Partial Thermal Condensation Mediated Synthesis of High-Density Nickel Single Atom Sites on Carbon Nitride for Selective Photooxidation of Methane into Methanol

Partial Thermal Condensation Mediated Synthesis of High-Density Nickel Single Atom Sites on Carbon
Nitride for Selective Photooxidation of Methane into Methanol
Pawan Kumar, Peter Antal, Xiyang Wang, Jiu Wang, Dhwanil Trivedi, Ondřej František
Fellner, Yimin A. Wu, Ivan Nemec, Vinicius Tadeu Santana, Josef Kopp, Petr
Neugebauer, Jinguang Hu, Md Golam Kibria, Subodh Kumar
Small DOI: https://doi.org/10.1002/smll.202304574

a) Synthetic scheme of NiCN SAC using melem coordinated nickel ion followed by thermal annealing. b) HR-TEM images of NiCN SAC at 20 nm scale bar showing the absence of
any nanoparticles dispersion on graphenic sheets. AC-HAADF-STEM images of NiCN SAC at c) 5 nm scale bar showing the dense population of Ni SA in CN scaffold. d) at 1 nm
scale bar showing the bright spots of Ni in the carbonaceous framework. Red circles show the presence of Ni atoms. e) STEM HAADF image and EDS mapping of the area for f) C
g) Ni h) N i) O j) composite of Ni, N, and C.

a) XRD pattern of CN and NiCN. b) FTIR spectra of
melem, CN, and NiCN. c) PL emission spectra CN and
NiCN. d) UV–vis spectra of CN and NiCN

Core-level high-resolution XPS spectra of NiCN in a) C1s region, b) N1s region, and c) Ni2p region. EEMS map for N K-edge of d) CN, e) NiCN, and EEMS map for Ni L-edge of f)
NiCl2, g) NiO, and h) NiCN. i) N K-edge NEXAFS spectra of CN (dark gray) and NiCN (dark red). j) Ni L-edge NEXAFS spectra of NiCl2 (yellow) NiO (blue), and NiCN (dark red).

Synchrotron-based Wide Angle X-ray Scattering (WAXS) 2D images and corresponding Q values of a,b) NiCN and c,d) CN. No additional peaks for any nanoparticle/nanoclusters
were observed. e) XANES spectra and f) FT-EXAFS spectra of Ni metal foil, NiNC, and NiCN. Wavelet transform (WT) EXAFS map of g) Ni foil, h) NiNC, and i) NiCN.

a) J--t curve showing the photoresponse of CN and NiCN as a function of time b) Schematic diagram of the photocatalytic reactor used for the CH4 oxidation reaction c) 1H NMR spectra of reaction product after
photocatalytic reaction, Lower to the upper panel: CN using 1000 µL H2O2 (showing the high intensity of CH3OOH), NiCN using 250 µL H2O2 (showing only CH3OH signals), NiCN using 1000 µL H2O2 (showing
reduced CH3OH peak and the emergence of CH3OOH signal) d) Photocatalytic oxidation of CH4 to oxygenates and their distribution using CN, NiCN, and other control catalysts under various conditions, Time: 2 h,
CH4 pressure-20 bar (2mPa), Light Source: AM1.5G e) CH3OH selectivity using various catalysts f) EPR spectra of the NiCN without H2O2 Conditions: 0.5 mg catalyst, H2O:MeOH (20:1) 200 µL, 200 mM DMPO. g)
EPR spectra of the CN with H2O2. Simulation parameters for component 1: aN = 1.60 mT, aH = 2.26 mT, peak-to-peak linewidth 0.13 mT (assigned to carbon-based DMPO adducts). component 2: aN = 1.50 mT,
aH = 1.50 mT, peak-to-peak linewidth 0.13 mT (assigned to DMPO-OH adduct). Ratio carbon-based adduct and DMPO-OH adduct: 0.6. Conditions: 0.5 mg catalyst, H2O:H2O2:MeOH (20:1:1) 200 µL, 200 mM
DMPO h) EPR spectra of the NiCN with H2O2. Simulation parameters for component 1: aN = 1.60 mT, aH = 2.26 mT, peak-to-peak linewidth 0.13 mT (assigned to carbon-based DMPO adducts). component 2: aN =
1.50 mT, aH = 1.50 mT, peak-to-peak linewidth 0.13 mT (assigned to DMPO-OH adduct). Ratio carbon-based adduct and DMPO-OH adduct: 0.3 Conditions: 0.5 mg catalyst, H2O:H2O2:MeOH (20:1:1) 200 µL,
200 mM DMPO i) Plausible mechanism of oxidation of CH4 in the presence of H2O2 and NiCN SAC.

Figure S1. HR-TEM images of NiCN SAC at (a-c) 50 nm scale bar showing the nanosheet structures and (d) at 20 nm scale bar
showing the absence of any nanoparticle/nanoclusters and amorphous nature. (e) EDX spectra display the presence of Ni, C
and N in the materials.

