Process to convert reduced sulfur species and water into hydrogen and sulfuric acid
In an aspect, provided herein are methods for producing sulfuric acid and hydrogen gas, the methods comprising steps of: providing sulfur dioxide formed by thermal conversion of a sulfur-containing species; electrochemically oxidizing said sulfur dioxide to sulfuric acid in the presence of water; and electrochemically forming hydrogen gas via a reduction reaction. In some embodiments, the methods comprise a step of thermally converting said sulfur-containing species to said sulfur dioxide. Systems configured to perform these methods are also disclosed herein. Also provided herein are methods and systems for producing sulfuric acid and hydrogen gas by electrochemically forming the sulfuric acid and the hydrogen gas in a mixture comprising a sulfur material, a supporting acid, and water. Also provided herein are methods and systems for producing a cement material.
1. A method for producing sulfuric acid and hydrogen gas, said method comprising steps of:
electrochemically forming the sulfuric acid and the hydrogen gas in a liquid mixture comprising a sulfur material, a supporting acid, and water;
wherein the supporting acid is provided in the liquid mixture at an amount to raise the boiling point of the liquid mixture such that the liquid mixture does not boil under conditions in which the electrochemically forming step proceeds;
wherein the step of electrochemically forming is characterized by the formula FX1:
1/X S X +YO 2 +ZH 2 O→H 2 SO 4 +(Z−1)H 2 (FX1)
wherein:
X is an integer selected from the range of 1 to 8;
Y is 0, ½, or 1; and
Z is 3 or 4.
2. The method of claim 1 , wherein X is 8, Y is 0, and Z is 4.
3. The method of claim 1 , wherein the supporting acid is sulfuric acid.
4. The method of claim 1 , wherein the liquid mixture is exposed to at least one of a first catalyst and a second catalyst during the step of electrochemically forming.
5. The method of claim 1 , wherein a molar ratio of the quantity of hydrogen gas produced to the quantity of sulfuric acid produced during the step of electrochemically forming is equal to 3.
6. The method of claim 1 , wherein the liquid mixture has a temperature selected from the range of 118° C. to 160° C. during the step of electrochemically forming.
7. The method of claim 1 , wherein the step of electrochemically forming is characterized by a current density of at least 10 mA/cm 2 at a voltage of less than 1.23 V vs. NHE.
8. The method of claim 1 , comprising heating the liquid mixture to a temperature such that the sulfur material is molten sulfur.
9. The method of claim 1 , wherein an amount of the supporting acid in the liquid mixture during the step of electrochemically forming is selected from the range of 10 mass % to 80 mass %.
10. The method of claim 4 , wherein the liquid mixture is exposed to the first catalyst during the step of electrochemically forming—and wherein the first catalyst comprises Pt, Ru, Ir, tungsten carbide, Au, Ag, or any combination of these.
11. The method of claim 4 , wherein the step of electrochemically forming comprises a reduction reaction to form hydrogen gas, the reduction reaction occurring in the presence of the second catalyst.
12. The method of claim 11 , wherein the second catalyst comprises a hydrogen evolution catalyst or a catalyst comprising Pt, stainless steel, Cobalt phosphide, Ni, MoS, or any combination of these.
13. The method of claim 1 , wherein the liquid mixture further comprises dissolved oxygen.