2 | 204 |
| −0.64 (vs RHE) | C2H5OH (12%) | – | |||
| Cu nanocrystals | 0.1 m KHCO3 | −0.95 (vs RHE) | C3H7OH | 1.74 mA cm−2 | 111 |
| Mo–Bi alloy | 0.5 m [bmim]BF4/MeCN | −0.70 (vs RHE) | CH3OH (71.2%) | 12.1 mA cm−2 | 126 |
| Cu2O | 0.1 m KHCO3 | −0.99 (vs RHE) | C2H4 (34–39%) | 30–35 mA cm−2 | 178 |
| C2H5OH (9–16%) | |||||
| Cu2O | 0.5 m KHCO3 | −2.0 (vs Co3O4) | C2H5OH (96.2%) | 4.5 mA cm−2 | 185 |
| Cu2O/multiwalled CNT | 0.5 m NaHCO3 | −0.80 (vs RHE) | CH3OH (38.0%) | 7.5 mA cm−2 | 188 |
| Oxidized Cu | 0.5 m KHCO3 | −1.10 (vs SCE) | CH3OH (38.0%) | – | 189 |