Figure S2. HR-TEM image of CN at (a) 50 nm and (b) 2 nm scale bar.

Figure S3. (a) N2 adsorption desorption isotherm of NiCN shouwing type-II, H3 hysteresis loop for mesoporous nature (b)
BJH pore size distribution of NiCN showing average pore diameter of 2.9 nm.

Figure S4. Time-resolved PL lifetime spectra of CN (blue dots) and NiCN (red dots). The solid line represents fitting of the
spectra

Figure S5. (a) XPS survey scan of CN for elemental analysis. HR-XPS spectra of CN in (b) C1s (c) N1s (d) O1s regions.

Figure S6. (a) XPS survey scan of NiCN SAC for elemental analysis. HR-XPS spectra of NiCN SAC in (b) O1s (c) Na1s (d) Cl2p
regions.

Figure S7. EEMS map for C K-edge region of (a) CN (b) NiCN SAC
(c) C K-edge NEXAFS spectra of CN (black) and NiCN SAC (red).

Figure S8. (a) FT-EXAFS spectra and fit and (b) WT-EXAFS map of NiO

Figure S9. EXAFS spectra in k-space (k3-weighted) and fitting for (a) Ni foil (b) NiO (c) NiNC (d) NiCN

Figure S10. EXAFS spectra in q-space. Lower to the upper panel: Ni nitrate, Ni foam, NiNC and NiCN SAC

Figure S11. Structure of (a) NiCN (b) NiNC showing first shell coordination Ni-N bond length

Figure S12. EIS Nyquist plot of CN (black) and NiCN (red)

Figure S13. Mott-Schottky plot of CN (black) and NiCN (red).

Figure S14. Digital photograph of photoreactor used for the CH4 oxidation to CH3OH.

Figure S15. 1H NMR spectra of CH4 oxidation reaction product in the absence of catalyst and H2O2 under AM1.5G irradiation.

Figure S16. 1H NMR spectra of CH4 oxidation reaction product using CN as catalyst, under AM1.5 solar irradiation with
250 μL H2O2.

Figure S17. 1H NMR spectra of CH4 oxidation reaction product using CN as catalyst, under AM1.5 solar irradiation
with 500 μL H2O2.

Figure S18. 1H NMR spectra of CH4 oxidation reaction product using CN as catalyst, under AM1.5 solar irradiation
with 1000 μL H2O2.

Figure S19. 1H NMR spectra of CH4 oxidation reaction product using CN as a catalyst, without irradiation and H2O2.

Figure S20. 1H NMR spectra of CH4 oxidation reaction product using NiCN SAC as a catalyst, under AM1.5G
irradiation and without H2O2.

Figure S21. 1H NMR spectra of CH4 oxidation reaction product using NiCN SAC as a catalyst, under AM1.5G irradiation
and 50 μL H2O2.

and 100 μL H2O2.

Figure S23. 1H NMR spectra of CH4 oxidation reaction product using NiCN SAC as a catalyst, under AM1.5G
irradiation and 250 μL H2O2.

and 500 μL H2O2.

Figure S25. 1H NMR spectra of CH4 oxidation reaction product using NiCN SAC as a catalyst, under AM1.5G irradiation and
1000 μL H2O2.

Figure S26. 1H NMR spectra of CH4 oxidation reaction product using NiO as a catalyst, under AM1.5G irradiation and 250 μL
H2O2.

Figure S27. (a-b) TEM images of recycled
NiCN catalysts at 20 nm scale showing
absence of any nanoparticulate structure.
(c-d) AC-HAADF-STEM images of recycled
NiCN catalysts showing presence of
isolated Ni sites and demonstrate absence
of any nanoparticles/nanoclusters.

Figure S28. EPR spectra of the CN experiments without H2O2. Simulation parameters: aN = 1.57 mT, aH = 2.32 mT, peak-to-
peak linewidth 0.17 mT (assigned to carbon based DMPO adducts) Conditions: 0.5mg catalyst, H2O:MeOH (20:1) 200uL,
200mM DMPO

Partial Thermal Condensation Mediated Synthesis of High-Density Nickel Single Atom Sites on Carbon Nitride for Selective Photooxidation of Methane into Methanol

Recommended

Recommended

More Related Content

Similar to Partial Thermal Condensation Mediated Synthesis of High-Density Nickel Single Atom Sites on Carbon Nitride for Selective Photooxidation of Methane into Methanol

Similar to Partial Thermal Condensation Mediated Synthesis of High-Density Nickel Single Atom Sites on Carbon Nitride for Selective Photooxidation of Methane into Methanol (20)

More from Pawan Kumar

More from Pawan Kumar (20)

Recently uploaded

Recently uploaded (20)

Partial Thermal Condensation Mediated Synthesis of High-Density Nickel Single Atom Sites on Carbon Nitride for Selective Photooxidation of Methane into Methanol