Spectroscopy — Extension of charge separation distance over isolated dual-metal sites in metal-organic frameworks for efficient CO2 photoreduction

6 measurement groups · 84 results

Reported values remain attached to the sample, method, conditions, extraction quality and source location that produced them.

Operando DRIFTS / FTIR spectra

Infrared spectroscopy

CuCo-THQ powder · Nanosheet

Bruker TENSOR II with MCT detector and BaF2-window photocatalytic in situ infrared chamber; He cleanup, CO2 adsorption in dark, then H2O bubbled by CO2 at 30 mL min-1 under light.

Atmosphere: CO2 and H2O vapour after He pre-treatment
Geometry: in situ infrared chamber
Context: CuCo-THQ target powder and Cu-THQ comparison
Measurement source: p003 · 2.6 Operando FTIR spectra · Fig. 4e,f, Fig. S49-S50

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
DRIFTS bidentate carbonate band	1558 cm-1	—	—	Text Exact Reported	p008 · 3.4 The investigation of the reaction mechanism · Fig. 4e and Fig. S49
DRIFTS bidentate carbonate band	1652 cm-1	—	—	Text Exact Reported	p008 · 3.4 The investigation of the reaction mechanism · Fig. 4e and Fig. S49
DRIFTS bicarbonate band	1227 cm-1	—	—	Text Exact Reported	p008 · 3.4 The investigation of the reaction mechanism · Fig. 4e and Fig. S49
DRIFTS bicarbonate band	1417 cm-1	—	—	Text Exact Reported	p008 · 3.4 The investigation of the reaction mechanism · Fig. 4e and Fig. S49
*DRIFTS CO intermediate band**	2077 cm-1	—	—	Text Exact Reported	p008 · 3.4 The investigation of the reaction mechanism · Fig. 4f
*DRIFTS COOH intermediate band**	1526 cm-1	—	—	Text Exact Reported	p008 · 3.4 The investigation of the reaction mechanism · Fig. 4f
DRIFTS monodentate carbonate band	1457 cm-1	—	—	Text Exact Reported	p008 · 3.4 The investigation of the reaction mechanism · Fig. 4e and Fig. S49
DRIFTS monodentate carbonate band	1507 cm-1	—	—	Text Exact Reported	p008 · 3.4 The investigation of the reaction mechanism · Fig. 4e and Fig. S49
DRIFTS monodentate carbonate band	1540 cm-1	—	—	Text Exact Reported	p008 · 3.4 The investigation of the reaction mechanism · Fig. 4e and Fig. S49
CO2-to-CO intermediate pathway	CO2 -> COOH -> CO -> CO	—	—	Qualitative Qualitative	p008 · 3.4 The investigation of the reaction mechanism · Fig. 4e,f

Quasi in-situ XPS under dark and light irradiation

X-ray photoelectron spectroscopy

CuCo-THQ powder · Nanosheet

Photocatalyst pressed into self-supporting wafer in reaction microdevice with polyimide windows; impurities removed under He; spectra collected in dark and after 15 min Xe lamp irradiation.

Atmosphere: He pre-treatment; light-irradiated reaction microdevice
Geometry: self-supporting wafer
Context: CuCo-THQ target powder, compared with Cu-THQ
Measurement source: p003 · 2.5 Quasi in-situ XPS measurement · Fig. 4c,d and Fig. S38

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
CuCo-THQ Co 2p light-induced binding-energy shift	positive shift of Co 2p binding energy	—	—	Qualitative Qualitative	p006 · 3.4 The investigation of the reaction mechanism · Fig. 4d
CuCo-THQ Cu 2p light-induced binding-energy shift	negative shift of 0.3 eV	—	—	Text Exact Reported	p006 · 3.4 The investigation of the reaction mechanism · Fig. 4c
CuCo-THQ light-induced EPR g value	g = ~2.003	—	—	Figure Axis Approximate	S23 / S34 · Supplementary Figures · Fig. S37

Time-resolved photoluminescence (TRPL) and steady-state PL

Photoluminescence and fluorescence spectroscopy

CuCo-THQ powder · Nanosheet

TRPL on Edinburgh Instruments FLS1000; steady-state PL with 375 nm excitation at room temperature.

