Supporting Information

Thermal Conversion of MOF by Microwave: Tuning the

Heterostructure of Bimetal Phosphide/Graphene for Highly

Enhanced Electrocatalytic Performance

Fanxing Bu,†a Wenshu Chen,†b Mohamed F. Aly Aboud,c Imran Shakir,*c,d Jiajun Gu,*b Yuxi Xu*a

a State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China b State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, 200240, Chinac Sustainable Energy Technologies Center, College of Engineering, King Saud University, Riyadh 11421, Kingdom of Saudi Arabia d Department of Materials Science and Engineering, University of California, Los Angeles, CA 90095, USA.

Figure S1. Typical photographs of (a) Ni-Fe PBA/GO/NaH2PO2 sponge and (b) FeNiP/PG sponge

Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A.This journal is © The Royal Society of Chemistry 2019

Figure S2. (a) SEM picture of Ni-Fe PBA/GO sponge, (b) TEM picture and (c) XRD

picture of Ni-Fe PBA/GO composite.

Figure S3. TEM pictures of (a) PG, (b) GC/PG and (c) RGO obtained by chemical

chemical etching of FeNiP/PG, FeNiP/GC/PG and FeNiP/RGO. The insets in Figure

a, b and c are the structural models for (a) PG, (b) GC/PG and (c) RGO.

Figure S4. (a) XRD pictures of the products obtained at 5s during the formation

process of FeNiP/GC/PG and FeNiP/PG, TEM pictures of the products obtained at 5s

during the formation process of FeNiP/GC/PG (b) and FeNiP/PG (c).

Figure S5. XPS spectra of Fe 2p3/2 of FeNiP/PG, FeNiP/GC/PG and FeNiP/RGO.

Figure S6. IR-corrected LSV curves for holey FeNiP/graphene based catalysts after the

electrochemical active surface area normalization for OER (a) and HER (b). The specific

capacitance was converted into an electrochemical active surface area (ECSA) by the

methods reported by Li’s group (J. Am. Chem. Soc. 2018, 140, 5241-5247.). The

specific capacitance for a flat surface is assumed to 40 μF cm-2. The ECSA of FeNiP/PG,

FeNiP/GC/PG and FeNiP/RGO for OER are 96.7 cm2 mg-1, 100.8 cm2 mg-1 and 70.3

cm2 mg-1, respectively. The ECSA of FeNiP/PG, FeNiP/GC/PG and FeNiP/RGO for

OER are 163.4 cm2 mg-1, 122.3 cm2 mg-1 and 91.5 cm2 mg-1 respectively.

Figure S7. TEM images of (a) FeNiP/PG, (b) FeNiP/GC/PG and (c) FeNiP/RGO

after CV activation (OER) between 0-1.6 V versus RHE. TEM images of (d)

FeNiP/PG, (e) FeNiP/GC/PG and (f) FeNiP/RGO after CV activation (HER) between

-1.5-0 V versus RHE.

Figure S8. (a) HRTEM picture of the FeNiP/PG catalyst after CV activation between

0.0 and 1.6 V vs. RHE at 50 mV s-1 in KOH for 20 times and the corresponding XPS

spectra of (b) Ni 2p3/2 and (c) P 2p.

Figure S9. HAADF-STEM elemental mapping of the FeNiP/PG catalyst after CV

activation between 0.0 and 1.6 V vs. RHE at 50 mV s-1 in KOH for 20 times.

Figure S10. XRD pictures of FeNiP/PG, FeNiP/GC/PG and FeNiP/RGO after CV

activation between 0.0 and 1.6 V vs. RHE at 50 mV s-1 in KOH for 20 times.

Figure S11. TEM images of (a) Ni2P/PG and (b) FeP/PG. (c) XRD pictures of

Ni2P/PG and FeP/PG.

