Hydrogen evolution rate

Feldstein and Lancsek [30] measured plating rate, potential, and hydrogen evolution rate during the reduction of Ni2 + and Co2 + with H2P02 in the presence of various additives. They concluded that the deposition process could be described by a modified hydride mechanism. The basic steps of the process were identified as follows ... 

Fig. 4. Hydrogen evolution rate against temperature for a-Si H sample for different heating rates b (Beyer and Wagner, 1982). 

The hydrogen evolution rate dN/dt is given by dM/dt, normalized by the sample s volume (Ad). The diffusion coefficient DH can be extracted from the temperature Tp at which the hydrogen evolution rate dN/dt reaches its peak. That is,... 

A hydrogen evolution rate of about 35 pmol/hr over the first few hours of reaction using NiO powder was reported. This decreased with time reaching a value of 20 pmol/h after 55 hours. The energy efficiency was calculated using the equation [206]... 

Charge separation occurs immediately and the electron passes to an island of platinum on the surface of the particle, where it effects proton reduction. Meanwhile, [Ru(bipy)3]3+ efficiently oxidizes OH- to 02 at the adsorbed islands of Ru02. Thorough studies of this reaction have shown quantum yields up to 0.002 at pH 4 and hydrogen evolution rates of 0.38 cm3 h 1, whereas with MV2+ present = 0.06 at pH 5.5 and hydrogen is produced at 1.2 cm3 If from 25 cm3 of... 

The importance of electronic interaction as the basic mechanism leading to synergetic effects is also suggested by results showing that the simultaneous underpotential deposition of Cd and Tl on Ag(lll) results in an enhancement of the hydrogen evolution rate while inhibitory effects are shown by the two kinds of adatoms separately [317]. 

The terms aanodic and cathodic are the transfer coefficients [Eq. (7.143)] for the anodic and cathodic components of the corrosion reaction, respectively. Their values will depend upon the reactions making up the corrosion situation. If one assumes that a hydrogen evolution rate controlled by charge transfer is the cathodic reaction, acathodic = 1/2 and if, e.g., the metal dissolution is controlled by charge transfer to form a divalent cation, aanodic = 2. Then, from (12.37), the maximum value of V - Ecorr allowable for the approximation of Eq. (12.35) is... 

Our strategy here was to develop Pt colloids of minimum particle size which would render the water reduction by the electron relay R peirticularly effective. The goal was to obteiin hydrogen evolution rates in the microsecond time domain which would compete with beick electron transfer. First a centrifuged Pt sol protected by polyvinyl alcohol weis employed which gave clear and almost colorless aqueous suspensions even at hi Pt concentrations ( 28). Flash photolysis technique was applied for the first time to study the dynamics of intervention of the Pt particles in the water reduction process. Methylviologen (MV ) wets reduced... 

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