Temperature: room temperature
Geometry: powders ground and packed into 0.5 cm x 1 cm x 0.1 cm cuvette
Context: Cu-THQ and CuM-THQ powders
Measurement source: S2-S3 / S34 · 1.2 Characterization · Fig. 4a and Fig. S35

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Cu-THQ fluorescence lifetime	0.12 ns	—	—	Text Exact Reported	p006 · 3.4 The investigation of the reaction mechanism · Fig. 4a
CuCo-THQ fluorescence lifetimeMarked as a best value within this paper	2.49 ns	—	—	Text Exact Reported	p006 · 3.4 The investigation of the reaction mechanism · Fig. 4a
CuFe-THQ fluorescence lifetime	0.19 ns	—	—	Text Exact Reported	p006 · 3.4 The investigation of the reaction mechanism · Fig. 4a
CuNi-THQ fluorescence lifetime	1.27 ns	—	—	Text Exact Reported	p006 · 3.4 The investigation of the reaction mechanism · Fig. 4a

UV-vis diffuse reflectance spectroscopy and Tauc analysis

UV-visible and optical absorption spectroscopy

CuCo-THQ powder · Nanosheet

Hitachi UH-4150, 800-200 nm range, BaSO4 background; Tauc plots used for band gaps.

Geometry: powder pressed into 1.5 cm diameter, 0.1 cm high round sample
Context: Cu-THQ and CuM-THQ powders
Measurement source: S2-S4 / S34 · 1.2 Characterization; 1.3 The calculation of band gap energy · Fig. S34, Fig. S39-S42

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Cu-THQ band gap	1.74 eV	—	—	Text Exact Reported	p007 · 3.4 The investigation of the reaction mechanism · Fig. S39-S42
CuCo-THQ band gap	1.72 eV	—	—	Text Exact Reported	p007 · 3.4 The investigation of the reaction mechanism · Fig. S39-S42
CuFe-THQ band gapMarked as a best value within this paper	1.64 eV	—	—	Text Exact Reported	p007 · 3.4 The investigation of the reaction mechanism · Fig. S39-S42
CuNi-THQ band gap	1.78 eV	—	—	Text Exact Reported	p007 · 3.4 The investigation of the reaction mechanism · Fig. S39-S42

Cu K-edge XANES, FT-EXAFS fitting and wavelet-transform XAFS

X-ray absorption spectroscopy

CuCo-THQ powder · Nanosheet

XAFS at BSRF 1W1B; fluorescence mode for samples; Cu foil, CuO2 and CuO references in transmission; Artemis/Ifeffit fitting.

Geometry: 8 mm diameter, 1 mm thick pellets without binder or diluent
Context: Cu-THQ and CuM-THQ powders
Measurement source: S34 / S34 · 4. Supplementary Tables · Table S4

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Cu-Cu and Cu-M bond absence in XAS	No obvious Cu-Cu and Cu-M bonds; no Cu-Cu peaks at 8.2 A-1 in WT-XAFS	—	—	Text Exact Reported	p004 · 3.2 Electronic and coordination structure analysis · Fig. 2c,e and Fig. S17-S27
Cu-THQ EXAFS Cu-O bond length	1.94 +/- 0.01 A	—	+/- 0.01	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
Cu-THQ Cu-O coordination number	2.3 +/- 0.3	—	+/- 0.3	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
Cu-THQ EXAFS Cu-O bond length	1.94 +/- 0.01 A	—	+/- 0.01	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
Cu-THQ EXAFS Cu-O coordination number	2.3 +/- 0.3	—	+/- 0.3	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
Cu-THQ EXAFS Delta E0	8 +/- 1 eV	—	+/- 1	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
Cu-THQ EXAFS R factor	0.014	—	—	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
Cu-THQ EXAFS Debye-Waller factor sigma2	0.007 +/- 0.002 A2	—	+/- 0.002	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuCo-THQ Cu-O coordination number	2.5 +/- 0.3	—	+/- 0.3	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuCo-THQ EXAFS Cu-O bond length	1.94 +/- 0.01 A	—	+/- 0.01	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuCo-THQ EXAFS Cu-O coordination number	2.5 +/- 0.3	—	+/- 0.3	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuCo-THQ EXAFS Delta E0	8 +/- 2 eV	—	+/- 2	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuCo-THQ EXAFS R factor	0.018	—	—	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuCo-THQ EXAFS Debye-Waller factor sigma2	0.005 +/- 0.002 A2	—	+/- 0.002	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuFe-THQ Cu-O coordination number	3.1 +/- 0.3	—	+/- 0.3	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuFe-THQ EXAFS Cu-O bond length	1.95 +/- 0.01 A	—	+/- 0.01	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuFe-THQ EXAFS Cu-O coordination number	3.1 +/- 0.3	—	+/- 0.3	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuFe-THQ EXAFS Delta E0	8 +/- 1 eV	—	+/- 1	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuFe-THQ EXAFS R factor	0.010	—	—	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuFe-THQ EXAFS Debye-Waller factor sigma2	0.006 +/- 0.001 A2	—	+/- 0.001	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuNi-THQ Cu-O coordination number	2.6 +/- 0.4	—	+/- 0.4	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuNi-THQ EXAFS Cu-O bond length	1.93 +/- 0.02 A	—	+/- 0.02	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuNi-THQ EXAFS Cu-O coordination number	2.6 +/- 0.4	—	+/- 0.4	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuNi-THQ EXAFS Delta E0	7 +/- 2 eV	—	+/- 2	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuNi-THQ EXAFS R factor	0.019	—	—	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4
CuNi-THQ EXAFS Debye-Waller factor sigma2	0.005 +/- 0.002 A2	—	+/- 0.002	SI Table Exact Reported	S34 / S34 · 4. Supplementary Tables · Table S4

