Supporting Information Ni-Mo Nanocatalysts on N-Doped Graphite Nanotubes for Highly Efficient Electrochemical Hydrogen Evolution in Acid Teng Wang, Yanru Guo, Zhenxing Zhou, Xinghua Chang, Jie Zheng *, and Xingguo Li * Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China);
Table S1. Elemental composition of Ni-NGTs and NiMo-NGTs by ICP method sample Ni(wt%) Mo(wt%) C (wt%) N (wt%) Ni-NGTs 34.7 0.0 55.5 3.84 NiMo-NGTs 14.9 34.8 31.3 1.37 Figure S1. Full-range XPS spectra of NiMo-NGTs Table S2. Elemental composition on surface of NiMo-NGTs from XPS spectra. sample Ni (wt%) Mo (wt%) C (wt%) N (wt%) NiMo-NGTs 2.7 0.07 85.7 7.5
Figure. S2 Cyclic voltammetry tests in a non-faradaic region (0.04 to 0.12 V vs RHE) with different scan rates to determine the electrochemical double layer capacitance C dl : the NiMo-NGTs (a) and Ni-NGTs (b) in 0.5 M H 2 SO 4. Figure. S3 TEM images of the NiMo-NGTs catalyst after chronopotentiometry at constant current density of 20 ma cm -2 ;
Figure S4 Chronopotentiometry test of NiMo-NGTs at different current density in 0.5 M H 2 SO 4 Figure S5. Linear polarization curves after 10,000 cyclic voltammetry (CV) cycles of NiMo-NGTs in 0.5 M H 2 SO 4 Table S3. Key parameters of the poly-si solar cell in AM1.5 condition Voc (V) I sc (ma) P max (W) Fill factor 2.32 200 0.330 71.1%
Figure S6. (a) linear polarization curve of RuO 2 for OER catalysis in in 0.5 M H 2 SO 4. (b) i-v curve of polarization curve of the electrolyzer with and without ir correction. Figure. S7. XPS spectra of NiMo-NGTs and Mo-NC catalyst: (a) Mo 3d and (b) N 1s
Figure. S8.electrochemical properties of NiMo-NGTs, Mo-NC, NiMo-NC, CoMo-NGTs catalysts in 0.5 M H 2 SO 4 : linear polarization curves (a) and the Tafel plots (b), Figure S9. Cyclic voltammetry tests in a non-faradaic region (0.04 to 0.12 V vs RHE) with different scan rates to determine the electrochemical double layer capacitance C dl : (a) Mo-NC and (b) NiMo-NC. (c) The current vs scan rate (i C -v) plots to calculate the double layer capacitance C dl of Mo-NC, compared with the result of NiMo-NGTs.
Table S4 Summary of the HER catalytic activity of representative Ni/Mo-based catalysts in acid solutions Catalyst Electrolyte Loading (mg/cm 2 ) η (mv) j (ma cm -2 ) Ref. 2 65 10 This work NiMo-NGTs 0.5 M H 2 SO 4 2 79 20 This work NiMoN x nanosheets CoMoN x nanosheets Ni-Mo nanopowders 0.5 M H 2 SO 4 0.25 150 1 1 0.5 M H 2 SO 4 0.24 190 10 2 0.5 M H 2 SO 4 3 80 20 3 Mo 2 C 0.1 M HClO 4 2 152 10 4 MoP 0.5 M H 2 SO 4 1 117 10 5 MoB 1 M H 2 SO 4 2.5 235 20 6 MoCNs@carbon 0.5 M H 2 SO 4 0.25 78 10 7 Mo 2 C-NC 0.5 M H 2 SO 4 0.28 124 10 8 Ni 2 P NPs 0.5 M H 2 SO 4 1 130 20 9 NiP 2 @ carbon cloth 0.5 M H 2 SO 4 4.3 99 20 10 REFERENCE 1. Chen, W. F.; Sasaki, K.; Ma, C.; Frenkel, A. I.; Marinkovic, N.; Muckerman, J. T.; Zhu, Y.; Adzic, R. R., Hydrogen-Evolution Catalysts Based on Non-Noble Metal Nickel-Molybdenum Nitride Nanosheets. Angew. Chem. Int. Ed. 2012, 51, 6131-6135. 2. Cao, B.; Veith, G. M.; Neuefeind, J. C.; Adzic, R. R.; Khalifah, P. G., Mixed
Close-Packed Cobalt Molybdenum Nitrides as Non-Noble Metal Electrocatalysts for the Hydrogen Evolution Reaction. J. Am. Chem. Soc. 2013, 135, 19186-19192. 3. McKone, J. R.; Sadtler, B. F.; Werlang, C. A.; Lewis, N. S.; Gray, H. B., Ni Mo Nanopowders for Efficient Electrochemical Hydrogen Evolution. ACS Catal. 2013, 3, 166-169. 4. Chen, W. F.; Wang, C. H.; Sasaki, K.; Marinkovic, N.; Xu, W.; Muckerman, J. T.; Zhu, Y.; Adzic, R. R., Highly Active and Durable Nanostructured Molybdenum Carbide Electrocatalysts for Hydrogen Production. Energy Environ. Sci. 2013, 6, 943-951. 5. Kibsgaard, J.; Jaramillo, T. F., Molybdenum Phosphosulfide: An Active, Acid-Stable, Earth-Abundant Catalyst for the Hydrogen Evolution Reaction. Angew. Chem. Int. Ed. 2014, 53, 14433-14437. 6. Vrubel, H.; Hu, X., Molybdenum Boride and Carbide Catalyze Hydrogen Evolution in Both Acidic and Basic Solutions. Angew. Chem. Int. Ed. 2012, 51, 12703-12706. 7. Ma, R.; Zhou, Y.; Chen, Y.; Li, P.; Liu, Q.; Wang, J., Ultrafine Molybdenum Carbide Nanoparticles Composited with Carbon as a Highly Active Hydrogen-Evolution Electrocatalyst. Angew. Chem. Int. Ed. 2015, 54, 14723-14727. 8. Liu, Y.; Yu, G.; Li, G. D.; Sun, Y.; Asefa, T.; Chen, W.; Zou, X., Coupling Mo2 C with Nitrogen-Rich Nanocarbon Leads to Efficient Hydrogen-Evolution Electrocatalytic Sites. Angew. Chem. Int. Ed. 2015, 54, 10752-10757. 9. Popczun, E. J.; McKone, J. R.; Read, C. G.; Biacchi, A. J.; Wiltrout, A. M.; Lewis, N. S.; Schaak, R. E., Nanostructured Nickel Phosphide as an Electrocatalyst for the
Hydrogen Evolution Reaction. J. Am. Chem. Soc. 2013, 135, 9267-9270. 10. Jiang, P.; Liu, Q.; Sun, X., NiP 2 Nanosheet Arrays Supported on Carbon Cloth: An Efficient 3d Hydrogen Evolution Cathode in Both Acidic and Alkaline Solutions. Nanoscale 2014, 6, 13440-13445.