Figure S12. (a) iR-corrected polarization curves of FeNiP/PG, Ni2P/PG and FeP/PG

for OER. (b) iR-corrected polarization curves of FeNiP/PG, FeP/PG and Ni2P/PG for

HER.

Table S1. Comparison of OER performance for FeNi@NC/RGO with other metal phosphide

electrocatalysts in 1 M KOH.

Sample Overpotential (mV)a Tafel slope (mV Dec-1) References

FeNiP/PG 229 49.7

FeNiP/GC/PG 239 61.4

FeNiP/RGO 246 80.5

This work

Ni2P 290 59 Energy Environ. Sci. 2015, 8, 2347-2351.

Nanoporous FeCoP 270 30 Energy Environ. Sci. 2016, 9, 2257-2261.

CoP NS/C 253 85.6 Green Chem. 2016, 18, 2287-2295.

CoP film 345 47 Angew. Chem. Int. Ed. 2015, 127, 6349-6352.

CoP Nanoarry 281 62 ChemSusChem 2016, 9, 472-477.

Ni0.51 Co0.49 P film 239 45 Adv. Funct. Mater. 2016, 26, 7644-7651.

Co4Ni1P/C 245 61 Adv. Funct. Mater. 2017, 27, 1703455.

Holey NiCoP 280 NA J. Am. Chem. Soc. 2018, 140, 5241-5247.

Ni2P/rGO 260 62 J. Mater. Chem. A 2018, 6, 1682-1691.

NiCoP/C 330 96 Angew. Chem. Int. Ed. 2017, 56, 3897-3900.

CoP/GC 345 49 J. Mater. Chem. A 2016, 4, 13742-13745.

CoP/NCNHP 310 70 J. Am. Chem. Soc. 2018, 140, 2610-2618.

Ni2P/C/G 285 44 Chem. Commun. 2017, 53, 8372-8375.

CoP/RGO 340 66 Chem. Sci. 2016, 7, 1690-1695.

a. The overpotential to achieve 10 mA cm-2.

Table S2. Comparison of overall water splitting performance for FeNiP/PG with

other non-noble-metal electrocatalysts at basic media (1M KOH).

sample

Overpotential

for OER

(mV)a

Overpotential

for HER

(mV)a

Overpotential

for overall

water splitting

(V)a

Reference

FeNiP/PG 229 173 1.58 This work

Holey NiCoP 280 <90 1.56 J. Am. Chem. Soc. 2018, 140, 5241.

Co0.9S0.58P0.42 266 141 1.59 ACS Nano 2017, 11, 11031.

FeB 296 61 1.57 Adv. Energy Mater. 2017, 7, 1700513

Co4Ni1P/C 245 129 1.59 Adv. Funct. Mater. 2017, 27, 1703455.

CoP/RGO 340 150 1.7 Chem. Sci. 2016, 7, 1690.

Ni2P/rGO 260 142 1.61 J. Mater. Chem. A, 2018, 6, 1682.

CoP/MXene 298 168 1.58 ACS Nano 2018, 12, 8017.

Co9S8@NOSC-900 340 320 1.6 Adv. Funct. Mater. 2017, 27, 1606585.

Fe-Fe3C/CNT/Carbon

Rods320 330 NA Chem. Commun.,2017, 53, 2044

Fe-N4 SAs/NPC 430 202 1.67 Angew. Chem. Int. Ed. 2018, 57, 8614

Fe-Ni@NC-CNTs 274 202 1.8 Angew. Chem. Int. Ed. 2018, 57, 8921

Co/NBC 302 117 1.68 Adv. Funct. Mater. 2018, 28, 1801136

PO-Ni/Ni-N-CNFs 420 262 1.69 Nano Energy 2018, 51, 286.

Co-P/NC/CC 171 330 1.77 RSC Adv., 2016,6, 73336.

Sulfurized stainless

steel foil136 262 1.64 ACS Sustainable Chem. Eng. 2017, 5, 4778.

a. The overpotential to achieve 10 mA cm-2.