X-ray photoelectron spectroscopy (XPS) and Cu LMM Auger spectroscopy

X-ray photoelectron spectroscopy

CuCo-THQ powder · Nanosheet

ESCALAB 250Xi XPS with Al Kalpha radiation; Cu 2p, O 1s, Co/Ni/Fe high-resolution spectra and Cu LMM Auger compared.

Geometry: powder or pressed sample for XPS
Context: Cu-THQ and CuM-THQ powders
Measurement source: S33 / S34 · 4. Supplementary Tables · Table S3

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Cu LMM Auger metallic Cu absence	no metallic Cu peak at 568 eV	—	—	Text Exact Reported	p004 · 3.2 Electronic and coordination structure analysis · Fig. S12
Cu-THQ Cu 2p3/2 Cu2+ binding energy	934.34 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
Cu-THQ Cu 2p3/2 Cu+ binding energy	932.27 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
Cu-THQ Cu2+ binding energy	934.34 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
Cu-THQ Cu2+ FWHM	1.57 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
Cu-THQ Cu2+ peak area	16484	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
Cu-THQ Cu2+ atomic percent	56.6 at%	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
Cu-THQ Cu+ binding energy	932.27 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
Cu-THQ Cu+ FWHM	2.01 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
Cu-THQ Cu+ peak area	12652	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
Cu-THQ Cu+ atomic percent	43.4 at%	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuCo-THQ Cu2+ binding energy	934.16 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuCo-THQ Cu2+ FWHM	1.51 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuCo-THQ Cu2+ peak area	14273	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuCo-THQ Cu2+ atomic percent	50.2 at%	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuCo-THQ Cu+ binding energy	932.10 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuCo-THQ Cu+ FWHM	1.93 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuCo-THQ Cu+ peak area	14181	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuCo-THQ Cu+ atomic percent	49.8 at%	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuFe-THQ reported Cu+ fraction / Cu+/Cu2+ descriptor from XPS	0.47	—	—	Calculated From Reported Rounded Reported	p004 · 3.2 Electronic and coordination structure analysis · Table S3
CuFe-THQ Cu2+ binding energy	934.30 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuFe-THQ Cu2+ FWHM	2.04 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuFe-THQ Cu2+ peak area	15109	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuFe-THQ Cu2+ atomic percent	53.2 at%	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuFe-THQ Cu+ binding energy	932.19 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuFe-THQ Cu+ FWHM	1.78 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuFe-THQ Cu+ peak area	11792	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuFe-THQ Cu+ atomic percent	46.8 at%	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuNi-THQ reported Cu+ fraction / Cu+/Cu2+ descriptor from XPS	0.48	—	—	Calculated From Reported Rounded Reported	p004 · 3.2 Electronic and coordination structure analysis · Table S3
CuNi-THQ Cu2+ binding energy	934.21 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuNi-THQ Cu2+ FWHM	2.13 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuNi-THQ Cu2+ peak area	9710	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuNi-THQ Cu2+ atomic percent	52.4 at%	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuNi-THQ Cu+ binding energy	932.05 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuNi-THQ Cu+ FWHM	1.80 eV	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuNi-THQ Cu+ peak area	8819	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3
CuNi-THQ Cu+ atomic percent	47.6 at%	—	—	SI Table Exact Reported	S33 / S34 · 4. Supplementary Tables · Table S3