The electrocatalytic activity of NiMo nanoparticles (NPs) fabricated by means of current pulses from a binary electrolyte was characterized using cyclic voltammetry. The pulse current density, jpulse, was varied in the range of 7 to 430 mA/cm2, whereas the pulse time, tpulse, was kept constant at two seconds. Mean NP size, Dmean, ranged within 27 and 38 nm at jpulse values between 15 and 140 mA/cm2; with Dmean increasing as jpulse was higher. NP dispersion (i. e., number of objects per unit area of substrate) was lower when jpulse values were also low (15 and 35 mA/cm2), which showed consistency with a promoted nuclei formation and prolonged NP growth at higher jpulse values. An improved catalytic performance for hydrogen evolution was determined upon increasing jpulse in the range of 7 to 70 mA/cm2 and remaining practically unvaried at higher jpulse values. The electrosynthesis of two distinct catalytic materials was indicated by electro- chemical characterization of deposits; the material with greatest catalytic activity also showed high instability, causing a dramatic decay (~80%) in the activity after two consecutive cycles of operation. Ni and Mo content in electrodeposits were both sensitive to variations in jpulse.
hydrogen, evolution, nanoparticles, electrodeposition, NiMo alloy
 L.P. Bicelli, Int. J. Hydrogen Energy, 11, 555 (1986).
 N. Getoff, Int. J. Hydrogen Energy, 15, 407 (1990).
 M. Hoel, S. Kvemdokk, Resour. Energy Econ., 18, 115 (1996).
 F. Li, I. Ciani, P. Bertoncello, P.R. Unwin, J. Zhao, C.R. Bradbury, D.J. Fermin, J. Phys. Chem. C, 112, 9686 (2008).
 F.W. Campbell, S.R. Belding, R. Baron, L. Xiao, R.G. Comp- ton, J. Phys. Chem. C, 113, 14852 (2009).
 M.K. Neylon, S. Choi, H. Kwon, K.E. Curry, L.T. Thompson, Appl. Catal. A-Gen., 183, 253 (1999).
 I.A. Raj, K.I. Vasu, J. Appl. Electrochem., 20, 32 (1990).
 E. Navarro-Flores, Z. Chong, S. Omanovic, J. Mol. Catal. A- Chem. 226, 179 (2005).
 A. Damian, S. Omanovic, J. Power Sources 158, 464 (2006).
 S. Martinez, M. Metikos-Hukovic, L. Valek, J. Mol. Catal. A-Chem., 245, 114 (2005).
 M. Videa, D. Crespo, G. Casillas, G. Zavala, J. New Mat. Electr. Sys., 13, 239 (2010)
 L. Huang, F.Z. Yang, S.K. Xu, S.M. Zhou, T.I. Met. Finish., 79, 136 (2001).
 R. Schulz, J.Y. Hout, M.L. Trudeau, L. Dignard-Bailey, Z.H. Yan, S. Jin, A. Lamarre, E. Ghali, A. Van Neste, J. Mater. Res., 9, 2998 (1994).
 E. Budevski, G. Staikov, W.J. Lorenz, Electrochim. Acta, 45, 2559 (2000).
 M. Ueda, H. Dietz, A. Anders, H. Kneppe, A. Meixner, W. Plieth, Electrochim. Acta, 48, 377 (2002).
 G.T. Martinez, G. Zavala, M. Videa, J. Mex. Chem. Soc., 53, 7 (2009).
 E.J. Podlaha, D. Landolt, J. Electrochem. Soc., 143, 885 (1996).
 E.J. Podlaha, D. Landolt, J. Electrochem. Soc., 144, 1672 (1997).