Process to make iron based electrocatalyst, an anode material, an electrochemical system and a process for water conversion, catalysis and fuel generation

Abstract

This invention provides a simple approach for the straightforward and direct preparation of iron-oxide based electrocatalytic materials film (FeO x —Ci) on a simple Fe substrate by controlled surface-anodization and/or self-deposition in simple and low-cost carbonate buffer. The FeO x —Ci based electrocatalysts may advantageously be employed as electrode and as anode material in water oxidation, water conversion systems and fuel generation assemblies. The FeO x —Ci exhibits remarkably low over potential (η≈360) for anodic oxygen evolution relative to other Fe-oxide based catalysts, and show very high activity and stability for long-term water electrolysis operation.

What is claimed is: 
     
         1 . A method of making a catalytic comprising:
 providing an anode and a cathode in an electrochemical cell;   cleaning the electrodes with acid wash and water;   immersing the electrodes in an aqueous bicarbonate/carbonate buffer system at a pH ranging from 8.5 to 13; and,   applying constant current or constant potential to the electrodes suitable to electrochemically produce surface anodizing leading to deposit of iron oxide on the surface of the anode.   
     
     
         2 . The method of  claim 1 , wherein, the anode is made of iron metal, an iron alloy or an iron-derived material. 
     
     
         3 . The method of  claim 1 , wherein the anode is coated with nanoparticles. 
     
     
         4 . The method of  claim 1 , wherein the applied voltage is higher than 1.40 volts. 
     
     
         5 . The method of  claim 1 , wherein the voltage is applied from 0.1 minutes to 24 hours or more. 
     
     
         6 . The method of  claim 1 , wherein the applied current is above 0.1 milliampere per square meter of the surface of anode. 
     
     
         7 . The method of  claim 1 , wherein the size of deposited particles ranges between 25 and 250 nm. 
     
     
         8 . The method of  claim 1 , wherein the thickness deposited iron oxide on the anode is 5 to 250 nm. 
     
     
         9 . The method of  claim 1 , wherein the electrolytic solution is free of transition metal ions. 
     
     
         10 . A method of converting water into oxygen and releasing hydrogen comprising:
 providing the anode of  claim 1  and a cathode in an electrochemical cell;   applying a suitable voltage to split water molecules into electrons and protons to make hydrogen as fuel, energy carrier, chemical feedstock, or non-fossil fuel when combined with carbon dioxide.