Electronic Supplementary Material

A photoactive process cascaded electrocatalysis for enhancedmethanol oxidation over Pt-MXene-TiO2 composite Yue Sun§, Yunjie Zhou§, Yan Liu, Qingyao Wu, Mengmeng Zhu, Hui Huang, Yang Liu (), Mingwang Shao (), and Zhenhui Kang ()

Institute of Functional Nano and Soft Materials Laboratory (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials &Devices, Soochow University, Suzhou 215123, China § Yue Sun and Yunjie Zhou contributed equally to this work. Supporting information to https://doi.org/10.1007/s12274-020-2910-x

1. Experimental Section Adsorption equilibrium measurements.

To explore the adsorption property of the as-prepared catalysts towards methanol molecules, the adsorption equilibrium measurements were carried out. In this experiment, saturated methanol steam and 5 mL reactors were needed. Firstly, two reactors were prapared, 10 mg PMT powders were added into one reactor and the other one keep empty. Subsequently, 10 μL of saturated methanol steam was injected into two 5 mL reactors, respectively. After standing still for predetermined time intervals, the residual concentration of methanol in the reactor was determined by Agilent gas chromatography. Then the residual concentration percentage of methanol in the reactor and the amount of adsorbed methanol by PMT were obtained.

The saturated mass concentration of methanol can be calculated by using the following Eqution S1:

/(( 273.15) )c PM t R= + where c, P, M, t and R are the saturated mass concentration of gas, saturation vapor pressure, molar mass, temperature and gas constant, respectively.

The amount of residual methanol was calculated using Eqution S2:

m cv= where m, c and v are mass of methanol, the saturated mass concentration of methanol gas and volume of methanol gas.

2. Supplementary Figures

 Figure S1 SEM images of MXene (a), MT(b).

Address correspondence to Zhenhui Kang, zhkang@suda.edu.cn; Mingwang Shao, mwshao@suda.edu.cn; Yang Liu, yangl@suda.edu.cn

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 Figure S2 SEM image of PM.

 

 Figure S3 Morphology and structural characterization. (a) TEM image of the distribution of Pt NPs on MXene nanosheets. (b) The HRTEM image of PM. (c) HAADF-STEM image of PM and (d-h) EDS mapping, the corresponding elements were (d) Pt, (e) Ti, (f) O, (g) C and (h) the overlay of Pt, Ti, O and C.

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 Figure S4 XRD patterns of PM and PMT.

 

 Figure S5 FT-IR spectra of PM and PMT.

 

 Figure S6 XPS full spectrum of PMT.

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 Figure S7 High-resolution Pt 4f XPS spectra of commercial Pt/C.

 Figure S8 CV curves of PM with and without UV, as well as PMT at a scan rate of 50 mV s-1.

(a) CV curves in 0.5 M H2SO4. The ECSA was determined by calculating the H2 desorption area of CV curves according to the following Eq.

ECSA Q / (0.21 m )H Pt= ´ Where, QH is the charge for the hydrogen desorption or adsorption in the hydrogen region. 0.21 mC cm-2 is the value of charge

transfer during the process of adsorption of one monolayer of H atoms on the surface of Pt. mPt is the mass of Pt. The content of Pt in various samples was evaluated by ICP, shown in Table S2.

(b) CV curves in 0.5 M H2SO4 + 1 M CH3OH solution. (c) CO stripping voltammograms obtained in 0.5 M H2SO4 solution. (d) CA curves in 0.5 M H2SO4 + 1 M CH3OH at 0.6 V vs. SCE.

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 Figure S9 CV curves of PMT under UV illumination with different intensity (dark, 20, 30, 40 and 50 mW cm-2).

 Figure S10 (a) and (b) are corresponding to CO stripping and after stripping spectra of PM and PM with UV illumination, respectively. (c) and (d) are corresponding to CO stripping and after stripping spectra of PMT and PMT under UV, respectively.

 Figure S11 Nyquist plots for PMT catalysts with and without UV irradiation in MOR.

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 Figure S12 UV-vis spectra of PM and PMT.

