METHOD FOR EVALUATING HYDROGEN GENERATION REACTION
An embodiment is a method for evaluating a hydrogen generation reaction on a steel material includes preparing a steel material saturated with hydrogen. The hydrogen-saturated steel material is immersed in an electrolyte solution containing an additive that promotes hydrogen intrusion. A voltage sweep is applied between the steel material and a reference electrode and a current is measured between the steel material and a counter electrode. Reaction rate coefficients for hydrogen generation reactions are determined based on the measured current.
1 - 6 . (canceled)
7 . A hydrogen generation reaction assay method, comprising:
charging hydrogen into a steel material to be evaluated until a hydrogen storage capacity is saturated;
immersing the steel material with a saturated amount of hydrogen storage, a reference electrode, and a counter electrode in an electrolyte solution containing an additive that promotes hydrogen intrusion into the steel material, and then measuring a change in a current flowing between the steel material and the counter electrode when sweeping a voltage between the steel material and the reference electrode, the steel material serving as a working electrode; and
evaluating a hydrogen generation reaction on a surface of the steel material based on the measured change in the current.
8 . The hydrogen generation reaction assay method according to claim 7 , wherein the additive is ammonium thiocyanate.
9 . The hydrogen generation reaction assay method according to claim 7 , wherein charging hydrogen into the steel material comprises using a cathodic hydrogen charging method with the electrolyte solution.
10 . The hydrogen generation reaction assay method according to claim 7 , wherein charging hydrogen into the steel material comprises placing the steel material in a hydrogen atmosphere.
11 . The hydrogen generation reaction assay method according to claim 10 , wherein the hydrogen atmosphere is at a pressure higher than atmospheric pressure.
12 . The hydrogen generation reaction assay method according to claim 7 , wherein evaluating the hydrogen generation reaction comprises:
determining a reaction rate coefficient of the hydrogen generation reaction based on the measured change in the current; and
evaluating the hydrogen generation reaction on the surface of the steel material from the determined reaction rate coefficient.
13 . The hydrogen generation reaction assay method according to claim 7 , wherein the steel material has a rod shape.
14 . The hydrogen generation reaction assay method according to claim 7 , wherein the electrolyte solution comprises a 1 mol/L aqueous sodium hydrogen carbonate solution.
15 . The hydrogen generation reaction assay method according to claim 7 , wherein the reference electrode is an Ag/AgCl electrode and the counter electrode is a Pt electrode.
16 . The hydrogen generation reaction assay method according to claim 7 , wherein charging hydrogen into the steel material comprises charging for 72 hours.
17 . The hydrogen generation reaction assay method according to claim 7 , wherein sweeping the voltage comprises sweeping from a natural potential to −1.2 V vs. Ag/AgCl at a scanning speed of 20 mV/min.
18 . The hydrogen generation reaction assay method according to claim 7 , wherein evaluating the hydrogen generation reaction comprises:
determining reaction rate coefficients of a Volmer reaction, a Heyrovsky reaction, and a Tafel reaction based on the measured change in the current; and
evaluating the hydrogen generation reaction on the surface of the steel material using the determined reaction rate coefficients.
19 . The hydrogen generation reaction assay method according to claim 18 , wherein determining the reaction rate coefficients comprises fitting a formula of cathode charge current density to a polarization curve using a least squares method.
20 . A method for evaluating a hydrogen generation reaction on a steel material, comprising:
preparing a steel material saturated with hydrogen;
immersing the hydrogen-saturated steel material in an electrolyte solution containing an additive that promotes hydrogen intrusion;
applying a voltage sweep between the steel material and a reference electrode while measuring a current between the steel material and a counter electrode; and
determining reaction rate coefficients for hydrogen generation reactions based on the measured current.
21 . The method of claim 20 , wherein preparing the steel material saturated with hydrogen comprises charging hydrogen into the steel material using a cathodic hydrogen charging method.
22 . The method of claim 20 , wherein preparing the steel material saturated with hydrogen comprises exposing the steel material to a high-pressure hydrogen atmosphere.
23 . The method of claim 20 , wherein the additive is ammonium thiocyanate.
24 . The method of claim 20 , wherein determining the reaction rate coefficients comprises:
fitting a formula of cathode charge current density to a polarization curve obtained from the measured current; and
calculating reaction rate coefficients for Volmer, Heyrovsky, and Tafel reactions.
25 . The method of claim 20 , wherein the voltage sweep is performed from a natural potential to −1.2 V vs. Ag/AgCl at a scanning speed of 20 mV/min.
26 . The method of claim 20 , wherein the steel material has a rod shape.