1Faculty of Chemistry and Chemical Engineering, Malek-Ashtar University of Technology
2Malek-Ashtar University of Technology, Tehran 15875-1774, IRAN
In this study Ni catalyst have been activated during hydrogen evolution reaction (HER) by adding Mo ions into the alkaline electrolyte. After dissolving different amounts of ammonium molybdate in the 1M NaOH as electrolyte, Ni catalyst was used as cathode for HER. Afterwards a comparison between hydrogen overpotential measured in Ni catalyst with and without in situ activation has been made; the in situ activation shows an improvement of electrocatalytic properties of Ni catalyst for hydrogen evolution reaction. In the other words impact increase of in situ activation of Mo ions on the Ni structure, show that extremely significant impact in improving the Ni catalyst activation during in situ activation. The values of Tafel slope for Ni catalyst without Mo is an average of about 141 mVdec-1, while by using in situ activation by activator Mo ion this value is about 172 mVdec-1. As well as the values of overpotential for Ni catalyst, are an average of about 625 mV, by using in situ activation, these values are about 482 mV at the current density of 250 mAcm-2 (η250). In this study electrochemical data obtained from linear sweep voltammetry (LSV), the steady state polarization Tafel curves, electrochemical impedance spectroscopy (EIS).
[] Xia M, Lei T, Lv NL, Li NF. Synthesis and electrocatalytic hydrogen evolution performance of Ni-Mo-Cu alloy coating electrode. Int J Hydrogen Energy 2014;39:4794-802.
 Herraiz-Cardona I, Gonzales-BuchC, Valero-Vidal C, Ortega E, Perez-Herranz V. Co-modification of Ni-based type Raney electrodeposits for hydrogen evolution reaction in alkaline media. J Power Sources 2013;240:698-704.
 Popczun EJ, McKeon JR, Read CG, Biacchi AJ, Wiltrout AM, Lewis NS. Nanostructured nickel phosphide as an electrocatalyst for the hydrogen evolution reaction. J Am Chem Soc 2013;135:9267-9270.
 Warren EL, McKeon JR, Atwater HA, Gray HB, Lewis NS. Hydrogen-evolution characteristics of Ni-Mo-coated, radial junction, n+ p-silicon microwire array photocathodes. Energy Environmental Sci 2012;5:9653-9661.
 Jaksic MM. Electrocatalysis of hydrogen evolution in the light of the Brewer-Engle theory for bonding in metals and intermetallic phases. Electrochim Acta 1984;29:539-1550.
 Quaino P, Juarez F, Santos E, Scgemickler W. Volcano plots in hydrogen electrocatalysis uses and abuses. Beilstein J Nanotechnol 2014; 5: 846-854.
 Stojic DL, Marceta MP, Sovilj SP, Miljanic SS. Hydrogen generation from water electrolysis-possibities of energy saving. J Power Sources 2003; 118:315-39.
 Wang M,Wang Z, Yu X, Guo Z. Facile one-step electrodeposition preparation of porous NiMo film as electrocatalyst for hydrogen evolution reaction. Int J Hydrogen Energy 2015;40:2173-218.
 Guettaf Temam E, Ben Temam H, Benramache S. Surface morphology and electrochemical characterization of electrodeposited Ni-Mo nanocomposites as cathodes for
hydrogen evolution. Chin Phys B 2015;24:10‑5.
 Gennero de Chialvo MR, Chialvo AC. Hydrogen evolution reaction on smooth Ni(1-x) +Mo(x) alloys (0 < x < 0125). J Electroanal Chem 1998;448:87‑93.
 Maslovara SL, Marceta Kaninski MP, Perovic IM, Lausevic PZ, Tasic GC, Radak BB. Novel ternary Ni-Co-Mo based ionic activator for efficient alkaline water electrolysis. Int J Hydrogen Energy 2013;38: 15928-15933.
 Nikolic VM, Maslovara SL, Tasic GS, Brdaric TP, Lausevic PZ, Radak BB, Marketa Kaninski MP. Kinetic of hydrogen evolution reaction in alkaline electrolysis on a Ni cathode in the presence of Ni-Co-Mo based ionic activators. Applied Catalysis B: Envionmental 2015; 179: 88-94.
 Choquette Y, Brossard L, Menard H. Insitu activation of the RANEY-Ni composite‑coated electrode for the hydrogen evolution teaction. Int J Hydrogen Energy 1990; 15(8): 551-555.
 Tasic, GS, Maslovara, SP, Zugic, DL, Maksic, AD, Marceta Kaninski MP. Characterization of the Ni-Mo catalyst formed in-situ during hydrogen generation from alkaline water electrolysis, Int. J. Hydrogen Energy 2011; 36: 11588-11595.
 Macdonald JR, Schoonman J, Lehnen AP. Applicability and power of complex nonlinear least squares for the analysis of impedance and admittance data. J Electroanal Chem 1982;131:77‑95.
 Wu L, Zeng Y, Xiao YF, He YH. Effect of Mo content on porous Ni3Al-Mo electrodes for hydrogen evolution reaction. J Powder Metallurgy 2014; 57.5: 387-393.
 Krstajic N, Popovic M, Grgur B, Vojnovic M, Sepa D. On the kinetics of the hydrogen evolution reaction on nickel in alkaline solution. J Electroanal Chem 2001; 512:16-26.
 Lasia A, Rami A. Kinetics of hydrogen evolution on nickel electrodes. J Electroanal Chem 1990;294:123-141.
 Lasia A. Studies of the hydrogen evolution reaction on active electrodes. Curr Top Electrochem 1993;2:239.
 Anani A, Mao Z, Srinvasan S, Dispersion deposition of metal—Particle composites and the evaluation of dispersion deposited nickel—Lanthanum nickelate electrocatalyst for hydrogen evolution. J Appl Electrochem 1991;21:683- 689.
 Elumalai P, Vasan HN, Munichandraiah N, Shivashankar SA. Kinetics of hydrogen evolution on submicron size Co, Ni, Pd and Co-Ni catalyst powder electrodes by d.c. polarization and a.c. impedance studies. J Appl Electrochem 2002;32:1005-10.
 Brug GJ, ALG van der Eden, Rehbach MS, Sluyters JH. The analysis of electrode impedances complicated by the presence of a constant phase element. J Electroanal Chem 1984;176:275-95.
 Trasatti S, Petrii OA. Real surface area measurements in electrochemistry. Pure Appl Chem 1991;63:711-34.
 Los P, Lasia A, Menard H, Brossard L. Impedance studies of porous lanthanum-phosphate-bonded nickel electrodes in concentrated sodium hydroxide solution. J Electroanal Chem 1993;360:101-18.