 Figure S13 Electrocatalytic performance of PMT-6h, PMT and PMT-18h. (a) CV curves in 0.5 M H2SO4. (b) CV curves in 0.5 M H2SO4 + 1 M CH3OH solution. (c) CO stripping voltammograms obtained in 0.5 M H2SO4 solution. (d) CA curves in 0.5 M H2SO4 + 1 M CH3OH at 0.6 V vs. SCE. All the curves are all measured at a scan rate of 50 mV s-1.

 Figure S14 (a) and (b) are corresponding to CO stripping and after stripping spectra of PMT-6h and PMT-18h with UV irradiation, respectively.

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 Figure S15 Nyquist plots for PMT-6h, PMT and PMT-18h catalysts with UV illumination in MOR.

 Figure S16 The electrocatalytic performance of Pt-TiO2 with and without UV illumination. (a) CV curves in 0.5 M H2SO4. (b) CV curves in 0.5 M H2SO4 + 1 M CH3OH solution. (c) CO stripping voltammograms obtained in 0.5 M H2SO4 solution. (d) CA curves in 0.5 M H2SO4 + 1 M CH3OH at 0.6 V vs. SCE. All the curves are all measured at a scan rate of 50 mV s-1.

 Figure S17 The electrocatalytic performance of Pt+MXene+TiO2 with and without UV illumination. (a) CV curves in 0.5 M H2SO4. (b) CV curves in 0.5 M H2SO4 + 1 M CH3OH solution. (c) CO stripping voltammograms obtained in 0.5 M H2SO4 solution. (d) CA curves in 0.5 M H2SO4 + 1 M CH3OH at 0.6 V vs. SCE. All the curves are all measured at a scan rate of 50 mV s-1.

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 Figure S18 CV curves of PMT under visible light illumination with different intensity (dark, 20, 30, 40 and 50 mW cm-2).

3. Supplementary tables.

Table S1 Short name for different samples

Samples Pt-MXene-TiO2-6h Pt-MXene-TiO2-12h Pt-MXene-TiO2-18h Pt-MXene MXene-TiO2-12h Label PMT-6h PMT PMT-18h PM MT

Table S2 ICP results of samples

Element PM (mg/g)

PMT (mg/g)

PMT-6h (mg/g)

PMT-18h (mg/g)

Pt 98.94 99.93 96.17 98.11

Table S3 Comparison of the catalytic activities with catalysts reported in the literatures.

Electrode Optical source

Power (light intensity) Solution ECSA

(m2 g-1Pt)

Current density (mA mg-1

Pt) without light

Current density (mA mg-1

Pt) with light

Increase ((Ilight-Idark)/Idark)

×100% Ref.

Pt-MXene-TiO2 UV 100 W (50 mW cm-2)

0.5 M H2SO4

+1 M CH3OH 64.3 703.31 2750.42 291 This work

Pt NPs/TiO2 MRs UV 50 W (200 mW

cm-2) 0.5 M H2SO4

+1 M CH3OH 75.4 1020 2285 124 [S1]

Pt/ZnO/GNs UV /Visible

15 W (0.3 mW cm-2)

0.5 M H2SO4

+1 M CH3OH 97.7 957.3 1724.2 /1935.5

80 [S2]

Pt/gC3N4 Visible 150 W

(--) 1 M H2SO4

+1 M CH3OH 128.7 ~50.0 ~90.0 80 [S3]

Pt/TiO2/GNs UV 15 W (--)

0.5 M H2SO4

+1 M CH3OH 96.7 820 1360 66 [S4]

Pt–TiO2/C UV 100 W

(--) 0.5 M H2SO4

+1 M CH3OH 89.6 1043 2597 149 [S5]

Pt@ZnO@CC UV 100 W

(--) 0.5 M H2SO4

+1 M CH3OH -- ~215.0 ~321.7 50 [S6]

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photoelectrocatalytic oxidation of methanol. J. Mater. Chem. 2012, 22, 4025-4031. [S6] Su, C. Y.; Hsueh, Y. C.; Kei, C. C.; Lin, C. T.; Perng, T. P. Fabrication of high-activity hybrid Pt@ZnO catalyst on carbon cloth by atomic layer

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