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1 Electronic Supplementary Material (ESI) for ChemComm. This journal is The Royal Society of Chemistry 2018 Electronic Supplementary Information One-Dimensional Nanorods: A Novel and High Efficient Oxygen Evolution Reaction Catalyst Derived from Metal Organic Framework Composite Yanqiang Li, a, *, Haibin Xu, a Huiyong Huang, a Chao Wang, a Liguo Gao, a Tingli Ma a,b * a State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering, Dalian University of Technology, Panjin Campus, Panjin , China b Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu, Fukuoka , Japan. *Corresponding author. address: tinglima@dlut.edu.cn; yanqiangli@dlut.edu.cn

2 Experimental section 1 Synthesis of MoO3, MoO3@ZIF-67 and MoO2-Co2Mo3O8@C nanorods The MoO3 nanorods were prepared according to the published procedure [31]. For a typical procedure, 1.4 g of ammonium heptamolybdate tetrahydrate was dissolved in 40 ml of mixed solution of 65% HNO3 and H2O with a volume ratio of 1:5. The solution was transferred into a Teflon-lined stainless steel autoclave and heated at 200 o C for 20 h. After cooling to room temperature, the product was filtered out, washed several times with ethanol and then dried at 70 o C for further use. For the synthesis of MoO3@ZIF-67 composite, 50 mg of MoO3 nanorods were dispersed in 40 ml of CH3OH solution and sonicated for 10 minutes. Then mg of Co(NO3) 6H2O and 246 mg of 2-methylimidazole were added. The solution was transferred into a Teflon-lined stainless steel autoclave and heated at 70 o C for 3h. After cooling to room temperature, the product was filtered out, washed several times with methanol and dried at 60 o C for further use. The obtained MoO3@ZIF-67 was thermal annealed at 500 o C or 700 o C for 2h in flowing N2 atmosphere, and the obtained samples were denoted as MoO2- Co@C and For composition, ZIF-67 was also thermal annealed at 700 o C to obtain Co@C. Besides, Co3O4 was also prepared by thermal annealing ZIF-67 under air conditions at 450 o C comparison. for 2h for 2 Characterization The compositions of the catalysts were investigated by Powder X-Ray diffractions (PXRD) using a Riguku D/MAX 2550 diffractometer. Catalysts morphologies were characterized by Field Emission Scanning Electron Microscopy (FE-SEM, Nova NanoSEM 450). Transmission electron microscopy (TEM) and high resolution TEM images were obtained using FEI, Tecnai G2 F20 with an accelerating voltage of 200 kv. X-ray photoelectron spectroscopy (XPS) was conducted with ESCALAB 250Xi (ThermoFisher).

3 Pore structure was characterized by N2 sorption at -196 C (Quantrachrome Quadrasorb Si-MP) and evaluated by Quenched Solid State Density Functional Theory (QSDFT) model assuming slit-shaped pores. 3 Electrochemical measurements The catalytic tests were carried out in a standard three-electrode cell in O2 saturated 1 M KOH solution, using a platinum wire as the counter electrode and Ag/AgCl as the reference electrode. A glassy carbon disk (5 mm in diameter) was used as the working electrode, and the catalyst ink was pipetted onto it with a loading of 0.20 mg cm -2. The current densities were normalized to the geometric area of the glassy carbon electrode and the scan rate for the electrochemical measurements was 5 mv s -1. All potentials were referenced to reversible hydrogen electrode (RHE) scale by E (RHE) = E (Ag/AgCl) pH V V. Figure S1 PXRD of the synthesized MoO3, ZIF-67 and MoO3@ZIF-67. The peaks at about 7.4 o, 10.4 o, o, 22.5 o for MoO3@ZIF-67 are all peaks that only can be found in ZIF-67, demonstrating that ZIF-67 was assembled on the MoO3 nanorods successfully.

4 Figure S2 SEM images of the MoO3, and Figure S3 PXRD of the synthesized ZIF-67 and

5 Figure S4 SEM images of annealed at 900 o C. Figure S5 High-resolution TEM image of MoO2-Co2Mo3O8@C.

6 Figure S6 XPS survey of the Figure S7 XRD of the Co3O4 synthesized by thermal annealing ZIF-67 under air condition and 450 o C.

7 Figure S8 Cyclic voltammetry curves of MoO3, and MoO2- at different scan rate from 20 to 200 mv s -1.

8 Table S1 Summary for the properties of recent reported OER catalysts. Catalyst Electrolyte ma cm -2 / mv Tafel slope / mv dec -1 Reference MoO2-Co2Mo3O8@C 1 M KOH This work CeO2/CoSe2 1 M KOH CoP hollow polyhedra 1 M KOH Co2P NPs 1 M KOH NiCo2S4 NA/CC 1 M KOH CoP/rGO M KOH CoSe2 1 M KOH Co-Mo-B 1 M KOH NiCoP/C 1 M KOH CoSe2 1 M KOH Mo N/C@MoS2 0.1 M KOH Reference: 1. Y. R. Zheng, M. R. Gao, Q. Gao, H. H. Li, J. Xu, Z. Y. Wu and S. H. Yu, Small, 2015, 11, D. Zhou, L. He, W. Zhu, X. Hou, K. Wang, G. Du, C. Zheng, X. Sun, and A. M. Asiri, J. Mater. Chem. A, 2016, 4, M. Liu and J. Li, ACS Appl. Mater. Interfaces, 2016, 8, D. Liu, Q. Lu, Y. Luo, X. Sun and A. M. Asiri, Nanoscale, 2015, 7, L. Jiao, Y. Zhou and H. Jiang, Chem. Sci., 2016, 7, I. Kwak, H. S. Im, D. M. Jang, Y. W. Kim, K. Park, Y. R Lim, E. H. Cha and J. Park, ACS Appl. Mater. Interfaces, 2016, 8, S. Guptaa, N. Patela, R. Fernandesa, S. Hanchatea, A. Miotellob and D.C. Kotharia, Electrochimica Acta, 2017, 232, P. He, X. Yu and X. (David) Lou, Angew. Chem. Int. Ed, 2017, 129, X. Liu, Y. Liu and L. Fan, J. Mater. Chem. A, 2017, 5, I. Amiinu, Z. Pu, X. Liu, K. Owusu, H. G. Monestel, F. Boakye, H. Zhang and S. Mu, Adv. Funct. Mater., 2017,