Supplementary materials

Facile synthesis of double-layered CoNiO2/CoO nanowire arrays as

multifunction electrodes for hydrogen electrocatalysis and supercapacitors.

Yayu Guan, Haicheng Xuan*, Hongsheng Li, Rui Wang, Guohong Zhang, Xiaohong

Liang, Hui Li, Peide Han, Youwei Du, and Yucheng Wu.

College of Materials Science and Engineering, Key Laboratory of Interface Science

and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of

Technology, Taiyuan 030024, People’s Republic of China

*Corresponding author. Tel.: +86 351 6018843; fax: +86 351 6018843.

E-mail address: xuanhaicheng@tyut.edu.cn (H.C. Xuan)

Fig. S1. XRD patterns of CoNiO2/CoO-140-400.

Fig. S2. SEM images of CoNiO2/CoO-140-400.

Fig. S3. The selected area electron diffraction of CoNiO2/CoO-140-400.

Fig. S4. SEM of CoNiO2/CoO-120-400, CoNiO2/CoO-140-400, CoNiO2/CoO-160-

400.

Fig. S5. Electrochemical impedance spectroscopy studies of CoNiO2/CoO-120-400,

CoNiO2/CoO-140-400 and CoNiO2/CoO-160-400 for HER at open circuit potential.

Fig. S6. Electrochemical impedance spectroscopy studies of CoNiO2/CoO-140-300,

CoNiO2/CoO-140-400 and CoNiO2/CoO-140-500 for HER at open circuit potential.

Fig. S7. Electrochemical impedance spectroscopy studies of CoO, CoNiO2 and

CoNiO2/CoO-140-400 for HER at open circuit potential.

Fig. S8. (a) Polarization curves of NF-400 and rGO/NF-400. (b) GCD curves of NF-

400 and rGO/NF-400.

Fig. S9. (a) Polarization curves recorded at 1 mV s-1 of NF||NF, CoNiO2/CoO-140-

400|| CoNiO2/CoO-140-400, and Pt/C||RuO2. (b) Time-dependent current density

curve made at a static cell voltage of 1.57 V.

Fig. S10. Electrochemical impedance spectroscopy studies of the CoO, CoNiO2 and

CoNiO2/CoO-140-400 for supercapacitor at open circuit potential.

Table. S1. Comparison of HER performance for CoNiO2/CoO-140-400 with other

recently reported non-noble-metal related HER catalysts in 1 M KOH.

Catalyst Tafel slope(mV dec-1)

Current density(j, mA cm-2)

η at thecorresponding

j (mV)

Ref.

NiCo-300 82.7 10 156 [1]

NiCoP-HA/CC 99.8 10 89 [2]

P8.6-Co3O4/NF 86 10 97 [3]

Co@N-CNTs@rGO 55 10 108 [4]

NiCo/CNF - 10 220 [5]

NiCoO@CoS 68 10 100 [6]

N-rGO/NiCo-NiO-

CoO/NF

89 10 130 [7]

(Ni0.33Co0.67)S2/CC 127 10 156 [8]

NiCo2S4/Ni3S2/NF 105.2 10 119 [9]

CoNiO2/CoO-140-

400

92.4 10 70 This

work

Table. S2. Comparison of the overall water splitting for CoNiO2/CoO-140-400 with

other non-noble-metal bifunctional electrocatalysts in 1 M KOH.

Catalyst J (mA cm-2) Voltage (V) Ref.

NiCo-300 10 1.688 [1]

Ag NWs/Co 10 1.90 [10]

CoFe/NF 10 1.64 [11]

Co3O4@MoS2 10 1.59 [12]

CoP/NG 10 1.58 [13]

CoFe@NiFe/NF 10 1.59 [14]

Co9S8@NiCo LDH/NF 10 1.63 [15]

Ni1Mo1P NSs@MCNTs 10 1.60 [16]

Octahedral Co3O4 particles 10 1.60 [17]

CoNiO2/CoO-140-400 10 1.57 This work

Table. S3. Comparison of electrochemical performance for CoNiO2/CoO-140-400

with other non-noble-metal electrodes.

Electrode Electrolyte Areal capacitance(F cm-2)

Ref.

ZnCo2O4@NiMoO4·H2O 1 M KOH 3.53 at 1 mA cm-2 [18]

ZnO@CoMoO4 1 M KOH 1.52 at 2 mA cm-2 [19]

NiFe-LDHS 1 M KOH 0.99 at 2 mA cm-2 [20]

NiCo-LDH@NiCo2S4@CFP 1 M KOH 2.86 at 4 mA cm-2 [21]

NiFe-LDH@NiCo2O4@CC 2 M KOH 1.90 at 1 mA cm-2 [22]

NiCo-LDH-CNFP 1 M KOH 2.03 at 2.1 mA cm-2 [23]

NiCo-LDH/Mn3O4 3 M KOH 5.16 at 1 mA cm-2 [24]

NiCo2O4@MnO2 6 M KOH 5.3 at 1 mA cm-2 [25]

Co3S4@Ni3S4 /Ni Foam 2 M KOH 3.6 at 0.8 mA cm-2 [26]

CoNiO2/CoO-140-400 2 M KOH 5.37 at 1 mA cm-2 This

work

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